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 3c28a9f8e687f4e8c02201b12b5b7d4d7be2e7f9..de91a85e5e8a4acd3a87031cbf0e647764ff38e9 100644 (file)
--- 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 df328117f1d803adfa8cf9957747fd70fdf8576e..7a31dd08bed1ca90be9c2b4247ba255ee2625471 100644 (file)
--- 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