Add support for incremental backup.
authorRobert Haas <rhaas@postgresql.org>
Wed, 20 Dec 2023 14:49:12 +0000 (09:49 -0500)
committerRobert Haas <rhaas@postgresql.org>
Wed, 20 Dec 2023 14:49:12 +0000 (09:49 -0500)
To take an incremental backup, you use the new replication command
UPLOAD_MANIFEST to upload the manifest for the prior backup. This
prior backup could either be a full backup or another incremental
backup.  You then use BASE_BACKUP with the INCREMENTAL option to take
the backup.  pg_basebackup now has an --incremental=PATH_TO_MANIFEST
option to trigger this behavior.

An incremental backup is like a regular full backup except that
some relation files are replaced with files with names like
INCREMENTAL.${ORIGINAL_NAME}, and the backup_label file contains
additional lines identifying it as an incremental backup. The new
pg_combinebackup tool can be used to reconstruct a data directory
from a full backup and a series of incremental backups.

Patch by me.  Reviewed by Matthias van de Meent, Dilip Kumar, Jakub
Wartak, Peter Eisentraut, and รlvaro Herrera. Thanks especially to
Jakub for incredibly helpful and extensive testing.

Discussion: http://postgr.es/m/CA+TgmoYOYZfMCyOXFyC-P+-mdrZqm5pP2N7S-r0z3_402h9rsA@mail.gmail.com

49 files changed:
doc/src/sgml/backup.sgml
doc/src/sgml/config.sgml
doc/src/sgml/protocol.sgml
doc/src/sgml/ref/allfiles.sgml
doc/src/sgml/ref/pg_basebackup.sgml
doc/src/sgml/ref/pg_combinebackup.sgml [new file with mode: 0644]
doc/src/sgml/reference.sgml
src/backend/access/transam/xlogbackup.c
src/backend/access/transam/xlogrecovery.c
src/backend/backup/Makefile
src/backend/backup/basebackup.c
src/backend/backup/basebackup_incremental.c [new file with mode: 0644]
src/backend/backup/meson.build
src/backend/replication/repl_gram.y
src/backend/replication/repl_scanner.l
src/backend/replication/walsender.c
src/backend/storage/ipc/ipci.c
src/bin/Makefile
src/bin/meson.build
src/bin/pg_basebackup/bbstreamer_file.c
src/bin/pg_basebackup/pg_basebackup.c
src/bin/pg_basebackup/t/010_pg_basebackup.pl
src/bin/pg_combinebackup/.gitignore [new file with mode: 0644]
src/bin/pg_combinebackup/Makefile [new file with mode: 0644]
src/bin/pg_combinebackup/backup_label.c [new file with mode: 0644]
src/bin/pg_combinebackup/backup_label.h [new file with mode: 0644]
src/bin/pg_combinebackup/copy_file.c [new file with mode: 0644]
src/bin/pg_combinebackup/copy_file.h [new file with mode: 0644]
src/bin/pg_combinebackup/load_manifest.c [new file with mode: 0644]
src/bin/pg_combinebackup/load_manifest.h [new file with mode: 0644]
src/bin/pg_combinebackup/meson.build [new file with mode: 0644]
src/bin/pg_combinebackup/nls.mk [new file with mode: 0644]
src/bin/pg_combinebackup/pg_combinebackup.c [new file with mode: 0644]
src/bin/pg_combinebackup/reconstruct.c [new file with mode: 0644]
src/bin/pg_combinebackup/reconstruct.h [new file with mode: 0644]
src/bin/pg_combinebackup/t/001_basic.pl [new file with mode: 0644]
src/bin/pg_combinebackup/t/002_compare_backups.pl [new file with mode: 0644]
src/bin/pg_combinebackup/t/003_timeline.pl [new file with mode: 0644]
src/bin/pg_combinebackup/t/004_manifest.pl [new file with mode: 0644]
src/bin/pg_combinebackup/t/005_integrity.pl [new file with mode: 0644]
src/bin/pg_combinebackup/write_manifest.c [new file with mode: 0644]
src/bin/pg_combinebackup/write_manifest.h [new file with mode: 0644]
src/bin/pg_resetwal/pg_resetwal.c
src/include/access/xlogbackup.h
src/include/backup/basebackup.h
src/include/backup/basebackup_incremental.h [new file with mode: 0644]
src/include/nodes/replnodes.h
src/test/perl/PostgreSQL/Test/Cluster.pm
src/tools/pgindent/typedefs.list

index 8cb24d6ae542f4e20e5dfd6d9f6a157bf3a4688a..b3468eea3cb999f8121e89379fb71de69c41273b 100644 (file)
@@ -857,12 +857,79 @@ test ! -f /mnt/server/archivedir/00000001000000A900000065 &amp;&amp; cp pg_wal/0
    </para>
   </sect2>
 
+  <sect2 id="backup-incremental-backup">
+   <title>Making an Incremental Backup</title>
+
+   <para>
+    You can use <xref linkend="app-pgbasebackup"/> to take an incremental
+    backup by specifying the <literal>--incremental</literal> option. You must
+    supply, as an argument to <literal>--incremental</literal>, the backup
+    manifest to an earlier backup from the same server. In the resulting
+    backup, non-relation files will be included in their entirety, but some
+    relation files may be replaced by smaller incremental files which contain
+    only the blocks which have been changed since the earlier backup and enough
+    metadata to reconstruct the current version of the file.
+   </para>
+
+   <para>
+    To figure out which blocks need to be backed up, the server uses WAL
+    summaries, which are stored in the data directory, inside the directory
+    <literal>pg_wal/summaries</literal>. If the required summary files are not
+    present, an attempt to take an incremental backup will fail. The summaries
+    present in this directory must cover all LSNs from the start LSN of the
+    prior backup to the start LSN of the current backup. Since the server looks
+    for WAL summaries just after establishing the start LSN of the current
+    backup, the necessary summary files probably won't be instantly present
+    on disk, but the server will wait for any missing files to show up.
+    This also helps if the WAL summarization process has fallen behind.
+    However, if the necessary files have already been removed, or if the WAL
+    summarizer doesn't catch up quickly enough, the incremental backup will
+    fail.
+   </para>
+
+   <para>
+    When restoring an incremental backup, it will be necessary to have not
+    only the incremental backup itself but also all earlier backups that
+    are required to supply the blocks omitted from the incremental backup.
+    See <xref linkend="app-pgcombinebackup"/> for further information about
+    this requirement.
+   </para>
+
+   <para>
+    Note that all of the requirements for making use of a full backup also
+    apply to an incremental backup. For instance, you still need all of the
+    WAL segment files generated during and after the file system backup, and
+    any relevant WAL history files. And you still need to create a
+    <literal>recovery.signal</literal> (or <literal>standby.signal</literal>)
+    and perform recovery, as described in
+    <xref linkend="backup-pitr-recovery" />. The requirement to have earlier
+    backups available at restore time and to use
+    <literal>pg_combinebackup</literal> is an additional requirement on top of
+    everything else. Keep in mind that <application>PostgreSQL</application>
+    has no built-in mechanism to figure out which backups are still needed as
+    a basis for restoring later incremental backups. You must keep track of
+    the relationships between your full and incremental backups on your own,
+    and be certain not to remove earlier backups if they might be needed when
+    restoring later incremental backups.
+   </para>
+
+   <para>
+    Incremental backups typically only make sense for relatively large
+    databases where a significant portion of the data does not change, or only
+    changes slowly. For a small database, it's simpler to ignore the existence
+    of incremental backups and simply take full backups, which are simpler
+    to manage. For a large database all of which is heavily modified,
+    incremental backups won't be much smaller than full backups.
+   </para>
+  </sect2>
+
   <sect2 id="backup-lowlevel-base-backup">
    <title>Making a Base Backup Using the Low Level API</title>
    <para>
-    The procedure for making a base backup using the low level
-    APIs contains a few more steps than
-    the <xref linkend="app-pgbasebackup"/> method, but is relatively
+    Instead of taking a full or incremental base backup using
+    <xref linkend="app-pgbasebackup"/>, you can take a base backup using the
+    low-level API. This procedure contains a few more steps than
+    the <application>pg_basebackup</application> method, but is relatively
     simple. It is very important that these steps are executed in
     sequence, and that the success of a step is verified before
     proceeding to the next step.
@@ -1118,7 +1185,8 @@ SELECT * FROM pg_backup_stop(wait_for_archive => true);
    </listitem>
    <listitem>
     <para>
-     Restore the database files from your file system backup.  Be sure that they
+     If you're restoring a full backup, you can restore the database files
+     directly into the target directories.  Be sure that they
      are restored with the right ownership (the database system user, not
      <literal>root</literal>!) and with the right permissions.  If you are using
      tablespaces,
@@ -1126,6 +1194,19 @@ SELECT * FROM pg_backup_stop(wait_for_archive => true);
      were correctly restored.
     </para>
    </listitem>
+   <listitem>
+    <para>
+     If you're restoring an incremental backup, you'll need to restore the
+     incremental backup and all earlier backups upon which it directly or
+     indirectly depends to the machine where you are performing the restore.
+     These backups will need to be placed in separate directories, not the
+     target directories where you want the running server to end up.
+     Once this is done, use <xref linkend="app-pgcombinebackup"/> to pull
+     data from the full backup and all of the subsequent incremental backups
+     and write out a synthetic full backup to the target directories. As above,
+     verify that permissions and tablespace links are correct.
+    </para>
+   </listitem>
    <listitem>
     <para>
      Remove any files present in <filename>pg_wal/</filename>; these came from the
index ee985850275d010e11c335fdc2fbd0acb7ff4b45..b5624ca884741c60d2eb395e3dea7611d57e9516 100644 (file)
@@ -4153,13 +4153,11 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"'  # Windows
    <sect2 id="runtime-config-wal-summarization">
     <title>WAL Summarization</title>
 
- <!--
     <para>
      These settings control WAL summarization, a feature which must be
      enabled in order to perform an
      <link linkend="backup-incremental-backup">incremental backup</link>.
     </para>
- -->
 
     <variablelist>
      <varlistentry id="guc-summarize-wal" xreflabel="summarize_wal">
index af3f016f7467756dad9f5f1ebe208daed9aed5f5..9a66918171a56ab3d59b1b1d311d01559fe6ff01 100644 (file)
@@ -2599,6 +2599,19 @@ psql "dbname=postgres replication=database" -c "IDENTIFY_SYSTEM;"
      </listitem>
     </varlistentry>
 
+    <varlistentry id="protocol-replication-upload-manifest">
+     <term>
+      <literal>UPLOAD_MANIFEST</literal>
+      <indexterm><primary>UPLOAD_MANIFEST</primary></indexterm>
+     </term>
+     <listitem>
+      <para>
+       Uploads a backup manifest in preparation for taking an incremental
+       backup.
+      </para>
+     </listitem>
+    </varlistentry>
+
     <varlistentry id="protocol-replication-base-backup" xreflabel="BASE_BACKUP">
      <term><literal>BASE_BACKUP</literal> [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ]
       <indexterm><primary>BASE_BACKUP</primary></indexterm>
@@ -2838,6 +2851,17 @@ psql "dbname=postgres replication=database" -c "IDENTIFY_SYSTEM;"
           </para>
          </listitem>
         </varlistentry>
+
+        <varlistentry>
+         <term><literal>INCREMENTAL</literal></term>
+         <listitem>
+          <para>
+           Requests an incremental backup. The
+           <literal>UPLOAD_MANIFEST</literal> command must be executed
+           before running a base backup with this option.
+          </para>
+         </listitem>
+        </varlistentry>
        </variablelist>
       </para>
 
index 54b5f22d6ec9f1f11f2cb5cdf7113daeaa9b0df1..fda4690eab52c2919ce0a81bdc796ca6f05c0184 100644 (file)
@@ -202,6 +202,7 @@ Complete list of usable sgml source files in this directory.
 <!ENTITY pgBasebackup       SYSTEM "pg_basebackup.sgml">
 <!ENTITY pgbench            SYSTEM "pgbench.sgml">
 <!ENTITY pgChecksums        SYSTEM "pg_checksums.sgml">
+<!ENTITY pgCombinebackup    SYSTEM "pg_combinebackup.sgml">
 <!ENTITY pgConfig           SYSTEM "pg_config-ref.sgml">
 <!ENTITY pgControldata      SYSTEM "pg_controldata.sgml">
 <!ENTITY pgCtl              SYSTEM "pg_ctl-ref.sgml">
index 0b87fd2d4d6212e8c6b64c38ea7864204cbe36be..7c183a5cfd20ea4cf581a0a9aeec41bbdeb4e8bb 100644 (file)
@@ -38,11 +38,25 @@ PostgreSQL documentation
   </para>
 
   <para>
-   <application>pg_basebackup</application> makes an exact copy of the database
-   cluster's files, while making sure the server is put into and
-   out of backup mode automatically. Backups are always taken of the entire
-   database cluster; it is not possible to back up individual databases or
-   database objects. For selective backups, another tool such as
+   <application>pg_basebackup</application> can take a full or incremental
+   base backup of the database. When used to take a full backup, it makes an
+   exact copy of the database cluster's files. When used to take an incremental
+   backup, some files that would have been part of a full backup may be
+   replaced with incremental versions of the same files, containing only those
+   blocks that have been modified since the reference backup. An incremental
+   backup cannot be used directly; instead,
+   <xref linkend="app-pgcombinebackup"/> must first
+   be used to combine it with the previous backups upon which it depends.
+   See <xref linkend="backup-incremental-backup" /> for more information
+   about incremental backups, and <xref linkend="backup-pitr-recovery" />
+   for steps to recover from a backup.
+  </para>
+
+  <para>
+   In any mode, <application>pg_basebackup</application> makes sure the server
+   is put into and out of backup mode automatically. Backups are always taken of
+   the entire database cluster; it is not possible to back up individual
+   databases or database objects. For selective backups, another tool such as
    <xref linkend="app-pgdump"/> must be used.
   </para>
 
@@ -197,6 +211,19 @@ PostgreSQL documentation
       </listitem>
      </varlistentry>
 
+     <varlistentry>
+      <term><option>-i <replaceable class="parameter">old_manifest_file</replaceable></option></term>
+      <term><option>--incremental=<replaceable class="parameter">old_meanifest_file</replaceable></option></term>
+      <listitem>
+       <para>
+        Performs an <link linkend="backup-incremental-backup">incremental
+        backup</link>. The backup manifest for the reference
+        backup must be provided, and will be uploaded to the server, which will
+        respond by sending the requested incremental backup.
+       </para>
+      </listitem>
+     </varlistentry>
+
      <varlistentry>
       <term><option>-R</option></term>
       <term><option>--write-recovery-conf</option></term>
diff --git a/doc/src/sgml/ref/pg_combinebackup.sgml b/doc/src/sgml/ref/pg_combinebackup.sgml
new file mode 100644 (file)
index 0000000..e172967
--- /dev/null
@@ -0,0 +1,240 @@
+<!--
+doc/src/sgml/ref/pg_combinebackup.sgml
+PostgreSQL documentation
+-->
+
+<refentry id="app-pgcombinebackup">
+ <indexterm zone="app-pgcombinebackup">
+  <primary>pg_combinebackup</primary>
+ </indexterm>
+
+ <refmeta>
+  <refentrytitle><application>pg_combinebackup</application></refentrytitle>
+  <manvolnum>1</manvolnum>
+  <refmiscinfo>Application</refmiscinfo>
+ </refmeta>
+
+ <refnamediv>
+  <refname>pg_combinebackup</refname>
+  <refpurpose>reconstruct a full backup from an incremental backup and dependent backups</refpurpose>
+ </refnamediv>
+
+ <refsynopsisdiv>
+  <cmdsynopsis>
+   <command>pg_combinebackup</command>
+   <arg rep="repeat"><replaceable>option</replaceable></arg>
+   <arg rep="repeat"><replaceable>backup_directory</replaceable></arg>
+  </cmdsynopsis>
+ </refsynopsisdiv>
+
+ <refsect1>
+  <title>Description</title>
+  <para>
+   <application>pg_combinebackup</application> is used to reconstruct a
+   synthetic full backup from an
+   <link linkend="backup-incremental-backup">incremental backup</link> and the
+   earlier backups upon which it depends.
+  </para>
+
+  <para>
+   Specify all of the required backups on the command line from oldest to newest.
+   That is, the first backup directory should be the path to the full backup, and
+   the last should be the path to the final incremental backup
+   that you wish to restore. The reconstructed backup will be written to the
+   output directory specified by the <option>-o</option> option.
+  </para>
+
+  <para>
+   Although <application>pg_combinebackup</application> will attempt to verify
+   that the backups you specify form a legal backup chain from which a correct
+   full backup can be reconstructed, it is not designed to help you keep track
+   of which backups depend on which other backups. If you remove the one or
+   more of the previous backups upon which your incremental
+   backup relies, you will not be able to restore it.
+  </para>
+
+  <para>
+   Since the output of <application>pg_combinebackup</application> is a
+   synthetic full backup, it can be used as an input to a future invocation of
+   <application>pg_combinebackup</application>. The synthetic full backup would
+   be specified on the command line in lieu of the chain of backups from which
+   it was reconstructed.
+  </para>
+ </refsect1>
+
+ <refsect1>
+  <title>Options</title>
+
+   <para>
+    <variablelist>
+     <varlistentry>
+      <term><option>-d</option></term>
+      <term><option>--debug</option></term>
+      <listitem>
+       <para>
+        Print lots of debug logging output on <filename>stderr</filename>.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry>
+      <term><option>-n</option></term>
+      <term><option>--dry-run</option></term>
+      <listitem>
+       <para>
+        The <option>-n</option>/<option>--dry-run</option> option instructs
+        <command>pg_cominebackup</command> to figure out what would be done
+        without actually creating the target directory or any output files.
+        It is particularly useful in comination with <option>--debug</option>.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry>
+      <term><option>-N</option></term>
+      <term><option>--no-sync</option></term>
+      <listitem>
+       <para>
+        By default, <command>pg_combinebackup</command> will wait for all files
+        to be written safely to disk.  This option causes
+        <command>pg_combinebackup</command> to return without waiting, which is
+        faster, but means that a subsequent operating system crash can leave
+        the output backup corrupt.  Generally, this option is useful for testing
+        but should not be used when creating a production installation.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry>
+      <term><option>-o <replaceable class="parameter">outputdir</replaceable></option></term>
+      <term><option>--output=<replaceable class="parameter">outputdir</replaceable></option></term>
+      <listitem>
+       <para>
+        Specifies the output directory to which the synthetic full backup
+        should be written. Currently, this argument is required.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry>
+      <term><option>-T <replaceable class="parameter">olddir</replaceable>=<replaceable class="parameter">newdir</replaceable></option></term>
+      <term><option>--tablespace-mapping=<replaceable class="parameter">olddir</replaceable>=<replaceable class="parameter">newdir</replaceable></option></term>
+      <listitem>
+       <para>
+        Relocates the tablespace in directory <replaceable>olddir</replaceable>
+        to <replaceable>newdir</replaceable> during the backup.
+        <replaceable>olddir</replaceable> is the absolute path of the tablespace
+        as it exists in the first backup specified on the command line,
+        and <replaceable>newdir</replaceable> is the absolute path to use for the
+        tablespace in the reconstructed backup.  If either path needs to contain
+        an equal sign (<literal>=</literal>), precede that with a backslash.
+        This option can be specified multiple times for multiple tablespaces.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry>
+      <term><option>--manifest-checksums=<replaceable class="parameter">algorithm</replaceable></option></term>
+      <listitem>
+       <para>
+        Like <xref linkend="app-pgbasebackup"/>,
+        <application>pg_combinebackup</application> writes a backup manifest
+        in the output directory. This option specifies the checksum algorithm
+        that should be applied to each file included in the backup manifest.
+        Currently, the available algorithms are <literal>NONE</literal>,
+        <literal>CRC32C</literal>, <literal>SHA224</literal>,
+        <literal>SHA256</literal>, <literal>SHA384</literal>,
+        and <literal>SHA512</literal>.  The default is <literal>CRC32C</literal>.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry>
+      <term><option>--no-manifest</option></term>
+      <listitem>
+       <para>
+        Disables generation of a backup manifest. If this option is not
+        specified, a backup manifest for the reconstructed backup will be
+        written to the output directory.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry>
+      <term><option>--sync-method=<replaceable class="parameter">method</replaceable></option></term>
+      <listitem>
+       <para>
+        When set to <literal>fsync</literal>, which is the default,
+        <command>pg_combinebackup</command> will recursively open and synchronize
+        all files in the backup directory.  When the plain format is used, the
+        search for files will follow symbolic links for the WAL directory and
+        each configured tablespace.
+       </para>
+       <para>
+        On Linux, <literal>syncfs</literal> may be used instead to ask the
+        operating system to synchronize the whole file system that contains the
+        backup directory.  When the plain format is used,
+        <command>pg_combinebackup</command> will also synchronize the file systems
+        that contain the WAL files and each tablespace.  See
+        <xref linkend="syncfs"/> for more information about using
+        <function>syncfs()</function>.
+       </para>
+       <para>
+        This option has no effect when <option>--no-sync</option> is used.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry>
+       <term><option>-V</option></term>
+       <term><option>--version</option></term>
+       <listitem>
+       <para>
+        Prints the <application>pg_combinebackup</application> version and
+        exits.
+       </para>
+       </listitem>
+     </varlistentry>
+
+     <varlistentry>
+       <term><option>-?</option></term>
+       <term><option>--help</option></term>
+       <listitem>
+       <para>
+        Shows help about <application>pg_combinebackup</application> command
+        line arguments, and exits.
+       </para>
+       </listitem>
+     </varlistentry>
+
+    </variablelist>
+   </para>
+
+ </refsect1>
+
+ <refsect1>
+  <title>Environment</title>
+
+  <para>
+   This utility, like most other <productname>PostgreSQL</productname> utilities,
+   uses the environment variables supported by <application>libpq</application>
+   (see <xref linkend="libpq-envars"/>).
+  </para>
+
+  <para>
+   The environment variable <envar>PG_COLOR</envar> specifies whether to use
+   color in diagnostic messages. Possible values are
+   <literal>always</literal>, <literal>auto</literal> and
+   <literal>never</literal>.
+  </para>
+ </refsect1>
+
+ <refsect1>
+  <title>See Also</title>
+
+  <simplelist type="inline">
+   <member><xref linkend="app-pgbasebackup"/></member>
+  </simplelist>
+ </refsect1>
+
+</refentry>
index e11b4b6130753970f978ca45b37b0dd345694d1f..a07d2b5e01e605374c98ff40d6a34c675903db61 100644 (file)
    &pgamcheck;
    &pgBasebackup;
    &pgbench;
+   &pgCombinebackup;
    &pgConfig;
    &pgDump;
    &pgDumpall;
index 21d68133ae1065aafd8bfbb2faecdfa765991727..f51d4282bb8dd11a33ca6f98d2baa8fc695f25c9 100644 (file)
@@ -77,6 +77,16 @@ build_backup_content(BackupState *state, bool ishistoryfile)
        appendStringInfo(result, "STOP TIMELINE: %u\n", state->stoptli);
    }
 
+   /* either both istartpoint and istarttli should be set, or neither */
+   Assert(XLogRecPtrIsInvalid(state->istartpoint) == (state->istarttli == 0));
+   if (!XLogRecPtrIsInvalid(state->istartpoint))
+   {
+       appendStringInfo(result, "INCREMENTAL FROM LSN: %X/%X\n",
+                        LSN_FORMAT_ARGS(state->istartpoint));
+       appendStringInfo(result, "INCREMENTAL FROM TLI: %u\n",
+                        state->istarttli);
+   }
+
    data = result->data;
    pfree(result);
 
index a2c8fa3981ca6e6db1745b499f7d99ef067afbc5..6f4f81f99277f4127c090bd442ed1d9b7f7817ef 100644 (file)
@@ -1295,6 +1295,12 @@ read_backup_label(XLogRecPtr *checkPointLoc, TimeLineID *backupLabelTLI,
                                 tli_from_file, BACKUP_LABEL_FILE)));
    }
 
+   if (fscanf(lfp, "INCREMENTAL FROM LSN: %X/%X\n", &hi, &lo) > 0)
+       ereport(FATAL,
+               (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+                errmsg("this is an incremental backup, not a data directory"),
+                errhint("Use pg_combinebackup to reconstruct a valid data directory.")));
+
    if (ferror(lfp) || FreeFile(lfp))
        ereport(FATAL,
                (errcode_for_file_access(),
index a67b3c58d4741a4d16feede0ca9ae61ee68bbe74..751e6d3d5e2e4b182b1383c91bfcc194d147a539 100644 (file)
@@ -19,6 +19,7 @@ OBJS = \
    basebackup.o \
    basebackup_copy.o \
    basebackup_gzip.o \
+   basebackup_incremental.o \
    basebackup_lz4.o \
    basebackup_zstd.o \
    basebackup_progress.o \
index 35dd79babcb3774ac27b1e287a7891403c4c21f7..5ee9628422e05b35fc24087cf5bb9abb6d460377 100644 (file)
 #include "access/xlogbackup.h"
 #include "backup/backup_manifest.h"
 #include "backup/basebackup.h"
+#include "backup/basebackup_incremental.h"
 #include "backup/basebackup_sink.h"
 #include "backup/basebackup_target.h"
+#include "catalog/pg_tablespace_d.h"
 #include "commands/defrem.h"
 #include "common/compression.h"
 #include "common/file_perm.h"
@@ -33,6 +35,7 @@
 #include "pgtar.h"
 #include "port.h"
 #include "postmaster/syslogger.h"
+#include "postmaster/walsummarizer.h"
 #include "replication/walsender.h"
 #include "replication/walsender_private.h"
 #include "storage/bufpage.h"
@@ -64,6 +67,7 @@ typedef struct
    bool        fastcheckpoint;
    bool        nowait;
    bool        includewal;
+   bool        incremental;
    uint32      maxrate;
    bool        sendtblspcmapfile;
    bool        send_to_client;
@@ -76,21 +80,28 @@ typedef struct
 } basebackup_options;
 
 static int64 sendTablespace(bbsink *sink, char *path, Oid spcoid, bool sizeonly,
-                           struct backup_manifest_info *manifest);
+                           struct backup_manifest_info *manifest,
+                           IncrementalBackupInfo *ib);
 static int64 sendDir(bbsink *sink, const char *path, int basepathlen, bool sizeonly,
                     List *tablespaces, bool sendtblspclinks,
-                    backup_manifest_info *manifest, Oid spcoid);
+                    backup_manifest_info *manifest, Oid spcoid,
+                    IncrementalBackupInfo *ib);
 static bool sendFile(bbsink *sink, const char *readfilename, const char *tarfilename,
                     struct stat *statbuf, bool missing_ok,
                     Oid dboid, Oid spcoid, RelFileNumber relfilenumber,
                     unsigned segno,
-                    backup_manifest_info *manifest);
+                    backup_manifest_info *manifest,
+                    unsigned num_incremental_blocks,
+                    BlockNumber *incremental_blocks,
+                    unsigned truncation_block_length);
 static off_t read_file_data_into_buffer(bbsink *sink,
                                        const char *readfilename, int fd,
                                        off_t offset, size_t length,
                                        BlockNumber blkno,
                                        bool verify_checksum,
                                        int *checksum_failures);
+static void push_to_sink(bbsink *sink, pg_checksum_context *checksum_ctx,
+                        size_t *bytes_done, void *data, size_t length);
 static bool verify_page_checksum(Page page, XLogRecPtr start_lsn,
                                 BlockNumber blkno,
                                 uint16 *expected_checksum);
@@ -102,7 +113,8 @@ static int64 _tarWriteHeader(bbsink *sink, const char *filename,
                             bool sizeonly);
 static void _tarWritePadding(bbsink *sink, int len);
 static void convert_link_to_directory(const char *pathbuf, struct stat *statbuf);
-static void perform_base_backup(basebackup_options *opt, bbsink *sink);
+static void perform_base_backup(basebackup_options *opt, bbsink *sink,
+                               IncrementalBackupInfo *ib);
 static void parse_basebackup_options(List *options, basebackup_options *opt);
 static int compareWalFileNames(const ListCell *a, const ListCell *b);
 static int basebackup_read_file(int fd, char *buf, size_t nbytes, off_t offset,
@@ -220,7 +232,8 @@ static const struct exclude_list_item excludeFiles[] =
  * clobbered by longjmp" from stupider versions of gcc.
  */
 static void
-perform_base_backup(basebackup_options *opt, bbsink *sink)
+perform_base_backup(basebackup_options *opt, bbsink *sink,
+                   IncrementalBackupInfo *ib)
 {
    bbsink_state state;
    XLogRecPtr  endptr;
@@ -270,6 +283,10 @@ perform_base_backup(basebackup_options *opt, bbsink *sink)
        ListCell   *lc;
        tablespaceinfo *newti;
 
+       /* If this is an incremental backup, execute preparatory steps. */
+       if (ib != NULL)
+           PrepareForIncrementalBackup(ib, backup_state);
+
        /* Add a node for the base directory at the end */
        newti = palloc0(sizeof(tablespaceinfo));
        newti->size = -1;
@@ -289,10 +306,10 @@ perform_base_backup(basebackup_options *opt, bbsink *sink)
 
                if (tmp->path == NULL)
                    tmp->size = sendDir(sink, ".", 1, true, state.tablespaces,
-                                       true, NULL, InvalidOid);
+                                       true, NULL, InvalidOid, NULL);
                else
                    tmp->size = sendTablespace(sink, tmp->path, tmp->oid, true,
-                                              NULL);
+                                              NULL, NULL);
                state.bytes_total += tmp->size;
            }
            state.bytes_total_is_valid = true;
@@ -330,7 +347,7 @@ perform_base_backup(basebackup_options *opt, bbsink *sink)
 
                /* Then the bulk of the files... */
                sendDir(sink, ".", 1, false, state.tablespaces,
-                       sendtblspclinks, &manifest, InvalidOid);
+                       sendtblspclinks, &manifest, InvalidOid, ib);
 
                /* ... and pg_control after everything else. */
                if (lstat(XLOG_CONTROL_FILE, &statbuf) != 0)
@@ -340,7 +357,7 @@ perform_base_backup(basebackup_options *opt, bbsink *sink)
                                    XLOG_CONTROL_FILE)));
                sendFile(sink, XLOG_CONTROL_FILE, XLOG_CONTROL_FILE, &statbuf,
                         false, InvalidOid, InvalidOid,
-                        InvalidRelFileNumber, 0, &manifest);
+                        InvalidRelFileNumber, 0, &manifest, 0, NULL, 0);
            }
            else
            {
@@ -348,7 +365,7 @@ perform_base_backup(basebackup_options *opt, bbsink *sink)
 
                bbsink_begin_archive(sink, archive_name);
 
-               sendTablespace(sink, ti->path, ti->oid, false, &manifest);
+               sendTablespace(sink, ti->path, ti->oid, false, &manifest, ib);
            }
 
            /*
@@ -610,7 +627,7 @@ perform_base_backup(basebackup_options *opt, bbsink *sink)
 
            sendFile(sink, pathbuf, pathbuf, &statbuf, false,
                     InvalidOid, InvalidOid, InvalidRelFileNumber, 0,
-                    &manifest);
+                    &manifest, 0, NULL, 0);
 
