Fixed #28194 -- Added support for normalization and cover density to SearchRank.

2 files changed, 35 insertions, 1 deletions

diff --git a/docs/ref/contrib/postgres/search.txt b/docs/ref/contrib/postgres/search.txt
index 65d54cfd8d..f00bddbee4 100644
--- a/docs/ref/contrib/postgres/search.txt
+++ b/docs/ref/contrib/postgres/search.txt
@@ -118,7 +118,7 @@ See :ref:`postgresql-fts-search-configuration` for an explanation of the
 ``SearchRank``
 ==============
 
-.. class:: SearchRank(vector, query, weights=None)
+.. class:: SearchRank(vector, query, weights=None, normalization=None, cover_density=False)
 
 So far, we've returned the results for which any match between the vector and
 the query are possible. It's likely you may wish to order the results by some
@@ -137,6 +137,32 @@ order by relevancy::
 See :ref:`postgresql-fts-weighting-queries` for an explanation of the
 ``weights`` parameter.
 
+Set the ``cover_density`` parameter to ``True`` to enable the cover density
+ranking, which means that the proximity of matching query terms is taken into
+account.
+
+Provide an integer to the ``normalization`` parameter to control rank
+normalization. This integer is a bit mask, so you can combine multiple
+behaviors::
+
+    >>> from django.db.models import Value
+    >>> Entry.objects.annotate(
+    ...     rank=SearchRank(
+    ...         vector,
+    ...         query,
+    ...         normalization=Value(2).bitor(Value(4)),
+    ...     )
+    ... )
+
+The PostgreSQL documentation has more details about `different rank
+normalization options`_.
+
+.. _different rank normalization options: https://www.postgresql.org/docs/current/textsearch-controls.html#TEXTSEARCH-RANKING
+
+.. versionadded:: 3.1
+
+    The ``normalization`` and ``cover_density`` parameters were added.
+
 ``SearchHeadline``
 ==================
 
diff --git a/docs/releases/3.1.txt b/docs/releases/3.1.txt
index d9c0a5db11..9961aebbab 100644
--- a/docs/releases/3.1.txt
+++ b/docs/releases/3.1.txt
@@ -160,6 +160,14 @@ Minor features
 
 * :lookup:`search` lookup now supports query expressions.
 
+* The new ``cover_density`` parameter of
+  :class:`~django.contrib.postgres.search.SearchRank` allows ranking by cover
+  density.
+
+* The new ``normalization`` parameter of
+  :class:`~django.contrib.postgres.search.SearchRank` allows rank
+  normalization.
+
 :mod:`django.contrib.redirects`
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~