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From: John Huttley <John@mib-infotech.co.nz>
To: Dan Langille <dan@langille.org>
Cc: pgsql-performance@postgresql.org
Subject: Re: Slow updates, poor IO
Date: Mon, 29 Sep 2008 16:47:09 +1300
Message-ID: <48E04FBD.9030304@mib-infotech.co.nz> (raw)
In-Reply-To: <1DFA2F1D-56D0-46B1-B9E1-27E994822FF4@langille.org>
References: <48DBE587.3050406@mib-infotech.co.nz>
	<20080926131556.GA1005@commandprompt.com>
	<48DD6A4A.10209@mib-infotech.co.nz>
	<dcc563d10809270809g17938b7fvf28a3624028e0f3b@mail.gmail.com>
	<48DEB4D4.1020100@mib-infotech.co.nz>
	<6110.1222612388@sss.pgh.pa.us>
	<48DFFCDB.3020000@mib-infotech.co.nz>
	<48E003AC.5000306@mib-infotech.co.nz>
	<Pine.GSO.4.64.0809282125550.24903@westnet.com>
	<48E036F4.3040609@mib-infotech.co.nz>
	<1DFA2F1D-56D0-46B1-B9E1-27E994822FF4@langille.org>

I've canned the db and got rid my of data.
I'm in the midst of doing some other benchmarking for a possible change 
to the bacula database.

Loading up 1M records into a table of 60M records complete with indexes.
It's still going...

--john


Dan Langille wrote:
>
> On Sep 28, 2008, at 10:01 PM, John Huttley wrote:
>
>>
>>
>> Greg Smith wrote:
>>> On Mon, 29 Sep 2008, John Huttley wrote:
>>>
>>>> checkpoint _segments=16 is fine, going to 64 made no improvement.
>>>
>>> You might find that it does *after* increasing shared_buffers.  If 
>>> the buffer cache is really small, the checkpoints can't have very 
>>> much work to do, so their impact on performance is smaller.  Once 
>>> you've got a couple of hundred MB on there, the per-checkpoint 
>>> overhead can be considerable.
>>>
>> Ahh bugger, I've just trashed my test setup.
>
> Pardon?  How did you do that?
>



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