================================= PostgreSQL specific model indexes ================================= .. module:: django.contrib.postgres.indexes The following are PostgreSQL specific :doc:`indexes ` available from the ``django.contrib.postgres.indexes`` module. ``BloomIndex`` ============== .. class:: BloomIndex(*expressions, length=None, columns=(), **options) Creates a bloom_ index. To use this index access you need to activate the bloom_ extension on PostgreSQL. You can install it using the :class:`~django.contrib.postgres.operations.BloomExtension` migration operation. Provide an integer number of bits from 1 to 4096 to the ``length`` parameter to specify the length of each index entry. PostgreSQL's default is 80. The ``columns`` argument takes a tuple or list of up to 32 values that are integer number of bits from 1 to 4095. .. _bloom: https://www.postgresql.org/docs/current/bloom.html ``BrinIndex`` ============= .. class:: BrinIndex(*expressions, 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. .. _automatic summarization: https://www.postgresql.org/docs/current/brin.html#BRIN-OPERATION ``BTreeIndex`` ============== .. class:: BTreeIndex(*expressions, fillfactor=None, deduplicate_items=None, **options) 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. Provide a boolean value to the deduplicate_items_ parameter to control whether deduplication is enabled. PostgreSQL enables deduplication by default. .. versionchanged:: 5.1 The ``deduplicate_items`` parameter was added. .. _fillfactor: https://www.postgresql.org/docs/current/sql-createindex.html#SQL-CREATEINDEX-STORAGE-PARAMETERS .. _deduplicate_items: https://www.postgresql.org/docs/current/btree-implementation.html#BTREE-DEDUPLICATION ``GinIndex`` ============ .. class:: GinIndex(*expressions, 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 :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 kilobytes 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(*expressions, buffering=None, fillfactor=None, **options) Creates a `GiST index `_. These indexes are automatically created on spatial fields with :attr:`spatial_index=True `. They're also useful on other types, such as :class:`~django.contrib.postgres.fields.HStoreField` or the :ref:`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 :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(*expressions, fillfactor=None, **options) 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. .. _fillfactor: https://www.postgresql.org/docs/current/sql-createindex.html#SQL-CREATEINDEX-STORAGE-PARAMETERS ``SpGistIndex`` =============== .. class:: SpGistIndex(*expressions, fillfactor=None, **options) 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. .. _fillfactor: https://www.postgresql.org/docs/current/sql-createindex.html#SQL-CREATEINDEX-STORAGE-PARAMETERS ``OpClass()`` expressions ========================= .. class:: OpClass(expression, name) An ``OpClass()`` expression represents the ``expression`` with a custom `operator class`_ that can be used to define functional indexes, functional unique constraints, or exclusion constraints. To use it, you need to add ``'django.contrib.postgres'`` in your :setting:`INSTALLED_APPS`. Set the ``name`` parameter to the name of the `operator class`_. For example:: Index( OpClass(Lower("username"), name="varchar_pattern_ops"), name="lower_username_idx", ) creates an index on ``Lower('username')`` using ``varchar_pattern_ops``. :: UniqueConstraint( OpClass(Upper("description"), name="text_pattern_ops"), name="upper_description_unique", ) creates a unique constraint on ``Upper('description')`` using ``text_pattern_ops``. :: ExclusionConstraint( name="exclude_overlapping_ops", expressions=[ (OpClass("circle", name="circle_ops"), RangeOperators.OVERLAPS), ], ) creates an exclusion constraint on ``circle`` using ``circle_ops``. .. _operator class: https://www.postgresql.org/docs/current/indexes-opclass.html