diff --git a/doc/src/sgml/mvcc.sgml b/doc/src/sgml/mvcc.sgml
index 24613e3c75..73934e5cf3 100644
--- a/doc/src/sgml/mvcc.sgml
+++ b/doc/src/sgml/mvcc.sgml
@@ -970,8 +970,7 @@ ERROR: could not serialize access due to read/write dependencies among transact
- Acquired by CREATE COLLATION,
- CREATE TRIGGER, and many forms of
+ Acquired by CREATE TRIGGER and many forms of
ALTER TABLE (see ).
diff --git a/doc/src/sgml/ref/create_collation.sgml b/doc/src/sgml/ref/create_collation.sgml
index 5bc9af5499..038797fce1 100644
--- a/doc/src/sgml/ref/create_collation.sgml
+++ b/doc/src/sgml/ref/create_collation.sgml
@@ -162,6 +162,13 @@ CREATE COLLATION [ IF NOT EXISTS ] name FROM
Notes
+
+ CREATE COLLATION takes a SHARE ROW
+ EXCLUSIVE lock, which is self-conflicting, on the
+ pg_collation system catalog, so only one
+ CREATE COLLATION command can run at a time.
+
+
Use DROP COLLATION to remove user-defined collations.