Correct docs about partitions and EXCLUDE constraints.

jeff-davis · jeff-davis-aster · jeff-davis · commit 0f5ac7f321fb · 2025-06-19T12:43:49.000-07:00
In version 17 we added support for cross-partition EXCLUDE constraints, as long as they included all partition key columns and compared them with equality (see 8c852ba). I updated the docs for exclusion constraints, but I missed that the docs for CREATE TABLE still said that they were not supported. This commit fixes that. Author: Paul A. Jungwirth <pj@illuminatedcomputing.com> Co-authored-by: Jeff Davis <pgsql@j-davis.com> Discussion: https://postgr.es/m/c955d292-b92d-42d1-a2a0-1ec6715a2546@illuminatedcomputing.com Backpatch-through: 17
diff --git a/doc/src/sgml/ref/create_table.sgml b/doc/src/sgml/ref/create_table.sgml
@@ -442,11 +442,6 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
       the values in the new row, an error will be reported.
      </para>
 
-     <para>
-      Partitioned tables do not support <literal>EXCLUDE</literal> constraints;
-      however, you can define these constraints on individual partitions.
-     </para>
-
      <para>
       See <xref linkend="ddl-partitioning"/> for more discussion on table
       partitioning.
@@ -1125,6 +1120,18 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
       exclusion constraint on a subset of the table; internally this creates a
       partial index. Note that parentheses are required around the predicate.
      </para>
+
+     <para>
+      When establishing an exclusion constraint for a multi-level partition
+      hierarchy, all the columns in the partition key of the target
+      partitioned table, as well as those of all its descendant partitioned
+      tables, must be included in the constraint definition.  Additionally,
+      those columns must be compared using the equality operator.  These
+      restrictions ensure that potentially-conflicting rows will exist in the
+      same partition.  The constraint may also refer to other columns which
+      are not a part of any partition key, which can be compared using any
+      appropriate operator.
+     </para>
     </listitem>
    </varlistentry>
 
