diff --git a/doc/src/sgml/logical-replication.sgml b/doc/src/sgml/logical-replication.sgml
index c5de2040f7..4f4d54758c 100644
--- a/doc/src/sgml/logical-replication.sgml
+++ b/doc/src/sgml/logical-replication.sgml
@@ -135,9 +135,9 @@
    the key.  When replica identity <literal>FULL</literal> is specified,
    indexes can be used on the subscriber side for searching the rows.  Candidate
    indexes must be btree, non-partial, and have at least one column reference
-   (i.e. cannot consist of only expressions).  These restrictions
-   on the non-unique index properties adhere to some of the restrictions that
-   are enforced for primary keys.  If there are no such suitable indexes,
+   at the leftmost column indexes (i.e. cannot consist of only expressions).  These
+   restrictions on the non-unique index properties adhere to some of the restrictions
+   that are enforced for primary keys.  If there are no such suitable indexes,
    the search on the subscriber side can be very inefficient, therefore
    replica identity <literal>FULL</literal> should only be used as a
    fallback if no other solution is possible.  If a replica identity other