            /* unconditionally mark file as archived */
            StatusFilePath(pathbuf, fname, ".done");
@@ -686,6 +703,7 @@ parse_basebackup_options(List *options, basebackup_options *opt)
    bool        o_checkpoint = false;
    bool        o_nowait = false;
    bool        o_wal = false;
+   bool        o_incremental = false;
    bool        o_maxrate = false;
    bool        o_tablespace_map = false;
    bool        o_noverify_checksums = false;
@@ -764,6 +782,20 @@ parse_basebackup_options(List *options, basebackup_options *opt)
            opt->includewal = defGetBoolean(defel);
            o_wal = true;
        }
+       else if (strcmp(defel->defname, "incremental") == 0)
+       {
+           if (o_incremental)
+               ereport(ERROR,
+                       (errcode(ERRCODE_SYNTAX_ERROR),
+                        errmsg("duplicate option \"%s\"", defel->defname)));
+           opt->incremental = defGetBoolean(defel);
+           if (opt->incremental && !summarize_wal)
+               ereport(ERROR,
+                       (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+                        errmsg("incremental backups cannot be taken unless WAL summarization is enabled")));
+           opt->incremental = defGetBoolean(defel);
+           o_incremental = true;
+       }
        else if (strcmp(defel->defname, "max_rate") == 0)
        {
            int64       maxrate;
@@ -956,7 +988,7 @@ parse_basebackup_options(List *options, basebackup_options *opt)
  * the filesystem, bypassing the buffer cache.
  */
 void
-SendBaseBackup(BaseBackupCmd *cmd)
+SendBaseBackup(BaseBackupCmd *cmd, IncrementalBackupInfo *ib)
 {
    basebackup_options opt;
    bbsink     *sink;
@@ -980,6 +1012,20 @@ SendBaseBackup(BaseBackupCmd *cmd)
        set_ps_display(activitymsg);
    }
 
+   /*
+    * If we're asked to perform an incremental backup and the user has not
+    * supplied a manifest, that's an ERROR.
+    *
+    * If we're asked to perform a full backup and the user did supply a
+    * manifest, just ignore it.
+    */
+   if (!opt.incremental)
+       ib = NULL;
+   else if (ib == NULL)
+       ereport(ERROR,
+               (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+                errmsg("must UPLOAD_MANIFEST before performing an incremental BASE_BACKUP")));
+
    /*
     * If the target is specifically 'client' then set up to stream the backup
     * to the client; otherwise, it's being sent someplace else and should not
@@ -1011,7 +1057,7 @@ SendBaseBackup(BaseBackupCmd *cmd)
     */
    PG_TRY();
    {
-       perform_base_backup(&opt, sink);
+       perform_base_backup(&opt, sink, ib);
    }
    PG_FINALLY();
    {
@@ -1089,7 +1135,7 @@ sendFileWithContent(bbsink *sink, const char *filename, const char *content,
  */
 static int64
 sendTablespace(bbsink *sink, char *path, Oid spcoid, bool sizeonly,
-              backup_manifest_info *manifest)
+              backup_manifest_info *manifest, IncrementalBackupInfo *ib)
 {
    int64       size;
    char        pathbuf[MAXPGPATH];
@@ -1123,7 +1169,7 @@ sendTablespace(bbsink *sink, char *path, Oid spcoid, bool sizeonly,
 
    /* Send all the files in the tablespace version directory */
    size += sendDir(sink, pathbuf, strlen(path), sizeonly, NIL, true, manifest,
-                   spcoid);
+                   spcoid, ib);
 
    return size;
 }
@@ -1143,7 +1189,7 @@ sendTablespace(bbsink *sink, char *path, Oid spcoid, bool sizeonly,
 static int64
 sendDir(bbsink *sink, const char *path, int basepathlen, bool sizeonly,
        List *tablespaces, bool sendtblspclinks, backup_manifest_info *manifest,
-       Oid spcoid)
+       Oid spcoid, IncrementalBackupInfo *ib)
 {
    DIR        *dir;
    struct dirent *de;
@@ -1152,7 +1198,16 @@ sendDir(bbsink *sink, const char *path, int basepathlen, bool sizeonly,
    int64       size = 0;
    const char *lastDir;        /* Split last dir from parent path. */
    bool        isRelationDir = false;  /* Does directory contain relations? */
+   bool        isGlobalDir = false;
    Oid         dboid = InvalidOid;
+   BlockNumber *relative_block_numbers = NULL;
+
+   /*
+    * Since this array is relatively large, avoid putting it on the stack.
+    * But we don't need it at all if this is not an incremental backup.
+    */
+   if (ib != NULL)
+       relative_block_numbers = palloc(sizeof(BlockNumber) * RELSEG_SIZE);
 
    /*
     * Determine if the current path is a database directory that can contain
@@ -1185,7 +1240,10 @@ sendDir(bbsink *sink, const char *path, int basepathlen, bool sizeonly,
        }
    }
    else if (strcmp(path, "./global") == 0)
+   {
        isRelationDir = true;
+       isGlobalDir = true;
+   }
 
    dir = AllocateDir(path);
    while ((de = ReadDir(dir, path)) != NULL)
@@ -1334,11 +1392,13 @@ sendDir(bbsink *sink, const char *path, int basepathlen, bool sizeonly,
                                    &statbuf, sizeonly);
 
            /*
-            * Also send archive_status directory (by hackishly reusing
-            * statbuf from above ...).
+            * Also send archive_status and summaries directories (by
+            * hackishly reusing statbuf from above ...).
             */
            size += _tarWriteHeader(sink, "./pg_wal/archive_status", NULL,
                                    &statbuf, sizeonly);
+           size += _tarWriteHeader(sink, "./pg_wal/summaries", NULL,
+                                   &statbuf, sizeonly);
 
            continue;           /* don't recurse into pg_wal */
        }
@@ -1407,16 +1467,64 @@ sendDir(bbsink *sink, const char *path, int basepathlen, bool sizeonly,
 
            if (!skip_this_dir)
                size += sendDir(sink, pathbuf, basepathlen, sizeonly, tablespaces,
-                               sendtblspclinks, manifest, spcoid);
+                               sendtblspclinks, manifest, spcoid, ib);
        }
        else if (S_ISREG(statbuf.st_mode))
        {
            bool        sent = false;
+           unsigned    num_blocks_required = 0;
+           unsigned    truncation_block_length = 0;
+           char        tarfilenamebuf[MAXPGPATH * 2];
+           char       *tarfilename = pathbuf + basepathlen + 1;
+           FileBackupMethod method = BACK_UP_FILE_FULLY;
+
+           if (ib != NULL && isRelationFile)
+           {
+               Oid         relspcoid;
+               char       *lookup_path;
+
+               if (OidIsValid(spcoid))
+               {
+                   relspcoid = spcoid;
+                   lookup_path = psprintf("pg_tblspc/%u/%s", spcoid,
+                                          tarfilename);
+               }
+               else
+               {
+                   if (isGlobalDir)
+                       relspcoid = GLOBALTABLESPACE_OID;
+                   else
+                       relspcoid = DEFAULTTABLESPACE_OID;
+                   lookup_path = pstrdup(tarfilename);
+               }
+
+               method = GetFileBackupMethod(ib, lookup_path, dboid, relspcoid,
+                                            relfilenumber, relForkNum,
+                                            segno, statbuf.st_size,
+                                            &num_blocks_required,
+                                            relative_block_numbers,
+                                            &truncation_block_length);
+               if (method == BACK_UP_FILE_INCREMENTALLY)
+               {
+                   statbuf.st_size =
+                       GetIncrementalFileSize(num_blocks_required);
+                   snprintf(tarfilenamebuf, sizeof(tarfilenamebuf),
+                            "%s/INCREMENTAL.%s",
+                            path + basepathlen + 1,
+                            de->d_name);
+                   tarfilename = tarfilenamebuf;
+               }
+
+               pfree(lookup_path);
+           }
 
            if (!sizeonly)
-               sent = sendFile(sink, pathbuf, pathbuf + basepathlen + 1, &statbuf,
+               sent = sendFile(sink, pathbuf, tarfilename, &statbuf,
                                true, dboid, spcoid,
-                               relfilenumber, segno, manifest);
+                               relfilenumber, segno, manifest,
+                               num_blocks_required,
+                               method == BACK_UP_FILE_INCREMENTALLY ? relative_block_numbers : NULL,
+                               truncation_block_length);
 
            if (sent || sizeonly)
            {
@@ -1434,6 +1542,10 @@ sendDir(bbsink *sink, const char *path, int basepathlen, bool sizeonly,
            ereport(WARNING,
                    (errmsg("skipping special file \"%s\"", pathbuf)));
    }
+
+   if (relative_block_numbers != NULL)
+       pfree(relative_block_numbers);
+
    FreeDir(dir);
    return size;
 }
@@ -1446,6 +1558,12 @@ sendDir(bbsink *sink, const char *path, int basepathlen, bool sizeonly,
  * If dboid is anything other than InvalidOid then any checksum failures
  * detected will get reported to the cumulative stats system.
  *
+ * If the file is to be sent incrementally, then num_incremental_blocks
+ * should be the number of blocks to be sent, and incremental_blocks
+ * an array of block numbers relative to the start of the current segment.
+ * If the whole file is to be sent, then incremental_blocks should be NULL,
+ * and num_incremental_blocks can have any value, as it will be ignored.
+ *
  * Returns true if the file was successfully sent, false if 'missing_ok',
  * and the file did not exist.
  */
@@ -1453,7 +1571,8 @@ static bool
 sendFile(bbsink *sink, const char *readfilename, const char *tarfilename,
         struct stat *statbuf, bool missing_ok, Oid dboid, Oid spcoid,
         RelFileNumber relfilenumber, unsigned segno,
-        backup_manifest_info *manifest)
+        backup_manifest_info *manifest, unsigned num_incremental_blocks,
+        BlockNumber *incremental_blocks, unsigned truncation_block_length)
 {
    int         fd;
    BlockNumber blkno = 0;
@@ -1462,6 +1581,7 @@ sendFile(bbsink *sink, const char *readfilename, const char *tarfilename,
    pgoff_t     bytes_done = 0;
    bool        verify_checksum = false;
    pg_checksum_context checksum_ctx;
+   int         ibindex = 0;
 
    if (pg_checksum_init(&checksum_ctx, manifest->checksum_type) < 0)
        elog(ERROR, "could not initialize checksum of file \"%s\"",
@@ -1494,22 +1614,111 @@ sendFile(bbsink *sink, const char *readfilename, const char *tarfilename,
        RelFileNumberIsValid(relfilenumber))
        verify_checksum = true;
 
+   /*
+    * If we're sending an incremental file, write the file header.
+    */
+   if (incremental_blocks != NULL)
+   {
+       unsigned    magic = INCREMENTAL_MAGIC;
+       size_t      header_bytes_done = 0;
+
+       /* Emit header data. */
+       push_to_sink(sink, &checksum_ctx, &header_bytes_done,
+                    &magic, sizeof(magic));
+       push_to_sink(sink, &checksum_ctx, &header_bytes_done,
+                    &num_incremental_blocks, sizeof(num_incremental_blocks));
+       push_to_sink(sink, &checksum_ctx, &header_bytes_done,
+                    &truncation_block_length, sizeof(truncation_block_length));
+       push_to_sink(sink, &checksum_ctx, &header_bytes_done,
+                    incremental_blocks,
+                    sizeof(BlockNumber) * num_incremental_blocks);
+
+       /* Flush out any data still in the buffer so it's again empty. */
+       if (header_bytes_done > 0)
+       {
+           bbsink_archive_contents(sink, header_bytes_done);
+           if (pg_checksum_update(&checksum_ctx,
+                                  (uint8 *) sink->bbs_buffer,
+                                  header_bytes_done) < 0)
+               elog(ERROR, "could not update checksum of base backup");
+       }
+
+       /* Update our notion of file position. */
+       bytes_done += sizeof(magic);
+       bytes_done += sizeof(num_incremental_blocks);
+       bytes_done += sizeof(truncation_block_length);
+       bytes_done += sizeof(BlockNumber) * num_incremental_blocks;
+   }
+
    /*
     * Loop until we read the amount of data the caller told us to expect. The
     * file could be longer, if it was extended while we were sending it, but
     * for a base backup we can ignore such extended data. It will be restored
     * from WAL.
     */
-   while (bytes_done < statbuf->st_size)
+   while (1)
    {
-       size_t      remaining = statbuf->st_size - bytes_done;
+       /*
+        * Determine whether we've read all the data that we need, and if not,
+        * read some more.
+        */
+       if (incremental_blocks == NULL)
+       {
+           size_t      remaining = statbuf->st_size - bytes_done;
+
+           /*
+            * If we've read the required number of bytes, then it's time to
+            * stop.
+            */
+           if (bytes_done >= statbuf->st_size)
+               break;
+
+           /*
+            * Read as many bytes as will fit in the buffer, or however many
+            * are left to read, whichever is less.
+            */
+           cnt = read_file_data_into_buffer(sink, readfilename, fd,
+                                            bytes_done, remaining,
+                                            blkno + segno * RELSEG_SIZE,
+                                            verify_checksum,
+                                            &checksum_failures);
+       }
+       else
+       {
+           BlockNumber relative_blkno;
 
-       /* Try to read some more data. */
-       cnt = read_file_data_into_buffer(sink, readfilename, fd, bytes_done,
-                                        remaining,
-                                        blkno + segno * RELSEG_SIZE,
-                                        verify_checksum,
-                                        &checksum_failures);
+           /*
+            * If we've read all the blocks, then it's time to stop.
+            */
+           if (ibindex >= num_incremental_blocks)
+               break;
+
+           /*
+            * Read just one block, whichever one is the next that we're
+            * supposed to include.
+            */
+           relative_blkno = incremental_blocks[ibindex++];
+           cnt = read_file_data_into_buffer(sink, readfilename, fd,
+                                            relative_blkno * BLCKSZ,
+                                            BLCKSZ,
+                                            relative_blkno + segno * RELSEG_SIZE,
+                                            verify_checksum,
+                                            &checksum_failures);
+
+           /*
+            * If we get a partial read, that must mean that the relation is
+            * being truncated. Ultimately, it should be truncated to a
+            * multiple of BLCKSZ, since this path should only be reached for
+            * relation files, but we might transiently observe an
+            * intermediate value.
+            *
+            * It should be fine to treat this just as if the entire block had
+            * been truncated away - i.e. fill this and all later blocks with
+            * zeroes. WAL replay will fix things up.
+            */
+           if (cnt < BLCKSZ)
+               break;
+       }
 
        /*
         * If the amount of data we were able to read was not a multiple of
@@ -1692,6 +1901,56 @@ read_file_data_into_buffer(bbsink *sink, const char *readfilename, int fd,
    return cnt;
 }
 
