=================================
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(pages_per_range=None, **options)

    Creates a `BRIN index
    <https://www.postgresql.org/docs/current/static/brin-intro.html>`_.

    The ``pages_per_range`` argument takes a positive integer.

``GinIndex``
============

.. class:: GinIndex(fastupdate=None, gin_pending_list_limit=None, **options)

    Creates a `gin index
    <https://www.postgresql.org/docs/current/static/gin.html>`_.

    To use this index on data types not in the `built-in operator classes
    <https://www.postgresql.org/docs/current/static/gin-builtin-opclasses.html>`_,
    you need to activate the `btree_gin extension
    <https://www.postgresql.org/docs/current/static/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. This parameter requires PostgreSQL ≥ 9.5.

    .. _GIN Fast Update Technique: https://www.postgresql.org/docs/current/static/gin-implementation.html#GIN-FAST-UPDATE
    .. _gin_pending_list_limit: https://www.postgresql.org/docs/current/static/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/static/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/static/gist-builtin-opclasses.html>`_,
    you need to activate the `btree_gist extension
    <https://www.postgresql.org/docs/current/static/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/static/gist-implementation.html#GIST-BUFFERING-BUILD
    .. _fillfactor: https://www.postgresql.org/docs/current/static/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/static/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/static/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/static/sql-createindex.html#SQL-CREATEINDEX-STORAGE-PARAMETERS