Add a new column output to pgmincore*()

The new column (databit) contain a varbit suitable to be inserted
into a table.
This is particulary usefull to warm the cache buffer on standby servers.

The next step is to allow restore from this bitstring.

diff --git a/ChangeLog b/ChangeLog
index 617cac820b2205898445c3991f110fbcd6925c9c..f087e313e794b045ebdcf2091251e6b71cf61636 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,6 @@
 //2011 Cédric Villemain <cedric@villemain.org>
-  * 0.4.2 - Add Debian packaging (Dimitri Fontaine)
+  * 0.5.0 - Output varbit containing vector information with pgmincore*()
+                 - Add Debian packaging (Dimitri Fontaine)
                  - Update to work with PostgreSQL >= 9.1 (Jeff Janes)
 
 04/30/2010 Cédric Villemain <cedric@villemain.org>

diff --git a/pgfincore.c b/pgfincore.c
index a83325ead120e2667f080b933207540fa712d55c..0f2ff341abcbf06d7ca18466bccef9e7ef9ca183 100644 (file)
--- a/pgfincore.c
+++ b/pgfincore.c
@@ -21,6 +21,7 @@
 #include "catalog/namespace.h" /* makeRangeVarFromNameList */
 #include "utils/builtins.h" /* textToQualifiedNameList */
 #include "utils/rel.h" /* Relation */
+#include "utils/varbit.h" /* bitstring datatype */
 #include "funcapi.h" /* SRF */
 #include "catalog/pg_type.h" /* TEXTOID for tuple_desc */
 #include "storage/fd.h"
@@ -41,7 +42,7 @@ PG_MODULE_MAGIC;
 /* } */
 
 #define PGSYSCONF_COLS  2
-#define PGFINCORE_COLS  5
+#define PGFINCORE_COLS  6
 
 /*
 *
@@ -159,8 +160,7 @@ pgfincore(PG_FUNCTION_ARGS)
        {
                relation_close(fctx->rel, AccessShareLock);
                elog(NOTICE,
-                        "pgfincore does not work with temporary and unlogged tables.",
-                        fctx->relationpath);
+                        "pgfincore does not work with temporary and unlogged tables.");
                pfree(fctx);
                SRF_RETURN_DONE(funcctx);
        }
@@ -254,6 +254,11 @@ pgmincore_file(char *filename, int action, FunctionCallInfo fcinfo)
   int64  block_mem  = 0;
   int64  group_mem  = 0;
 
+  VarBit *databit;
+  int len, slen, bitlen;
+  bits8      *r;
+  bits8           x = 0;
+
   // for open file
   int fd;
   // for stat file
@@ -273,6 +278,7 @@ pgmincore_file(char *filename, int action, FunctionCallInfo fcinfo)
   TupleDescInitEntry(tupdesc, (AttrNumber) 3, "block_disk", INT8OID, -1, 0);
   TupleDescInitEntry(tupdesc, (AttrNumber) 4, "block_mem",  INT8OID, -1, 0);
   TupleDescInitEntry(tupdesc, (AttrNumber) 5, "group_mem",  INT8OID, -1, 0);
+  TupleDescInitEntry(tupdesc, (AttrNumber) 6, "data",          VARBITOID, -1, 0);
   tupdesc = BlessTupleDesc(tupdesc);
 
 /* Do the main work */
@@ -331,6 +337,20 @@ pgmincore_file(char *filename, int action, FunctionCallInfo fcinfo)
          goto error;
        }
 
+       /*
+        * prepare the bit string
+        */
+       slen = st.st_size/pageSize;
+       bitlen = slen;
+       len = VARBITTOTALLEN(bitlen);
+       /* set to 0 so that *r is always initialised and string is zero-padded */
+       databit = (VarBit *) palloc0(len);
+       SET_VARSIZE(databit, len);
+       VARBITLEN(databit) = Min(bitlen, bitlen);
+
+       r = VARBITS(databit);
+       x = HIGHBIT;
+
        /* handle the results */
        for (pageIndex = 0; pageIndex <= st.st_size/pageSize; pageIndex++)
        {
@@ -338,6 +358,7 @@ pgmincore_file(char *filename, int action, FunctionCallInfo fcinfo)
          if (vec[pageIndex] & 1)
          {
                block_mem++;
+               *r |= x;
                elog (DEBUG5, "in memory blocks : %lld / %lld",
                          pageIndex, block_disk);
 
@@ -348,6 +369,13 @@ pgmincore_file(char *filename, int action, FunctionCallInfo fcinfo)
          }
          else
                flag=1;
+
+         x >>= 1;
+        if (x == 0)
+        {
+          x = HIGHBIT;
+          r++;
+        }
        }
   }
   elog(DEBUG1, "pgfincore %s: %lld of %lld block in linux cache, %lld groups",
@@ -383,9 +411,9 @@ pgmincore_file(char *filename, int action, FunctionCallInfo fcinfo)
   values[2] = Int64GetDatum(block_disk);
   values[3] = Int64GetDatum(block_mem);
   values[4] = Int64GetDatum(group_mem);
-
+  values[5] = VarBitPGetDatum(databit);
   memset(nulls, 0, sizeof(nulls));
-
+ 
   tuple = heap_form_tuple(tupdesc, values, nulls);
 
   //   free things
@@ -400,6 +428,7 @@ error:
   values[2] = Int64GetDatum(false);
   values[3] = Int64GetDatum(false);
   values[4] = Int64GetDatum(false);
+  values[5] = VarBitPGetDatum((VarBit *) palloc0(0));
   memset(nulls, 0, sizeof(nulls));
   tuple = heap_form_tuple(tupdesc, values, nulls);
   return HeapTupleGetDatum(tuple);

diff --git a/pgfincore.sql.in b/pgfincore.sql.in
index d05b78125e0e348cd11a8e093e664ee1c40a2e55..5af6e765e74d616b5157aecdd8bc4bf5de0c61b5 100644 (file)
--- a/pgfincore.sql.in
+++ b/pgfincore.sql.in
@@ -21,7 +21,8 @@ pgmincore(IN regclass,
                  OUT block_size bigint,
                  OUT block_disk bigint,
                  OUT block_mem bigint,
-                 OUT group_mem bigint)
+                 OUT group_mem bigint,
+                 OUT data      varbit)
 RETURNS setof record
 AS 'SELECT pgfincore($1, ''main'', 10)'
 LANGUAGE SQL;
@@ -32,7 +33,8 @@ pgmincore_snapshot(IN regclass,
                  OUT block_size bigint,
                  OUT block_disk bigint,
                  OUT block_mem bigint,
-                 OUT group_mem bigint)
+                 OUT group_mem bigint,
+                 OUT data      varbit)
 RETURNS setof record
 AS 'SELECT pgfincore($1, ''main'', 11)'
 LANGUAGE SQL;