From: Michael Paquier <michael@paquier.xyz>
Date: Thu, 20 Jan 2022 07:55:12 +0000 (+0900)
Subject: doc: Mention the level of locks taken on objects in COMMENT
X-Git-Tag: REL_10_20~24
X-Git-Url: http://git.postgresql.org/gitweb/?a=commitdiff_plain;h=6fc08323b5368f74ad0e4030104d42a28e24ca14;p=postgresql.git

doc: Mention the level of locks taken on objects in COMMENT

This information was nowhere to be found.  This adds one note on the
page of COMMENT, and one note in the section dedicated to explicit
locking, both telling that a SHARE UPDATE EXCLUSIVE lock is taken on the
object commented.

Author: Nikolai Berkoff
Reviewed-by: Laurenz Albe
Discussion: https://postgr.es/m/_0HDHIGcCdCsUyXn22QwI2FEuNR6Fs71rtgGX6hfyBlUh5rrnE2qMmvIFu9EY4Pijr2gUmJEAXCjuNU2Oxku9TryLp9CdHllpsCfN3gD0-Y=@pm.me
Backpatch-through: 10
---

diff --git a/doc/src/sgml/mvcc.sgml b/doc/src/sgml/mvcc.sgml
index 3c28a9f8e68..de91a85e5e8 100644
--- a/doc/src/sgml/mvcc.sgml
+++ b/doc/src/sgml/mvcc.sgml
@@ -950,7 +950,7 @@ ERROR:  could not serialize access due to read/write dependencies among transact
         <para>
          Acquired by <command>VACUUM</command> (without <option>FULL</option>),
          <command>ANALYZE</>, <command>CREATE INDEX CONCURRENTLY</>,
-         <command>CREATE STATISTICS</> and
+         <command>CREATE STATISTICS</>, <command>COMMENT ON</> and
          <command>ALTER TABLE VALIDATE</command> and other
          <command>ALTER TABLE</command> variants (for full details see
          <xref linkend="SQL-ALTERTABLE">).
diff --git a/doc/src/sgml/ref/comment.sgml b/doc/src/sgml/ref/comment.sgml
index df328117f1d..7a31dd08bed 100644
--- a/doc/src/sgml/ref/comment.sgml
+++ b/doc/src/sgml/ref/comment.sgml
@@ -88,6 +88,11 @@ COMMENT ON
    Comments are automatically dropped when their object is dropped.
   </para>
 
+  <para>
+   A <literal>SHARE UPDATE EXCLUSIVE</literal> lock is acquired on the
+   object to be commented.
+  </para>
+
   <para>
    For most kinds of object, only the object's owner can set the comment.
    Roles don't have owners, so the rule for <literal>COMMENT ON ROLE</> is