Remaining VACUUM patches

There are two additional patches in the VACUUM code. One is Heikki's
patch to recalculate OldestXmin in the vacuum run.

http://groups.google.es/group/pgsql.patches/browse_thread/thread/b2cfc901534d8990/40ba5b2fbb8f5b91
(much nicer than our archives because the whole thread is there, not
just month-sized pieces).

That thread ended without any conclusion; it is said that the patch will
be reconsidered when Simon Riggs' patch about the WAL flushing bug
lands, but I don't know what patch is that. Is it in the patch queue?
Was it already applied?

The problem with the patch is that the DBT-2 test showed decreased
performance, but that was still under investigation.

What is the status of this?

The other patch was ITAGAKI Takahiro's patch to fix n_dead_tuples in
pgstats after VACUUM when there is concurrent update activity. This
patch is still on hold largely because the above patch would cause it to
be a bit obsolete. So I think if we're not going to apply the former,
we should apply this one.

http://archives.postgresql.org/pgsql-hackers/2007-02/msg00051.php

http://archives.postgresql.org/pgsql-patches/2007-02/msg00021.php

Comments?

--
Alvaro Herrera http://www.CommandPrompt.com/
PostgreSQL Replication, Consulting, Custom Development, 24x7 support