+/*
+ * Push data into a bbsink.
+ *
+ * It's better, when possible, to read data directly into the bbsink's buffer,
+ * rather than using this function to copy it into the buffer; this function is
+ * for cases where that approach is not practical.
+ *
+ * bytes_done should point to a count of the number of bytes that are
+ * currently used in the bbsink's buffer. Upon return, the bytes identified by
+ * data and length will have been copied into the bbsink's buffer, flushing
+ * as required, and *bytes_done will have been updated accordingly. If the
+ * buffer was flushed, the previous contents will also have been fed to
+ * checksum_ctx.
+ *
+ * Note that after one or more calls to this function it is the caller's
+ * responsibility to perform any required final flush.
+ */
+static void
+push_to_sink(bbsink *sink, pg_checksum_context *checksum_ctx,
+            size_t *bytes_done, void *data, size_t length)
+{
+   while (length > 0)
+   {
+       size_t      bytes_to_copy;
+
+       /*
+        * We use < here rather than <= so that if the data exactly fills the
+        * remaining buffer space, we trigger a flush now.
+        */
+       if (length < sink->bbs_buffer_length - *bytes_done)
+       {
+           /* Append remaining data to buffer. */
+           memcpy(sink->bbs_buffer + *bytes_done, data, length);
+           *bytes_done += length;
+           return;
+       }
+
+       /* Copy until buffer is full and flush it. */
+       bytes_to_copy = sink->bbs_buffer_length - *bytes_done;
+       memcpy(sink->bbs_buffer + *bytes_done, data, bytes_to_copy);
+       data = ((char *) data) + bytes_to_copy;
+       length -= bytes_to_copy;
+       bbsink_archive_contents(sink, sink->bbs_buffer_length);
+       if (pg_checksum_update(checksum_ctx, (uint8 *) sink->bbs_buffer,
+                              sink->bbs_buffer_length) < 0)
+           elog(ERROR, "could not update checksum");
+       *bytes_done = 0;
+   }
+}
+
 /*
  * Try to verify the checksum for the provided page, if it seems appropriate
  * to do so.
diff --git a/src/backend/backup/basebackup_incremental.c b/src/backend/backup/basebackup_incremental.c
new file mode 100644 (file)
index 0000000..1e5a5ac
--- /dev/null
@@ -0,0 +1,1003 @@
+/*-------------------------------------------------------------------------
+ *
+ * basebackup_incremental.c
+ *   code for incremental backup support
+ *
+ * This code isn't actually in charge of taking an incremental backup;
+ * the actual construction of the incremental backup happens in
+ * basebackup.c. Here, we're concerned with providing the necessary
+ * supports for that operation. In particular, we need to parse the
+ * backup manifest supplied by the user taking the incremental backup
+ * and extract the required information from it.
+ *
+ * Portions Copyright (c) 2010-2022, PostgreSQL Global Development Group
+ *
+ * IDENTIFICATION
+ *   src/backend/backup/basebackup_incremental.c
+ *
+ *-------------------------------------------------------------------------
+ */
+#include "postgres.h"
+
+#include "access/timeline.h"
+#include "access/xlog.h"
+#include "access/xlogrecovery.h"
+#include "backup/basebackup_incremental.h"
+#include "backup/walsummary.h"
+#include "common/blkreftable.h"
+#include "common/parse_manifest.h"
+#include "common/hashfn.h"
+#include "postmaster/walsummarizer.h"
+
+#define    BLOCKS_PER_READ         512
+
+/*
+ * Details extracted from the WAL ranges present in the supplied backup manifest.
+ */
+typedef struct
+{
+   TimeLineID  tli;
+   XLogRecPtr  start_lsn;
+   XLogRecPtr  end_lsn;
+} backup_wal_range;
+
+/*
+ * Details extracted from the file list present in the supplied backup manifest.
+ */
+typedef struct
+{
+   uint32      status;
+   const char *path;
+   size_t      size;
+} backup_file_entry;
+
+static uint32 hash_string_pointer(const char *s);
+#define SH_PREFIX               backup_file
+#define SH_ELEMENT_TYPE            backup_file_entry
+#define SH_KEY_TYPE             const char *
+#define SH_KEY                  path
+#define SH_HASH_KEY(tb, key)    hash_string_pointer(key)
+#define SH_EQUAL(tb, a, b)     (strcmp(a, b) == 0)
+#define SH_SCOPE                static inline
+#define SH_DECLARE
+#define SH_DEFINE
+#include "lib/simplehash.h"
+
+struct IncrementalBackupInfo
+{
+   /* Memory context for this object and its subsidiary objects. */
+   MemoryContext mcxt;
+
+   /* Temporary buffer for storing the manifest while parsing it. */
+   StringInfoData buf;
+
+   /* WAL ranges extracted from the backup manifest. */
+   List       *manifest_wal_ranges;
+
+   /*
+    * Files extracted from the backup manifest.
+    *
+    * We don't really need this information, because we use WAL summaries to
+    * figure what's changed. It would be unsafe to just rely on the list of
+    * files that existed before, because it's possible for a file to be
+    * removed and a new one created with the same name and different
+    * contents. In such cases, the whole file must still be sent. We can tell
+    * from the WAL summaries whether that happened, but not from the file
+    * list.
+    *
+    * Nonetheless, this data is useful for sanity checking. If a file that we
+    * think we shouldn't need to send is not present in the manifest for the
+    * prior backup, something has gone terribly wrong. We retain the file
+    * names and sizes, but not the checksums or last modified times, for
+    * which we have no use.
+    *
+    * One significant downside of storing this data is that it consumes
+    * memory. If that turns out to be a problem, we might have to decide not
+    * to retain this information, or to make it optional.
+    */
+   backup_file_hash *manifest_files;
+
+   /*
+    * Block-reference table for the incremental backup.
+    *
+    * It's possible that storing the entire block-reference table in memory
+    * will be a problem for some users. The in-memory format that we're using
+    * here is pretty efficient, converging to little more than 1 bit per
+    * block for relation forks with large numbers of modified blocks. It's
+    * possible, however, that if you try to perform an incremental backup of
+    * a database with a sufficiently large number of relations on a
+    * sufficiently small machine, you could run out of memory here. If that
+    * turns out to be a problem in practice, we'll need to be more clever.
+    */
+   BlockRefTable *brtab;
+};
+
+static void manifest_process_file(JsonManifestParseContext *context,
+                                 char *pathname,
+                                 size_t size,
+                                 pg_checksum_type checksum_type,
+                                 int checksum_length,
+                                 uint8 *checksum_payload);
+static void manifest_process_wal_range(JsonManifestParseContext *context,
+                                      TimeLineID tli,
+                                      XLogRecPtr start_lsn,
+                                      XLogRecPtr end_lsn);
+static void manifest_report_error(JsonManifestParseContext *ib,
+                                 const char *fmt,...)
+           pg_attribute_printf(2, 3) pg_attribute_noreturn();
+static int compare_block_numbers(const void *a, const void *b);
+
+/*
+ * Create a new object for storing information extracted from the manifest
+ * supplied when creating an incremental backup.
+ */
+IncrementalBackupInfo *
+CreateIncrementalBackupInfo(MemoryContext mcxt)
+{
+   IncrementalBackupInfo *ib;
+   MemoryContext oldcontext;
+
+   oldcontext = MemoryContextSwitchTo(mcxt);
+
+   ib = palloc0(sizeof(IncrementalBackupInfo));
+   ib->mcxt = mcxt;
+   initStringInfo(&ib->buf);
+
+   /*
+    * It's hard to guess how many files a "typical" installation will have in
+    * the data directory, but a fresh initdb creates almost 1000 files as of
+    * this writing, so it seems to make sense for our estimate to
+    * substantially higher.
+    */
+   ib->manifest_files = backup_file_create(mcxt, 10000, NULL);
+
+   MemoryContextSwitchTo(oldcontext);
+
+   return ib;
+}
+
+/*
+ * Before taking an incremental backup, the caller must supply the backup
+ * manifest from a prior backup. Each chunk of manifest data recieved
+ * from the client should be passed to this function.
+ */
+void
+AppendIncrementalManifestData(IncrementalBackupInfo *ib, const char *data,
+                             int len)
+{
+   MemoryContext oldcontext;
+
+   /* Switch to our memory context. */
+   oldcontext = MemoryContextSwitchTo(ib->mcxt);
+
+   /*
+    * XXX. Our json parser is at present incapable of parsing json blobs
+    * incrementally, so we have to accumulate the entire backup manifest
+    * before we can do anything with it. This should really be fixed, since
+    * some users might have very large numbers of files in the data
+    * directory.
+    */
+   appendBinaryStringInfo(&ib->buf, data, len);
+
+   /* Switch back to previous memory context. */
+   MemoryContextSwitchTo(oldcontext);
+}
+
+/*
+ * Finalize an IncrementalBackupInfo object after all manifest data has
+ * been supplied via calls to AppendIncrementalManifestData.
+ */
+void
+FinalizeIncrementalManifest(IncrementalBackupInfo *ib)
+{
+   JsonManifestParseContext context;
+   MemoryContext oldcontext;
+
+   /* Switch to our memory context. */
+   oldcontext = MemoryContextSwitchTo(ib->mcxt);
+
+   /* Parse the manifest. */
+   context.private_data = ib;
+   context.per_file_cb = manifest_process_file;
+   context.per_wal_range_cb = manifest_process_wal_range;
+   context.error_cb = manifest_report_error;
+   json_parse_manifest(&context, ib->buf.data, ib->buf.len);
+
+   /* Done with the buffer, so release memory. */
+   pfree(ib->buf.data);
+   ib->buf.data = NULL;
+
+   /* Switch back to previous memory context. */
+   MemoryContextSwitchTo(oldcontext);
+}
+
+/*
+ * Prepare to take an incremental backup.
+ *
+ * Before this function is called, AppendIncrementalManifestData and
+ * FinalizeIncrementalManifest should have already been called to pass all
+ * the manifest data to this object.
+ *
+ * This function performs sanity checks on the data extracted from the
+ * manifest and figures out for which WAL ranges we need summaries, and
+ * whether those summaries are available. Then, it reads and combines the
+ * data from those summary files. It also updates the backup_state with the
+ * reference TLI and LSN for the prior backup.
+ */
+void
+PrepareForIncrementalBackup(IncrementalBackupInfo *ib,
+                           BackupState *backup_state)
+{
+   MemoryContext oldcontext;
+   List       *expectedTLEs;
+   List       *all_wslist,
+              *required_wslist = NIL;
+   ListCell   *lc;
+   TimeLineHistoryEntry **tlep;
+   int         num_wal_ranges;
+   int         i;
+   bool        found_backup_start_tli = false;
+   TimeLineID  earliest_wal_range_tli = 0;
+   XLogRecPtr  earliest_wal_range_start_lsn = InvalidXLogRecPtr;
+   TimeLineID  latest_wal_range_tli = 0;
+   XLogRecPtr  summarized_lsn;
+   XLogRecPtr  pending_lsn;
+   XLogRecPtr  prior_pending_lsn = InvalidXLogRecPtr;
+   int         deadcycles = 0;
+   TimestampTz initial_time,
+               current_time;
+
+   Assert(ib->buf.data == NULL);
+
+   /* Switch to our memory context. */
+   oldcontext = MemoryContextSwitchTo(ib->mcxt);
+
+   /*
+    * A valid backup manifest must always contain at least one WAL range
+    * (usually exactly one, unless the backup spanned a timeline switch).
+    */
+   num_wal_ranges = list_length(ib->manifest_wal_ranges);
+   if (num_wal_ranges == 0)
+       ereport(ERROR,
+               (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+                errmsg("manifest contains no required WAL ranges")));
+
+   /*
+    * Match up the TLIs that appear in the WAL ranges of the backup manifest
+    * with those that appear in this server's timeline history. We expect
+    * every backup_wal_range to match to a TimeLineHistoryEntry; if it does
+    * not, that's an error.
+    *
+    * This loop also decides which of the WAL ranges is the manifest is most
+    * ancient and which one is the newest, according to the timeline history
+    * of this server, and stores TLIs of those WAL ranges into
+    * earliest_wal_range_tli and latest_wal_range_tli. It also updates
+    * earliest_wal_range_start_lsn to the start LSN of the WAL range for
+    * earliest_wal_range_tli.
+    *
+    * Note that the return value of readTimeLineHistory puts the latest
+    * timeline at the beginning of the list, not the end. Hence, the earliest
+    * TLI is the one that occurs nearest the end of the list returned by
+    * readTimeLineHistory, and the latest TLI is the one that occurs closest
+    * to the beginning.
+    */
+   expectedTLEs = readTimeLineHistory(backup_state->starttli);
+   tlep = palloc0(num_wal_ranges * sizeof(TimeLineHistoryEntry *));
+   for (i = 0; i < num_wal_ranges; ++i)
+   {
+       backup_wal_range *range = list_nth(ib->manifest_wal_ranges, i);
+       bool        saw_earliest_wal_range_tli = false;
+       bool        saw_latest_wal_range_tli = false;
+
+       /* Search this server's history for this WAL range's TLI. */
+       foreach(lc, expectedTLEs)
+       {
+           TimeLineHistoryEntry *tle = lfirst(lc);
+
+           if (tle->tli == range->tli)
+           {
+               tlep[i] = tle;
+               break;
+           }
+
+           if (tle->tli == earliest_wal_range_tli)
+               saw_earliest_wal_range_tli = true;
+           if (tle->tli == latest_wal_range_tli)
+               saw_latest_wal_range_tli = true;
+       }
+
+       /*
+        * An incremental backup can only be taken relative to a backup that
+        * represents a previous state of this server. If the backup requires
+        * WAL from a timeline that's not in our history, that definitely
+        * isn't the case.
+        */
+       if (tlep[i] == NULL)
+           ereport(ERROR,
+                   (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+                    errmsg("timeline %u found in manifest, but not in this server's history",
+                           range->tli)));
+
+       /*
+        * If we found this TLI in the server's history before encountering
+        * the latest TLI seen so far in the server's history, then this TLI
+        * is the latest one seen so far.
+        *
+        * If on the other hand we saw the earliest TLI seen so far before
+        * finding this TLI, this TLI is earlier than the earliest one seen so
+        * far. And if this is the first TLI for which we've searched, it's
+        * also the earliest one seen so far.
+        *
+        * On the first loop iteration, both things should necessarily be
+        * true.
+        */
+       if (!saw_latest_wal_range_tli)
+           latest_wal_range_tli = range->tli;
+       if (earliest_wal_range_tli == 0 || saw_earliest_wal_range_tli)
+       {
+           earliest_wal_range_tli = range->tli;
+           earliest_wal_range_start_lsn = range->start_lsn;
+       }
+   }
+
+   /*
+    * Propagate information about the prior backup into the backup_label that
+    * will be generated for this backup.
+    */
+   backup_state->istartpoint = earliest_wal_range_start_lsn;
+   backup_state->istarttli = earliest_wal_range_tli;
+
+   /*
+    * Sanity check start and end LSNs for the WAL ranges in the manifest.
+    *
+    * Commonly, there won't be any timeline switches during the prior backup
+    * at all, but if there are, they should happen at the same LSNs that this
+    * server switched timelines.
+    *
+    * Whether there are any timeline switches during the prior backup or not,
+    * the prior backup shouldn't require any WAL from a timeline prior to the
+    * start of that timeline. It also shouldn't require any WAL from later
+    * than the start of this backup.
+    *
+    * If any of these sanity checks fail, one possible explanation is that
+    * the user has generated WAL on the same timeline with the same LSNs more
+    * than once. For instance, if two standbys running on timeline 1 were
+    * both promoted and (due to a broken archiving setup) both selected new
+    * timeline ID 2, then it's possible that one of these checks might trip.
+    *
+    * Note that there are lots of ways for the user to do something very bad
+    * without tripping any of these checks, and they are not intended to be
+    * comprehensive. It's pretty hard to see how we could be certain of
+    * anything here. However, if there's a problem staring us right in the
+    * face, it's best to report it, so we do.
+    */
+   for (i = 0; i < num_wal_ranges; ++i)
+   {
+       backup_wal_range *range = list_nth(ib->manifest_wal_ranges, i);
+
+       if (range->tli == earliest_wal_range_tli)
+       {
+           if (range->start_lsn < tlep[i]->begin)
+               ereport(ERROR,
+                       (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+                        errmsg("manifest requires WAL from initial timeline %u starting at %X/%X, but that timeline begins at %X/%X",
+                               range->tli,
+                               LSN_FORMAT_ARGS(range->start_lsn),
+                               LSN_FORMAT_ARGS(tlep[i]->begin))));
+       }
+       else
+       {
+           if (range->start_lsn != tlep[i]->begin)
+               ereport(ERROR,
+                       (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+                        errmsg("manifest requires WAL from continuation timeline %u starting at %X/%X, but that timeline begins at %X/%X",
+                               range->tli,
+                               LSN_FORMAT_ARGS(range->start_lsn),
+                               LSN_FORMAT_ARGS(tlep[i]->begin))));
+       }
+
+       if (range->tli == latest_wal_range_tli)
+       {
+           if (range->end_lsn > backup_state->startpoint)
+               ereport(ERROR,
+                       (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+                        errmsg("manifest requires WAL from final timeline %u ending at %X/%X, but this backup starts at %X/%X",
+                               range->tli,
+                               LSN_FORMAT_ARGS(range->end_lsn),
+                               LSN_FORMAT_ARGS(backup_state->startpoint))));
+       }
+       else
+       {
+           if (range->end_lsn != tlep[i]->end)
+               ereport(ERROR,
+                       (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+                        errmsg("manifest requires WAL from non-final timeline %u ending at %X/%X, but this server switched timelines at %X/%X",
+                               range->tli,
+                               LSN_FORMAT_ARGS(range->end_lsn),
+                               LSN_FORMAT_ARGS(tlep[i]->end))));
+       }
+
+   }
+
+   /*
+    * Wait for WAL summarization to catch up to the backup start LSN (but
+    * time out if it doesn't do so quickly enough).
+    */
+   initial_time = current_time = GetCurrentTimestamp();
+   while (1)
+   {
+       long        timeout_in_ms = 10000;
+       unsigned    elapsed_seconds;
+
+       /*
+        * Align the wait time to prevent drift. This doesn't really matter,
+        * but we'd like the warnings about how long we've been waiting to say
+        * 10 seconds, 20 seconds, 30 seconds, 40 seconds ... without ever
+        * drifting to something that is not a multiple of ten.
+        */
+       timeout_in_ms -=
+           TimestampDifferenceMilliseconds(current_time, initial_time) %
+           timeout_in_ms;
+
+       /* Wait for up to 10 seconds. */
+       summarized_lsn = WaitForWalSummarization(backup_state->startpoint,
+                                                10000, &pending_lsn);
+
+       /* If WAL summarization has progressed sufficiently, stop waiting. */
+       if (summarized_lsn >= backup_state->startpoint)
+           break;
+
+       /*
+        * Keep track of the number of cycles during which there has been no
+        * progression of pending_lsn. If pending_lsn is not advancing, that
+        * means that not only are no new files appearing on disk, but we're
+        * not even incorporating new records into the in-memory state.
+        */
+       if (pending_lsn > prior_pending_lsn)
+       {
+           prior_pending_lsn = pending_lsn;
+           deadcycles = 0;
+       }
+       else
+           ++deadcycles;
+
+       /*
+        * If we've managed to wait for an entire minute withot the WAL
+        * summarizer absorbing a single WAL record, error out; probably
+        * something is wrong.
+        *
+        * We could consider also erroring out if the summarizer is taking too
+        * long to catch up, but it's not clear what rate of progress would be
+        * acceptable and what would be too slow. So instead, we just try to
+        * error out in the case where there's no progress at all. That seems
+        * likely to catch a reasonable number of the things that can go wrong
+        * in practice (e.g. the summarizer process is completely hung, say
+        * because somebody hooked up a debugger to it or something) without
+        * giving up too quickly when the sytem is just slow.
+        */
+       if (deadcycles >= 6)
+           ereport(ERROR,
+                   (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+                    errmsg("WAL summarization is not progressing"),
+                    errdetail("Summarization is needed through %X/%X, but is stuck at %X/%X on disk and %X/%X in memory.",
+                              LSN_FORMAT_ARGS(backup_state->startpoint),
+                              LSN_FORMAT_ARGS(summarized_lsn),
+                              LSN_FORMAT_ARGS(pending_lsn))));
+
+       /*
+        * Otherwise, just let the user know what's happening.
+        */
+       current_time = GetCurrentTimestamp();
+       elapsed_seconds =
+           TimestampDifferenceMilliseconds(initial_time, current_time) / 1000;
+       ereport(WARNING,
+               (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+                errmsg("still waiting for WAL summarization through %X/%X after %d seconds",
+                       LSN_FORMAT_ARGS(backup_state->startpoint),
+                       elapsed_seconds),
+                errdetail("Summarization has reached %X/%X on disk and %X/%X in memory.",
+                          LSN_FORMAT_ARGS(summarized_lsn),
+                          LSN_FORMAT_ARGS(pending_lsn))));
+   }
+
+   /*
+    * Retrieve a list of all WAL summaries on any timeline that overlap with
+    * the LSN range of interest. We could instead call GetWalSummaries() once
+    * per timeline in the loop that follows, but that would involve reading
+    * the directory multiple times. It should be mildly faster - and perhaps
+    * a bit safer - to do it just once.
+    */
+   all_wslist = GetWalSummaries(0, earliest_wal_range_start_lsn,
+                                backup_state->startpoint);
+
+   /*
+    * We need WAL summaries for everything that happened during the prior
+    * backup and everything that happened afterward up until the point where
+    * the current backup started.
+    */
+   foreach(lc, expectedTLEs)
+   {
+       TimeLineHistoryEntry *tle = lfirst(lc);
+       XLogRecPtr  tli_start_lsn = tle->begin;
+       XLogRecPtr  tli_end_lsn = tle->end;
+       XLogRecPtr  tli_missing_lsn = InvalidXLogRecPtr;
+       List       *tli_wslist;
+
+       /*
+        * Working through the history of this server from the current
+        * timeline backwards, we skip everything until we find the timeline
+        * where this backup started. Most of the time, this means we won't
+        * skip anything at all, as it's unlikely that the timeline has
+        * changed since the beginning of the backup moments ago.
+        */
+       if (tle->tli == backup_state->starttli)
+       {
+           found_backup_start_tli = true;
+           tli_end_lsn = backup_state->startpoint;
+       }
+       else if (!found_backup_start_tli)
+           continue;
+
+       /*
+        * Find the summaries that overlap the LSN range of interest for this
+        * timeline. If this is the earliest timeline involved, the range of
+        * interest begins with the start LSN of the prior backup; otherwise,
+        * it begins at the LSN at which this timeline came into existence. If
+        * this is the latest TLI involved, the range of interest ends at the
+        * start LSN of the current backup; otherwise, it ends at the point
+        * where we switched from this timeline to the next one.
+        */
+       if (tle->tli == earliest_wal_range_tli)
+           tli_start_lsn = earliest_wal_range_start_lsn;
+       tli_wslist = FilterWalSummaries(all_wslist, tle->tli,
+                                       tli_start_lsn, tli_end_lsn);
+
+       /*
+        * There is no guarantee that the WAL summaries we found cover the
+        * entire range of LSNs for which summaries are required, or indeed
+        * that we found any WAL summaries at all. Check whether we have a
+        * problem of that sort.
+        */
+       if (!WalSummariesAreComplete(tli_wslist, tli_start_lsn, tli_end_lsn,
+                                    &tli_missing_lsn))
+       {
+           if (XLogRecPtrIsInvalid(tli_missing_lsn))
+               ereport(ERROR,
+                       (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+                        errmsg("WAL summaries are required on timeline %u from %X/%X to %X/%X, but no summaries for that timeline and LSN range exist",
+                               tle->tli,
+                               LSN_FORMAT_ARGS(tli_start_lsn),
+                               LSN_FORMAT_ARGS(tli_end_lsn))));
+           else
+               ereport(ERROR,
+                       (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+                        errmsg("WAL summaries are required on timeline %u from %X/%X to %X/%X, but the summaries for that timeline and LSN range are incomplete",
+                               tle->tli,
+                               LSN_FORMAT_ARGS(tli_start_lsn),
+                               LSN_FORMAT_ARGS(tli_end_lsn)),
+                        errdetail("The first unsummarized LSN is this range is %X/%X.",
+                                  LSN_FORMAT_ARGS(tli_missing_lsn))));
+       }
+
+       /*
+        * Remember that we need to read these summaries.
+        *
+        * Technically, it's possible that this could read more files than
+        * required, since tli_wslist in theory could contain redundant
+        * summaries. For instance, if we have a summary from 0/10000000 to
+        * 0/20000000 and also one from 0/00000000 to 0/30000000, then the
+        * latter subsumes the former and the former could be ignored.
+        *
+        * We ignore this possibility because the WAL summarizer only tries to
+        * generate summaries that do not overlap. If somehow they exist,
+        * we'll do a bit of extra work but the results should still be
+        * correct.
+        */
+       required_wslist = list_concat(required_wslist, tli_wslist);
+
+       /*
+        * Timelines earlier than the one in which the prior backup began are
+        * not relevant.
+        */
+       if (tle->tli == earliest_wal_range_tli)
+           break;
+   }
+
+   /*
+    * Read all of the required block reference table files and merge all of
+    * the data into a single in-memory block reference table.
+    *
+    * See the comments for struct IncrementalBackupInfo for some thoughts on
+    * memory usage.
+    */
+   ib->brtab = CreateEmptyBlockRefTable();
+   foreach(lc, required_wslist)
+   {
+       WalSummaryFile *ws = lfirst(lc);
+       WalSummaryIO wsio;
+       BlockRefTableReader *reader;
+       RelFileLocator rlocator;
+       ForkNumber  forknum;
+       BlockNumber limit_block;
+       BlockNumber blocks[BLOCKS_PER_READ];
+
+       wsio.file = OpenWalSummaryFile(ws, false);
+       wsio.filepos = 0;
+       ereport(DEBUG1,
+               (errmsg_internal("reading WAL summary file \"%s\"",
+                                FilePathName(wsio.file))));
+       reader = CreateBlockRefTableReader(ReadWalSummary, &wsio,
+                                          FilePathName(wsio.file),
+                                          ReportWalSummaryError, NULL);
+       while (BlockRefTableReaderNextRelation(reader, &rlocator, &forknum,
+                                              &limit_block))
+       {
+           BlockRefTableSetLimitBlock(ib->brtab, &rlocator,
+                                      forknum, limit_block);
+
+           while (1)
+           {
+               unsigned    nblocks;
+               unsigned    i;
+
+               nblocks = BlockRefTableReaderGetBlocks(reader, blocks,
+                                                      BLOCKS_PER_READ);
+               if (nblocks == 0)
+                   break;
+
+               for (i = 0; i < nblocks; ++i)
+                   BlockRefTableMarkBlockModified(ib->brtab, &rlocator,
+                                                  forknum, blocks[i]);
+           }
+       }
+       DestroyBlockRefTableReader(reader);
+       FileClose(wsio.file);
+   }
+
+   /* Switch back to previous memory context. */
+   MemoryContextSwitchTo(oldcontext);
+}
+
+/*
+ * Get the pathname that should be used when a file is sent incrementally.
+ *
+ * The result is a palloc'd string.
+ */
+char *
+GetIncrementalFilePath(Oid dboid, Oid spcoid, RelFileNumber relfilenumber,
+                      ForkNumber forknum, unsigned segno)
+{
+   char       *path;
+   char       *lastslash;
+   char       *ipath;
+
+   path = GetRelationPath(dboid, spcoid, relfilenumber, InvalidBackendId,
+                          forknum);
+
+   lastslash = strrchr(path, '/');
+   Assert(lastslash != NULL);
+   *lastslash = '\0';
+
+   if (segno > 0)
+       ipath = psprintf("%s/INCREMENTAL.%s.%u", path, lastslash + 1, segno);
+   else
+       ipath = psprintf("%s/INCREMENTAL.%s", path, lastslash + 1);
+
+   pfree(path);
+
+   return ipath;
+}
+
+/*
+ * How should we back up a particular file as part of an incremental backup?
+ *
+ * If the return value is BACK_UP_FILE_FULLY, caller should back up the whole
+ * file just as if this were not an incremental backup.
+ *
+ * If the return value is BACK_UP_FILE_INCREMENTALLY, caller should include
+ * an incremental file in the backup instead of the entire file. On return,
+ * *num_blocks_required will be set to the number of blocks that need to be
+ * sent, and the actual block numbers will have been stored in
+ * relative_block_numbers, which should be an array of at least RELSEG_SIZE.
+ * In addition, *truncation_block_length will be set to the value that should
+ * be included in the incremental file.
+ */
+FileBackupMethod
+GetFileBackupMethod(IncrementalBackupInfo *ib, const char *path,
+                   Oid dboid, Oid spcoid,
+                   RelFileNumber relfilenumber, ForkNumber forknum,
+                   unsigned segno, size_t size,
+                   unsigned *num_blocks_required,
+                   BlockNumber *relative_block_numbers,
+                   unsigned *truncation_block_length)
+{
+   BlockNumber absolute_block_numbers[RELSEG_SIZE];
+   BlockNumber limit_block;
+   BlockNumber start_blkno;
+   BlockNumber stop_blkno;
+   RelFileLocator rlocator;
+   BlockRefTableEntry *brtentry;
+   unsigned    i;
+   unsigned    nblocks;
+
+   /* Should only be called after PrepareForIncrementalBackup. */
+   Assert(ib->buf.data == NULL);
+
+   /*
+    * dboid could be InvalidOid if shared rel, but spcoid and relfilenumber
+    * should have legal values.
+    */
+   Assert(OidIsValid(spcoid));
+   Assert(RelFileNumberIsValid(relfilenumber));
+
+   /*
+    * If the file size is too large or not a multiple of BLCKSZ, then
+    * something weird is happening, so give up and send the whole file.
+    */
+   if ((size % BLCKSZ) != 0 || size / BLCKSZ > RELSEG_SIZE)
+       return BACK_UP_FILE_FULLY;
+
+   /*
+    * The free-space map fork is not properly WAL-logged, so we need to
+    * backup the entire file every time.
+    */
+   if (forknum == FSM_FORKNUM)
+       return BACK_UP_FILE_FULLY;
+
+   /*
+    * If this file was not part of the prior backup, back it up fully.
+    *
+    * If this file was created after the prior backup and before the start of
+    * the current backup, then the WAL summary information will tell us to
+    * back up the whole file. However, if this file was created after the
+    * start of the current backup, then the WAL summary won't know anything
+    * about it. Without this logic, we would erroneously conclude that it was
+    * OK to send it incrementally.
+    *
+    * Note that the file could have existed at the time of the prior backup,
+    * gotten deleted, and then a new file with the same name could have been
+    * created.  In that case, this logic won't prevent the file from being
+    * backed up incrementally. But, if the deletion happened before the start
+    * of the current backup, the limit block will be 0, inducing a full
+    * backup. If the deletion happened after the start of the current backup,
+    * reconstruction will erroneously combine blocks from the current
+    * lifespan of the file with blocks from the previous lifespan -- but in
+    * this type of case, WAL replay to reach backup consistency should remove
+    * and recreate the file anyway, so the initial bogus contents should not
+    * matter.
+    */
+   if (backup_file_lookup(ib->manifest_files, path) == NULL)
+   {
+       char       *ipath;
+
+       ipath = GetIncrementalFilePath(dboid, spcoid, relfilenumber,
+                                      forknum, segno);
+       if (backup_file_lookup(ib->manifest_files, ipath) == NULL)
+           return BACK_UP_FILE_FULLY;
+   }
+
+   /* Look up the block reference table entry. */
+   rlocator.spcOid = spcoid;
+   rlocator.dbOid = dboid;
+   rlocator.relNumber = relfilenumber;
+   brtentry = BlockRefTableGetEntry(ib->brtab, &rlocator, forknum,
+                                    &limit_block);
+
+   /*
+    * If there is no entry, then there have been no WAL-logged changes to the
+    * relation since the predecessor backup was taken, so we can back it up
+    * incrementally and need not include any modified blocks.
+    *
+    * However, if the file is zero-length, we should do a full backup,
+    * because an incremental file is always more than zero length, and it's
+    * silly to take an incremental backup when a full backup would be
+    * smaller.
+    */
+   if (brtentry == NULL)
+   {
+       if (size == 0)
+           return BACK_UP_FILE_FULLY;
+       *num_blocks_required = 0;
+       *truncation_block_length = size / BLCKSZ;
+       return BACK_UP_FILE_INCREMENTALLY;
+   }
+
+   /*
+    * If the limit_block is less than or equal to the point where this
+    * segment starts, send the whole file.
+    */
+   if (limit_block <= segno * RELSEG_SIZE)
+       return BACK_UP_FILE_FULLY;
+
+   /*
+    * Get relevant entries from the block reference table entry.
+    *
+    * We shouldn't overflow computing the start or stop block numbers, but if
+    * it manages to happen somehow, detect it and throw an error.
+    */
+   start_blkno = segno * RELSEG_SIZE;
+   stop_blkno = start_blkno + (size / BLCKSZ);
+   if (start_blkno / RELSEG_SIZE != segno || stop_blkno < start_blkno)
+       ereport(ERROR,
+               errcode(ERRCODE_INTERNAL_ERROR),
+               errmsg_internal("overflow computing block number bounds for segment %u with size %zu",
+                               segno, size));
+   nblocks = BlockRefTableEntryGetBlocks(brtentry, start_blkno, stop_blkno,
+                                         absolute_block_numbers, RELSEG_SIZE);
+   Assert(nblocks <= RELSEG_SIZE);
+
+   /*
+    * If we're going to have to send nearly all of the blocks, then just send
+    * the whole file, because that won't require much extra storage or
+    * transfer and will speed up and simplify backup restoration. It's not
+    * clear what threshold is most appropriate here and perhaps it ought to
+    * be configurable, but for now we're just going to say that if we'd need
+    * to send 90% of the blocks anyway, give up and send the whole file.
+    *
+    * NB: If you change the threshold here, at least make sure to back up the
+    * file fully when every single block must be sent, because there's
+    * nothing good about sending an incremental file in that case.
+    */
+   if (nblocks * BLCKSZ > size * 0.9)
+       return BACK_UP_FILE_FULLY;
+
+   /*
+    * Looks like we can send an incremental file, so sort the absolute the
+    * block numbers and then transpose absolute block numbers to relative
+    * block numbers.
+    *
+    * NB: If the block reference table was using the bitmap representation
+    * for a given chunk, the block numbers in that chunk will already be
+    * sorted, but when the array-of-offsets representation is used, we can
+    * receive block numbers here out of order.
+    */
+   qsort(absolute_block_numbers, nblocks, sizeof(BlockNumber),
+         compare_block_numbers);
+   for (i = 0; i < nblocks; ++i)
+       relative_block_numbers[i] = absolute_block_numbers[i] - start_blkno;
+   *num_blocks_required = nblocks;
+
+   /*
+    * The truncation block length is the minimum length of the reconstructed
+    * file. Any block numbers below this threshold that are not present in
+    * the backup need to be fetched from the prior backup. At or above this
+    * threshold, blocks should only be included in the result if they are
+    * present in the backup. (This may require inserting zero blocks if the
+    * blocks included in the backup are non-consecutive.)
+    */
+   *truncation_block_length = size / BLCKSZ;
+   if (BlockNumberIsValid(limit_block))
+   {
+       unsigned    relative_limit = limit_block - segno * RELSEG_SIZE;
+
+       if (*truncation_block_length < relative_limit)
+           *truncation_block_length = relative_limit;
+   }
+
+   /* Send it incrementally. */
+   return BACK_UP_FILE_INCREMENTALLY;
+}
+
+/*
+ * Compute the size for an incremental file containing a given number of blocks.
+ */
+extern size_t
+GetIncrementalFileSize(unsigned num_blocks_required)
+{
+   size_t      result;
+
+   /* Make sure we're not going to overflow. */
+   Assert(num_blocks_required <= RELSEG_SIZE);
+
+   /*
+    * Three four byte quantities (magic number, truncation block length,
+    * block count) followed by block numbers followed by block contents.
+    */
+   result = 3 * sizeof(uint32);
+   result += (BLCKSZ + sizeof(BlockNumber)) * num_blocks_required;
+
+   return result;
+}
+
+/*
+ * Helper function for filemap hash table.
+ */
+static uint32
+hash_string_pointer(const char *s)
+{
+   unsigned char *ss = (unsigned char *) s;
+
+   return hash_bytes(ss, strlen(s));
+}
+
+/*
+ * This callback is invoked for each file mentioned in the backup manifest.
+ *
+ * We store the path to each file and the size of each file for sanity-checking
+ * purposes. For further details, see comments for IncrementalBackupInfo.
+ */
+static void
+manifest_process_file(JsonManifestParseContext *context,
+                     char *pathname, size_t size,
+                     pg_checksum_type checksum_type,
+                     int checksum_length,
+                     uint8 *checksum_payload)
+{
+   IncrementalBackupInfo *ib = context->private_data;
+   backup_file_entry *entry;
+   bool        found;
+
+   entry = backup_file_insert(ib->manifest_files, pathname, &found);
+   if (!found)
+   {
+       entry->path = MemoryContextStrdup(ib->manifest_files->ctx,
+                                         pathname);
+       entry->size = size;
+   }
+}
+
+/*
+ * This callback is invoked for each WAL range mentioned in the backup
+ * manifest.
+ *
+ * We're just interested in learning the oldest LSN and the corresponding TLI
+ * that appear in any WAL range.
+ */
+static void
+manifest_process_wal_range(JsonManifestParseContext *context,
+                          TimeLineID tli, XLogRecPtr start_lsn,
+                          XLogRecPtr end_lsn)
+{
+   IncrementalBackupInfo *ib = context->private_data;
+   backup_wal_range *range = palloc(sizeof(backup_wal_range));
+
+   range->tli = tli;
+   range->start_lsn = start_lsn;
+   range->end_lsn = end_lsn;
+   ib->manifest_wal_ranges = lappend(ib->manifest_wal_ranges, range);
+}
+
+/*
+ * This callback is invoked if an error occurs while parsing the backup
+ * manifest.
+ */
+static void
+manifest_report_error(JsonManifestParseContext *context, const char *fmt,...)
+{
+   StringInfoData errbuf;
+
+   initStringInfo(&errbuf);
+
+   for (;;)
+   {
+       va_list     ap;
+       int         needed;
+
+       va_start(ap, fmt);
+       needed = appendStringInfoVA(&errbuf, fmt, ap);
+       va_end(ap);
+       if (needed == 0)
+           break;
+       enlargeStringInfo(&errbuf, needed);
+   }
+
+   ereport(ERROR,
+           errmsg_internal("%s", errbuf.data));
+}
+
+/*
+ * Quicksort comparator for block numbers.
+ */
+static int
+compare_block_numbers(const void *a, const void *b)
+{
+   BlockNumber aa = *(BlockNumber *) a;
+   BlockNumber bb = *(BlockNumber *) b;
+
+   if (aa > bb)
+       return 1;
+   else if (aa == bb)
+       return 0;
+   else
+       return -1;
+}
index 5d4ebe3ebeddd897641c5de50b0af30c5f517627..2a6a2dc7c0e8db553dd4dff8ed86f75e766b83a3 100644 (file)
@@ -5,6 +5,7 @@ backend_sources += files(
   'basebackup.c',
   'basebackup_copy.c',
   'basebackup_gzip.c',
+  'basebackup_incremental.c',
   'basebackup_lz4.c',
   'basebackup_progress.c',
   'basebackup_server.c',
index 0c874e33cf6ab00fef55ade3b3750cd13166fe8f..a5d118ed683aa267bfa2562c61e46744b26c091e 100644 (file)
@@ -76,11 +76,12 @@ Node *replication_parse_result;
 %token K_EXPORT_SNAPSHOT
 %token K_NOEXPORT_SNAPSHOT
 %token K_USE_SNAPSHOT
+%token K_UPLOAD_MANIFEST
 
 %type <node>   command
 %type <node>   base_backup start_replication start_logical_replication
                create_replication_slot drop_replication_slot identify_system
-               read_replication_slot timeline_history show
+               read_replication_slot timeline_history show upload_manifest
 %type <list>   generic_option_list
 %type <defelt> generic_option
 %type <uintval>    opt_timeline
@@ -114,6 +115,7 @@ command:
            | read_replication_slot
            | timeline_history
            | show
+           | upload_manifest
            ;
 
 /*
@@ -307,6 +309,15 @@ timeline_history:
                }
            ;
 
+/* UPLOAD_MANIFEST doesn't currently accept any arguments */
+upload_manifest:
+           K_UPLOAD_MANIFEST
+               {
+                   UploadManifestCmd *cmd = makeNode(UploadManifestCmd);
+
+                   $$ = (Node *) cmd;
+               }
+
 opt_physical:
            K_PHYSICAL
            | /* EMPTY */
@@ -411,6 +422,7 @@ ident_or_keyword:
            | K_EXPORT_SNAPSHOT             { $$ = "export_snapshot"; }
            | K_NOEXPORT_SNAPSHOT           { $$ = "noexport_snapshot"; }
            | K_USE_SNAPSHOT                { $$ = "use_snapshot"; }
+           | K_UPLOAD_MANIFEST             { $$ = "upload_manifest"; }
        ;
 
 %%
index 1cc7fb858cd581acf018214fbdfacf568faee285..4805da08ee3dfabd025d43e4d48b276d045eed5b 100644 (file)
@@ -136,6 +136,7 @@ EXPORT_SNAPSHOT     { return K_EXPORT_SNAPSHOT; }
 NOEXPORT_SNAPSHOT  { return K_NOEXPORT_SNAPSHOT; }
 USE_SNAPSHOT       { return K_USE_SNAPSHOT; }
 WAIT               { return K_WAIT; }
+UPLOAD_MANIFEST        { return K_UPLOAD_MANIFEST; }
 
 {space}+       { /* do nothing */ }
 
@@ -303,6 +304,7 @@ replication_scanner_is_replication_command(void)
        case K_DROP_REPLICATION_SLOT:
        case K_READ_REPLICATION_SLOT:
        case K_TIMELINE_HISTORY:
+       case K_UPLOAD_MANIFEST:
        case K_SHOW:
            /* Yes; push back the first token so we can parse later. */
            repl_pushed_back_token = first_token;
index 3bc9c823895e12aacb628a550a287e0de22e8fcd..dbcda325540dc7131099fda640b2af2b52f9db57 100644 (file)
@@ -58,6 +58,7 @@
 #include "access/xlogrecovery.h"
 #include "access/xlogutils.h"
 #include "backup/basebackup.h"
+#include "backup/basebackup_incremental.h"
 #include "catalog/pg_authid.h"
 #include "catalog/pg_type.h"
 #include "commands/dbcommands.h"
@@ -137,6 +138,17 @@ bool       wake_wal_senders = false;
  */
 static XLogReaderState *xlogreader = NULL;
 
+/*
+ * If the UPLOAD_MANIFEST command is used to provide a backup manifest in
+ * preparation for an incremental backup, uploaded_manifest will be point
+ * to an object containing information about its contexts, and
+ * uploaded_manifest_mcxt will point to the memory context that contains
+ * that object and all of its subordinate data. Otherwise, both values will
+ * be NULL.
+ */
+static IncrementalBackupInfo *uploaded_manifest = NULL;
+static MemoryContext uploaded_manifest_mcxt = NULL;
+
 /*
  * These variables keep track of the state of the timeline we're currently
  * sending. sendTimeLine identifies the timeline. If sendTimeLineIsHistoric,
@@ -233,6 +245,9 @@ static void XLogSendLogical(void);
 static void WalSndDone(WalSndSendDataCallback send_data);
 static XLogRecPtr GetStandbyFlushRecPtr(TimeLineID *tli);
 static void IdentifySystem(void);
+static void UploadManifest(void);
+static bool HandleUploadManifestPacket(StringInfo buf, off_t *offset,
+                                      IncrementalBackupInfo *ib);
 static void ReadReplicationSlot(ReadReplicationSlotCmd *cmd);
 static void CreateReplicationSlot(CreateReplicationSlotCmd *cmd);
 static void DropReplicationSlot(DropReplicationSlotCmd *cmd);
@@ -660,6 +675,143 @@ SendTimeLineHistory(TimeLineHistoryCmd *cmd)
    pq_endmessage(&buf);
 }
 
+/*
+ * Handle UPLOAD_MANIFEST command.
+ */
+static void
+UploadManifest(void)
+{
+   MemoryContext mcxt;
+   IncrementalBackupInfo *ib;
+   off_t       offset = 0;
+   StringInfoData buf;
+
+   /*
+    * parsing the manifest will use the cryptohash stuff, which requires a
+    * resource owner
+    */
+   Assert(CurrentResourceOwner == NULL);
+   CurrentResourceOwner = ResourceOwnerCreate(NULL, "base backup");
+
+   /* Prepare to read manifest data into a temporary context. */
+   mcxt = AllocSetContextCreate(CurrentMemoryContext,
+                                "incremental backup information",
+                                ALLOCSET_DEFAULT_SIZES);
+   ib = CreateIncrementalBackupInfo(mcxt);
+
+   /* Send a CopyInResponse message */
+   pq_beginmessage(&buf, 'G');
+   pq_sendbyte(&buf, 0);
+   pq_sendint16(&buf, 0);
+   pq_endmessage_reuse(&buf);
+   pq_flush();
+
+   /* Recieve packets from client until done. */
+   while (HandleUploadManifestPacket(&buf, &offset, ib))
+       ;
+
+   /* Finish up manifest processing. */
+   FinalizeIncrementalManifest(ib);
+
+   /*
+    * Discard any old manifest information and arrange to preserve the new
+    * information we just got.
+    *
+    * We assume that MemoryContextDelete and MemoryContextSetParent won't
+    * fail, and thus we shouldn't end up bailing out of here in such a way as
+    * to leave dangling pointrs.
+    */
+   if (uploaded_manifest_mcxt != NULL)
+       MemoryContextDelete(uploaded_manifest_mcxt);
+   MemoryContextSetParent(mcxt, CacheMemoryContext);
+   uploaded_manifest = ib;
+   uploaded_manifest_mcxt = mcxt;
+
+   /* clean up the resource owner we created */
+   WalSndResourceCleanup(true);
+}
+
+/*
+ * Process one packet received during the handling of an UPLOAD_MANIFEST
+ * operation.
+ *
+ * 'buf' is scratch space. This function expects it to be initialized, doesn't
+ * care what the current contents are, and may override them with completely
+ * new contents.
+ *
+ * The return value is true if the caller should continue processing
+ * additional packets and false if the UPLOAD_MANIFEST operation is complete.
+ */
+static bool
+HandleUploadManifestPacket(StringInfo buf, off_t *offset,
+                          IncrementalBackupInfo *ib)
+{
+   int         mtype;
+   int         maxmsglen;
+
+   HOLD_CANCEL_INTERRUPTS();
+
+   pq_startmsgread();
+   mtype = pq_getbyte();
+   if (mtype == EOF)
+       ereport(ERROR,
+               (errcode(ERRCODE_CONNECTION_FAILURE),
+                errmsg("unexpected EOF on client connection with an open transaction")));
+
+   switch (mtype)
+   {
+       case 'd':               /* CopyData */
+           maxmsglen = PQ_LARGE_MESSAGE_LIMIT;
+           break;
+       case 'c':               /* CopyDone */
+       case 'f':               /* CopyFail */
+       case 'H':               /* Flush */
+       case 'S':               /* Sync */
+           maxmsglen = PQ_SMALL_MESSAGE_LIMIT;
+           break;
+       default:
+           ereport(ERROR,
+                   (errcode(ERRCODE_PROTOCOL_VIOLATION),
+                    errmsg("unexpected message type 0x%02X during COPY from stdin",
+                           mtype)));
+           maxmsglen = 0;      /* keep compiler quiet */
+           break;
+   }
+
+   /* Now collect the message body */
+   if (pq_getmessage(buf, maxmsglen))
+       ereport(ERROR,
+               (errcode(ERRCODE_CONNECTION_FAILURE),
+                errmsg("unexpected EOF on client connection with an open transaction")));
+   RESUME_CANCEL_INTERRUPTS();
+
+   /* Process the message */
+   switch (mtype)
+   {
+       case 'd':               /* CopyData */
+           AppendIncrementalManifestData(ib, buf->data, buf->len);
+           return true;
+
+       case 'c':               /* CopyDone */
+           return false;
+
+       case 'H':               /* Sync */
+       case 'S':               /* Flush */
+           /* Ignore these while in CopyOut mode as we do elsewhere. */
+           return true;
+
+       case 'f':
+           ereport(ERROR,
+                   (errcode(ERRCODE_QUERY_CANCELED),
+                    errmsg("COPY from stdin failed: %s",
+                           pq_getmsgstring(buf))));
+   }
+
+   /* Not reached. */
+   Assert(false);
+   return false;
+}
+
 /*
  * Handle START_REPLICATION command.
  *
@@ -1801,7 +1953,7 @@ exec_replication_command(const char *cmd_string)
            cmdtag = "BASE_BACKUP";
            set_ps_display(cmdtag);
            PreventInTransactionBlock(true, cmdtag);
-           SendBaseBackup((BaseBackupCmd *) cmd_node);
+           SendBaseBackup((BaseBackupCmd *) cmd_node, uploaded_manifest);
            EndReplicationCommand(cmdtag);
            break;
 
