1. =================================

  2. PostgreSQL specific model indexes

  3. =================================

  4. 

  5. .. module:: django.contrib.postgres.indexes

  6. 

  7. The following are PostgreSQL specific :doc:`indexes </ref/models/indexes>`

  8. available from the ``django.contrib.postgres.indexes`` module.

  9. 

  10. ``BloomIndex``

  11. ==============

  12. 

  13. .. class:: BloomIndex(*expressions, length=None, columns=(), **options)

  14. 

  15.     Creates a bloom_ index.

  16. 

  17.     To use this index access you need to activate the bloom_ extension on

  18.     PostgreSQL. You can install it using the

  19.     :class:`~django.contrib.postgres.operations.BloomExtension` migration

  20.     operation.

  21. 

  22.     Provide an integer number of bits from 1 to 4096 to the ``length``

  23.     parameter to specify the length of each index entry. PostgreSQL's default

  24.     is 80.

  25. 

  26.     The ``columns`` argument takes a tuple or list of up to 32 values that are

  27.     integer number of bits from 1 to 4095.

  28. 

  29.     .. _bloom: https://www.postgresql.org/docs/current/bloom.html

  30. 

  31. ``BrinIndex``

  32. =============

  33. 

  34. .. class:: BrinIndex(*expressions, autosummarize=None, pages_per_range=None, **options)

  35. 

  36.     Creates a `BRIN index

  37.     <https://www.postgresql.org/docs/current/brin-intro.html>`_.

  38. 

  39.     Set the ``autosummarize`` parameter to ``True`` to enable `automatic

  40.     summarization`_ to be performed by autovacuum.

  41. 

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

  43. 

  44.     .. _automatic summarization: https://www.postgresql.org/docs/current/brin-intro.html#BRIN-OPERATION

  45. 

  46. ``BTreeIndex``

  47. ==============

  48. 

  49. .. class:: BTreeIndex(*expressions, fillfactor=None, **options)

  50. 

  51.     Creates a B-Tree index.

  52. 

  53.     Provide an integer value from 10 to 100 to the fillfactor_ parameter to

  54.     tune how packed the index pages will be. PostgreSQL's default is 90.

  55. 

  56.     .. _fillfactor: https://www.postgresql.org/docs/current/sql-createindex.html#SQL-CREATEINDEX-STORAGE-PARAMETERS

  57. 

  58. ``GinIndex``

  59. ============

  60. 

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

  62. 

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

  64. 

  65.     To use this index on data types not in the `built-in operator classes

  66.     <https://www.postgresql.org/docs/current/gin-builtin-opclasses.html>`_,

  67.     you need to activate the `btree_gin extension

  68.     <https://www.postgresql.org/docs/current/btree-gin.html>`_ on

  69.     PostgreSQL. You can install it using the

  70.     :class:`~django.contrib.postgres.operations.BtreeGinExtension` migration

  71.     operation.

  72. 

  73.     Set the ``fastupdate`` parameter to ``False`` to disable the `GIN Fast

  74.     Update Technique`_ that's enabled by default in PostgreSQL.

  75. 

  76.     Provide an integer number of kilobytes to the gin_pending_list_limit_

  77.     parameter to tune the maximum size of the GIN pending list which is used

  78.     when ``fastupdate`` is enabled.

  79. 

  80.     .. _GIN Fast Update Technique: https://www.postgresql.org/docs/current/gin-implementation.html#GIN-FAST-UPDATE

  81.     .. _gin_pending_list_limit: https://www.postgresql.org/docs/current/runtime-config-client.html#GUC-GIN-PENDING-LIST-LIMIT

  82. 

  83. ``GistIndex``

  84. =============

  85. 

  86. .. class:: GistIndex(*expressions, buffering=None, fillfactor=None, **options)

  87. 

  88.     Creates a `GiST index

  89.     <https://www.postgresql.org/docs/current/gist.html>`_. These indexes are

  90.     automatically created on spatial fields with :attr:`spatial_index=True

  91.     <django.contrib.gis.db.models.BaseSpatialField.spatial_index>`. They're

  92.     also useful on other types, such as

  93.     :class:`~django.contrib.postgres.fields.HStoreField` or the :ref:`range

  94.     fields <range-fields>`.

  95. 

