Mention limitation of unique in partitioned tables

alvherre · alvherre · commit ec4eaab78b07 · 2019-07-10T09:12:49.000-04:00
Per gripe from Phil Bayer. Authors: Amit Langote and others Discussion: https://postgr.es/m/156236160709.1192.4498528196556144085@wrigleys.postgresql.org
diff --git a/doc/src/sgml/ddl.sgml b/doc/src/sgml/ddl.sgml
@@ -4003,6 +4003,15 @@ ALTER INDEX measurement_city_id_logdate_key
       </para>
      </listitem>
 
+     <listitem>
+      <para>
+       Unique constraints on partitioned tables must include all the
+       partition key columns.  This limitation exists because
+       <productname>PostgreSQL</productname> can only enforce
+       uniqueness in each partition individually.
+      </para>
+     </listitem>
+
      <listitem>
       <para>
        <literal>BEFORE ROW</literal> triggers, if necessary, must be defined