@@ -1863,6 +2015,14 @@ exec_replication_command(const char *cmd_string)
            }
            break;
 
+       case T_UploadManifestCmd:
+           cmdtag = "UPLOAD_MANIFEST";
+           set_ps_display(cmdtag);
+           PreventInTransactionBlock(true, cmdtag);
+           UploadManifest();
+           EndReplicationCommand(cmdtag);
+           break;
+
        default:
            elog(ERROR, "unrecognized replication command node tag: %u",
                 cmd_node->type);
index 0e0ac22bdd675bbc8514cb025383145529876a5c..706140eb9f4864a4c4ecf74016124a3eb674b253 100644 (file)
@@ -32,6 +32,7 @@
 #include "postmaster/bgworker_internals.h"
 #include "postmaster/bgwriter.h"
 #include "postmaster/postmaster.h"
+#include "postmaster/walsummarizer.h"
 #include "replication/logicallauncher.h"
 #include "replication/origin.h"
 #include "replication/slot.h"
@@ -140,6 +141,7 @@ CalculateShmemSize(int *num_semaphores)
    size = add_size(size, ReplicationOriginShmemSize());
    size = add_size(size, WalSndShmemSize());
    size = add_size(size, WalRcvShmemSize());
+   size = add_size(size, WalSummarizerShmemSize());
    size = add_size(size, PgArchShmemSize());
    size = add_size(size, ApplyLauncherShmemSize());
    size = add_size(size, BTreeShmemSize());
@@ -337,6 +339,7 @@ CreateOrAttachShmemStructs(void)
    ReplicationOriginShmemInit();
    WalSndShmemInit();
    WalRcvShmemInit();
+   WalSummarizerShmemInit();
    PgArchShmemInit();
    ApplyLauncherShmemInit();
 
index 373077bf52b2e5d34f8a72a5d87939bc70333444..aa2210925e28f589bf1e9e9cfa322448ba6041a3 100644 (file)
@@ -19,6 +19,7 @@ SUBDIRS = \
    pg_archivecleanup \
    pg_basebackup \
    pg_checksums \
+   pg_combinebackup \
    pg_config \
    pg_controldata \
    pg_ctl \
index 67cb50630c5a31383104d63ce23f4e7437c98778..4cb6fd59bb876cdd03440ca560b9482b1a4b3731 100644 (file)
@@ -5,6 +5,7 @@ subdir('pg_amcheck')
 subdir('pg_archivecleanup')
 subdir('pg_basebackup')
 subdir('pg_checksums')
+subdir('pg_combinebackup')
 subdir('pg_config')
 subdir('pg_controldata')
 subdir('pg_ctl')
index 45f32974ff6e3ee171f951375c2c20e5aa13eceb..6b78ee283d97d3d7bec8d4eaf14452ff7f004d66 100644 (file)
@@ -296,6 +296,7 @@ should_allow_existing_directory(const char *pathname)
    if (strcmp(filename, "pg_wal") == 0 ||
        strcmp(filename, "pg_xlog") == 0 ||
        strcmp(filename, "archive_status") == 0 ||
+       strcmp(filename, "summaries") == 0 ||
        strcmp(filename, "pg_tblspc") == 0)
        return true;
 
index f32684a8f233810b3b9a0f2084828ec973618736..5795b91261fce53d792a537bde0a20a62749bd50 100644 (file)
@@ -101,6 +101,11 @@ typedef void (*WriteDataCallback) (size_t nbytes, char *buf,
  */
 #define MINIMUM_VERSION_FOR_TERMINATED_TARFILE 150000
 
+/*
+ * pg_wal/summaries exists beginning with version 17.
+ */
+#define MINIMUM_VERSION_FOR_WAL_SUMMARIES 170000
+
 /*
  * Different ways to include WAL
  */
@@ -217,7 +222,8 @@ static void ReceiveBackupManifestInMemoryChunk(size_t r, char *copybuf,
                                               void *callback_data);
 static void BaseBackup(char *compression_algorithm, char *compression_detail,
                       CompressionLocation compressloc,
-                      pg_compress_specification *client_compress);
+                      pg_compress_specification *client_compress,
+                      char *incremental_manifest);
 
 static bool reached_end_position(XLogRecPtr segendpos, uint32 timeline,
                                 bool segment_finished);
@@ -390,6 +396,8 @@ usage(void)
    printf(_("\nOptions controlling the output:\n"));
    printf(_("  -D, --pgdata=DIRECTORY receive base backup into directory\n"));
    printf(_("  -F, --format=p|t       output format (plain (default), tar)\n"));
+   printf(_("  -i, --incremental=OLDMANIFEST\n"));
+   printf(_("                         take incremental backup\n"));
    printf(_("  -r, --max-rate=RATE    maximum transfer rate to transfer data directory\n"
             "                         (in kB/s, or use suffix \"k\" or \"M\")\n"));
    printf(_("  -R, --write-recovery-conf\n"
@@ -688,6 +696,23 @@ StartLogStreamer(char *startpos, uint32 timeline, char *sysidentifier,
 
        if (pg_mkdir_p(statusdir, pg_dir_create_mode) != 0 && errno != EEXIST)
            pg_fatal("could not create directory \"%s\": %m", statusdir);
+
+       /*
+        * For newer server versions, likewise create pg_wal/summaries
+        */
+       if (PQserverVersion(conn) < MINIMUM_VERSION_FOR_WAL_SUMMARIES)
+       {
+           char        summarydir[MAXPGPATH];
+
+           snprintf(summarydir, sizeof(summarydir), "%s/%s/summaries",
+                    basedir,
+                    PQserverVersion(conn) < MINIMUM_VERSION_FOR_PG_WAL ?
+                    "pg_xlog" : "pg_wal");
+
+           if (pg_mkdir_p(statusdir, pg_dir_create_mode) != 0 &&
+               errno != EEXIST)
+               pg_fatal("could not create directory \"%s\": %m", summarydir);
+       }
    }
 
    /*
@@ -1728,7 +1753,9 @@ ReceiveBackupManifestInMemoryChunk(size_t r, char *copybuf,
 
 static void
 BaseBackup(char *compression_algorithm, char *compression_detail,
-          CompressionLocation compressloc, pg_compress_specification *client_compress)
+          CompressionLocation compressloc,
+          pg_compress_specification *client_compress,
+          char *incremental_manifest)
 {
    PGresult   *res;
    char       *sysidentifier;
@@ -1794,7 +1821,76 @@ BaseBackup(char *compression_algorithm, char *compression_detail,
        exit(1);
 
    /*
-    * Start the actual backup
+    * If the user wants an incremental backup, we must upload the manifest
+    * for the previous backup upon which it is to be based.
+    */
+   if (incremental_manifest != NULL)
+   {
+       int         fd;
+       char        mbuf[65536];
+       int         nbytes;
+
+       /* Reject if server is too old. */
+       if (serverVersion < MINIMUM_VERSION_FOR_WAL_SUMMARIES)
+           pg_fatal("server does not support incremental backup");
+
+       /* Open the file. */
+       fd = open(incremental_manifest, O_RDONLY | PG_BINARY, 0);
+       if (fd < 0)
+           pg_fatal("could not open file \"%s\": %m", incremental_manifest);
+
+       /* Tell the server what we want to do. */
+       if (PQsendQuery(conn, "UPLOAD_MANIFEST") == 0)
+           pg_fatal("could not send replication command \"%s\": %s",
+                    "UPLOAD_MANIFEST", PQerrorMessage(conn));
+       res = PQgetResult(conn);
+       if (PQresultStatus(res) != PGRES_COPY_IN)
+       {
+           if (PQresultStatus(res) == PGRES_FATAL_ERROR)
+               pg_fatal("could not upload manifest: %s",
+                        PQerrorMessage(conn));
+           else
+               pg_fatal("could not upload manifest: unexpected status %s",
+                        PQresStatus(PQresultStatus(res)));
+       }
+
+       /* Loop, reading from the file and sending the data to the server. */
+       while ((nbytes = read(fd, mbuf, sizeof mbuf)) > 0)
+       {
+           if (PQputCopyData(conn, mbuf, nbytes) < 0)
+               pg_fatal("could not send COPY data: %s",
+                        PQerrorMessage(conn));
+       }
+
+       /* Bail out if we exited the loop due to an error. */
+       if (nbytes < 0)
+           pg_fatal("could not read file \"%s\": %m", incremental_manifest);
+
+       /* End the COPY operation. */
+       if (PQputCopyEnd(conn, NULL) < 0)
+           pg_fatal("could not send end-of-COPY: %s",
+                    PQerrorMessage(conn));
+
+       /* See whether the server is happy with what we sent. */
+       res = PQgetResult(conn);
+       if (PQresultStatus(res) == PGRES_FATAL_ERROR)
+           pg_fatal("could not upload manifest: %s",
+                    PQerrorMessage(conn));
+       else if (PQresultStatus(res) != PGRES_COMMAND_OK)
+           pg_fatal("could not upload manifest: unexpected status %s",
+                    PQresStatus(PQresultStatus(res)));
+
+       /* Consume ReadyForQuery message from server. */
+       res = PQgetResult(conn);
+       if (res != NULL)
+           pg_fatal("unexpected extra result while sending manifest");
+
+       /* Add INCREMENTAL option to BASE_BACKUP command. */
+       AppendPlainCommandOption(&buf, use_new_option_syntax, "INCREMENTAL");
+   }
+
+   /*
+    * Continue building up the options list for the BASE_BACKUP command.
     */
    AppendStringCommandOption(&buf, use_new_option_syntax, "LABEL", label);
    if (estimatesize)
@@ -1901,6 +1997,7 @@ BaseBackup(char *compression_algorithm, char *compression_detail,
    else
        basebkp = psprintf("BASE_BACKUP %s", buf.data);
 
+   /* OK, try to start the backup. */
    if (PQsendQuery(conn, basebkp) == 0)
        pg_fatal("could not send replication command \"%s\": %s",
                 "BASE_BACKUP", PQerrorMessage(conn));
@@ -2256,6 +2353,7 @@ main(int argc, char **argv)
        {"version", no_argument, NULL, 'V'},
        {"pgdata", required_argument, NULL, 'D'},
        {"format", required_argument, NULL, 'F'},
+       {"incremental", required_argument, NULL, 'i'},
        {"checkpoint", required_argument, NULL, 'c'},
        {"create-slot", no_argument, NULL, 'C'},
        {"max-rate", required_argument, NULL, 'r'},
@@ -2293,6 +2391,7 @@ main(int argc, char **argv)
    int         option_index;
    char       *compression_algorithm = "none";
    char       *compression_detail = NULL;
+   char       *incremental_manifest = NULL;
    CompressionLocation compressloc = COMPRESS_LOCATION_UNSPECIFIED;
    pg_compress_specification client_compress;
 
@@ -2317,7 +2416,7 @@ main(int argc, char **argv)
 
    atexit(cleanup_directories_atexit);
 
-   while ((c = getopt_long(argc, argv, "c:Cd:D:F:h:l:nNp:Pr:Rs:S:t:T:U:vwWX:zZ:",
+   while ((c = getopt_long(argc, argv, "c:Cd:D:F:h:i:l:nNp:Pr:Rs:S:t:T:U:vwWX:zZ:",
                            long_options, &option_index)) != -1)
    {
        switch (c)
@@ -2352,6 +2451,9 @@ main(int argc, char **argv)
            case 'h':
                dbhost = pg_strdup(optarg);
                break;
+           case 'i':
+               incremental_manifest = pg_strdup(optarg);
+               break;
            case 'l':
                label = pg_strdup(optarg);
                break;
@@ -2765,7 +2867,7 @@ main(int argc, char **argv)
    }
 
    BaseBackup(compression_algorithm, compression_detail, compressloc,
-              &client_compress);
+              &client_compress, incremental_manifest);
 
    success = true;
    return 0;
index b9f5e1266b424ec487d6ce968d45f978e3d15739..bf765291e7d5a26126146b79a1afc2705a9347ca 100644 (file)
@@ -223,10 +223,10 @@ SKIP:
        "check backup dir permissions");
 }
 
-# Only archive_status directory should be copied in pg_wal/.
+# Only archive_status and summaries directories should be copied in pg_wal/.
 is_deeply(
    [ sort(slurp_dir("$tempdir/backup/pg_wal/")) ],
-   [ sort qw(. .. archive_status) ],
+   [ sort qw(. .. archive_status summaries) ],
    'no WAL files copied');
 
