diff --git a/doc/src/sgml/mvcc.sgml b/doc/src/sgml/mvcc.sgml
index 24613e3c75..4ec853b77a 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..195d960603 100644
--- a/doc/src/sgml/ref/create_collation.sgml
+++ b/doc/src/sgml/ref/create_collation.sgml
@@ -163,6 +163,13 @@ CREATE COLLATION [ IF NOT EXISTS ] name FROM Notes
+ Note that CREATE COLLATION takes a
+ SHARE ROW EXCLUSIVE lock on
+ pg_collation system calatlog, which prevents
+ concurrent sessions from running the same command.
+
+
+
Use DROP COLLATION to remove user-defined collations.