doc: Improve CREATE COLLATION locking documentation

Move out of the concurrency control chapter, where mostly only user
table locks are discussed, and move to CREATE COLLATION reference page.

Author: Amit Langote 
Author: Kyotaro HORIGUCHI 

diff --git a/doc/src/sgml/mvcc.sgml b/doc/src/sgml/mvcc.sgml
index 24613e3c75401a79cf40f240b742d838858cd987..73934e5cf37df9797210f41cc2ff775ff61b78eb 100644 (file)
--- 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 5bc9af5499e7b1a26da9a2f36aaa3a653cfe7158..038797fce116520361337c18ec17a1623047f0a6 100644 (file)
--- 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.