 # Contents of these directories should not be copied.
diff --git a/src/bin/pg_combinebackup/.gitignore b/src/bin/pg_combinebackup/.gitignore
new file mode 100644 (file)
index 0000000..d7e6174
--- /dev/null
@@ -0,0 +1 @@
+pg_combinebackup
diff --git a/src/bin/pg_combinebackup/Makefile b/src/bin/pg_combinebackup/Makefile
new file mode 100644 (file)
index 0000000..78ba05e
--- /dev/null
@@ -0,0 +1,52 @@
+#-------------------------------------------------------------------------
+#
+# Makefile for src/bin/pg_combinebackup
+#
+# Portions Copyright (c) 1996-2023, PostgreSQL Global Development Group
+# Portions Copyright (c) 1994, Regents of the University of California
+#
+# src/bin/pg_combinebackup/Makefile
+#
+#-------------------------------------------------------------------------
+
+PGFILEDESC = "pg_combinebackup - combine incremental backups"
+PGAPPICON=win32
+
+subdir = src/bin/pg_combinebackup
+top_builddir = ../../..
+include $(top_builddir)/src/Makefile.global
+
+override CPPFLAGS := -I$(libpq_srcdir) $(CPPFLAGS)
+LDFLAGS_INTERNAL += -L$(top_builddir)/src/fe_utils -lpgfeutils
+
+OBJS = \
+   $(WIN32RES) \
+   pg_combinebackup.o \
+   backup_label.o \
+   copy_file.o \
+   load_manifest.o \
+   reconstruct.o \
+   write_manifest.o
+
+all: pg_combinebackup
+
+pg_combinebackup: $(OBJS) | submake-libpgport submake-libpgfeutils
+   $(CC) $(CFLAGS) $^ $(LDFLAGS) $(LDFLAGS_EX) $(LIBS) -o $@$(X)
+
+install: all installdirs
+   $(INSTALL_PROGRAM) pg_combinebackup$(X) '$(DESTDIR)$(bindir)/pg_combinebackup$(X)'
+
+installdirs:
+   $(MKDIR_P) '$(DESTDIR)$(bindir)'
+
+uninstall:
+   rm -f '$(DESTDIR)$(bindir)/pg_combinebackup$(X)'
+
+clean distclean maintainer-clean:
+   rm -f pg_combinebackup$(X) $(OBJS)
+
+check:
+   $(prove_check)
+
+installcheck:
+   $(prove_installcheck)
diff --git a/src/bin/pg_combinebackup/backup_label.c b/src/bin/pg_combinebackup/backup_label.c
new file mode 100644 (file)
index 0000000..922e008
--- /dev/null
@@ -0,0 +1,283 @@
+/*-------------------------------------------------------------------------
+ *
+ * Read and manipulate backup label files
+ *
+ * Portions Copyright (c) 1996-2023, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ * src/bin/pg_combinebackup/backup_label.c
+ *
+ *-------------------------------------------------------------------------
+ */
+#include "postgres_fe.h"
+
+#include <unistd.h>
+
+#include "access/xlogdefs.h"
+#include "backup_label.h"
+#include "common/logging.h"
+#include "common/file_perm.h"
+#include "write_manifest.h"
+
+static int get_eol_offset(StringInfo buf);
+static bool line_starts_with(char *s, char *e, char *match, char **sout);
+static bool parse_lsn(char *s, char *e, XLogRecPtr *lsn, char **c);
+static bool parse_tli(char *s, char *e, TimeLineID *tli);
+
+/*
+ * Parse a backup label file, starting at buf->cursor.
+ *
+ * We expect to find a START WAL LOCATION line, followed by a LSN, followed
+ * by a space; the resulting LSN is stored into *start_lsn.
+ *
+ * We expect to find a START TIMELINE line, followed by a TLI, followed by
+ * a newline; the resulting TLI is stored into *start_tli.
+ *
+ * We expect to find either both INCREMENTAL FROM LSN and INCREMENTAL FROM TLI
+ * or neither. If these are found, they should be followed by an LSN or TLI
+ * respectively and then by a newline, and the values will be stored into
+ * *previous_lsn and *previous_tli, respectively.
+ *
+ * Other lines in the provided backup_label data are ignored. filename is used
+ * for error reporting; errors are fatal.
+ */
+void
+parse_backup_label(char *filename, StringInfo buf,
+                  TimeLineID *start_tli, XLogRecPtr *start_lsn,
+                  TimeLineID *previous_tli, XLogRecPtr *previous_lsn)
+{
+   int         found = 0;
+
+   *start_tli = 0;
+   *start_lsn = InvalidXLogRecPtr;
+   *previous_tli = 0;
+   *previous_lsn = InvalidXLogRecPtr;
+
+   while (buf->cursor < buf->len)
+   {
+       char       *s = &buf->data[buf->cursor];
+       int         eo = get_eol_offset(buf);
+       char       *e = &buf->data[eo];
+       char       *c;
+
+       if (line_starts_with(s, e, "START WAL LOCATION: ", &s))
+       {
+           if (!parse_lsn(s, e, start_lsn, &c))
+               pg_fatal("%s: could not parse %s",
+                        filename, "START WAL LOCATION");
+           if (c >= e || *c != ' ')
+               pg_fatal("%s: improper terminator for %s",
+                        filename, "START WAL LOCATION");
+           found |= 1;
+       }
+       else if (line_starts_with(s, e, "START TIMELINE: ", &s))
+       {
+           if (!parse_tli(s, e, start_tli))
+               pg_fatal("%s: could not parse TLI for %s",
+                        filename, "START TIMELINE");
+           if (*start_tli == 0)
+               pg_fatal("%s: invalid TLI", filename);
+           found |= 2;
+       }
+       else if (line_starts_with(s, e, "INCREMENTAL FROM LSN: ", &s))
+       {
+           if (!parse_lsn(s, e, previous_lsn, &c))
+               pg_fatal("%s: could not parse %s",
+                        filename, "INCREMENTAL FROM LSN");
+           if (c >= e || *c != '\n')
+               pg_fatal("%s: improper terminator for %s",
+                        filename, "INCREMENTAL FROM LSN");
+           found |= 4;
+       }
+       else if (line_starts_with(s, e, "INCREMENTAL FROM TLI: ", &s))
+       {
+           if (!parse_tli(s, e, previous_tli))
+               pg_fatal("%s: could not parse %s",
+                        filename, "INCREMENTAL FROM TLI");
+           if (*previous_tli == 0)
+               pg_fatal("%s: invalid TLI", filename);
+           found |= 8;
+       }
+
+       buf->cursor = eo;
+   }
+
+   if ((found & 1) == 0)
+       pg_fatal("%s: could not find %s", filename, "START WAL LOCATION");
+   if ((found & 2) == 0)
+       pg_fatal("%s: could not find %s", filename, "START TIMELINE");
+   if ((found & 4) != 0 && (found & 8) == 0)
+       pg_fatal("%s: %s requires %s", filename,
+                "INCREMENTAL FROM LSN", "INCREMENTAL FROM TLI");
+   if ((found & 8) != 0 && (found & 4) == 0)
+       pg_fatal("%s: %s requires %s", filename,
+                "INCREMENTAL FROM TLI", "INCREMENTAL FROM LSN");
+}
+
+/*
+ * Write a backup label file to the output directory.
+ *
+ * This will be identical to the provided backup_label file, except that the
+ * INCREMENTAL FROM LSN and INCREMENTAL FROM TLI lines will be omitted.
+ *
+ * The new file will be checksummed using the specified algorithm. If
+ * mwriter != NULL, it will be added to the manifest.
+ */
+void
+write_backup_label(char *output_directory, StringInfo buf,
+                  pg_checksum_type checksum_type, manifest_writer *mwriter)
+{
+   char        output_filename[MAXPGPATH];
+   int         output_fd;
+   pg_checksum_context checksum_ctx;
+   uint8       checksum_payload[PG_CHECKSUM_MAX_LENGTH];
+   int         checksum_length;
+
+   pg_checksum_init(&checksum_ctx, checksum_type);
+
+   snprintf(output_filename, MAXPGPATH, "%s/backup_label", output_directory);
+
+   if ((output_fd = open(output_filename,
+                         O_WRONLY | O_CREAT | O_EXCL | PG_BINARY,
+                         pg_file_create_mode)) < 0)
+       pg_fatal("could not open file \"%s\": %m", output_filename);
+
+   while (buf->cursor < buf->len)
+   {
+       char       *s = &buf->data[buf->cursor];
+       int         eo = get_eol_offset(buf);
+       char       *e = &buf->data[eo];
+
+       if (!line_starts_with(s, e, "INCREMENTAL FROM LSN: ", NULL) &&
+           !line_starts_with(s, e, "INCREMENTAL FROM TLI: ", NULL))
+       {
+           ssize_t     wb;
+
+           wb = write(output_fd, s, e - s);
+           if (wb != e - s)
+           {
+               if (wb < 0)
+                   pg_fatal("could not write file \"%s\": %m", output_filename);
+               else
+                   pg_fatal("could not write file \"%s\": wrote only %d of %d bytes",
+                            output_filename, (int) wb, (int) (e - s));
+           }
+           if (pg_checksum_update(&checksum_ctx, (uint8 *) s, e - s) < 0)
+               pg_fatal("could not update checksum of file \"%s\"",
+                        output_filename);
+       }
+
+       buf->cursor = eo;
+   }
+
+   if (close(output_fd) != 0)
+       pg_fatal("could not close \"%s\": %m", output_filename);
+
+   checksum_length = pg_checksum_final(&checksum_ctx, checksum_payload);
+
+   if (mwriter != NULL)
+   {
+       struct stat sb;
+
+       /*
+        * We could track the length ourselves, but must stat() to get the
+        * mtime.
+        */
+       if (stat(output_filename, &sb) < 0)
+           pg_fatal("could not stat file \"%s\": %m", output_filename);
+       add_file_to_manifest(mwriter, "backup_label", sb.st_size,
+                            sb.st_mtime, checksum_type,
+                            checksum_length, checksum_payload);
+   }
+}
+
+/*
+ * Return the offset at which the next line in the buffer starts, or there
+ * is none, the offset at which the buffer ends.
+ *
+ * The search begins at buf->cursor.
+ */
+static int
+get_eol_offset(StringInfo buf)
+{
+   int         eo = buf->cursor;
+
+   while (eo < buf->len)
+   {
+       if (buf->data[eo] == '\n')
+           return eo + 1;
+       ++eo;
+   }
+
+   return eo;
+}
+
+/*
+ * Test whether the line that runs from s to e (inclusive of *s, but not
+ * inclusive of *e) starts with the match string provided, and return true
+ * or false according to whether or not this is the case.
+ *
+ * If the function returns true and if *sout != NULL, stores a pointer to the
+ * byte following the match into *sout.
+ */
+static bool
+line_starts_with(char *s, char *e, char *match, char **sout)
+{
+   while (s < e && *match != '\0' && *s == *match)
+       ++s, ++match;
+
+   if (*match == '\0' && sout != NULL)
+       *sout = s;
+
+   return (*match == '\0');
+}
+
+/*
+ * Parse an LSN starting at s and not stopping at or before e. The return value
+ * is true on success and otherwise false. On success, stores the result into
+ * *lsn and sets *c to the first character that is not part of the LSN.
+ */
+static bool
+parse_lsn(char *s, char *e, XLogRecPtr *lsn, char **c)
+{
+   char        save = *e;
+   int         nchars;
+   bool        success;
+   unsigned    hi;
+   unsigned    lo;
+
+   *e = '\0';
+   success = (sscanf(s, "%X/%X%n", &hi, &lo, &nchars) == 2);
+   *e = save;
+
+   if (success)
+   {
+       *lsn = ((XLogRecPtr) hi) << 32 | (XLogRecPtr) lo;
+       *c = s + nchars;
+   }
+
+   return success;
+}
+
+/*
+ * Parse a TLI starting at s and stopping at or before e. The return value is
+ * true on success and otherwise false. On success, stores the result into
+ * *tli. If the first character that is not part of the TLI is anything other
+ * than a newline, that is deemed a failure.
+ */
+static bool
+parse_tli(char *s, char *e, TimeLineID *tli)
+{
+   char        save = *e;
+   int         nchars;
+   bool        success;
+
+   *e = '\0';
+   success = (sscanf(s, "%u%n", tli, &nchars) == 1);
+   *e = save;
+
+   if (success && s[nchars] != '\n')
+       success = false;
+
+   return success;
+}
diff --git a/src/bin/pg_combinebackup/backup_label.h b/src/bin/pg_combinebackup/backup_label.h
new file mode 100644 (file)
index 0000000..3af7ea2
--- /dev/null
@@ -0,0 +1,30 @@
+/*-------------------------------------------------------------------------
+ *
+ * Read and manipulate backup label files
+ *
+ * Portions Copyright (c) 1996-2023, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ * src/bin/pg_combinebackup/backup_label.h
+ *
+ *-------------------------------------------------------------------------
+ */
+#ifndef BACKUP_LABEL_H
+#define BACKUP_LABEL_H
+
+#include "access/xlogdefs.h"
+#include "common/checksum_helper.h"
+#include "lib/stringinfo.h"
+
+struct manifest_writer;
+
+extern void parse_backup_label(char *filename, StringInfo buf,
+                              TimeLineID *start_tli,
+                              XLogRecPtr *start_lsn,
+                              TimeLineID *previous_tli,
+                              XLogRecPtr *previous_lsn);
+extern void write_backup_label(char *output_directory, StringInfo buf,
+                              pg_checksum_type checksum_type,
+                              struct manifest_writer *mwriter);
+
+#endif                         /* BACKUP_LABEL_H */
diff --git a/src/bin/pg_combinebackup/copy_file.c b/src/bin/pg_combinebackup/copy_file.c
new file mode 100644 (file)
index 0000000..40a55e3
--- /dev/null
@@ -0,0 +1,169 @@
+/*
+ * Copy entire files.
+ *
+ * Portions Copyright (c) 1996-2023, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ * src/bin/pg_combinebackup/copy_file.h
+ *
+ *-------------------------------------------------------------------------
+ */
+#include "postgres_fe.h"
+
+#ifdef HAVE_COPYFILE_H
+#include <copyfile.h>
+#endif
+#include <fcntl.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
+#include "common/file_perm.h"
+#include "common/logging.h"
+#include "copy_file.h"
+
+static void copy_file_blocks(const char *src, const char *dst,
+                            pg_checksum_context *checksum_ctx);
+
+#ifdef WIN32
+static void copy_file_copyfile(const char *src, const char *dst);
+#endif
+
+/*
+ * Copy a regular file, optionally computing a checksum, and emitting
+ * appropriate debug messages. But if we're in dry-run mode, then just emit
+ * the messages and don't copy anything.
+ */
+void
+copy_file(const char *src, const char *dst,
+         pg_checksum_context *checksum_ctx, bool dry_run)
+{
+   /*
+    * In dry-run mode, we don't actually copy anything, nor do we read any
+    * data from the source file, but we do verify that we can open it.
+    */
+   if (dry_run)
+   {
+       int         fd;
+
+       if ((fd = open(src, O_RDONLY | PG_BINARY, 0)) < 0)
+           pg_fatal("could not open \"%s\": %m", src);
+       if (close(fd) < 0)
+           pg_fatal("could not close \"%s\": %m", src);
+   }
+
+   /*
+    * If we don't need to compute a checksum, then we can use any special
+    * operating system primitives that we know about to copy the file; this
+    * may be quicker than a naive block copy.
+    */
+   if (checksum_ctx->type == CHECKSUM_TYPE_NONE)
+   {
+       char       *strategy_name = NULL;
+       void        (*strategy_implementation) (const char *, const char *) = NULL;
+
+#ifdef WIN32
+       strategy_name = "CopyFile";
+       strategy_implementation = copy_file_copyfile;
+#endif
+
+       if (strategy_name != NULL)
+       {
+           if (dry_run)
+               pg_log_debug("would copy \"%s\" to \"%s\" using strategy %s",
+                            src, dst, strategy_name);
+           else
+           {
+               pg_log_debug("copying \"%s\" to \"%s\" using strategy %s",
+                            src, dst, strategy_name);
+               (*strategy_implementation) (src, dst);
+           }
+           return;
+       }
+   }
+
+   /*
+    * Fall back to the simple approach of reading and writing all the blocks,
+    * feeding them into the checksum context as we go.
+    */
+   if (dry_run)
+   {
+       if (checksum_ctx->type == CHECKSUM_TYPE_NONE)
+           pg_log_debug("would copy \"%s\" to \"%s\"",
+                        src, dst);
+       else
+           pg_log_debug("would copy \"%s\" to \"%s\" and checksum with %s",
+                        src, dst, pg_checksum_type_name(checksum_ctx->type));
+   }
+   else
+   {
+       if (checksum_ctx->type == CHECKSUM_TYPE_NONE)
+           pg_log_debug("copying \"%s\" to \"%s\"",
+                        src, dst);
+       else
+           pg_log_debug("copying \"%s\" to \"%s\" and checksumming with %s",
+                        src, dst, pg_checksum_type_name(checksum_ctx->type));
+       copy_file_blocks(src, dst, checksum_ctx);
+   }
+}
+
+/*
+ * Copy a file block by block, and optionally compute a checksum as we go.
+ */
+static void
+copy_file_blocks(const char *src, const char *dst,
+                pg_checksum_context *checksum_ctx)
+{
+   int         src_fd;
+   int         dest_fd;
+   uint8      *buffer;
+   const int   buffer_size = 50 * BLCKSZ;
+   ssize_t     rb;
+   unsigned    offset = 0;
+
+   if ((src_fd = open(src, O_RDONLY | PG_BINARY, 0)) < 0)
+       pg_fatal("could not open file \"%s\": %m", src);
+
+   if ((dest_fd = open(dst, O_WRONLY | O_CREAT | O_EXCL | PG_BINARY,
+                       pg_file_create_mode)) < 0)
+       pg_fatal("could not open file \"%s\": %m", dst);
+
+   buffer = pg_malloc(buffer_size);
+
+   while ((rb = read(src_fd, buffer, buffer_size)) > 0)
+   {
+       ssize_t     wb;
+
+       if ((wb = write(dest_fd, buffer, rb)) != rb)
+       {
+           if (wb < 0)
+               pg_fatal("could not write file \"%s\": %m", dst);
+           else
+               pg_fatal("could not write file \"%s\": wrote only %d of %d bytes at offset %u",
+                        dst, (int) wb, (int) rb, offset);
+       }
+
+       if (pg_checksum_update(checksum_ctx, buffer, rb) < 0)
+           pg_fatal("could not update checksum of file \"%s\"", dst);
+
+       offset += rb;
+   }
+
+   if (rb < 0)
+       pg_fatal("could not read file \"%s\": %m", dst);
+
+   pg_free(buffer);
+   close(src_fd);
+   close(dest_fd);
+}
+
+#ifdef WIN32
+static void
+copy_file_copyfile(const char *src, const char *dst)
+{
+   if (CopyFile(src, dst, true) == 0)
+   {
+       _dosmaperr(GetLastError());
+       pg_fatal("could not copy \"%s\" to \"%s\": %m", src, dst);
+   }
+}
+#endif                         /* WIN32 */
diff --git a/src/bin/pg_combinebackup/copy_file.h b/src/bin/pg_combinebackup/copy_file.h
new file mode 100644 (file)
index 0000000..031030b
--- /dev/null
@@ -0,0 +1,19 @@
+/*
+ * Copy entire files.
+ *
+ * Portions Copyright (c) 1996-2023, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ * src/bin/pg_combinebackup/copy_file.h
+ *
+ *-------------------------------------------------------------------------
+ */
+#ifndef COPY_FILE_H
+#define COPY_FILE_H
+
+#include "common/checksum_helper.h"
+
+extern void copy_file(const char *src, const char *dst,
+                     pg_checksum_context *checksum_ctx, bool dry_run);
+
+#endif                         /* COPY_FILE_H */
diff --git a/src/bin/pg_combinebackup/load_manifest.c b/src/bin/pg_combinebackup/load_manifest.c
new file mode 100644 (file)
index 0000000..ad32323
--- /dev/null
@@ -0,0 +1,245 @@
+/*-------------------------------------------------------------------------
+ *
+ * Load data from a backup manifest into memory.
+ *
+ * Portions Copyright (c) 1996-2023, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ * src/bin/pg_combinebackup/load_manifest.c
+ *
+ *-------------------------------------------------------------------------
+ */
+
+#include "postgres_fe.h"
+
+#include <sys/stat.h>
+#include <unistd.h>
+
+#include "common/hashfn.h"
+#include "common/logging.h"
+#include "common/parse_manifest.h"
+#include "load_manifest.h"
+
+/*
+ * For efficiency, we'd like our hash table containing information about the
+ * manifest to start out with approximately the correct number of entries.
+ * There's no way to know the exact number of entries without reading the whole
+ * file, but we can get an estimate by dividing the file size by the estimated
+ * number of bytes per line.
+ *
+ * This could be off by about a factor of two in either direction, because the
+ * checksum algorithm has a big impact on the line lengths; e.g. a SHA512
+ * checksum is 128 hex bytes, whereas a CRC-32C value is only 8, and there
+ * might be no checksum at all.
+ */
+#define ESTIMATED_BYTES_PER_MANIFEST_LINE  100
+
+/*
+ * Define a hash table which we can use to store information about the files
+ * mentioned in the backup manifest.
+ */
+static uint32 hash_string_pointer(char *s);
+#define SH_PREFIX      manifest_files
+#define SH_ELEMENT_TYPE    manifest_file
+#define SH_KEY_TYPE        char *
+#define    SH_KEY          pathname
+#define SH_HASH_KEY(tb, key)   hash_string_pointer(key)
+#define SH_EQUAL(tb, a, b)     (strcmp(a, b) == 0)
+#define    SH_SCOPE        extern
+#define SH_RAW_ALLOCATOR   pg_malloc0
+#define SH_DEFINE
+#include "lib/simplehash.h"
+
+static void combinebackup_per_file_cb(JsonManifestParseContext *context,
+                                     char *pathname, size_t size,
+                                     pg_checksum_type checksum_type,
+                                     int checksum_length,
+                                     uint8 *checksum_payload);
+static void combinebackup_per_wal_range_cb(JsonManifestParseContext *context,
+                                          TimeLineID tli,
+                                          XLogRecPtr start_lsn,
+                                          XLogRecPtr end_lsn);
+static void report_manifest_error(JsonManifestParseContext *context,
+                                 const char *fmt,...)
+           pg_attribute_printf(2, 3) pg_attribute_noreturn();
+
+/*
+ * Load backup_manifest files from an array of backups and produces an array
+ * of manifest_data objects.
+ *
+ * NB: Since load_backup_manifest() can return NULL, the resulting array could
+ * contain NULL entries.
+ */
+manifest_data **
+load_backup_manifests(int n_backups, char **backup_directories)
+{
+   manifest_data **result;
+   int         i;
+
+   result = pg_malloc(sizeof(manifest_data *) * n_backups);
+   for (i = 0; i < n_backups; ++i)
+       result[i] = load_backup_manifest(backup_directories[i]);
+
+   return result;
+}
+
+/*
+ * Parse the backup_manifest file in the named backup directory. Construct a
+ * hash table with information about all the files it mentions, and a linked
+ * list of all the WAL ranges it mentions.
+ *
+ * If the backup_manifest file simply doesn't exist, logs a warning and returns
+ * NULL. Any other error, or any error parsing the contents of the file, is
+ * fatal.
+ */
+manifest_data *
+load_backup_manifest(char *backup_directory)
+{
+   char        pathname[MAXPGPATH];
+   int         fd;
+   struct stat statbuf;
+   off_t       estimate;
+   uint32      initial_size;
+   manifest_files_hash *ht;
+   char       *buffer;
+   int         rc;
+   JsonManifestParseContext context;
+   manifest_data *result;
+
+   /* Open the manifest file. */
+   snprintf(pathname, MAXPGPATH, "%s/backup_manifest", backup_directory);
+   if ((fd = open(pathname, O_RDONLY | PG_BINARY, 0)) < 0)
+   {
+       if (errno == ENOENT)
+       {
+           pg_log_warning("\"%s\" does not exist", pathname);
+           return NULL;
+       }
+       pg_fatal("could not open file \"%s\": %m", pathname);
+   }
+
+   /* Figure out how big the manifest is. */
+   if (fstat(fd, &statbuf) != 0)
+       pg_fatal("could not stat file \"%s\": %m", pathname);
+
+   /* Guess how large to make the hash table based on the manifest size. */
+   estimate = statbuf.st_size / ESTIMATED_BYTES_PER_MANIFEST_LINE;
+   initial_size = Min(PG_UINT32_MAX, Max(estimate, 256));
+
+   /* Create the hash table. */
+   ht = manifest_files_create(initial_size, NULL);
+
+   /*
+    * Slurp in the whole file.
+    *
+    * This is not ideal, but there's currently no way to get pg_parse_json()
+    * to perform incremental parsing.
+    */
+   buffer = pg_malloc(statbuf.st_size);
+   rc = read(fd, buffer, statbuf.st_size);
+   if (rc != statbuf.st_size)
+   {
+       if (rc < 0)
+           pg_fatal("could not read file \"%s\": %m", pathname);
+       else
+           pg_fatal("could not read file \"%s\": read %d of %lld",
+                    pathname, rc, (long long int) statbuf.st_size);
+   }
+
+   /* Close the manifest file. */
+   close(fd);
+
+   /* Parse the manifest. */
+   result = pg_malloc0(sizeof(manifest_data));
+   result->files = ht;
+   context.private_data = result;
+   context.per_file_cb = combinebackup_per_file_cb;
+   context.per_wal_range_cb = combinebackup_per_wal_range_cb;
+   context.error_cb = report_manifest_error;
+   json_parse_manifest(&context, buffer, statbuf.st_size);
+
+   /* All done. */
+   pfree(buffer);
+   return result;
+}
+
+/*
+ * Report an error while parsing the manifest.
+ *
+ * We consider all such errors to be fatal errors. The manifest parser
+ * expects this function not to return.
+ */
+static void
+report_manifest_error(JsonManifestParseContext *context, const char *fmt,...)
+{
+   va_list     ap;
+
+   va_start(ap, fmt);
+   pg_log_generic_v(PG_LOG_ERROR, PG_LOG_PRIMARY, gettext(fmt), ap);
+   va_end(ap);
+
+   exit(1);
+}
+
+/*
+ * Record details extracted from the backup manifest for one file.
+ */
+static void
+combinebackup_per_file_cb(JsonManifestParseContext *context,
+                         char *pathname, size_t size,
+                         pg_checksum_type checksum_type,
+                         int checksum_length, uint8 *checksum_payload)
+{
+   manifest_data *manifest = context->private_data;
+   manifest_file *m;
+   bool        found;
+
+   /* Make a new entry in the hash table for this file. */
+   m = manifest_files_insert(manifest->files, pathname, &found);
+   if (found)
+       pg_fatal("duplicate path name in backup manifest: \"%s\"", pathname);
+
+   /* Initialize the entry. */
+   m->size = size;
+   m->checksum_type = checksum_type;
+   m->checksum_length = checksum_length;
+   m->checksum_payload = checksum_payload;
+}
+
+/*
+ * Record details extracted from the backup manifest for one WAL range.
+ */
+static void
+combinebackup_per_wal_range_cb(JsonManifestParseContext *context,
+                              TimeLineID tli,
+                              XLogRecPtr start_lsn, XLogRecPtr end_lsn)
+{
+   manifest_data *manifest = context->private_data;
+   manifest_wal_range *range;
+
+   /* Allocate and initialize a struct describing this WAL range. */
+   range = palloc(sizeof(manifest_wal_range));
+   range->tli = tli;
+   range->start_lsn = start_lsn;
+   range->end_lsn = end_lsn;
+   range->prev = manifest->last_wal_range;
+   range->next = NULL;
+
+   /* Add it to the end of the list. */
+   if (manifest->first_wal_range == NULL)
+       manifest->first_wal_range = range;
+   else
+       manifest->last_wal_range->next = range;
+   manifest->last_wal_range = range;
+}
+
+/*
+ * Helper function for manifest_files hash table.
+ */
+static uint32
+hash_string_pointer(char *s)
+{
+   unsigned char *ss = (unsigned char *) s;
+
+   return hash_bytes(ss, strlen(s));
+}
diff --git a/src/bin/pg_combinebackup/load_manifest.h b/src/bin/pg_combinebackup/load_manifest.h
new file mode 100644 (file)
index 0000000..2bfeeff
--- /dev/null
@@ -0,0 +1,67 @@
+/*-------------------------------------------------------------------------
+ *
+ * Load data from a backup manifest into memory.
+ *
+ * Portions Copyright (c) 1996-2023, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ * src/bin/pg_combinebackup/load_manifest.h
+ *
+ *-------------------------------------------------------------------------
+ */
+#ifndef LOAD_MANIFEST_H
+#define LOAD_MANIFEST_H
+
+#include "access/xlogdefs.h"
+#include "common/checksum_helper.h"
+
+/*
+ * Each file described by the manifest file is parsed to produce an object
+ * like this.
+ */
+typedef struct manifest_file
+{
+   uint32      status;         /* hash status */
+   char       *pathname;
+   size_t      size;
+   pg_checksum_type checksum_type;
+   int         checksum_length;
+   uint8      *checksum_payload;
+} manifest_file;
+
+#define SH_PREFIX      manifest_files
+#define SH_ELEMENT_TYPE    manifest_file
+#define SH_KEY_TYPE        char *
+#define    SH_SCOPE        extern
+#define SH_RAW_ALLOCATOR   pg_malloc0
+#define SH_DECLARE
+#include "lib/simplehash.h"
+
+/*
+ * Each WAL range described by the manifest file is parsed to produce an
+ * object like this.
+ */
+typedef struct manifest_wal_range
+{
+   TimeLineID  tli;
+   XLogRecPtr  start_lsn;
+   XLogRecPtr  end_lsn;
+   struct manifest_wal_range *next;
+   struct manifest_wal_range *prev;
+} manifest_wal_range;
+
+/*
+ * All the data parsed from a backup_manifest file.
+ */
+typedef struct manifest_data
+{
+   manifest_files_hash *files;
+   manifest_wal_range *first_wal_range;
+   manifest_wal_range *last_wal_range;
+} manifest_data;
+
+extern manifest_data *load_backup_manifest(char *backup_directory);
+extern manifest_data **load_backup_manifests(int n_backups,
+                                            char **backup_directories);
+
+#endif                         /* LOAD_MANIFEST_H */
diff --git a/src/bin/pg_combinebackup/meson.build b/src/bin/pg_combinebackup/meson.build
new file mode 100644 (file)
index 0000000..e402d6f
--- /dev/null
@@ -0,0 +1,38 @@
+# Copyright (c) 2022-2023, PostgreSQL Global Development Group
+
+pg_combinebackup_sources = files(
+  'pg_combinebackup.c',
+  'backup_label.c',
+  'copy_file.c',
+  'load_manifest.c',
+  'reconstruct.c',
+  'write_manifest.c',
+)
+
+if host_system == 'windows'
+  pg_combinebackup_sources += rc_bin_gen.process(win32ver_rc, extra_args: [
+    '--NAME', 'pg_combinebackup',
+    '--FILEDESC', 'pg_combinebackup - combine incremental backups',])
+endif
+
+pg_combinebackup = executable('pg_combinebackup',
+  pg_combinebackup_sources,
+  dependencies: [frontend_code],
+  kwargs: default_bin_args,
+)
+bin_targets += pg_combinebackup
+
+tests += {
+  'name': 'pg_combinebackup',
+  'sd': meson.current_source_dir(),
+  'bd': meson.current_build_dir(),
+  'tap': {
+    'tests': [
+      't/001_basic.pl',
+      't/002_compare_backups.pl',
+      't/003_timeline.pl',
+      't/004_manifest.pl',
+      't/005_integrity.pl',
+    ],
+  }
+}
diff --git a/src/bin/pg_combinebackup/nls.mk b/src/bin/pg_combinebackup/nls.mk
new file mode 100644 (file)
index 0000000..c8e59d1
--- /dev/null
@@ -0,0 +1,11 @@
+# src/bin/pg_combinebackup/nls.mk
+CATALOG_NAME     = pg_combinebackup
+GETTEXT_FILES    = $(FRONTEND_COMMON_GETTEXT_FILES) \
+          backup_label.c \
+          copy_file.c \
+          load_manifest.c \
+          pg_combinebackup.c \
+          reconstruct.c \
+          write_manifest.c
+GETTEXT_TRIGGERS = $(FRONTEND_COMMON_GETTEXT_TRIGGERS)
+GETTEXT_FLAGS    = $(FRONTEND_COMMON_GETTEXT_FLAGS)
diff --git a/src/bin/pg_combinebackup/pg_combinebackup.c b/src/bin/pg_combinebackup/pg_combinebackup.c
new file mode 100644 (file)
index 0000000..85d3f4e
--- /dev/null
@@ -0,0 +1,1284 @@
+/*-------------------------------------------------------------------------
+ *
+ * pg_combinebackup.c
+ *     Combine incremental backups with prior backups.
+ *
+ * Copyright (c) 2017-2023, PostgreSQL Global Development Group
+ *
+ * IDENTIFICATION
+ *   src/bin/pg_combinebackup/pg_combinebackup.c
+ *
+ *-------------------------------------------------------------------------
+ */
+#include "postgres_fe.h"
+
+#include <dirent.h>
+#include <fcntl.h>
+#include <limits.h>
+
+#include "backup_label.h"
+#include "common/blkreftable.h"
+#include "common/checksum_helper.h"
+#include "common/controldata_utils.h"
+#include "common/file_perm.h"
+#include "common/file_utils.h"
+#include "common/logging.h"
+#include "copy_file.h"
+#include "fe_utils/option_utils.h"
+#include "lib/stringinfo.h"
+#include "load_manifest.h"
+#include "getopt_long.h"
+#include "reconstruct.h"
+#include "write_manifest.h"
+
+/* Incremental file naming convention. */
+#define INCREMENTAL_PREFIX         "INCREMENTAL."
+#define INCREMENTAL_PREFIX_LENGTH  (sizeof(INCREMENTAL_PREFIX) - 1)
+
+/*
+ * Tracking for directories that need to be removed, or have their contents
+ * removed, if the operation fails.
+ */
+typedef struct cb_cleanup_dir
+{
+   char       *target_path;
+   bool        rmtopdir;
+   struct cb_cleanup_dir *next;
+} cb_cleanup_dir;
+
+/*
+ * Stores a tablespace mapping provided using -T, --tablespace-mapping.
+ */
+typedef struct cb_tablespace_mapping
+{
+   char        old_dir[MAXPGPATH];
+   char        new_dir[MAXPGPATH];
+   struct cb_tablespace_mapping *next;
+} cb_tablespace_mapping;
+
+/*
+ * Stores data parsed from all command-line options.
+ */
+typedef struct cb_options
+{
+   bool        debug;
+   char       *output;
+   bool        dry_run;
+   bool        no_sync;
+   cb_tablespace_mapping *tsmappings;
+   pg_checksum_type manifest_checksums;
+   bool        no_manifest;
+   DataDirSyncMethod sync_method;
+} cb_options;
+
+/*
+ * Data about a tablespace.
+ *
+ * Every normal tablespace needs a tablespace mapping, but in-place tablespaces
+ * don't, so the list of tablespaces can contain more entries than the list of
+ * tablespace mappings.
+ */
+typedef struct cb_tablespace
+{
+   Oid         oid;
+   bool        in_place;
+   char        old_dir[MAXPGPATH];
+   char        new_dir[MAXPGPATH];
+   struct cb_tablespace *next;
+} cb_tablespace;
+
+/* Directories to be removed if we exit uncleanly. */
+cb_cleanup_dir *cleanup_dir_list = NULL;
+
+static void add_tablespace_mapping(cb_options *opt, char *arg);
+static StringInfo check_backup_label_files(int n_backups, char **backup_dirs);
+static void check_control_files(int n_backups, char **backup_dirs);
+static void check_input_dir_permissions(char *dir);
+static void cleanup_directories_atexit(void);
+static void create_output_directory(char *dirname, cb_options *opt);
+static void help(const char *progname);
+static bool parse_oid(char *s, Oid *result);
+static void process_directory_recursively(Oid tsoid,
+                                         char *input_directory,
+                                         char *output_directory,
+                                         char *relative_path,
+                                         int n_prior_backups,
+                                         char **prior_backup_dirs,
+                                         manifest_data **manifests,
+                                         manifest_writer *mwriter,
+                                         cb_options *opt);
+static int read_pg_version_file(char *directory);
+static void remember_to_cleanup_directory(char *target_path, bool rmtopdir);
+static void reset_directory_cleanup_list(void);
+static cb_tablespace *scan_for_existing_tablespaces(char *pathname,
+                                                   cb_options *opt);
+static void slurp_file(int fd, char *filename, StringInfo buf, int maxlen);
+
+/*
+ * Main program.
+ */
+int
+main(int argc, char *argv[])
+{
+   static struct option long_options[] = {
+       {"debug", no_argument, NULL, 'd'},
+       {"dry-run", no_argument, NULL, 'n'},
+       {"no-sync", no_argument, NULL, 'N'},
+       {"output", required_argument, NULL, 'o'},
+       {"tablespace-mapping", no_argument, NULL, 'T'},
+       {"manifest-checksums", required_argument, NULL, 1},
+       {"no-manifest", no_argument, NULL, 2},
+       {"sync-method", required_argument, NULL, 3},
+       {NULL, 0, NULL, 0}
+   };
+
+   const char *progname;
+   char       *last_input_dir;
+   int         optindex;
+   int         c;
+   int         n_backups;
+   int         n_prior_backups;
+   int         version;
+   char      **prior_backup_dirs;
+   cb_options  opt;
+   cb_tablespace *tablespaces;
+   cb_tablespace *ts;
+   StringInfo  last_backup_label;
+   manifest_data **manifests;
+   manifest_writer *mwriter;
+
+   pg_logging_init(argv[0]);
+   progname = get_progname(argv[0]);
+   handle_help_version_opts(argc, argv, progname, help);
+
+   memset(&opt, 0, sizeof(opt));
+   opt.manifest_checksums = CHECKSUM_TYPE_CRC32C;
+   opt.sync_method = DATA_DIR_SYNC_METHOD_FSYNC;
+
+   /* process command-line options */
+   while ((c = getopt_long(argc, argv, "dnNPo:T:",
+                           long_options, &optindex)) != -1)
+   {
+       switch (c)
+       {
+           case 'd':
+               opt.debug = true;
+               pg_logging_increase_verbosity();
+               break;
+           case 'n':
+               opt.dry_run = true;
+               break;
+           case 'N':
+               opt.no_sync = true;
+               break;
+           case 'o':
+               opt.output = optarg;
+               break;
+           case 'T':
+               add_tablespace_mapping(&opt, optarg);
+               break;
+           case 1:
+               if (!pg_checksum_parse_type(optarg,
+                                           &opt.manifest_checksums))
+                   pg_fatal("unrecognized checksum algorithm: \"%s\"",
+                            optarg);
+               break;
+           case 2:
+               opt.no_manifest = true;
+               break;
+           case 3:
+               if (!parse_sync_method(optarg, &opt.sync_method))
+                   exit(1);
+               break;
+           default:
+               /* getopt_long already emitted a complaint */
+               pg_log_error_hint("Try \"%s --help\" for more information.", progname);
+               exit(1);
+       }
+   }
+
+   if (optind >= argc)
+   {
+       pg_log_error("%s: no input directories specified", progname);
+       pg_log_error_hint("Try \"%s --help\" for more information.", progname);
+       exit(1);
+   }
+
+   if (opt.output == NULL)
+       pg_fatal("no output directory specified");
+
+   /* If no manifest is needed, no checksums are needed, either. */
+   if (opt.no_manifest)
+       opt.manifest_checksums = CHECKSUM_TYPE_NONE;
+
+   /* Read the server version from the final backup. */
+   version = read_pg_version_file(argv[argc - 1]);
+
+   /* Sanity-check control files. */
+   n_backups = argc - optind;
+   check_control_files(n_backups, argv + optind);
+
+   /* Sanity-check backup_label files, and get the contents of the last one. */
+   last_backup_label = check_backup_label_files(n_backups, argv + optind);
+
+   /*
+    * We'll need the pathnames to the prior backups. By "prior" we mean all
+    * but the last one listed on the command line.
+    */
+   n_prior_backups = argc - optind - 1;
+   prior_backup_dirs = argv + optind;
+
+   /* Load backup manifests. */
+   manifests = load_backup_manifests(n_backups, prior_backup_dirs);
+
+   /* Figure out which tablespaces are going to be included in the output. */
+   last_input_dir = argv[argc - 1];
+   check_input_dir_permissions(last_input_dir);
+   tablespaces = scan_for_existing_tablespaces(last_input_dir, &opt);
+
+   /*
+    * Create output directories.
+    *
+    * We create one output directory for the main data directory plus one for
+    * each non-in-place tablespace. create_output_directory() will arrange
+    * for those directories to be cleaned up on failure. In-place tablespaces
+    * aren't handled at this stage because they're located beneath the main
+    * output directory, and thus the cleanup of that directory will get rid
+    * of them. Plus, the pg_tblspc directory that needs to contain them
+    * doesn't exist yet.
+    */
+   atexit(cleanup_directories_atexit);
+   create_output_directory(opt.output, &opt);
+   for (ts = tablespaces; ts != NULL; ts = ts->next)
+       if (!ts->in_place)
+           create_output_directory(ts->new_dir, &opt);
+
+   /* If we need to write a backup_manifest, prepare to do so. */
+   if (!opt.dry_run && !opt.no_manifest)
+   {
+       mwriter = create_manifest_writer(opt.output);
+
+       /*
+        * Verify that we have a backup manifest for the final backup; else we
+        * won't have the WAL ranges for the resulting manifest.
+        */
+       if (manifests[n_prior_backups] == NULL)
+           pg_fatal("can't generate a manifest because no manifest is available for the final input backup");
+   }
+   else
+       mwriter = NULL;
+
+   /* Write backup label into output directory. */
+   if (opt.dry_run)
+       pg_log_debug("would generate \"%s/backup_label\"", opt.output);
+   else
+   {
+       pg_log_debug("generating \"%s/backup_label\"", opt.output);
+       last_backup_label->cursor = 0;
+       write_backup_label(opt.output, last_backup_label,
+                          opt.manifest_checksums, mwriter);
+   }
+
+   /* Process everything that's not part of a user-defined tablespace. */
+   pg_log_debug("processing backup directory \"%s\"", last_input_dir);
+   process_directory_recursively(InvalidOid, last_input_dir, opt.output,
+                                 NULL, n_prior_backups, prior_backup_dirs,
+                                 manifests, mwriter, &opt);
+
+   /* Process user-defined tablespaces. */
+   for (ts = tablespaces; ts != NULL; ts = ts->next)
+   {
+       pg_log_debug("processing tablespace directory \"%s\"", ts->old_dir);
+
+       /*
+        * If it's a normal tablespace, we need to set up a symbolic link from
+        * pg_tblspc/${OID} to the target directory; if it's an in-place
+        * tablespace, we need to create a directory at pg_tblspc/${OID}.
+        */
+       if (!ts->in_place)
+       {
+           char        linkpath[MAXPGPATH];
+
+           snprintf(linkpath, MAXPGPATH, "%s/pg_tblspc/%u", opt.output,
+                    ts->oid);
+
+           if (opt.dry_run)
+               pg_log_debug("would create symbolic link from \"%s\" to \"%s\"",
+                            linkpath, ts->new_dir);
+           else
+           {
+               pg_log_debug("creating symbolic link from \"%s\" to \"%s\"",
+                            linkpath, ts->new_dir);
+               if (symlink(ts->new_dir, linkpath) != 0)
+                   pg_fatal("could not create symbolic link from \"%s\" to \"%s\": %m",
+                            linkpath, ts->new_dir);
+           }
+       }
+       else
+       {
+           if (opt.dry_run)
+               pg_log_debug("would create directory \"%s\"", ts->new_dir);
+           else
+           {
+               pg_log_debug("creating directory \"%s\"", ts->new_dir);
+               if (pg_mkdir_p(ts->new_dir, pg_dir_create_mode) == -1)
+                   pg_fatal("could not create directory \"%s\": %m",
+                            ts->new_dir);
+           }
+       }
+
+       /* OK, now handle the directory contents. */
+       process_directory_recursively(ts->oid, ts->old_dir, ts->new_dir,
+                                     NULL, n_prior_backups, prior_backup_dirs,
+                                     manifests, mwriter, &opt);
+   }
+
+   /* Finalize the backup_manifest, if we're generating one. */
+   if (mwriter != NULL)
+       finalize_manifest(mwriter,
+                         manifests[n_prior_backups]->first_wal_range);
+
+   /* fsync that output directory unless we've been told not to do so */
+   if (!opt.no_sync)
+   {
+       if (opt.dry_run)
+           pg_log_debug("would recursively fsync \"%s\"", opt.output);
+       else
+       {
+           pg_log_debug("recursively fsyncing \"%s\"", opt.output);
+           sync_pgdata(opt.output, version * 10000, opt.sync_method);
+       }
+   }
+
+   /* It's a success, so don't remove the output directories. */
+   reset_directory_cleanup_list();
+   exit(0);
+}
+
+/*
+ * Process the option argument for the -T, --tablespace-mapping switch.
+ */
+static void
+add_tablespace_mapping(cb_options *opt, char *arg)
+{
+   cb_tablespace_mapping *tsmap = pg_malloc0(sizeof(cb_tablespace_mapping));
+   char       *dst;
+   char       *dst_ptr;
+   char       *arg_ptr;
+
+   /*
+    * Basically, we just want to copy everything before the equals sign to
+    * tsmap->old_dir and everything afterwards to tsmap->new_dir, but if
+    * there's more or less than one equals sign, that's an error, and if
+    * there's an equals sign preceded by a backslash, don't treat it as a
+    * field separator but instead copy a literal equals sign.
+    */
+   dst_ptr = dst = tsmap->old_dir;
+   for (arg_ptr = arg; *arg_ptr != '\0'; arg_ptr++)
+   {
+       if (dst_ptr - dst >= MAXPGPATH)
+           pg_fatal("directory name too long");
+
+       if (*arg_ptr == '\\' && *(arg_ptr + 1) == '=')
+           ;                   /* skip backslash escaping = */
