Re: WIP patch for tuple freezing issues

Tom Lane wrote:
> Attached is a draft patch for the WAL-and-freezing issues we've been
> discussing.  This incorporates Heikki and Simon's work on providing
> WAL-logging for tuple freezing actions and pg_clog truncation
> respectively, and adds on several other things:

Looks good. Just a few notes:

The patch seems to make VACUUM FULL FREEZE combination valid again,
which should be note in the docs.

This comment in vacuum.c:

/*
  * If we froze any tuples, mark the buffer dirty, and write a WAL
  * record recording the changes.  We must log the changes to be
  * crash-safe if we truncate clog at conclusion of the vacuum.
  */

is not accurate. As discussed earlier, a crash is a problem even if clog
is not truncated by this vacuum, because relfrozenxid is updated anyway.

--
   Heikki Linnakangas
   EnterpriseDB   http://www.enterprisedb.com