# Django 2.2.9.dev20191202104323 文档

# PostgreSQL specific model indexes

The following are PostgreSQL specific indexes available from the `django.contrib.postgres.indexes` module.

## `BrinIndex`

class `BrinIndex`(autosummarize=None, pages_per_range=None, **options)

  Creates a BRIN index.

  Set the `autosummarize` parameter to `True` to enable automatic summarization to be performed by autovacuum.

  The `pages_per_range` argument takes a positive integer.

  Changed in Django 2.2:

  The `autosummarize` parameter was added.

## `BTreeIndex`

class `BTreeIndex`(fillfactor=None, **options)
  New in Django 2.2.

  Creates a B-Tree index.

  Provide an integer value from 10 to 100 to the fillfactor parameter to tune how packed the index pages will be. PostgreSQL's default is 90.

## `GinIndex`

class `GinIndex`(fastupdate=None, gin_pending_list_limit=None, **options)

  Creates a gin index.

  To use this index on data types not in the built-in operator classes, you need to activate the btree_gin extension on PostgreSQL. You can install it using the `BtreeGinExtension` migration operation.

  Set the `fastupdate` parameter to `False` to disable the GIN Fast Update Technique that's enabled by default in PostgreSQL.

  Provide an integer number of bytes to the gin_pending_list_limit parameter to tune the maximum size of the GIN pending list which is used when `fastupdate` is enabled. This parameter requires PostgreSQL ≥ 9.5.

## `GistIndex`

class `GistIndex`(buffering=None, fillfactor=None, **options)

  Creates a GiST index. These indexes are automatically created on spatial fields with `spatial_index=True`. They're also useful on other types, such as `HStoreField` or the range fields.

  To use this index on data types not in the built-in gist operator classes, you need to activate the btree_gist extension on PostgreSQL. You can install it using the `BtreeGistExtension` migration operation.

  Set the `buffering` parameter to `True` or `False` to manually enable or disable buffering build of the index.

  Provide an integer value from 10 to 100 to the fillfactor parameter to tune how packed the index pages will be. PostgreSQL's default is 90.

## `HashIndex`

class `HashIndex`(fillfactor=None, **options)
  New in Django 2.2.

  Creates a hash index.

  Provide an integer value from 10 to 100 to the fillfactor parameter to tune how packed the index pages will be. PostgreSQL's default is 90.

  Use this index only on PostgreSQL 10 and later

  Hash indexes have been available in PostgreSQL for a long time, but they suffer from a number of data integrity issues in older versions.

## `SpGistIndex`

class `SpGistIndex`(fillfactor=None, **options)
  New in Django 2.2.

  Creates an SP-GiST index.

  Provide an integer value from 10 to 100 to the fillfactor parameter to tune how packed the index pages will be. PostgreSQL's default is 90.