+       else if (*arg_ptr == '=' && (arg_ptr == arg || *(arg_ptr - 1) != '\\'))
+       {
+           if (tsmap->new_dir[0] != '\0')
+               pg_fatal("multiple \"=\" signs in tablespace mapping");
+           else
+               dst = dst_ptr = tsmap->new_dir;
+       }
+       else
+           *dst_ptr++ = *arg_ptr;
+   }
+   if (!tsmap->old_dir[0] || !tsmap->new_dir[0])
+       pg_fatal("invalid tablespace mapping format \"%s\", must be \"OLDDIR=NEWDIR\"", arg);
+
+   /*
+    * All tablespaces are created with absolute directories, so specifying a
+    * non-absolute path here would never match, possibly confusing users.
+    *
+    * In contrast to pg_basebackup, both the old and new directories are on
+    * the local machine, so the local machine's definition of an absolute
+    * path is the only relevant one.
+    */
+   if (!is_absolute_path(tsmap->old_dir))
+       pg_fatal("old directory is not an absolute path in tablespace mapping: %s",
+                tsmap->old_dir);
+
+   if (!is_absolute_path(tsmap->new_dir))
+       pg_fatal("old directory is not an absolute path in tablespace mapping: %s",
+                tsmap->new_dir);
+
+   /* Canonicalize paths to avoid spurious failures when comparing. */
+   canonicalize_path(tsmap->old_dir);
+   canonicalize_path(tsmap->new_dir);
+
+   /* Add it to the list. */
+   tsmap->next = opt->tsmappings;
+   opt->tsmappings = tsmap;
+}
+
+/*
+ * Check that the backup_label files form a coherent backup chain, and return
+ * the contents of the backup_label file from the latest backup.
+ */
+static StringInfo
+check_backup_label_files(int n_backups, char **backup_dirs)
+{
+   StringInfo  buf = makeStringInfo();
+   StringInfo  lastbuf = buf;
+   int         i;
+   TimeLineID  check_tli = 0;
+   XLogRecPtr  check_lsn = InvalidXLogRecPtr;
+
+   /* Try to read each backup_label file in turn, last to first. */
+   for (i = n_backups - 1; i >= 0; --i)
+   {
+       char        pathbuf[MAXPGPATH];
+       int         fd;
+       TimeLineID  start_tli;
+       TimeLineID  previous_tli;
+       XLogRecPtr  start_lsn;
+       XLogRecPtr  previous_lsn;
+
+       /* Open the backup_label file. */
+       snprintf(pathbuf, MAXPGPATH, "%s/backup_label", backup_dirs[i]);
+       pg_log_debug("reading \"%s\"", pathbuf);
+       if ((fd = open(pathbuf, O_RDONLY, 0)) < 0)
+           pg_fatal("could not open file \"%s\": %m", pathbuf);
+
+       /*
+        * Slurp the whole file into memory.
+        *
+        * The exact size limit that we impose here doesn't really matter --
+        * most of what's supposed to be in the file is fixed size and quite
+        * short. However, the length of the backup_label is limited (at least
+        * by some parts of the code) to MAXGPATH, so include that value in
+        * the maximum length that we tolerate.
+        */
+       slurp_file(fd, pathbuf, buf, 10000 + MAXPGPATH);
+
+       /* Close the file. */
+       if (close(fd) != 0)
+           pg_fatal("could not close \"%s\": %m", pathbuf);
+
+       /* Parse the file contents. */
+       parse_backup_label(pathbuf, buf, &start_tli, &start_lsn,
+                          &previous_tli, &previous_lsn);
+
+       /*
+        * Sanity checks.
+        *
+        * XXX. It's actually not required that start_lsn == check_lsn. It
+        * would be OK if start_lsn > check_lsn provided that start_lsn is
+        * less than or equal to the relevant switchpoint. But at the moment
+        * we don't have that information.
+        */
+       if (i > 0 && previous_tli == 0)
+           pg_fatal("backup at \"%s\" is a full backup, but only the first backup should be a full backup",
+                    backup_dirs[i]);
+       if (i == 0 && previous_tli != 0)
+           pg_fatal("backup at \"%s\" is an incremental backup, but the first backup should be a full backup",
+                    backup_dirs[i]);
+       if (i < n_backups - 1 && start_tli != check_tli)
+           pg_fatal("backup at \"%s\" starts on timeline %u, but expected %u",
+                    backup_dirs[i], start_tli, check_tli);
+       if (i < n_backups - 1 && start_lsn != check_lsn)
+           pg_fatal("backup at \"%s\" starts at LSN %X/%X, but expected %X/%X",
+                    backup_dirs[i],
+                    LSN_FORMAT_ARGS(start_lsn),
+                    LSN_FORMAT_ARGS(check_lsn));
+       check_tli = previous_tli;
+       check_lsn = previous_lsn;
+
+       /*
+        * The last backup label in the chain needs to be saved for later use,
+        * while the others are only needed within this loop.
+        */
+       if (lastbuf == buf)
+           buf = makeStringInfo();
+       else
+           resetStringInfo(buf);
+   }
+
+   /* Free memory that we don't need any more. */
+   if (lastbuf != buf)
+   {
+       pfree(buf->data);
+       pfree(buf);
+   }
+
+   /*
+    * Return the data from the first backup_info that we read (which is the
+    * backup_label from the last directory specified on the command line).
+    */
+   return lastbuf;
+}
+
+/*
+ * Sanity check control files.
+ */
+static void
+check_control_files(int n_backups, char **backup_dirs)
+{
+   int         i;
+   uint64      system_identifier = 0;  /* placate compiler */
+
+   /* Try to read each control file in turn, last to first. */
+   for (i = n_backups - 1; i >= 0; --i)
+   {
+       ControlFileData *control_file;
+       bool        crc_ok;
+       char       *controlpath;
+
+       controlpath = psprintf("%s/%s", backup_dirs[i], "global/pg_control");
+       pg_log_debug("reading \"%s\"", controlpath);
+       control_file = get_controlfile(backup_dirs[i], &crc_ok);
+
+       /* Control file contents not meaningful if CRC is bad. */
+       if (!crc_ok)
+           pg_fatal("%s: crc is incorrect", controlpath);
+
+       /* Can't interpret control file if not current version. */
+       if (control_file->pg_control_version != PG_CONTROL_VERSION)
+           pg_fatal("%s: unexpected control file version",
+                    controlpath);
+
+       /* System identifiers should all match. */
+       if (i == n_backups - 1)
+           system_identifier = control_file->system_identifier;
+       else if (system_identifier != control_file->system_identifier)
+           pg_fatal("%s: expected system identifier %llu, but found %llu",
+                    controlpath, (unsigned long long) system_identifier,
+                    (unsigned long long) control_file->system_identifier);
+
+       /* Release memory. */
+       pfree(control_file);
+       pfree(controlpath);
+   }
+
+   /*
+    * If debug output is enabled, make a note of the system identifier that
+    * we found in all of the relevant control files.
+    */
+   pg_log_debug("system identifier is %llu",
+                (unsigned long long) system_identifier);
+}
+
+/*
+ * Set default permissions for new files and directories based on the
+ * permissions of the given directory. The intent here is that the output
+ * directory should use the same permissions scheme as the final input
+ * directory.
+ */
+static void
+check_input_dir_permissions(char *dir)
+{
+   struct stat st;
+
+   if (stat(dir, &st) != 0)
+       pg_fatal("could not stat \"%s\": %m", dir);
+
+   SetDataDirectoryCreatePerm(st.st_mode);
+}
+
+/*
+ * Clean up output directories before exiting.
+ */
+static void
+cleanup_directories_atexit(void)
+{
+   while (cleanup_dir_list != NULL)
+   {
+       cb_cleanup_dir *dir = cleanup_dir_list;
+
+       if (dir->rmtopdir)
+       {
+           pg_log_info("removing output directory \"%s\"", dir->target_path);
+           if (!rmtree(dir->target_path, dir->rmtopdir))
+               pg_log_error("failed to remove output directory");
+       }
+       else
+       {
+           pg_log_info("removing contents of output directory \"%s\"",
+                       dir->target_path);
+           if (!rmtree(dir->target_path, dir->rmtopdir))
+               pg_log_error("failed to remove contents of output directory");
+       }
+
+       cleanup_dir_list = cleanup_dir_list->next;
+       pfree(dir);
+   }
+}
+
+/*
+ * Create the named output directory, unless it already exists or we're in
+ * dry-run mode. If it already exists but is not empty, that's a fatal error.
+ *
+ * Adds the created directory to the list of directories to be cleaned up
+ * at process exit.
+ */
+static void
+create_output_directory(char *dirname, cb_options *opt)
+{
+   switch (pg_check_dir(dirname))
+   {
+       case 0:
+           if (opt->dry_run)
+           {
+               pg_log_debug("would create directory \"%s\"", dirname);
+               return;
+           }
+           pg_log_debug("creating directory \"%s\"", dirname);
+           if (pg_mkdir_p(dirname, pg_dir_create_mode) == -1)
+               pg_fatal("could not create directory \"%s\": %m", dirname);
+           remember_to_cleanup_directory(dirname, true);
+           break;
+
+       case 1:
+           pg_log_debug("using existing directory \"%s\"", dirname);
+           remember_to_cleanup_directory(dirname, false);
+           break;
+
+       case 2:
+       case 3:
+       case 4:
+           pg_fatal("directory \"%s\" exists but is not empty", dirname);
+
+       case -1:
+           pg_fatal("could not access directory \"%s\": %m", dirname);
+   }
+}
+
+/*
+ * help
+ *
+ * Prints help page for the program
+ *
+ * progname: the name of the executed program, such as "pg_combinebackup"
+ */
+static void
+help(const char *progname)
+{
+   printf(_("%s reconstructs full backups from incrementals.\n\n"), progname);
+   printf(_("Usage:\n"));
+   printf(_("  %s [OPTION]... DIRECTORY...\n"), progname);
+   printf(_("\nOptions:\n"));
+   printf(_("  -d, --debug               generate lots of debugging output\n"));
+   printf(_("  -n, --dry-run             don't actually do anything\n"));
+   printf(_("  -N, --no-sync             do not wait for changes to be written safely to disk\n"));
+   printf(_("  -o, --output              output directory\n"));
+   printf(_("  -T, --tablespace-mapping=OLDDIR=NEWDIR\n"));
+   printf(_("                            relocate tablespace in OLDDIR to NEWDIR\n"));
+   printf(_("      --manifest-checksums=SHA{224,256,384,512}|CRC32C|NONE\n"
+            "                            use algorithm for manifest checksums\n"));
+   printf(_("      --no-manifest         suppress generation of backup manifest\n"));
+   printf(_("      --sync-method=METHOD  set method for syncing files to disk\n"));
+   printf(_("  -?, --help                show this help, then exit\n"));
+
+   printf(_("\nReport bugs to <%s>.\n"), PACKAGE_BUGREPORT);
+   printf(_("%s home page: <%s>\n"), PACKAGE_NAME, PACKAGE_URL);
+}
+
+/*
+ * Try to parse a string as a non-zero OID without leading zeroes.
+ *
+ * If it works, return true and set *result to the answer, else return false.
+ */
+static bool
+parse_oid(char *s, Oid *result)
+{
+   Oid         oid;
+   char       *ep;
+
+   errno = 0;
+   oid = strtoul(s, &ep, 10);
+   if (errno != 0 || *ep != '\0' || oid < 1 || oid > PG_UINT32_MAX)
+       return false;
+
+   *result = oid;
+   return true;
+}
+
+/*
+ * Copy files from the input directory to the output directory, reconstructing
+ * full files from incremental files as required.
+ *
+ * If processing is a user-defined tablespace, the tsoid should be the OID
+ * of that tablespace and input_directory and output_directory should be the
+ * toplevel input and output directories for that tablespace. Otherwise,
+ * tsoid should be InvalidOid and input_directory and output_directory should
+ * be the main input and output directories.
+ *
+ * relative_path is the path beneath the given input and output directories
+ * that we are currently processing. If NULL, it indicates that we're
+ * processing the input and output directories themselves.
+ *
+ * n_prior_backups is the number of prior backups that we have available.
+ * This doesn't count the very last backup, which is referenced by
+ * output_directory, just the older ones. prior_backup_dirs is an array of
+ * the locations of those previous backups.
+ */
+static void
+process_directory_recursively(Oid tsoid,
+                             char *input_directory,
+                             char *output_directory,
+                             char *relative_path,
+                             int n_prior_backups,
+                             char **prior_backup_dirs,
+                             manifest_data **manifests,
+                             manifest_writer *mwriter,
+                             cb_options *opt)
+{
+   char        ifulldir[MAXPGPATH];
+   char        ofulldir[MAXPGPATH];
+   char        manifest_prefix[MAXPGPATH];
+   DIR        *dir;
+   struct dirent *de;
+   bool        is_pg_tblspc;
+   bool        is_pg_wal;
+   manifest_data *latest_manifest = manifests[n_prior_backups];
+   pg_checksum_type checksum_type;
+
+   /*
+    * pg_tblspc and pg_wal are special cases, so detect those here.
+    *
+    * pg_tblspc is only special at the top level, but subdirectories of
+    * pg_wal are just as special as the top level directory.
+    *
+    * Since incremental backup does not exist in pre-v10 versions, we don't
+    * have to worry about the old pg_xlog naming.
+    */
+   is_pg_tblspc = !OidIsValid(tsoid) && relative_path != NULL &&
+       strcmp(relative_path, "pg_tblspc") == 0;
+   is_pg_wal = !OidIsValid(tsoid) && relative_path != NULL &&
+       (strcmp(relative_path, "pg_wal") == 0 ||
+        strncmp(relative_path, "pg_wal/", 7) == 0);
+
+   /*
+    * If we're under pg_wal, then we don't need checksums, because these
+    * files aren't included in the backup manifest. Otherwise use whatever
+    * type of checksum is configured.
+    */
+   if (!is_pg_wal)
+       checksum_type = opt->manifest_checksums;
+   else
+       checksum_type = CHECKSUM_TYPE_NONE;
+
+   /*
+    * Append the relative path to the input and output directories, and
+    * figure out the appropriate prefix to add to files in this directory
+    * when looking them up in a backup manifest.
+    */
+   if (relative_path == NULL)
+   {
+       strncpy(ifulldir, input_directory, MAXPGPATH);
+       strncpy(ofulldir, output_directory, MAXPGPATH);
+       if (OidIsValid(tsoid))
+           snprintf(manifest_prefix, MAXPGPATH, "pg_tblspc/%u/", tsoid);
+       else
+           manifest_prefix[0] = '\0';
+   }
+   else
+   {
+       snprintf(ifulldir, MAXPGPATH, "%s/%s", input_directory,
+                relative_path);
+       snprintf(ofulldir, MAXPGPATH, "%s/%s", output_directory,
+                relative_path);
+       if (OidIsValid(tsoid))
+           snprintf(manifest_prefix, MAXPGPATH, "pg_tblspc/%u/%s/",
+                    tsoid, relative_path);
+       else
+           snprintf(manifest_prefix, MAXPGPATH, "%s/", relative_path);
+   }
+
+   /*
+    * Toplevel output directories have already been created by the time this
+    * function is called, but any subdirectories are our responsibility.
+    */
+   if (relative_path != NULL)
+   {
+       if (opt->dry_run)
+           pg_log_debug("would create directory \"%s\"", ofulldir);
+       else
+       {
+           pg_log_debug("creating directory \"%s\"", ofulldir);
+           if (mkdir(ofulldir, pg_dir_create_mode) == -1)
+               pg_fatal("could not create directory \"%s\": %m", ofulldir);
+       }
+   }
+
+   /* It's time to scan the directory. */
+   if ((dir = opendir(ifulldir)) == NULL)
+       pg_fatal("could not open directory \"%s\": %m", ifulldir);
+   while (errno = 0, (de = readdir(dir)) != NULL)
+   {
+       PGFileType  type;
+       char        ifullpath[MAXPGPATH];
+       char        ofullpath[MAXPGPATH];
+       char        manifest_path[MAXPGPATH];
+       Oid         oid = InvalidOid;
+       int         checksum_length = 0;
+       uint8      *checksum_payload = NULL;
+       pg_checksum_context checksum_ctx;
+
+       /* Ignore "." and ".." entries. */
+       if (strcmp(de->d_name, ".") == 0 ||
+           strcmp(de->d_name, "..") == 0)
+           continue;
+
+       /* Construct input path. */
+       snprintf(ifullpath, MAXPGPATH, "%s/%s", ifulldir, de->d_name);
+
+       /* Figure out what kind of directory entry this is. */
+       type = get_dirent_type(ifullpath, de, false, PG_LOG_ERROR);
+       if (type == PGFILETYPE_ERROR)
+           exit(1);
+
+       /*
+        * If we're processing pg_tblspc, then check whether the filename
+        * looks like it could be a tablespace OID. If so, and if the
+        * directory entry is a symbolic link or a directory, skip it.
+        *
+        * Our goal here is to ignore anything that would have been considered
+        * by scan_for_existing_tablespaces to be a tablespace.
+        */
+       if (is_pg_tblspc && parse_oid(de->d_name, &oid) &&
+           (type == PGFILETYPE_LNK || type == PGFILETYPE_DIR))
+           continue;
+
+       /* If it's a directory, recurse. */
+       if (type == PGFILETYPE_DIR)
+       {
+           char        new_relative_path[MAXPGPATH];
+
+           /* Append new pathname component to relative path. */
+           if (relative_path == NULL)
+               strncpy(new_relative_path, de->d_name, MAXPGPATH);
+           else
+               snprintf(new_relative_path, MAXPGPATH, "%s/%s", relative_path,
+                        de->d_name);
+
+           /* And recurse. */
+           process_directory_recursively(tsoid,
+                                         input_directory, output_directory,
+                                         new_relative_path,
+                                         n_prior_backups, prior_backup_dirs,
+                                         manifests, mwriter, opt);
+           continue;
+       }
+
+       /* Skip anything that's not a regular file. */
+       if (type != PGFILETYPE_REG)
+       {
+           if (type == PGFILETYPE_LNK)
+               pg_log_warning("skipping symbolic link \"%s\"", ifullpath);
+           else
+               pg_log_warning("skipping special file \"%s\"", ifullpath);
+           continue;
+       }
+
+       /*
+        * Skip the backup_label and backup_manifest files; they require
+        * special handling and are handled elsewhere.
+        */
+       if (relative_path == NULL &&
+           (strcmp(de->d_name, "backup_label") == 0 ||
+            strcmp(de->d_name, "backup_manifest") == 0))
+           continue;
+
+       /*
+        * If it's an incremental file, hand it off to the reconstruction
+        * code, which will figure out what to do.
+        */
+       if (strncmp(de->d_name, INCREMENTAL_PREFIX,
+                   INCREMENTAL_PREFIX_LENGTH) == 0)
+       {
+           /* Output path should not include "INCREMENTAL." prefix. */
+           snprintf(ofullpath, MAXPGPATH, "%s/%s", ofulldir,
+                    de->d_name + INCREMENTAL_PREFIX_LENGTH);
+
+
+           /* Manifest path likewise omits incremental prefix. */
+           snprintf(manifest_path, MAXPGPATH, "%s%s", manifest_prefix,
+                    de->d_name + INCREMENTAL_PREFIX_LENGTH);
+
+           /* Reconstruction logic will do the rest. */
+           reconstruct_from_incremental_file(ifullpath, ofullpath,
+                                             relative_path,
+                                             de->d_name + INCREMENTAL_PREFIX_LENGTH,
+                                             n_prior_backups,
+                                             prior_backup_dirs,
+                                             manifests,
+                                             manifest_path,
+                                             checksum_type,
+                                             &checksum_length,
+                                             &checksum_payload,
+                                             opt->debug,
+                                             opt->dry_run);
+       }
+       else
+       {
+           /* Construct the path that the backup_manifest will use. */
+           snprintf(manifest_path, MAXPGPATH, "%s%s", manifest_prefix,
+                    de->d_name);
+
+           /*
+            * It's not an incremental file, so we need to copy the entire
+            * file to the output directory.
+            *
+            * If a checksum of the required type already exists in the
+            * backup_manifest for the final input directory, we can save some
+            * work by reusing that checksum instead of computing a new one.
+            */
+           if (checksum_type != CHECKSUM_TYPE_NONE &&
+               latest_manifest != NULL)
+           {
+               manifest_file *mfile;
+
+               mfile = manifest_files_lookup(latest_manifest->files,
+                                             manifest_path);
+               if (mfile == NULL)
+               {
+                   char       *bmpath;
+
+                   /*
+                    * The directory is out of sync with the backup_manifest,
+                    * so emit a warning.
+                    */
+                   bmpath = psprintf("%s/%s", input_directory,
+                                     "backup_manifest");
+                   pg_log_warning("\"%s\" contains no entry for \"%s\"",
+                                  bmpath, manifest_path);
+                   pfree(bmpath);
+               }
+               else if (mfile->checksum_type == checksum_type)
+               {
+                   checksum_length = mfile->checksum_length;
+                   checksum_payload = mfile->checksum_payload;
+               }
+           }
+
+           /*
+            * If we're reusing a checksum, then we don't need copy_file() to
+            * compute one for us, but otherwise, it needs to compute whatever
+            * type of checksum we need.
+            */
+           if (checksum_length != 0)
+               pg_checksum_init(&checksum_ctx, CHECKSUM_TYPE_NONE);
+           else
+               pg_checksum_init(&checksum_ctx, checksum_type);
+
+           /* Actually copy the file. */
+           snprintf(ofullpath, MAXPGPATH, "%s/%s", ofulldir, de->d_name);
+           copy_file(ifullpath, ofullpath, &checksum_ctx, opt->dry_run);
+
+           /*
+            * If copy_file() performed a checksum calculation for us, then
+            * save the results (except in dry-run mode, when there's no
+            * point).
+            */
+           if (checksum_ctx.type != CHECKSUM_TYPE_NONE && !opt->dry_run)
+           {
+               checksum_payload = pg_malloc(PG_CHECKSUM_MAX_LENGTH);
+               checksum_length = pg_checksum_final(&checksum_ctx,
+                                                   checksum_payload);
+           }
+       }
+
+       /* Generate manifest entry, if needed. */
+       if (mwriter != NULL)
+       {
+           struct stat sb;
+
+           /*
+            * In order to generate a manifest entry, we need the file size
+            * and mtime. We have no way to know the correct mtime except to
+            * stat() the file, so just do that and get the size as well.
+            *
+            * If we didn't need the mtime here, we could try to obtain the
+            * file size from the reconstruction or file copy process above,
+            * although that is actually not convenient in all cases. If we
+            * write the file ourselves then clearly we can keep a count of
+            * bytes, but if we use something like CopyFile() then it's
+            * trickier. Since we have to stat() anyway to get the mtime,
+            * there's no point in worrying about it.
+            */
+           if (stat(ofullpath, &sb) < 0)
+               pg_fatal("could not stat file \"%s\": %m", ofullpath);
+
+           /* OK, now do the work. */
+           add_file_to_manifest(mwriter, manifest_path,
+                                sb.st_size, sb.st_mtime,
+                                checksum_type, checksum_length,
+                                checksum_payload);
+       }
+
+       /* Avoid leaking memory. */
+       if (checksum_payload != NULL)
+           pfree(checksum_payload);
+   }
+
+   closedir(dir);
+}
+
+/*
+ * Read the version number from PG_VERSION and convert it to the usual server
+ * version number format. (e.g. If PG_VERSION contains "14\n" this function
+ * will return 140000)
+ */
+static int
+read_pg_version_file(char *directory)
+{
+   char        filename[MAXPGPATH];
+   StringInfoData buf;
+   int         fd;
+   int         version;
+   char       *ep;
+
+   /* Construct pathname. */
+   snprintf(filename, MAXPGPATH, "%s/PG_VERSION", directory);
+
+   /* Open file. */
+   if ((fd = open(filename, O_RDONLY, 0)) < 0)
+       pg_fatal("could not open file \"%s\": %m", filename);
+
+   /* Read into memory. Length limit of 128 should be more than generous. */
+   initStringInfo(&buf);
+   slurp_file(fd, filename, &buf, 128);
+
+   /* Close the file. */
+   if (close(fd) != 0)
+       pg_fatal("could not close \"%s\": %m", filename);
+
+   /* Convert to integer. */
+   errno = 0;
+   version = strtoul(buf.data, &ep, 10);
+   if (errno != 0 || *ep != '\n')
+   {
+       /*
+        * Incremental backup is not relevant to very old server versions that
+        * used multi-part version number (e.g. 9.6, or 8.4). So if we see
+        * what looks like the beginning of such a version number, just bail
+        * out.
+        */
+       if (version < 10 && *ep == '.')
+           pg_fatal("%s: server version too old\n", filename);
+       pg_fatal("%s: could not parse version number\n", filename);
+   }
+
+   /* Debugging output. */
+   pg_log_debug("read server version %d from \"%s\"", version, filename);
+
+   /* Release memory and return result. */
+   pfree(buf.data);
+   return version * 10000;
+}
+
+/*
+ * Add a directory to the list of output directories to clean up.
+ */
+static void
+remember_to_cleanup_directory(char *target_path, bool rmtopdir)
+{
+   cb_cleanup_dir *dir = pg_malloc(sizeof(cb_cleanup_dir));
+
+   dir->target_path = target_path;
+   dir->rmtopdir = rmtopdir;
+   dir->next = cleanup_dir_list;
+   cleanup_dir_list = dir;
+}
+
+/*
+ * Empty out the list of directories scheduled for cleanup a exit.
+ *
+ * We want to remove the output directories only on a failure, so call this
+ * function when we know that the operation has succeeded.
+ *
+ * Since we only expect this to be called when we're about to exit, we could
+ * just set cleanup_dir_list to NULL and be done with it, but we free the
+ * memory to be tidy.
+ */
+static void
+reset_directory_cleanup_list(void)
+{
+   while (cleanup_dir_list != NULL)
+   {
+       cb_cleanup_dir *dir = cleanup_dir_list;
+
+       cleanup_dir_list = cleanup_dir_list->next;
+       pfree(dir);
+   }
+}
+
+/*
+ * Scan the pg_tblspc directory of the final input backup to get a canonical
+ * list of what tablespaces are part of the backup.
+ *
+ * 'pathname' should be the path to the toplevel backup directory for the
+ * final backup in the backup chain.
+ */
+static cb_tablespace *
+scan_for_existing_tablespaces(char *pathname, cb_options *opt)
+{
+   char        pg_tblspc[MAXPGPATH];
+   DIR        *dir;
+   struct dirent *de;
+   cb_tablespace *tslist = NULL;
+
+   snprintf(pg_tblspc, MAXPGPATH, "%s/pg_tblspc", pathname);
+   pg_log_debug("scanning \"%s\"", pg_tblspc);
+
+   if ((dir = opendir(pg_tblspc)) == NULL)
+       pg_fatal("could not open directory \"%s\": %m", pathname);
+
+   while (errno = 0, (de = readdir(dir)) != NULL)
+   {
+       Oid         oid;
+       char        tblspcdir[MAXPGPATH];
+       char        link_target[MAXPGPATH];
+       int         link_length;
+       cb_tablespace *ts;
+       cb_tablespace *otherts;
+       PGFileType  type;
+
+       /* Silently ignore "." and ".." entries. */
+       if (strcmp(de->d_name, ".") == 0 || strcmp(de->d_name, "..") == 0)
+           continue;
+
+       /* Construct full pathname. */
+       snprintf(tblspcdir, MAXPGPATH, "%s/%s", pg_tblspc, de->d_name);
+
+       /* Ignore any file name that doesn't look like a proper OID. */
+       if (!parse_oid(de->d_name, &oid))
+       {
+           pg_log_debug("skipping \"%s\" because the filename is not a legal tablespace OID",
+                        tblspcdir);
+           continue;
+       }
+
+       /* Only symbolic links and directories are tablespaces. */
+       type = get_dirent_type(tblspcdir, de, false, PG_LOG_ERROR);
+       if (type == PGFILETYPE_ERROR)
+           exit(1);
+       if (type != PGFILETYPE_LNK && type != PGFILETYPE_DIR)
+       {
+           pg_log_debug("skipping \"%s\" because it is neither a symbolic link nor a directory",
+                        tblspcdir);
+           continue;
+       }
+
+       /* Create a new tablespace object. */
+       ts = pg_malloc0(sizeof(cb_tablespace));
+       ts->oid = oid;
+
+       /*
+        * If it's a link, it's not an in-place tablespace. Otherwise, it must
+        * be a directory, and thus an in-place tablespace.
+        */
+       if (type == PGFILETYPE_LNK)
+       {
+           cb_tablespace_mapping *tsmap;
+
+           /* Read the link target. */
+           link_length = readlink(tblspcdir, link_target, sizeof(link_target));
+           if (link_length < 0)
+               pg_fatal("could not read symbolic link \"%s\": %m",
+                        tblspcdir);
+           if (link_length >= sizeof(link_target))
+               pg_fatal("symbolic link \"%s\" is too long", tblspcdir);
+           link_target[link_length] = '\0';
+           if (!is_absolute_path(link_target))
+               pg_fatal("symbolic link \"%s\" is relative", tblspcdir);
+
+           /* Caonicalize the link target. */
+           canonicalize_path(link_target);
+
+           /*
+            * Find the corresponding tablespace mapping and copy the relevant
+            * details into the new tablespace entry.
+            */
+           for (tsmap = opt->tsmappings; tsmap != NULL; tsmap = tsmap->next)
+           {
+               if (strcmp(tsmap->old_dir, link_target) == 0)
+               {
+                   strncpy(ts->old_dir, tsmap->old_dir, MAXPGPATH);
+                   strncpy(ts->new_dir, tsmap->new_dir, MAXPGPATH);
+                   ts->in_place = false;
+                   break;
+               }
+           }
+
+           /* Every non-in-place tablespace must be mapped. */
+           if (tsmap == NULL)
+               pg_fatal("tablespace at \"%s\" has no tablespace mapping",
+                        link_target);
+       }
+       else
+       {
+           /*
+            * For an in-place tablespace, there's no separate directory, so
+            * we just record the paths within the data directories.
+            */
+           snprintf(ts->old_dir, MAXPGPATH, "%s/%s", pg_tblspc, de->d_name);
+           snprintf(ts->new_dir, MAXPGPATH, "%s/pg_tblpc/%s", opt->output,
+                    de->d_name);
+           ts->in_place = true;
+       }
+
+       /* Tablespaces should not share a directory. */
+       for (otherts = tslist; otherts != NULL; otherts = otherts->next)
+           if (strcmp(ts->new_dir, otherts->new_dir) == 0)
+               pg_fatal("tablespaces with OIDs %u and %u both point at \"%s\"",
+                        otherts->oid, oid, ts->new_dir);
+
+       /* Add this tablespace to the list. */
+       ts->next = tslist;
+       tslist = ts;
+   }
+
+   return tslist;
+}
+
+/*
+ * Read a file into a StringInfo.
+ *
+ * fd is used for the actual file I/O, filename for error reporting purposes.
+ * A file longer than maxlen is a fatal error.
+ */
+static void
+slurp_file(int fd, char *filename, StringInfo buf, int maxlen)
+{
+   struct stat st;
+   ssize_t     rb;
+
+   /* Check file size, and complain if it's too large. */
+   if (fstat(fd, &st) != 0)
+       pg_fatal("could not stat \"%s\": %m", filename);
+   if (st.st_size > maxlen)
+       pg_fatal("file \"%s\" is too large", filename);
+
+   /* Make sure we have enough space. */
+   enlargeStringInfo(buf, st.st_size);
+
+   /* Read the data. */
+   rb = read(fd, &buf->data[buf->len], st.st_size);
+
+   /*
+    * We don't expect any concurrent changes, so we should read exactly the
+    * expected number of bytes.
+    */
+   if (rb != st.st_size)
+   {
+       if (rb < 0)
+           pg_fatal("could not read file \"%s\": %m", filename);
+       else
+           pg_fatal("could not read file \"%s\": read only %d of %d bytes",
+                    filename, (int) rb, (int) st.st_size);
+   }
+
+   /* Adjust buffer length for new data and restore trailing-\0 invariant */
+   buf->len += rb;
+   buf->data[buf->len] = '\0';
+}
diff --git a/src/bin/pg_combinebackup/reconstruct.c b/src/bin/pg_combinebackup/reconstruct.c
new file mode 100644 (file)
index 0000000..6decdd8
--- /dev/null
@@ -0,0 +1,687 @@
+/*-------------------------------------------------------------------------
+ *
+ * reconstruct.c
+ *     Reconstruct full file from incremental file and backup chain.
+ *
+ * Copyright (c) 2017-2023, PostgreSQL Global Development Group
+ *
+ * IDENTIFICATION
+ *   src/bin/pg_combinebackup/reconstruct.c
+ *
+ *-------------------------------------------------------------------------
+ */
+#include "postgres_fe.h"
+
+#include <unistd.h>
+
+#include "backup/basebackup_incremental.h"
+#include "common/logging.h"
+#include "common/file_perm.h"
+#include "copy_file.h"
+#include "lib/stringinfo.h"
+#include "reconstruct.h"
+#include "storage/block.h"
+
+/*
+ * An rfile stores the data that we need in order to be able to use some file
+ * on disk for reconstruction. For any given output file, we create one rfile
+ * per backup that we need to consult when we constructing that output file.
+ *
+ * If we find a full version of the file in the backup chain, then only
+ * filename and fd are initialized; the remaining fields are 0 or NULL.
+ * For an incremental file, header_length, num_blocks, relative_block_numbers,
+ * and truncation_block_length are also set.
+ *
+ * num_blocks_read and highest_offset_read always start out as 0.
+ */
+typedef struct rfile
+{
+   char       *filename;
+   int         fd;
+   size_t      header_length;
+   unsigned    num_blocks;
+   BlockNumber *relative_block_numbers;
+   unsigned    truncation_block_length;
+   unsigned    num_blocks_read;
+   off_t       highest_offset_read;
+} rfile;
+
+static void debug_reconstruction(int n_source,
+                                rfile **sources,
+                                bool dry_run);
+static unsigned find_reconstructed_block_length(rfile *s);
+static rfile *make_incremental_rfile(char *filename);
+static rfile *make_rfile(char *filename, bool missing_ok);
+static void write_reconstructed_file(char *input_filename,
+                                    char *output_filename,
+                                    unsigned block_length,
+                                    rfile **sourcemap,
+                                    off_t *offsetmap,
+                                    pg_checksum_context *checksum_ctx,
+                                    bool debug,
+                                    bool dry_run);
+static void read_bytes(rfile *rf, void *buffer, unsigned length);
+
+/*
+ * Reconstruct a full file from an incremental file and a chain of prior
+ * backups.
+ *
+ * input_filename should be the path to the incremental file, and
+ * output_filename should be the path where the reconstructed file is to be
+ * written.
+ *
+ * relative_path should be the relative path to the directory containing this
+ * file. bare_file_name should be the name of the file within that directory,
+ * without "INCREMENTAL.".
+ *
+ * n_prior_backups is the number of prior backups, and prior_backup_dirs is
+ * an array of pathnames where those backups can be found.
+ */
+void
+reconstruct_from_incremental_file(char *input_filename,
+                                 char *output_filename,
+                                 char *relative_path,
+                                 char *bare_file_name,
+                                 int n_prior_backups,
+                                 char **prior_backup_dirs,
+                                 manifest_data **manifests,
+                                 char *manifest_path,
+                                 pg_checksum_type checksum_type,
+                                 int *checksum_length,
+                                 uint8 **checksum_payload,
+                                 bool debug,
+                                 bool dry_run)
+{
+   rfile     **source;
+   rfile      *latest_source = NULL;
+   rfile     **sourcemap;
+   off_t      *offsetmap;
+   unsigned    block_length;
+   unsigned    i;
+   unsigned    sidx = n_prior_backups;
+   bool        full_copy_possible = true;
+   int         copy_source_index = -1;
+   rfile      *copy_source = NULL;
+   pg_checksum_context checksum_ctx;
+
+   /*
+    * Every block must come either from the latest version of the file or
+    * from one of the prior backups.
+    */
+   source = pg_malloc0(sizeof(rfile *) * (1 + n_prior_backups));
+
+   /*
+    * Use the information from the latest incremental file to figure out how
+    * long the reconstructed file should be.
+    */
+   latest_source = make_incremental_rfile(input_filename);
+   source[n_prior_backups] = latest_source;
+   block_length = find_reconstructed_block_length(latest_source);
+
+   /*
+    * For each block in the output file, we need to know from which file we
+    * need to obtain it and at what offset in that file it's stored.
+    * sourcemap gives us the first of these things, and offsetmap the latter.
+    */
+   sourcemap = pg_malloc0(sizeof(rfile *) * block_length);
+   offsetmap = pg_malloc0(sizeof(off_t) * block_length);
+
+   /*
+    * Every block that is present in the newest incremental file should be
+    * sourced from that file. If it precedes the truncation_block_length,
+    * it's a block that we would otherwise have had to find in an older
+    * backup and thus reduces the number of blocks remaining to be found by
+    * one; otherwise, it's an extra block that needs to be included in the
+    * output but would not have needed to be found in an older backup if it
+    * had not been present.
+    */
+   for (i = 0; i < latest_source->num_blocks; ++i)
+   {
+       BlockNumber b = latest_source->relative_block_numbers[i];
+
+       Assert(b < block_length);
+       sourcemap[b] = latest_source;
+       offsetmap[b] = latest_source->header_length + (i * BLCKSZ);
+
+       /*
+        * A full copy of a file from an earlier backup is only possible if no
+        * blocks are needed from any later incremental file.
+        */
+       full_copy_possible = false;
+   }
+
+   while (1)
+   {
+       char        source_filename[MAXPGPATH];
+       rfile      *s;
+
+       /*
+        * Move to the next backup in the chain. If there are no more, then
+        * we're done.
+        */
+       if (sidx == 0)
+           break;
+       --sidx;
+
+       /*
+        * Look for the full file in the previous backup. If not found, then
+        * look for an incremental file instead.
+        */
+       snprintf(source_filename, MAXPGPATH, "%s/%s/%s",
+                prior_backup_dirs[sidx], relative_path, bare_file_name);
+       if ((s = make_rfile(source_filename, true)) == NULL)
+       {
+           snprintf(source_filename, MAXPGPATH, "%s/%s/INCREMENTAL.%s",
+                    prior_backup_dirs[sidx], relative_path, bare_file_name);
+           s = make_incremental_rfile(source_filename);
+       }
+       source[sidx] = s;
+
+       /*
+        * If s->header_length == 0, then this is a full file; otherwise, it's
+        * an incremental file.
+        */
+       if (s->header_length == 0)
+       {
+           struct stat sb;
+           BlockNumber b;
+           BlockNumber blocklength;
+
+           /* We need to know the length of the file. */
+           if (fstat(s->fd, &sb) < 0)
+               pg_fatal("could not stat \"%s\": %m", s->filename);
+
+           /*
+            * Since we found a full file, source all blocks from it that
+            * exist in the file.
+            *
+            * Note that there may be blocks that don't exist either in this
+            * file or in any incremental file but that precede
+            * truncation_block_length. These are, presumably, zero-filled
+            * blocks that result from the server extending the file but
+            * taking no action on those blocks that generated any WAL.
+            *
+            * Sadly, we have no way of validating that this is really what
+            * happened, and neither does the server. From it's perspective,
+            * an unmodified block that contains data looks exactly the same
+            * as a zero-filled block that never had any data: either way,
+            * it's not mentioned in any WAL summary and the server has no
+            * reason to read it. From our perspective, all we know is that
+            * nobody had a reason to back up the block. That certainly means
+            * that the block didn't exist at the time of the full backup, but
+            * the supposition that it was all zeroes at the time of every
+            * later backup is one that we can't validate.
+            */
+           blocklength = sb.st_size / BLCKSZ;
+           for (b = 0; b < latest_source->truncation_block_length; ++b)
+           {
+               if (sourcemap[b] == NULL && b < blocklength)
+               {
+                   sourcemap[b] = s;
+                   offsetmap[b] = b * BLCKSZ;
+               }
+           }
+
+           /*
+            * If a full copy looks possible, check whether the resulting file
+            * should be exactly as long as the source file is. If so, a full
+            * copy is acceptable, otherwise not.
+            */
+           if (full_copy_possible)
+           {
+               uint64      expected_length;
+
+               expected_length =
+                   (uint64) latest_source->truncation_block_length;
+               expected_length *= BLCKSZ;
+               if (expected_length == sb.st_size)
+               {
+                   copy_source = s;
+                   copy_source_index = sidx;
+               }
+           }
+
+           /* We don't need to consider any further sources. */
+           break;
+       }
+
+       /*
+        * Since we found another incremental file, source all blocks from it
+        * that we need but don't yet have.
+        */
+       for (i = 0; i < s->num_blocks; ++i)
+       {
+           BlockNumber b = s->relative_block_numbers[i];
+
+           if (b < latest_source->truncation_block_length &&
+               sourcemap[b] == NULL)
+           {
+               sourcemap[b] = s;
+               offsetmap[b] = s->header_length + (i * BLCKSZ);
+
+               /*
+                * A full copy of a file from an earlier backup is only
+                * possible if no blocks are needed from any later incremental
+                * file.
+                */
+               full_copy_possible = false;
+           }
+       }
+   }
+
+   /*
+    * If a checksum of the required type already exists in the
+    * backup_manifest for the relevant input directory, we can save some work
+    * by reusing that checksum instead of computing a new one.
+    */
+   if (copy_source_index >= 0 && manifests[copy_source_index] != NULL &&
+       checksum_type != CHECKSUM_TYPE_NONE)
+   {
+       manifest_file *mfile;
+
+       mfile = manifest_files_lookup(manifests[copy_source_index]->files,
+                                     manifest_path);
+       if (mfile == NULL)
+       {
+           char       *path = psprintf("%s/backup_manifest",
