From: Mischa Sandberg <mischa.sandberg@telus.net>
To: Bill Chandler <billybobc1210@yahoo.com>
Cc: a3a18850@telus.net, pgsql-perform <pgsql-performance@postgresql.org>
Subject: Re: Index bloat problem?
Date: Thu, 21 Apr 2005 15:15:22 -0700
Message-ID: <1114121722.426825fa4474f@webmail.telus.net> (raw)
In-Reply-To: <20050421190318.26022.qmail@web51404.mail.yahoo.com>
References: <20050421190318.26022.qmail@web51404.mail.yahoo.com>
Quoting Bill Chandler <billybobc1210@yahoo.com>:
> ... The normal activity is to delete 3-5% of the rows per day,
> followed by a VACUUM ANALYZE.
...
> However, on occasion, deleting 75% of rows is a
> legitimate action for the client to take.
> > In case nobody else has asked: is your max_fsm_pages
> > big enough to handle all the deleted pages,
> > across ALL tables hit by the purge?
> This parameter is most likely set incorrectly. So
> that could be causing problems. Could that be a
> culprit for the index bloat, though?
Look at the last few lines of vacuum verbose output.
It will say something like:
free space map: 55 relations, 88416 pages stored; 89184 total pages needed
Allocated FSM size: 1000 relations + 1000000 pages = 5920 kB shared memory.
"1000000" here is [max_fsm_pages] from my postgresql.conf.
If the "total pages needed" is bigger than the pages
fsm is allocated for, then you are bleeding.
--
"Dreams come true, not free." -- S.Sondheim, ITW
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Reply to all the recipients using the --to and --cc options:
reply via email
To: pgsql-performance@postgresql.org
Cc: mischa.sandberg@telus.net, billybobc1210@yahoo.com
Subject: Re: Index bloat problem?
In-Reply-To: <1114121722.426825fa4474f@webmail.telus.net>
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox