| From: | Alvaro Herrera <alvherre(at)commandprompt(dot)com> |
|---|---|
| To: | Bruce Momjian <bruce(at)momjian(dot)us> |
| Cc: | Gregory Stark <stark(at)enterprisedb(dot)com>, Heikki Linnakangas <heikki(at)enterprisedb(dot)com>, Russell Smith <mr-russ(at)pws(dot)com(dot)au>, Darcy Buskermolen <darcyb(at)commandprompt(dot)com>, Simon Riggs <simon(at)2ndquadrant(dot)com>, "Matthew T(dot) O'Connor" <matthew(at)zeut(dot)net>, Pavan Deolasee <pavan(at)enterprisedb(dot)com>, Christopher Browne <cbbrowne(at)acm(dot)org>, pgsql-general(at)postgresql(dot)org, pgsql-hackers(at)postgresql(dot)org |
| Subject: | Re: [HACKERS] Autovacuum Improvements |
| Date: | 2007-01-22 19:07:42 |
| Message-ID: | 20070122190742.GN26006@alvh.no-ip.org |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-general pgsql-hackers |
Bruce Momjian wrote:
>
> Yep, agreed on the random I/O issue. The larger question is if you have
> a huge table, do you care to reclaim 3% of the table size, rather than
> just vacuum it when it gets to 10% dirty? I realize the vacuum is going
> to take a lot of time, but vacuuming to relaim 3% three times seems like
> it is going to be more expensive than just vacuuming the 10% once. And
> vacuuming to reclaim 1% ten times seems even more expensive. The
> partial vacuum idea is starting to look like a loser to me again.
But if the partial vacuum is able to clean the busiest pages and reclaim
useful space, currently-running transactions will be able to use that
space and thus not have to extend the table. Not that extension is a
problem on itself, but it'll keep your working set smaller.
--
Alvaro Herrera http://www.CommandPrompt.com/
PostgreSQL Replication, Consulting, Custom Development, 24x7 support
| From | Date | Subject | |
|---|---|---|---|
| Next Message | Richard Huxton | 2007-01-22 19:16:35 | Re: [HACKERS] Autovacuum Improvements |
| Previous Message | Kenneth Marshall | 2007-01-22 19:00:34 | Re: [HACKERS] Autovacuum Improvements |
| From | Date | Subject | |
|---|---|---|---|
| Next Message | Alvaro Herrera | 2007-01-22 19:08:49 | Re: savepoint improvements |
| Previous Message | Merlin Moncure | 2007-01-22 19:06:23 | Re: savepoint improvements |