  96.     To use this index on data types not in the built-in `gist operator classes

  97.     <https://www.postgresql.org/docs/current/gist-builtin-opclasses.html>`_,

  98.     you need to activate the `btree_gist extension

  99.     <https://www.postgresql.org/docs/current/btree-gist.html>`_ on PostgreSQL.

  100.     You can install it using the

  101.     :class:`~django.contrib.postgres.operations.BtreeGistExtension` migration

  102.     operation.

  103. 

  104.     Set the ``buffering`` parameter to ``True`` or ``False`` to manually enable

  105.     or disable `buffering build`_ of the index.

  106. 

  107.     Provide an integer value from 10 to 100 to the fillfactor_ parameter to

  108.     tune how packed the index pages will be. PostgreSQL's default is 90.

  109. 

  110.     .. _buffering build: https://www.postgresql.org/docs/current/gist-implementation.html#GIST-BUFFERING-BUILD

  111.     .. _fillfactor: https://www.postgresql.org/docs/current/sql-createindex.html#SQL-CREATEINDEX-STORAGE-PARAMETERS

  112. 

  113. ``HashIndex``

  114. =============

  115. 

  116. .. class:: HashIndex(*expressions, fillfactor=None, **options)

  117. 

  118.     Creates a hash index.

  119. 

  120.     Provide an integer value from 10 to 100 to the fillfactor_ parameter to

  121.     tune how packed the index pages will be. PostgreSQL's default is 90.

  122. 

  123.     .. _fillfactor: https://www.postgresql.org/docs/current/sql-createindex.html#SQL-CREATEINDEX-STORAGE-PARAMETERS

  124. 

  125. ``SpGistIndex``

  126. ===============

  127. 

  128. .. class:: SpGistIndex(*expressions, fillfactor=None, **options)

  129. 

  130.     Creates an `SP-GiST index

  131.     <https://www.postgresql.org/docs/current/spgist.html>`_.

  132. 

  133.     Provide an integer value from 10 to 100 to the fillfactor_ parameter to

  134.     tune how packed the index pages will be. PostgreSQL's default is 90.

  135. 

  136.     .. versionchanged:: 4.1

  137. 

  138.         Support for covering SP-GiST indexes on PostgreSQL 14+ was added.

  139. 

  140.     .. _fillfactor: https://www.postgresql.org/docs/current/sql-createindex.html#SQL-CREATEINDEX-STORAGE-PARAMETERS

  141. 

  142. ``OpClass()`` expressions

  143. =========================

  144. 

  145. .. class:: OpClass(expression, name)

  146. 

  147.     An ``OpClass()`` expression represents the ``expression`` with a custom

  148.     `operator class`_ that can be used to define functional indexes, functional

  149.     unique constraints, or exclusion constraints. To use it, you need to add

  150.     ``'django.contrib.postgres'`` in your :setting:`INSTALLED_APPS`. Set the

  151.     ``name`` parameter to the name of the `operator class`_.

  152. 

  153.     For example::

  154. 

  155.         Index(

  156.             OpClass(Lower('username'), name='varchar_pattern_ops'),

  157.             name='lower_username_idx',

  158.         )

  159. 

  160.     creates an index on ``Lower('username')`` using ``varchar_pattern_ops``.

  161.     ::

  162. 

  163.         UniqueConstraint(

  164.             OpClass(Upper('description'), name='text_pattern_ops'),

  165.             name='upper_description_unique',

  166.         )

  167. 

  168.     creates a unique constraint on ``Upper('description')`` using

  169.     ``text_pattern_ops``.

  170.     ::

  171. 

  172.         ExclusionConstraint(

  173.             name='exclude_overlapping_ops',

  174.             expressions=[

  175.                 (OpClass('circle', name='circle_ops'), RangeOperators.OVERLAPS),

  176.             ],

  177.         )

  178. 

  179.     creates an exclusion constraint on ``circle`` using ``circle_ops``.

  180. 

  181.     .. versionchanged:: 4.0

  182. 

  183.         Support for functional unique constraints was added.

  184. 

  185.     .. versionchanged:: 4.1

  186. 

  187.         Support for exclusion constraints was added.

  188. 

  189.     .. _operator class: https://www.postgresql.org/docs/current/indexes-opclass.html
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