django/docs/ref/contrib/postgres/indexes.txt

131 lines
4.8 KiB
Plaintext

=================================
PostgreSQL specific model indexes
=================================
.. module:: django.contrib.postgres.indexes
The following are PostgreSQL specific :doc:`indexes </ref/models/indexes>`
available from the ``django.contrib.postgres.indexes`` module.
``BrinIndex``
=============
.. class:: BrinIndex(autosummarize=None, pages_per_range=None, **options)
Creates a `BRIN index
<https://www.postgresql.org/docs/current/brin-intro.html>`_.
Set the ``autosummarize`` parameter to ``True`` to enable `automatic
summarization`_ to be performed by autovacuum.
The ``pages_per_range`` argument takes a positive integer.
.. _automatic summarization: https://www.postgresql.org/docs/current/brin-intro.html#BRIN-OPERATION
.. versionchanged:: 2.2
The ``autosummarize`` parameter was added.
``BTreeIndex``
==============
.. class:: BTreeIndex(fillfactor=None, **options)
.. versionadded:: 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.
.. _fillfactor: https://www.postgresql.org/docs/current/sql-createindex.html#SQL-CREATEINDEX-STORAGE-PARAMETERS
``GinIndex``
============
.. class:: GinIndex(fastupdate=None, gin_pending_list_limit=None, **options)
Creates a `gin index <https://www.postgresql.org/docs/current/gin.html>`_.
To use this index on data types not in the `built-in operator classes
<https://www.postgresql.org/docs/current/gin-builtin-opclasses.html>`_,
you need to activate the `btree_gin extension
<https://www.postgresql.org/docs/current/btree-gin.html>`_ on
PostgreSQL. You can install it using the
:class:`~django.contrib.postgres.operations.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.
.. _GIN Fast Update Technique: https://www.postgresql.org/docs/current/gin-implementation.html#GIN-FAST-UPDATE
.. _gin_pending_list_limit: https://www.postgresql.org/docs/current/runtime-config-client.html#GUC-GIN-PENDING-LIST-LIMIT
``GistIndex``
=============
.. class:: GistIndex(buffering=None, fillfactor=None, **options)
Creates a `GiST index
<https://www.postgresql.org/docs/current/gist.html>`_. These indexes are
automatically created on spatial fields with :attr:`spatial_index=True
<django.contrib.gis.db.models.BaseSpatialField.spatial_index>`. They're
also useful on other types, such as
:class:`~django.contrib.postgres.fields.HStoreField` or the :ref:`range
fields <range-fields>`.
To use this index on data types not in the built-in `gist operator classes
<https://www.postgresql.org/docs/current/gist-builtin-opclasses.html>`_,
you need to activate the `btree_gist extension
<https://www.postgresql.org/docs/current/btree-gist.html>`_ on PostgreSQL.
You can install it using the
:class:`~django.contrib.postgres.operations.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.
.. _buffering build: https://www.postgresql.org/docs/current/gist-implementation.html#GIST-BUFFERING-BUILD
.. _fillfactor: https://www.postgresql.org/docs/current/sql-createindex.html#SQL-CREATEINDEX-STORAGE-PARAMETERS
``HashIndex``
=============
.. class:: HashIndex(fillfactor=None, **options)
.. versionadded:: 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.
.. admonition:: 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.
.. _fillfactor: https://www.postgresql.org/docs/current/sql-createindex.html#SQL-CREATEINDEX-STORAGE-PARAMETERS
``SpGistIndex``
===============
.. class:: SpGistIndex(fillfactor=None, **options)
.. versionadded:: 2.2
Creates an `SP-GiST index
<https://www.postgresql.org/docs/current/spgist.html>`_.
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.
.. _fillfactor: https://www.postgresql.org/docs/current/sql-createindex.html#SQL-CREATEINDEX-STORAGE-PARAMETERS