+                                       prior_backup_dirs[copy_source_index]);
+
+           /*
+            * The directory is out of sync with the backup_manifest, so emit
+            * a warning.
+            */
+           /*- translator: the first %s is a backup manifest file, the second is a file absent therein */
+           pg_log_warning("\"%s\" contains no entry for \"%s\"",
+                          path,
+                          manifest_path);
+           pfree(path);
+       }
+       else if (mfile->checksum_type == checksum_type)
+       {
+           *checksum_length = mfile->checksum_length;
+           *checksum_payload = pg_malloc(*checksum_length);
+           memcpy(*checksum_payload, mfile->checksum_payload,
+                  *checksum_length);
+           checksum_type = CHECKSUM_TYPE_NONE;
+       }
+   }
+
+   /* Prepare for checksum calculation, if required. */
+   pg_checksum_init(&checksum_ctx, checksum_type);
+
+   /*
+    * If the full file can be created by copying a file from an older backup
+    * in the chain without needing to overwrite any blocks or truncate the
+    * result, then forget about performing reconstruction and just copy that
+    * file in its entirety.
+    *
+    * Otherwise, reconstruct.
+    */
+   if (copy_source != NULL)
+       copy_file(copy_source->filename, output_filename,
+                 &checksum_ctx, dry_run);
+   else
+   {
+       write_reconstructed_file(input_filename, output_filename,
+                                block_length, sourcemap, offsetmap,
+                                &checksum_ctx, debug, dry_run);
+       debug_reconstruction(n_prior_backups + 1, source, dry_run);
+   }
+
+   /* Save results of checksum calculation. */
+   if (checksum_type != CHECKSUM_TYPE_NONE)
+   {
+       *checksum_payload = pg_malloc(PG_CHECKSUM_MAX_LENGTH);
+       *checksum_length = pg_checksum_final(&checksum_ctx,
+                                            *checksum_payload);
+   }
+
+   /*
+    * Close files and release memory.
+    */
+   for (i = 0; i <= n_prior_backups; ++i)
+   {
+       rfile      *s = source[i];
+
+       if (s == NULL)
+           continue;
+       if (close(s->fd) != 0)
+           pg_fatal("could not close \"%s\": %m", s->filename);
+       if (s->relative_block_numbers != NULL)
+           pfree(s->relative_block_numbers);
+       pg_free(s->filename);
+   }
+   pfree(sourcemap);
+   pfree(offsetmap);
+   pfree(source);
+}
+
+/*
+ * Perform post-reconstruction logging and sanity checks.
+ */
+static void
+debug_reconstruction(int n_source, rfile **sources, bool dry_run)
+{
+   unsigned    i;
+
+   for (i = 0; i < n_source; ++i)
+   {
+       rfile      *s = sources[i];
+
+       /* Ignore source if not used. */
+       if (s == NULL)
+           continue;
+
+       /* If no data is needed from this file, we can ignore it. */
+       if (s->num_blocks_read == 0)
+           continue;
+
+       /* Debug logging. */
+       if (dry_run)
+           pg_log_debug("would have read %u blocks from \"%s\"",
+                        s->num_blocks_read, s->filename);
+       else
+           pg_log_debug("read %u blocks from \"%s\"",
+                        s->num_blocks_read, s->filename);
+
+       /*
+        * In dry-run mode, we don't actually try to read data from the file,
+        * but we do try to verify that the file is long enough that we could
+        * have read the data if we'd tried.
+        *
+        * If this fails, then it means that a non-dry-run attempt would fail,
+        * complaining of not being able to read the required bytes from the
+        * file.
+        */
+       if (dry_run)
+       {
+           struct stat sb;
+
+           if (fstat(s->fd, &sb) < 0)
+               pg_fatal("could not stat \"%s\": %m", s->filename);
+           if (sb.st_size < s->highest_offset_read)
+               pg_fatal("file \"%s\" is too short: expected %llu, found %llu",
+                        s->filename,
+                        (unsigned long long) s->highest_offset_read,
+                        (unsigned long long) sb.st_size);
+       }
+   }
+}
+
+/*
+ * When we perform reconstruction using an incremental file, the output file
+ * should be at least as long as the truncation_block_length. Any blocks
+ * present in the incremental file increase the output length as far as is
+ * necessary to include those blocks.
+ */
+static unsigned
+find_reconstructed_block_length(rfile *s)
+{
+   unsigned    block_length = s->truncation_block_length;
+   unsigned    i;
+
+   for (i = 0; i < s->num_blocks; ++i)
+       if (s->relative_block_numbers[i] >= block_length)
+           block_length = s->relative_block_numbers[i] + 1;
+
+   return block_length;
+}
+
+/*
+ * Initialize an incremental rfile, reading the header so that we know which
+ * blocks it contains.
+ */
+static rfile *
+make_incremental_rfile(char *filename)
+{
+   rfile      *rf;
+   unsigned    magic;
+
+   rf = make_rfile(filename, false);
+
+   /* Read and validate magic number. */
+   read_bytes(rf, &magic, sizeof(magic));
+   if (magic != INCREMENTAL_MAGIC)
+       pg_fatal("file \"%s\" has bad incremental magic number (0x%x not 0x%x)",
+                filename, magic, INCREMENTAL_MAGIC);
+
+   /* Read block count. */
+   read_bytes(rf, &rf->num_blocks, sizeof(rf->num_blocks));
+   if (rf->num_blocks > RELSEG_SIZE)
+       pg_fatal("file \"%s\" has block count %u in excess of segment size %u",
+                filename, rf->num_blocks, RELSEG_SIZE);
+
+   /* Read truncation block length. */
+   read_bytes(rf, &rf->truncation_block_length,
+              sizeof(rf->truncation_block_length));
+   if (rf->truncation_block_length > RELSEG_SIZE)
+       pg_fatal("file \"%s\" has truncation block length %u in excess of segment size %u",
+                filename, rf->truncation_block_length, RELSEG_SIZE);
+
+   /* Read block numbers if there are any. */
+   if (rf->num_blocks > 0)
+   {
+       rf->relative_block_numbers =
+           pg_malloc0(sizeof(BlockNumber) * rf->num_blocks);
+       read_bytes(rf, rf->relative_block_numbers,
+                  sizeof(BlockNumber) * rf->num_blocks);
+   }
+
+   /* Remember length of header. */
+   rf->header_length = sizeof(magic) + sizeof(rf->num_blocks) +
+       sizeof(rf->truncation_block_length) +
+       sizeof(BlockNumber) * rf->num_blocks;
+
+   return rf;
+}
+
+/*
+ * Allocate and perform basic initialization of an rfile.
+ */
+static rfile *
+make_rfile(char *filename, bool missing_ok)
+{
+   rfile      *rf;
+
+   rf = pg_malloc0(sizeof(rfile));
+   rf->filename = pstrdup(filename);
+   if ((rf->fd = open(filename, O_RDONLY | PG_BINARY, 0)) < 0)
+   {
+       if (missing_ok && errno == ENOENT)
+       {
+           pg_free(rf);
+           return NULL;
+       }
+       pg_fatal("could not open file \"%s\": %m", filename);
+   }
+
+   return rf;
+}
+
+/*
+ * Read the indicated number of bytes from an rfile into the buffer.
+ */
+static void
+read_bytes(rfile *rf, void *buffer, unsigned length)
+{
+   unsigned    rb = read(rf->fd, buffer, length);
+
+   if (rb != length)
+   {
+       if (rb < 0)
+           pg_fatal("could not read file \"%s\": %m", rf->filename);
+       else
+           pg_fatal("could not read file \"%s\": read only %d of %d bytes",
+                    rf->filename, (int) rb, length);
+   }
+}
+
+/*
+ * Write out a reconstructed file.
+ */
+static void
+write_reconstructed_file(char *input_filename,
+                        char *output_filename,
+                        unsigned block_length,
+                        rfile **sourcemap,
+                        off_t *offsetmap,
+                        pg_checksum_context *checksum_ctx,
+                        bool debug,
+                        bool dry_run)
+{
+   int         wfd = -1;
+   unsigned    i;
+   unsigned    zero_blocks = 0;
+
+   /* Debugging output. */
+   if (debug)
+   {
+       StringInfoData debug_buf;
+       unsigned    start_of_range = 0;
+       unsigned    current_block = 0;
+
+       /* Basic information about the output file to be produced. */
+       if (dry_run)
+           pg_log_debug("would reconstruct \"%s\" (%u blocks, checksum %s)",
+                        output_filename, block_length,
+                        pg_checksum_type_name(checksum_ctx->type));
+       else
+           pg_log_debug("reconstructing \"%s\" (%u blocks, checksum %s)",
+                        output_filename, block_length,
+                        pg_checksum_type_name(checksum_ctx->type));
+
+       /* Print out the plan for reconstructing this file. */
+       initStringInfo(&debug_buf);
+       while (current_block < block_length)
+       {
+           rfile      *s = sourcemap[current_block];
+
+           /* Extend range, if possible. */
+           if (current_block + 1 < block_length &&
+               s == sourcemap[current_block + 1])
+           {
+               ++current_block;
+               continue;
+           }
+
+           /* Add details about this range. */
+           if (s == NULL)
+           {
+               if (current_block == start_of_range)
+                   appendStringInfo(&debug_buf, " %u:zero", current_block);
+               else
+                   appendStringInfo(&debug_buf, " %u-%u:zero",
+                                    start_of_range, current_block);
+           }
+           else
+           {
+               if (current_block == start_of_range)
+                   appendStringInfo(&debug_buf, " %u:%s@" UINT64_FORMAT,
+                                    current_block,
+                                    s == NULL ? "ZERO" : s->filename,
+                                    (uint64) offsetmap[current_block]);
+               else
+                   appendStringInfo(&debug_buf, " %u-%u:%s@" UINT64_FORMAT,
+                                    start_of_range, current_block,
+                                    s == NULL ? "ZERO" : s->filename,
+                                    (uint64) offsetmap[current_block]);
+           }
+
+           /* Begin new range. */
+           start_of_range = ++current_block;
+
+           /* If the output is very long or we are done, dump it now. */
+           if (current_block == block_length || debug_buf.len > 1024)
+           {
+               pg_log_debug("reconstruction plan:%s", debug_buf.data);
+               resetStringInfo(&debug_buf);
+           }
+       }
+
+       /* Free memory. */
+       pfree(debug_buf.data);
+   }
+
+   /* Open the output file, except in dry_run mode. */
+   if (!dry_run &&
+       (wfd = open(output_filename,
+                   O_RDWR | PG_BINARY | O_CREAT | O_EXCL,
+                   pg_file_create_mode)) < 0)
+       pg_fatal("could not open file \"%s\": %m", output_filename);
+
+   /* Read and write the blocks as required. */
+   for (i = 0; i < block_length; ++i)
+   {
+       uint8       buffer[BLCKSZ];
+       rfile      *s = sourcemap[i];
+       unsigned    wb;
+
+       /* Update accounting information. */
+       if (s == NULL)
+           ++zero_blocks;
+       else
+       {
+           s->num_blocks_read++;
+           s->highest_offset_read = Max(s->highest_offset_read,
+                                        offsetmap[i] + BLCKSZ);
+       }
+
+       /* Skip the rest of this in dry-run mode. */
+       if (dry_run)
+           continue;
+
+       /* Read or zero-fill the block as appropriate. */
+       if (s == NULL)
+       {
+           /*
+            * New block not mentioned in the WAL summary. Should have been an
+            * uninitialized block, so just zero-fill it.
+            */
+           memset(buffer, 0, BLCKSZ);
+       }
+       else
+       {
+           unsigned    rb;
+
+           /* Read the block from the correct source, except if dry-run. */
+           rb = pg_pread(s->fd, buffer, BLCKSZ, offsetmap[i]);
+           if (rb != BLCKSZ)
+           {
+               if (rb < 0)
+                   pg_fatal("could not read file \"%s\": %m", s->filename);
+               else
+                   pg_fatal("could not read file \"%s\": read only %d of %d bytes at offset %u",
+                            s->filename, (int) rb, BLCKSZ,
+                            (unsigned) offsetmap[i]);
+           }
+       }
+
+       /* Write out the block. */
+       if ((wb = write(wfd, buffer, BLCKSZ)) != BLCKSZ)
+       {
+           if (wb < 0)
+               pg_fatal("could not write file \"%s\": %m", output_filename);
+           else
+               pg_fatal("could not write file \"%s\": wrote only %d of %d bytes",
+                        output_filename, (int) wb, BLCKSZ);
+       }
+
+       /* Update the checksum computation. */
+       if (pg_checksum_update(checksum_ctx, buffer, BLCKSZ) < 0)
+           pg_fatal("could not update checksum of file \"%s\"",
+                    output_filename);
+   }
+
+   /* Debugging output. */
+   if (zero_blocks > 0)
+   {
+       if (dry_run)
+           pg_log_debug("would have zero-filled %u blocks", zero_blocks);
+       else
+           pg_log_debug("zero-filled %u blocks", zero_blocks);
+   }
+
+   /* Close the output file. */
+   if (wfd >= 0 && close(wfd) != 0)
+       pg_fatal("could not close \"%s\": %m", output_filename);
+}
diff --git a/src/bin/pg_combinebackup/reconstruct.h b/src/bin/pg_combinebackup/reconstruct.h
new file mode 100644 (file)
index 0000000..d689aeb
--- /dev/null
@@ -0,0 +1,33 @@
+/*-------------------------------------------------------------------------
+ *
+ * reconstruct.h
+ *     Reconstruct full file from incremental file and backup chain.
+ *
+ * Copyright (c) 2017-2023, PostgreSQL Global Development Group
+ *
+ * IDENTIFICATION
+ *   src/bin/pg_combinebackup/reconstruct.h
+ *
+ *-------------------------------------------------------------------------
+ */
+#ifndef RECONSTRUCT_H
+#define RECONSTRUCT_H
+
+#include "common/checksum_helper.h"
+#include "load_manifest.h"
+
+extern void reconstruct_from_incremental_file(char *input_filename,
+                                             char *output_filename,
+                                             char *relative_path,
+                                             char *bare_file_name,
+                                             int n_prior_backups,
+                                             char **prior_backup_dirs,
+                                             manifest_data **manifests,
+                                             char *manifest_path,
+                                             pg_checksum_type checksum_type,
+                                             int *checksum_length,
+                                             uint8 **checksum_payload,
+                                             bool debug,
+                                             bool dry_run);
+
+#endif
diff --git a/src/bin/pg_combinebackup/t/001_basic.pl b/src/bin/pg_combinebackup/t/001_basic.pl
new file mode 100644 (file)
index 0000000..fb66075
--- /dev/null
@@ -0,0 +1,23 @@
+# Copyright (c) 2021-2023, PostgreSQL Global Development Group
+
+use strict;
+use warnings;
+use PostgreSQL::Test::Utils;
+use Test::More;
+
+my $tempdir = PostgreSQL::Test::Utils::tempdir;
+
+program_help_ok('pg_combinebackup');
+program_version_ok('pg_combinebackup');
+program_options_handling_ok('pg_combinebackup');
+
+command_fails_like(
+   ['pg_combinebackup'],
+   qr/no input directories specified/,
+   'input directories must be specified');
+command_fails_like(
+   [ 'pg_combinebackup', $tempdir ],
+   qr/no output directory specified/,
+   'output directory must be specified');
+
+done_testing();
diff --git a/src/bin/pg_combinebackup/t/002_compare_backups.pl b/src/bin/pg_combinebackup/t/002_compare_backups.pl
new file mode 100644 (file)
index 0000000..0b80455
--- /dev/null
@@ -0,0 +1,154 @@
+# Copyright (c) 2021-2023, PostgreSQL Global Development Group
+
+use strict;
+use warnings;
+use File::Compare;
+use PostgreSQL::Test::Cluster;
+use PostgreSQL::Test::Utils;
+use Test::More;
+
+# Set up a new database instance.
+my $primary = PostgreSQL::Test::Cluster->new('primary');
+$primary->init(has_archiving => 1, allows_streaming => 1);
+$primary->append_conf('postgresql.conf', 'summarize_wal = on');
+$primary->start;
+
+# Create some test tables, each containing one row of data, plus a whole
+# extra database.
+$primary->safe_psql('postgres', <<EOM);
+CREATE TABLE will_change (a int, b text);
+INSERT INTO will_change VALUES (1, 'initial test row');
+CREATE TABLE will_grow (a int, b text);
+INSERT INTO will_grow VALUES (1, 'initial test row');
+CREATE TABLE will_shrink (a int, b text);
+INSERT INTO will_shrink VALUES (1, 'initial test row');
+CREATE TABLE will_get_vacuumed (a int, b text);
+INSERT INTO will_get_vacuumed VALUES (1, 'initial test row');
+CREATE TABLE will_get_dropped (a int, b text);
+INSERT INTO will_get_dropped VALUES (1, 'initial test row');
+CREATE TABLE will_get_rewritten (a int, b text);
+INSERT INTO will_get_rewritten VALUES (1, 'initial test row');
+CREATE DATABASE db_will_get_dropped;
+EOM
+
+# Take a full backup.
+my $backup1path = $primary->backup_dir . '/backup1';
+$primary->command_ok(
+   [ 'pg_basebackup', '-D', $backup1path, '--no-sync', '-cfast' ],
+   "full backup");
+
+# Now make some database changes.
+$primary->safe_psql('postgres', <<EOM);
+UPDATE will_change SET b = 'modified value' WHERE a = 1;
+INSERT INTO will_grow
+   SELECT g, 'additional row' FROM generate_series(2, 5000) g;
+TRUNCATE will_shrink;
+VACUUM will_get_vacuumed;
+DROP TABLE will_get_dropped;
+CREATE TABLE newly_created (a int, b text);
+INSERT INTO newly_created VALUES (1, 'row for new table');
+VACUUM FULL will_get_rewritten;
+DROP DATABASE db_will_get_dropped;
+CREATE DATABASE db_newly_created;
+EOM
+
+# Take an incremental backup.
+my $backup2path = $primary->backup_dir . '/backup2';
+$primary->command_ok(
+   [ 'pg_basebackup', '-D', $backup2path, '--no-sync', '-cfast',
+     '--incremental', $backup1path . '/backup_manifest' ],
+   "incremental backup");
+
+# Find an LSN to which either backup can be recovered.
+my $lsn = $primary->safe_psql('postgres', "SELECT pg_current_wal_lsn();");
+
+# Make sure that the WAL segment containing that LSN has been archived.
+# PostgreSQL won't issue two consecutive XLOG_SWITCH records, and the backup
+# just issued one, so call txid_current() to generate some WAL activity
+# before calling pg_switch_wal().
+$primary->safe_psql('postgres', 'SELECT txid_current();');
+$primary->safe_psql('postgres', 'SELECT pg_switch_wal()');
+
+# Now wait for the LSN we chose above to be archived.
+my $archive_wait_query =
+  "SELECT pg_walfile_name('$lsn') <= last_archived_wal FROM pg_stat_archiver;";
+$primary->poll_query_until('postgres', $archive_wait_query)
+  or die "Timed out while waiting for WAL segment to be archived";
+
+# Perform PITR from the full backup. Disable archive_mode so that the archive
+# doesn't find out about the new timeline; that way, the later PITR below will
+# choose the same timeline.
+my $pitr1 = PostgreSQL::Test::Cluster->new('pitr1');
+$pitr1->init_from_backup($primary, 'backup1',
+                        standby => 1, has_restoring => 1);
+$pitr1->append_conf('postgresql.conf', qq{
+recovery_target_lsn = '$lsn'
+recovery_target_action = 'promote'
+archive_mode = 'off'
+});
+$pitr1->start();
+
+# Perform PITR to the same LSN from the incremental backup. Use the same
+# basic configuration as before.
+my $pitr2 = PostgreSQL::Test::Cluster->new('pitr2');
+$pitr2->init_from_backup($primary, 'backup2',
+                        standby => 1, has_restoring => 1,
+                        combine_with_prior => [ 'backup1' ]);
+$pitr2->append_conf('postgresql.conf', qq{
+recovery_target_lsn = '$lsn'
+recovery_target_action = 'promote'
+archive_mode = 'off'
+});
+$pitr2->start();
+
+# Wait until both servers exit recovery.
+$pitr1->poll_query_until('postgres',
+                        "SELECT NOT pg_is_in_recovery();")
+  or die "Timed out while waiting apply to reach LSN $lsn";
+$pitr2->poll_query_until('postgres',
+                        "SELECT NOT pg_is_in_recovery();")
+  or die "Timed out while waiting apply to reach LSN $lsn";
+
+# Perform a logical dump of each server, and check that they match.
+# It would be much nicer if we could physically compare the data files, but
+# that doesn't really work. The contents of the page hole aren't guaranteed to
+# be identical, and there can be other discrepancies as well. To make this work
+# we'd need the equivalent of each AM's rm_mask functon written or at least
+# callable from Perl, and that doesn't seem practical.
+#
+# NB: We're just using the primary's backup directory for scratch space here.
+# This could equally well be any other directory we wanted to pick.
+my $backupdir = $primary->backup_dir;
+my $dump1 = $backupdir . '/pitr1.dump';
+my $dump2 = $backupdir . '/pitr2.dump';
+$pitr1->command_ok([
+   'pg_dumpall', '-f', $dump1, '--no-sync', '--no-unlogged-table-data',
+       '-d', $pitr1->connstr('postgres'),
+   ],
+   'dump from PITR 1');
+$pitr1->command_ok([
+   'pg_dumpall', '-f', $dump2, '--no-sync', '--no-unlogged-table-data',
+       '-d', $pitr1->connstr('postgres'),
+   ],
+   'dump from PITR 2');
+
+# Compare the two dumps, there should be no differences.
+my $compare_res = compare($dump1, $dump2);
+note($dump1);
+note($dump2);
+is($compare_res, 0, "dumps are identical");
+
+# Provide more context if the dumps do not match.
+if ($compare_res != 0)
+{
+   my ($stdout, $stderr) =
+       run_command([ 'diff', '-u', $dump1, $dump2 ]);
+   print "=== diff of $dump1 and $dump2\n";
+   print "=== stdout ===\n";
+   print $stdout;
+   print "=== stderr ===\n";
+   print $stderr;
+   print "=== EOF ===\n";
+}
+
+done_testing();
diff --git a/src/bin/pg_combinebackup/t/003_timeline.pl b/src/bin/pg_combinebackup/t/003_timeline.pl
new file mode 100644 (file)
index 0000000..bc053ca
--- /dev/null
@@ -0,0 +1,90 @@
+# Copyright (c) 2021-2023, PostgreSQL Global Development Group
+#
+# This test aims to validate that restoring an incremental backup works
+# properly even when the reference backup is on a different timeline.
+
+use strict;
+use warnings;
+use File::Compare;
+use PostgreSQL::Test::Cluster;
+use PostgreSQL::Test::Utils;
+use Test::More;
+
+# Set up a new database instance.
+my $node1 = PostgreSQL::Test::Cluster->new('node1');
+$node1->init(has_archiving => 1, allows_streaming => 1);
+$node1->append_conf('postgresql.conf', 'summarize_wal = on');
+$node1->start;
+
+# Create a table and insert a test row into it.
+$node1->safe_psql('postgres', <<EOM);
+CREATE TABLE mytable (a int, b text);
+INSERT INTO mytable VALUES (1, 'aardvark');
+EOM
+
+# Take a full backup.
+my $backup1path = $node1->backup_dir . '/backup1';
+$node1->command_ok(
+   [ 'pg_basebackup', '-D', $backup1path, '--no-sync', '-cfast' ],
+   "full backup from node1");
+
+# Insert a second row on the original node.
+$node1->safe_psql('postgres', <<EOM);
+INSERT INTO mytable VALUES (2, 'beetle');
+EOM
+
+# Now take an incremental backup.
+my $backup2path = $node1->backup_dir . '/backup2';
+$node1->command_ok(
+   [ 'pg_basebackup', '-D', $backup2path, '--no-sync', '-cfast',
+     '--incremental', $backup1path . '/backup_manifest' ],
+   "incremental backup from node1");
+
+# Restore the incremental backup and use it to create a new node.
+my $node2 = PostgreSQL::Test::Cluster->new('node2');
+$node2->init_from_backup($node1, 'backup2',
+                        combine_with_prior => [ 'backup1' ]);
+$node2->start();
+
+# Insert rows on both nodes.
+$node1->safe_psql('postgres', <<EOM);
+INSERT INTO mytable VALUES (3, 'crab');
+EOM
+$node2->safe_psql('postgres', <<EOM);
+INSERT INTO mytable VALUES (4, 'dingo');
+EOM
+
+# Take another incremental backup, from node2, based on backup2 from node1.
+my $backup3path = $node1->backup_dir . '/backup3';
+$node2->command_ok(
+   [ 'pg_basebackup', '-D', $backup3path, '--no-sync', '-cfast',
+     '--incremental', $backup2path . '/backup_manifest' ],
+   "incremental backup from node2");
+
+# Restore the incremental backup and use it to create a new node.
+my $node3 = PostgreSQL::Test::Cluster->new('node3');
+$node3->init_from_backup($node1, 'backup3',
+                        combine_with_prior => [ 'backup1', 'backup2' ]);
+$node3->start();
+
+# Let's insert one more row.
+$node3->safe_psql('postgres', <<EOM);
+INSERT INTO mytable VALUES (5, 'elephant');
+EOM
+
+# Now check that we have the expected rows.
+my $result = $node3->safe_psql('postgres', <<EOM);
+select string_agg(a::text, ':'), string_agg(b, ':') from mytable;
+EOM
+is($result, '1:2:4:5|aardvark:beetle:dingo:elephant');
+
+# Let's also verify all the backups.
+for my $backup_name (qw(backup1 backup2 backup3))
+{
+   $node1->command_ok(
+       [ 'pg_verifybackup', $node1->backup_dir . '/' . $backup_name ],
+       "verify backup $backup_name");
+}
+
+# OK, that's all.
+done_testing();
diff --git a/src/bin/pg_combinebackup/t/004_manifest.pl b/src/bin/pg_combinebackup/t/004_manifest.pl
new file mode 100644 (file)
index 0000000..37de61a
--- /dev/null
@@ -0,0 +1,75 @@
+# Copyright (c) 2021-2023, PostgreSQL Global Development Group
+#
+# This test aims to validate that pg_combinebackup works in the degenerate
+# case where it is invoked on a single full backup and that it can produce
+# a new, valid manifest when it does. Secondarily, it checks that
+# pg_combinebackup does not produce a manifest when run with --no-manifest.
+
+use strict;
+use warnings;
+use File::Compare;
+use PostgreSQL::Test::Cluster;
+use PostgreSQL::Test::Utils;
+use Test::More;
+
+# Set up a new database instance.
+my $node = PostgreSQL::Test::Cluster->new('node');
+$node->init(has_archiving => 1, allows_streaming => 1);
+$node->start;
+
+# Take a full backup.
+my $original_backup_path = $node->backup_dir . '/original';
+$node->command_ok(
+   [ 'pg_basebackup', '-D', $original_backup_path, '--no-sync', '-cfast' ],
+   "full backup");
+
+# Verify the full backup.
+$node->command_ok([ 'pg_verifybackup', $original_backup_path ],
+   "verify original backup");
+
+# Process the backup with pg_combinebackup using various manifest options.
+sub combine_and_test_one_backup
+{
+   my ($backup_name, $failure_pattern, @extra_options) = @_;
+   my $revised_backup_path = $node->backup_dir . '/' . $backup_name;
+   $node->command_ok(
+       [ 'pg_combinebackup', $original_backup_path, '-o', $revised_backup_path,
+               '--no-sync', @extra_options ],
+       "pg_combinebackup with @extra_options");
+   if (defined $failure_pattern)
+   {
+       $node->command_fails_like(
+           [ 'pg_verifybackup', $revised_backup_path ],
+           $failure_pattern,
+           "unable to verify backup $backup_name");
+   }
+   else
+   {
+       $node->command_ok(
+           [ 'pg_verifybackup', $revised_backup_path ],
+           "verify backup $backup_name");
+   }
+}
+combine_and_test_one_backup('nomanifest',
+   qr/could not open file.*backup_manifest/, '--no-manifest');
+combine_and_test_one_backup('csum_none',
+   undef, '--manifest-checksums=NONE');
+combine_and_test_one_backup('csum_sha224',
+   undef, '--manifest-checksums=SHA224');
+
+# Verify that SHA224 is mentioned in the SHA224 manifest lots of times.
+my $sha224_manifest =
+   slurp_file($node->backup_dir . '/csum_sha224/backup_manifest');
+my $sha224_count = (() = $sha224_manifest =~ /SHA224/mig);
+cmp_ok($sha224_count,
+   '>', 100, "SHA224 is mentioned many times in SHA224 manifest");
+
+# Verify that SHA224 is mentioned in the SHA224 manifest lots of times.
+my $nocsum_manifest =
+   slurp_file($node->backup_dir . '/csum_none/backup_manifest');
+my $nocsum_count = (() = $nocsum_manifest =~ /Checksum-Algorithm/mig);
+is($nocsum_count, 0,
+   "Checksum_Algorithm is not mentioned in no-checksum manifest");
+
+# OK, that's all.
+done_testing();
diff --git a/src/bin/pg_combinebackup/t/005_integrity.pl b/src/bin/pg_combinebackup/t/005_integrity.pl
new file mode 100644 (file)
index 0000000..b1f63a4
--- /dev/null
@@ -0,0 +1,125 @@
+# Copyright (c) 2021-2023, PostgreSQL Global Development Group
+#
+# This test aims to validate that an incremental backup can be combined
+# with a valid prior backup and that it cannot be combined with an invalid
+# prior backup.
+
+use strict;
+use warnings;
+use File::Compare;
+use File::Path qw(rmtree);
+use PostgreSQL::Test::Cluster;
+use PostgreSQL::Test::Utils;
+use Test::More;
+
+# Set up a new database instance.
+my $node1 = PostgreSQL::Test::Cluster->new('node1');
+$node1->init(has_archiving => 1, allows_streaming => 1);
+$node1->append_conf('postgresql.conf', 'summarize_wal = on');
+$node1->start;
+
+# Set up another new database instance. We don't want to use the cached
+# INITDB_TEMPLATE for this, because we want it to be a separate cluster
+# with a different system ID.
+my $node2;
+{
+   local $ENV{'INITDB_TEMPLATE'} = undef;
+
+   $node2 = PostgreSQL::Test::Cluster->new('node2');
+   $node2->init(has_archiving => 1, allows_streaming => 1);
+   $node2->append_conf('postgresql.conf', 'summarize_wal = on');
+   $node2->start;
+}
+
+# Take a full backup from node1.
+my $backup1path = $node1->backup_dir . '/backup1';
+$node1->command_ok(
+   [ 'pg_basebackup', '-D', $backup1path, '--no-sync', '-cfast' ],
+   "full backup from node1");
+
+# Now take an incremental backup.
+my $backup2path = $node1->backup_dir . '/backup2';
+$node1->command_ok(
+   [ 'pg_basebackup', '-D', $backup2path, '--no-sync', '-cfast',
+     '--incremental', $backup1path . '/backup_manifest' ],
+   "incremental backup from node1");
+
+# Now take another incremental backup.
+my $backup3path = $node1->backup_dir . '/backup3';
+$node1->command_ok(
+   [ 'pg_basebackup', '-D', $backup3path, '--no-sync', '-cfast',
+     '--incremental', $backup2path . '/backup_manifest' ],
+   "another incremental backup from node1");
+
+# Take a full backup from node2.
+my $backupother1path = $node1->backup_dir . '/backupother1';
+$node2->command_ok(
+   [ 'pg_basebackup', '-D', $backupother1path, '--no-sync', '-cfast' ],
+   "full backup from node2");
+
+# Take an incremental backup from node2.
+my $backupother2path = $node1->backup_dir . '/backupother2';
+$node2->command_ok(
+   [ 'pg_basebackup', '-D', $backupother2path, '--no-sync', '-cfast',
+     '--incremental', $backupother1path . '/backup_manifest' ],
+   "incremental backup from node2");
+
+# Result directory.
+my $resultpath = $node1->backup_dir . '/result';
+
+# Can't combine 2 full backups.
+$node1->command_fails_like(
+   [ 'pg_combinebackup', $backup1path, $backup1path, '-o', $resultpath ],
+   qr/is a full backup, but only the first backup should be a full backup/,
+   "can't combine full backups");
+
+# Can't combine 2 incremental backups.
+$node1->command_fails_like(
+   [ 'pg_combinebackup', $backup2path, $backup2path, '-o', $resultpath ],
+   qr/is an incremental backup, but the first backup should be a full backup/,
+   "can't combine full backups");
+
+# Can't combine full backup with an incremental backup from a different system.
+$node1->command_fails_like(
+   [ 'pg_combinebackup', $backup1path, $backupother2path, '-o', $resultpath ],
+   qr/expected system identifier.*but found/,
+   "can't combine backups from different nodes");
+
+# Can't omit a required backup.
+$node1->command_fails_like(
+   [ 'pg_combinebackup', $backup1path, $backup3path, '-o', $resultpath ],
+   qr/starts at LSN.*but expected/,
+   "can't omit a required backup");
+
+# Can't combine backups in the wrong order.
+$node1->command_fails_like(
+   [ 'pg_combinebackup', $backup1path, $backup3path, $backup2path, '-o', $resultpath ],
+   qr/starts at LSN.*but expected/,
+   "can't combine backups in the wrong order");
+
+# Can combine 3 backups that match up properly.
+$node1->command_ok(
+   [ 'pg_combinebackup', $backup1path, $backup2path, $backup3path, '-o', $resultpath ],
+   "can combine 3 matching backups");
+rmtree($resultpath);
+
+# Can combine full backup with first incremental.
+my $synthetic12path = $node1->backup_dir . '/synthetic12';
+$node1->command_ok(
+   [ 'pg_combinebackup', $backup1path, $backup2path, '-o', $synthetic12path ],
+   "can combine 2 matching backups");
+
+# Can combine result of previous step with second incremental.
+$node1->command_ok(
+   [ 'pg_combinebackup', $synthetic12path, $backup3path, '-o', $resultpath ],
+   "can combine synthetic backup with later incremental");
+rmtree($resultpath);
+
+# Can't combine result of 1+2 with 2.
+$node1->command_fails_like(
+   [ 'pg_combinebackup', $synthetic12path, $backup2path, '-o', $resultpath ],
+   qr/starts at LSN.*but expected/,
+   "can't combine synthetic backup with included incremental");
+
+# OK, that's all.
+done_testing();
diff --git a/src/bin/pg_combinebackup/write_manifest.c b/src/bin/pg_combinebackup/write_manifest.c
new file mode 100644 (file)
index 0000000..8216013
--- /dev/null
@@ -0,0 +1,293 @@
+/*-------------------------------------------------------------------------
+ *
+ * Write a new backup manifest.
+ *
+ * Portions Copyright (c) 1996-2023, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ * src/bin/pg_combinebackup/write_manifest.c
+ *
+ *-------------------------------------------------------------------------
+ */
+
+#include "postgres_fe.h"
+
+#include <fcntl.h>
+#include <time.h>
+#include <unistd.h>
+
+#include "common/checksum_helper.h"
+#include "common/file_perm.h"
+#include "common/logging.h"
+#include "lib/stringinfo.h"
+#include "load_manifest.h"
+#include "mb/pg_wchar.h"
+#include "write_manifest.h"
+
+struct manifest_writer
+{
+   char        pathname[MAXPGPATH];
+   int         fd;
+   StringInfoData buf;
+   bool        first_file;
+   bool        still_checksumming;
+   pg_checksum_context manifest_ctx;
+};
+
+static void escape_json(StringInfo buf, const char *str);
+static void flush_manifest(manifest_writer *mwriter);
+static size_t hex_encode(const uint8 *src, size_t len, char *dst);
+
+/*
+ * Create a new backup manifest writer.
+ *
+ * The backup manifest will be written into a file named backup_manifest
+ * in the specified directory.
+ */
+manifest_writer *
+create_manifest_writer(char *directory)
+{
+   manifest_writer *mwriter = pg_malloc(sizeof(manifest_writer));
+
+   snprintf(mwriter->pathname, MAXPGPATH, "%s/backup_manifest", directory);
+   mwriter->fd = -1;
+   initStringInfo(&mwriter->buf);
+   mwriter->first_file = true;
+   mwriter->still_checksumming = true;
+   pg_checksum_init(&mwriter->manifest_ctx, CHECKSUM_TYPE_SHA256);
+
+   appendStringInfo(&mwriter->buf,
+                    "{ \"PostgreSQL-Backup-Manifest-Version\": 1,\n"
+                    "\"Files\": [");
+
+   return mwriter;
+}
+
+/*
+ * Add an entry for a file to a backup manifest.
+ *
+ * This is very similar to the backend's AddFileToBackupManifest, but
+ * various adjustments are required due to frontend/backend differences
+ * and other details.
+ */
+void
+add_file_to_manifest(manifest_writer *mwriter, const char *manifest_path,
+                    size_t size, pg_time_t mtime,
+                    pg_checksum_type checksum_type,
+                    int checksum_length,
+                    uint8 *checksum_payload)
+{
+   int         pathlen = strlen(manifest_path);
+
+   if (mwriter->first_file)
+   {
+       appendStringInfoChar(&mwriter->buf, '\n');
+       mwriter->first_file = false;
+   }
+   else
+       appendStringInfoString(&mwriter->buf, ",\n");
+
+   if (pg_encoding_verifymbstr(PG_UTF8, manifest_path, pathlen) == pathlen)
+   {
+       appendStringInfoString(&mwriter->buf, "{ \"Path\": ");
+       escape_json(&mwriter->buf, manifest_path);
+       appendStringInfoString(&mwriter->buf, ", ");
+   }
+   else
+   {
+       appendStringInfoString(&mwriter->buf, "{ \"Encoded-Path\": \"");
+       enlargeStringInfo(&mwriter->buf, 2 * pathlen);
+       mwriter->buf.len += hex_encode((const uint8 *) manifest_path, pathlen,
+                                      &mwriter->buf.data[mwriter->buf.len]);
+       appendStringInfoString(&mwriter->buf, "\", ");
+   }
+
+   appendStringInfo(&mwriter->buf, "\"Size\": %zu, ", size);
+
+   appendStringInfoString(&mwriter->buf, "\"Last-Modified\": \"");
+   enlargeStringInfo(&mwriter->buf, 128);
+   mwriter->buf.len += strftime(&mwriter->buf.data[mwriter->buf.len], 128,
+                                "%Y-%m-%d %H:%M:%S %Z",
+                                gmtime(&mtime));
+   appendStringInfoChar(&mwriter->buf, '"');
+
+   if (mwriter->buf.len > 128 * 1024)
+       flush_manifest(mwriter);
+
+   if (checksum_length > 0)
+   {
+       appendStringInfo(&mwriter->buf,
+                        ", \"Checksum-Algorithm\": \"%s\", \"Checksum\": \"",
+                        pg_checksum_type_name(checksum_type));
+
+       enlargeStringInfo(&mwriter->buf, 2 * checksum_length);
+       mwriter->buf.len += hex_encode(checksum_payload, checksum_length,
+                                      &mwriter->buf.data[mwriter->buf.len]);
+
+       appendStringInfoChar(&mwriter->buf, '"');
+   }
+
+   appendStringInfoString(&mwriter->buf, " }");
+
+   if (mwriter->buf.len > 128 * 1024)
+       flush_manifest(mwriter);
+}
+
+/*
+ * Finalize the backup_manifest.
+ */
+void
+finalize_manifest(manifest_writer *mwriter,
+                 manifest_wal_range *first_wal_range)
+{
+   uint8       checksumbuf[PG_SHA256_DIGEST_LENGTH];
+   int         len;
+   manifest_wal_range *wal_range;
+
+   /* Terminate the list of files. */
+   appendStringInfoString(&mwriter->buf, "\n],\n");
+
+   /* Start a list of LSN ranges. */
+   appendStringInfoString(&mwriter->buf, "\"WAL-Ranges\": [\n");
+
+   for (wal_range = first_wal_range; wal_range != NULL;
+        wal_range = wal_range->next)
+       appendStringInfo(&mwriter->buf,
+                        "%s{ \"Timeline\": %u, \"Start-LSN\": \"%X/%X\", \"End-LSN\": \"%X/%X\" }",
+                        wal_range == first_wal_range ? "" : ",\n",
+                        wal_range->tli,
+                        LSN_FORMAT_ARGS(wal_range->start_lsn),
+                        LSN_FORMAT_ARGS(wal_range->end_lsn));
+
+   /* Terminate the list of WAL ranges. */
+   appendStringInfoString(&mwriter->buf, "\n],\n");
+
+   /* Flush accumulated data and update checksum calculation. */
+   flush_manifest(mwriter);
+
+   /* Checksum only includes data up to this point. */
+   mwriter->still_checksumming = false;
+
+   /* Compute and insert manifest checksum. */
+   appendStringInfoString(&mwriter->buf, "\"Manifest-Checksum\": \"");
+   enlargeStringInfo(&mwriter->buf, 2 * PG_SHA256_DIGEST_STRING_LENGTH);
+   len = pg_checksum_final(&mwriter->manifest_ctx, checksumbuf);
+   Assert(len == PG_SHA256_DIGEST_LENGTH);
+   mwriter->buf.len +=
+       hex_encode(checksumbuf, len, &mwriter->buf.data[mwriter->buf.len]);
+   appendStringInfoString(&mwriter->buf, "\"}\n");
+
+   /* Flush the last manifest checksum itself. */
+   flush_manifest(mwriter);
+
+   /* Close the file. */
+   if (close(mwriter->fd) != 0)
+       pg_fatal("could not close \"%s\": %m", mwriter->pathname);
+   mwriter->fd = -1;
+}
+
+/*
+ * Produce a JSON string literal, properly escaping characters in the text.
+ */
+static void
+escape_json(StringInfo buf, const char *str)
+{
+   const char *p;
+
+   appendStringInfoCharMacro(buf, '"');
+   for (p = str; *p; p++)
+   {
+       switch (*p)
+       {
+           case '\b':
+               appendStringInfoString(buf, "\\b");
+               break;
+           case '\f':
+               appendStringInfoString(buf, "\\f");
+               break;
+           case '\n':
+               appendStringInfoString(buf, "\\n");
+               break;
+           case '\r':
+               appendStringInfoString(buf, "\\r");
+               break;
+           case '\t':
+               appendStringInfoString(buf, "\\t");
+               break;
+           case '"':
+               appendStringInfoString(buf, "\\\"");
+               break;
+           case '\\':
+               appendStringInfoString(buf, "\\\\");
+               break;
+           default:
+               if ((unsigned char) *p < ' ')
+                   appendStringInfo(buf, "\\u%04x", (int) *p);
+               else
+                   appendStringInfoCharMacro(buf, *p);
+               break;
+       }
+   }
+   appendStringInfoCharMacro(buf, '"');
+}
+
+/*
+ * Flush whatever portion of the backup manifest we have generated and
+ * buffered in memory out to a file on disk.
+ *
+ * The first call to this function will create the file. After that, we
+ * keep it open and just append more data.
+ */
+static void
+flush_manifest(manifest_writer *mwriter)
+{
+   char        pathname[MAXPGPATH];
+
+   if (mwriter->fd == -1 &&
+       (mwriter->fd = open(mwriter->pathname,
+                           O_WRONLY | O_CREAT | O_EXCL | PG_BINARY,
+                           pg_file_create_mode)) < 0)
+       pg_fatal("could not open file \"%s\": %m", mwriter->pathname);
+
+   if (mwriter->buf.len > 0)
+   {
+       ssize_t     wb;
+
+       wb = write(mwriter->fd, mwriter->buf.data, mwriter->buf.len);
+       if (wb != mwriter->buf.len)
+       {
+           if (wb < 0)
+               pg_fatal("could not write \"%s\": %m", mwriter->pathname);
+           else
+               pg_fatal("could not write file \"%s\": wrote only %d of %d bytes",
+                        pathname, (int) wb, mwriter->buf.len);
+       }
+
+       if (mwriter->still_checksumming)
+           pg_checksum_update(&mwriter->manifest_ctx,
+                              (uint8 *) mwriter->buf.data,
+                              mwriter->buf.len);
+       resetStringInfo(&mwriter->buf);
+   }
+}
+
+/*
+ * Encode bytes using two hexademical digits for each one.
+ */
+static size_t
+hex_encode(const uint8 *src, size_t len, char *dst)
+{
+   const uint8 *end = src + len;
+
+   while (src < end)
+   {
+       unsigned    n1 = (*src >> 4) & 0xF;
+       unsigned    n2 = *src & 0xF;
+
+       *dst++ = n1 < 10 ? '0' + n1 : 'a' + n1 - 10;
+       *dst++ = n2 < 10 ? '0' + n2 : 'a' + n2 - 10;
+       ++src;
+   }
+
+   return len * 2;
+}
diff --git a/src/bin/pg_combinebackup/write_manifest.h b/src/bin/pg_combinebackup/write_manifest.h
new file mode 100644 (file)
index 0000000..8fd7fe0
--- /dev/null
@@ -0,0 +1,33 @@
+/*-------------------------------------------------------------------------
+ *
+ * Write a new backup manifest.
+ *
+ * Portions Copyright (c) 1996-2023, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ * src/bin/pg_combinebackup/write_manifest.h
+ *
+ *-------------------------------------------------------------------------
+ */
+#ifndef WRITE_MANIFEST_H
+#define WRITE_MANIFEST_H
+
+#include "common/checksum_helper.h"
+#include "pgtime.h"
+
+struct manifest_wal_range;
+
+struct manifest_writer;
+typedef struct manifest_writer manifest_writer;
+
+extern manifest_writer *create_manifest_writer(char *directory);
+extern void add_file_to_manifest(manifest_writer *mwriter,
+                                const char *manifest_path,
+                                size_t size, pg_time_t mtime,
+                                pg_checksum_type checksum_type,
+                                int checksum_length,
+                                uint8 *checksum_payload);
+extern void finalize_manifest(manifest_writer *mwriter,
+                             struct manifest_wal_range *first_wal_range);
+
+#endif                         /* WRITE_MANIFEST_H */
index 3ae3fc06df20dd4758c755d31eeec468aee33ea4..5407f51a4e74ebc696552b9bb3adfdef974eba5c 100644 (file)
@@ -85,6 +85,7 @@ static void RewriteControlFile(void);
 static void FindEndOfXLOG(void);
 static void KillExistingXLOG(void);
 static void KillExistingArchiveStatus(void);
+static void KillExistingWALSummaries(void);
 static void WriteEmptyXLOG(void);
 static void usage(void);
 
