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4+ messages / 3 participants
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* Re: Bloat issue on 8.3; autovac ignores HOT new pages?
@ 2011-01-31 18:27 Josh Berkus <josh@agliodbs.com>
2011-01-31 21:23 ` Re: Bloat issue on 8.3; autovac ignores HOT new pages? Mark Kirkwood <mark.kirkwood@catalyst.net.nz>
2011-01-31 21:57 ` Re: Bloat issue on 8.3; autovac ignores HOT new pages? Scott Marlowe <scott.marlowe@gmail.com>
0 siblings, 2 replies; 4+ messages in thread
From: Josh Berkus @ 2011-01-31 18:27 UTC (permalink / raw)
To: Mark Kirkwood <mark.kirkwood@catalyst.net.nz>; +Cc: Robert Haas <robertmhaas@gmail.com>; pgsql-performance
Robert, Mark,
I have not been able to reproduce this issue in a clean test on 9.0. As
a result, I now think that it was related to the FSM being too small on
the user's 8.3 instance, and will consider it resolved.
--
-- Josh Berkus
PostgreSQL Experts Inc.
http://www.pgexperts.com
^ permalink raw reply [nested|flat] 4+ messages in thread
* Re: Bloat issue on 8.3; autovac ignores HOT new pages?
2011-01-31 18:27 Re: Bloat issue on 8.3; autovac ignores HOT new pages? Josh Berkus <josh@agliodbs.com>
@ 2011-01-31 21:23 ` Mark Kirkwood <mark.kirkwood@catalyst.net.nz>
1 sibling, 0 replies; 4+ messages in thread
From: Mark Kirkwood @ 2011-01-31 21:23 UTC (permalink / raw)
To: pgsql-performance
On 01/02/11 07:27, Josh Berkus wrote:
> Robert, Mark,
>
> I have not been able to reproduce this issue in a clean test on 9.0. As
> a result, I now think that it was related to the FSM being too small on
> the user's 8.3 instance, and will consider it resolved.
>
Right - it might be interesting to see if you can reproduce on 8.4. I
would hazard a guess that you will not (on disk FSM + visibility map
vacuum improvements seem to make this whole area way better).
Cheers
Mark
^ permalink raw reply [nested|flat] 4+ messages in thread
* Re: Bloat issue on 8.3; autovac ignores HOT new pages?
2011-01-31 18:27 Re: Bloat issue on 8.3; autovac ignores HOT new pages? Josh Berkus <josh@agliodbs.com>
@ 2011-01-31 21:57 ` Scott Marlowe <scott.marlowe@gmail.com>
2011-02-01 23:37 ` Re: Bloat issue on 8.3; autovac ignores HOT new pages? Mark Kirkwood <mark.kirkwood@catalyst.net.nz>
1 sibling, 1 reply; 4+ messages in thread
From: Scott Marlowe @ 2011-01-31 21:57 UTC (permalink / raw)
To: Josh Berkus <josh@agliodbs.com>; +Cc: Mark Kirkwood <mark.kirkwood@catalyst.net.nz>; Robert Haas <robertmhaas@gmail.com>; pgsql-performance
On Mon, Jan 31, 2011 at 11:27 AM, Josh Berkus <josh@agliodbs.com> wrote:
> Robert, Mark,
>
> I have not been able to reproduce this issue in a clean test on 9.0. As
> a result, I now think that it was related to the FSM being too small on
> the user's 8.3 instance, and will consider it resolved.
I used to try and size free space map to be a little bigger than it
needed to be. I now size 4 or 5 times what it needs to be. shared
memory is cheap. So is going to 8.4, but on legacy systems that you
can't upgrade, 8.3 with a huge FSM works well enough (with suitably
aggressive autovac).
^ permalink raw reply [nested|flat] 4+ messages in thread
* Re: Bloat issue on 8.3; autovac ignores HOT new pages?
2011-01-31 18:27 Re: Bloat issue on 8.3; autovac ignores HOT new pages? Josh Berkus <josh@agliodbs.com>
2011-01-31 21:57 ` Re: Bloat issue on 8.3; autovac ignores HOT new pages? Scott Marlowe <scott.marlowe@gmail.com>
@ 2011-02-01 23:37 ` Mark Kirkwood <mark.kirkwood@catalyst.net.nz>
0 siblings, 0 replies; 4+ messages in thread
From: Mark Kirkwood @ 2011-02-01 23:37 UTC (permalink / raw)
To: Scott Marlowe <scott.marlowe@gmail.com>; +Cc: Josh Berkus <josh@agliodbs.com>; Robert Haas <robertmhaas@gmail.com>; pgsql-performance
On 01/02/11 10:57, Scott Marlowe wrote:
> On Mon, Jan 31, 2011 at 11:27 AM, Josh Berkus<josh@agliodbs.com> wrote:
>> Robert, Mark,
>>
>> I have not been able to reproduce this issue in a clean test on 9.0. As
>> a result, I now think that it was related to the FSM being too small on
>> the user's 8.3 instance, and will consider it resolved.
> I used to try and size free space map to be a little bigger than it
> needed to be. I now size 4 or 5 times what it needs to be. shared
> memory is cheap. So is going to 8.4, but on legacy systems that you
> can't upgrade, 8.3 with a huge FSM works well enough (with suitably
> aggressive autovac).
>
Yeah, 8.3 with very aggressive autovac my experience too - I've had the
naptime cranked down to 10s or even 1s in some cases, to try to tame
bloat growth for web cache or session type tables that are heavily
volatile.
regards
Mark
^ permalink raw reply [nested|flat] 4+ messages in thread
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2011-01-31 18:27 Re: Bloat issue on 8.3; autovac ignores HOT new pages? Josh Berkus <josh@agliodbs.com>
2011-01-31 21:23 ` Mark Kirkwood <mark.kirkwood@catalyst.net.nz>
2011-01-31 21:57 ` Scott Marlowe <scott.marlowe@gmail.com>
2011-02-01 23:37 ` Mark Kirkwood <mark.kirkwood@catalyst.net.nz>
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