Correct overstatement in locking docs: we said ExclusiveLock is never

taken automatically, but this is only true with respect to user tables.

diff --git a/doc/src/sgml/mvcc.sgml b/doc/src/sgml/mvcc.sgml
index 01f697d426ae38bd28e1fb9d726de4e1a84df9a5..1aeec22b66cf43a24755f861d0827a42bfc03838 100644 (file)
--- a/doc/src/sgml/mvcc.sgml
+++ b/doc/src/sgml/mvcc.sgml
@@ -1,5 +1,5 @@
 
 
  
@@ -677,8 +677,9 @@ SELECT SUM(value) FROM mytab WHERE class = 2;
    
 
    
-         This lock mode is not automatically acquired by any
-         PostgreSQL command.
+         This lock mode is not automatically acquired on user tables by any
+         PostgreSQL command.  However it is
+         acquired on certain system catalogs in some operations.