@@ -493,6 +494,7 @@ main(int argc, char *argv[])
    RewriteControlFile();
    KillExistingXLOG();
    KillExistingArchiveStatus();
+   KillExistingWALSummaries();
    WriteEmptyXLOG();
 
    printf(_("Write-ahead log reset\n"));
@@ -1034,6 +1036,40 @@ KillExistingArchiveStatus(void)
        pg_fatal("could not close directory \"%s\": %m", ARCHSTATDIR);
 }
 
+/*
+ * Remove existing WAL summary files
+ */
+static void
+KillExistingWALSummaries(void)
+{
+#define WALSUMMARYDIR XLOGDIR  "/summaries"
+#define WALSUMMARY_NHEXCHARS   40
+
+   DIR        *xldir;
+   struct dirent *xlde;
+   char        path[MAXPGPATH + sizeof(WALSUMMARYDIR)];
+
+   xldir = opendir(WALSUMMARYDIR);
+   if (xldir == NULL)
+       pg_fatal("could not open directory \"%s\": %m", WALSUMMARYDIR);
+
+   while (errno = 0, (xlde = readdir(xldir)) != NULL)
+   {
+       if (strspn(xlde->d_name, "0123456789ABCDEF") == WALSUMMARY_NHEXCHARS &&
+           strcmp(xlde->d_name + WALSUMMARY_NHEXCHARS, ".summary") == 0)
+       {
+           snprintf(path, sizeof(path), "%s/%s", WALSUMMARYDIR, xlde->d_name);
+           if (unlink(path) < 0)
+               pg_fatal("could not delete file \"%s\": %m", path);
+       }
+   }
+
+   if (errno)
+       pg_fatal("could not read directory \"%s\": %m", WALSUMMARYDIR);
+
+   if (closedir(xldir))
+       pg_fatal("could not close directory \"%s\": %m", ARCHSTATDIR);
+}
 
 /*
  * Write an empty XLOG file, containing only the checkpoint record
index 1611358137b8d877f674d89ef68ad08e0e6499a1..90e04cad56993821c8c2bed9f45efa3f7fecacca 100644 (file)
@@ -28,6 +28,8 @@ typedef struct BackupState
    XLogRecPtr  checkpointloc;  /* last checkpoint location */
    pg_time_t   starttime;      /* backup start time */
    bool        started_in_recovery;    /* backup started in recovery? */
+   XLogRecPtr  istartpoint;    /* incremental based on backup at this LSN */
+   TimeLineID  istarttli;      /* incremental based on backup on this TLI */
 
    /* Fields saved at the end of backup */
    XLogRecPtr  stoppoint;      /* backup stop WAL location */
index 1432d9c206bbc81cbb6fda1977e4efbc539e4d58..345bd22534c11074f6515ade018e928651cc7920 100644 (file)
@@ -34,6 +34,9 @@ typedef struct
    int64       size;           /* total size as sent; -1 if not known */
 } tablespaceinfo;
 
-extern void SendBaseBackup(BaseBackupCmd *cmd);
+struct IncrementalBackupInfo;
+
+extern void SendBaseBackup(BaseBackupCmd *cmd,
+                          struct IncrementalBackupInfo *ib);
 
 #endif                         /* _BASEBACKUP_H */
diff --git a/src/include/backup/basebackup_incremental.h b/src/include/backup/basebackup_incremental.h
new file mode 100644 (file)
index 0000000..de99117
--- /dev/null
@@ -0,0 +1,55 @@
+/*-------------------------------------------------------------------------
+ *
+ * basebackup_incremental.h
+ *   API for incremental backup support
+ *
+ * Portions Copyright (c) 2010-2022, PostgreSQL Global Development Group
+ *
+ * src/include/backup/basebackup_incremental.h
+ *
+ *-------------------------------------------------------------------------
+ */
+#ifndef BASEBACKUP_INCREMENTAL_H
+#define BASEBACKUP_INCREMENTAL_H
+
+#include "access/xlogbackup.h"
+#include "common/relpath.h"
+#include "storage/block.h"
+#include "utils/palloc.h"
+
+#define INCREMENTAL_MAGIC          0xd3ae1f0d
+
+typedef enum
+{
+   BACK_UP_FILE_FULLY,
+   BACK_UP_FILE_INCREMENTALLY
+} FileBackupMethod;
+
+struct IncrementalBackupInfo;
+typedef struct IncrementalBackupInfo IncrementalBackupInfo;
+
+extern IncrementalBackupInfo *CreateIncrementalBackupInfo(MemoryContext);
+
+extern void AppendIncrementalManifestData(IncrementalBackupInfo *ib,
+                                         const char *data,
+                                         int len);
+extern void FinalizeIncrementalManifest(IncrementalBackupInfo *ib);
+
+extern void PrepareForIncrementalBackup(IncrementalBackupInfo *ib,
+                                       BackupState *backup_state);
+
+extern char *GetIncrementalFilePath(Oid dboid, Oid spcoid,
+                                   RelFileNumber relfilenumber,
+                                   ForkNumber forknum, unsigned segno);
+extern FileBackupMethod GetFileBackupMethod(IncrementalBackupInfo *ib,
+                                           const char *path,
+                                           Oid dboid, Oid spcoid,
+                                           RelFileNumber relfilenumber,
+                                           ForkNumber forknum,
+                                           unsigned segno, size_t size,
+                                           unsigned *num_blocks_required,
+                                           BlockNumber *relative_block_numbers,
+                                           unsigned *truncation_block_length);
+extern size_t GetIncrementalFileSize(unsigned num_blocks_required);
+
+#endif
index 5142a08729173bca802a6dc5b9f87e20c6445f5a..c98961c329fcbc9a8ab71a525bfedf6a2369ca82 100644 (file)
@@ -108,4 +108,13 @@ typedef struct TimeLineHistoryCmd
    TimeLineID  timeline;
 } TimeLineHistoryCmd;
 
+/* ----------------------
+ *     UPLOAD_MANIFEST command
+ * ----------------------
+ */
+typedef struct UploadManifestCmd
+{
+   NodeTag     type;
+} UploadManifestCmd;
+
 #endif                         /* REPLNODES_H */
index a020377761dff1fa9aa987f75b1b45ffe5d8e335..46cb2a65500e4f23a2324177591e2ead3a9a3307 100644 (file)
@@ -779,6 +779,10 @@ a tar-format backup, pass the name of the tar program to use in the
 keyword parameter tar_program.  Note that tablespace tar files aren't
 handled here.
 
+To restore from an incremental backup, pass the parameter combine_with_prior
+as a reference to an array of prior backup names with which this backup
+is to be combined using pg_combinebackup.
+
 Streaming replication can be enabled on this node by passing the keyword
 parameter has_streaming => 1. This is disabled by default.
 
@@ -816,7 +820,22 @@ sub init_from_backup
    mkdir $self->archive_dir;
 
    my $data_path = $self->data_dir;
-   if (defined $params{tar_program})
+   if (defined $params{combine_with_prior})
+   {
+       my @prior_backups = @{$params{combine_with_prior}};
+       my @prior_backup_path;
+
+       for my $prior_backup_name (@prior_backups)
+       {
+           push @prior_backup_path,
+               $root_node->backup_dir . '/' . $prior_backup_name;
+       }
+
+       local %ENV = $self->_get_env();
+       PostgreSQL::Test::Utils::system_or_bail('pg_combinebackup', '-d',
+           @prior_backup_path, $backup_path, '-o', $data_path);
+   }
+   elsif (defined $params{tar_program})
    {
        mkdir($data_path);
        PostgreSQL::Test::Utils::system_or_bail($params{tar_program}, 'xf',
index 9390049314250bde6d9cabe1301b79958d2be0b3..e37ef9aa76da0cbdef7c33db52b6097fae7d4baf 100644 (file)
@@ -4023,3 +4023,15 @@ SummarizerReadLocalXLogPrivate
 WalSummarizerData
 WalSummaryFile
 WalSummaryIO
+FileBackupMethod
+IncrementalBackupInfo
+UploadManifestCmd
+backup_file_entry
+backup_wal_range
+cb_cleanup_dir
+cb_options
+cb_tablespace
+cb_tablespace_mapping
+manifest_data
+manifest_writer
+rfile