@@ -743,18 +743,25 @@ ALTER TABLE [ IF EXISTS ] <replaceable class="PARAMETER">name</replaceable>
743743 </para>
744744
745745 <para>
746- A full table scan is performed on the table being attached to check that
747- no existing row in the table violates the partition constraint. It is
748- possible to avoid this scan by adding a valid <literal>CHECK</literal>
749- constraint to the table that would allow only the rows satisfying the
750- desired partition constraint before running this command. It will be
751- determined using such a constraint that the table need not be scanned
752- to validate the partition constraint. This does not work, however, if
753- any of the partition keys is an expression and the partition does not
754- accept <literal>NULL</literal> values. If attaching a list partition
755- that will not accept <literal>NULL</literal> values, also add
756- <literal>NOT NULL</literal> constraint to the partition key column,
757- unless it's an expression.
746+ If the new partition is a regular table, a full table scan is performed
747+ to check that no existing row in the table violates the partition
748+ constraint. It is possible to avoid this scan by adding a valid
749+ <literal>CHECK</literal> constraint to the table that would allow only
750+ the rows satisfying the desired partition constraint before running this
751+ command. It will be determined using such a constraint that the table
752+ need not be scanned to validate the partition constraint. This does not
753+ work, however, if any of the partition keys is an expression and the
754+ partition does not accept <literal>NULL</literal> values. If attaching
755+ a list partition that will not accept <literal>NULL</literal> values,
756+ also add <literal>NOT NULL</literal> constraint to the partition key
757+ column, unless it's an expression.
758+ </para>
759+
760+ <para>
761+ If the new partition is a foreign table, nothing is done to verify
762+ that all the rows in the foreign table obey the partition constraint.
763+ (See the discussion in <xref linkend="SQL-CREATEFOREIGNTABLE"> about
764+ constraints on the foreign table.)
758765 </para>
759766 </listitem>
760767 </varlistentry>