Re: Lock levels for ALTER TABLE

On Wed, Jan  9, 2013 at 10:27:54PM -0500, Tom Lane wrote:
> Bruce Momjian <bruce@momjian.us> writes:
> > EnterpriseDB reports that our documentation states that ALTER TABLE
> > takes SHARE UPDATE EXCLUSIVE and ACCESS EXCLUSIVE lock modes.
> 
> Where do they see that?  We certainly reverted all of the documentation
> that Simon changed in the original commit for that failed feature.
> Something might have slipped through the cracks though.

In mvcc.sgml, I see:
     <varlistentry>      <term>       <literal>SHARE UPDATE EXCLUSIVE</literal>      </term>      <listitem>
<para>       Conflicts with the <literal>SHARE UPDATE EXCLUSIVE</literal>,        <literal>SHARE</literal>,
<literal>SHAREROW        EXCLUSIVE</literal>, <literal>EXCLUSIVE</literal>, and        <literal>ACCESS
EXCLUSIVE</literal>lock modes.        This mode protects a table against        concurrent schema changes and
<command>VACUUM</>runs.       </para>
 
       <para>        Acquired by <command>VACUUM</command> (without <option>FULL</option>),        <command>ANALYZE</>,
<command>CREATEINDEX CONCURRENTLY</>, and
 
-->      some forms of <command>ALTER TABLE</command>.       </para>      </listitem>     </varlistentry>

and
     <varlistentry>      <term>       <literal>ACCESS EXCLUSIVE</literal>      </term>      <listitem>       <para>
  Conflicts with locks of all modes (<literal>ACCESS        SHARE</literal>, <literal>ROW SHARE</literal>, <literal>ROW
      EXCLUSIVE</literal>, <literal>SHARE UPDATE        EXCLUSIVE</literal>, <literal>SHARE</literal>, <literal>SHARE
    ROW EXCLUSIVE</literal>, <literal>EXCLUSIVE</literal>, and        <literal>ACCESS EXCLUSIVE</literal>).        This
modeguarantees that the        holder is the only transaction accessing the table in any way.       </para>
 
       <para>
-->      Acquired by the <command>ALTER TABLE</>, <command>DROP TABLE</>,        <command>TRUNCATE</command>,
<command>REINDEX</command>,       <command>CLUSTER</command>, and <command>VACUUM FULL</command>        commands.
This is also the default lock mode for <command>LOCK TABLE</command>        statements that do not specify a mode
explicitly.      </para>      </listitem>     </varlistentry>
 


--  Bruce Momjian  <bruce@momjian.us>        http://momjian.us EnterpriseDB
http://enterprisedb.com
 + It's impossible for everything to be true. +