| From: | Andres Freund <andres(at)2ndquadrant(dot)com> |
|---|---|
| To: | Josh Berkus <josh(at)agliodbs(dot)com> |
| Cc: | PostgreSQL-development <pgsql-hackers(at)postgreSQL(dot)org> |
| Subject: | Re: Vacuum, Freeze and Analyze: the big picture |
| Date: | 2013-05-30 19:16:13 |
| Message-ID: | 20130530191613.GA24645@awork2.anarazel.de |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-hackers |
On 2013-05-30 12:11:23 -0700, Josh Berkus wrote:
>
> > Inhowfar did 8.4 make freezing worse? I can't remember any new problems
> > there?
>
> Before the Visibility Map, we always vacuumed all pages in a relation
> when it was vacuumed at all. This means that we froze tuples at
> vacuum_min_freeze_age, not at autovacuum_max_freeze_age, which is when
> we do it post-8.4.
If we have reason to vacuum the relation we do it at
vacuum_freeze_table_age, not only at autovacuum_max_freeze_age. The
difference is that the latter triggers a vacuum, while the former only
changes a partial vacuum into a full one.
Calling that behaviour unconditionally worse is, err, interesting...
Greetings,
Andres Freund
--
Andres Freund http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Training & Services
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