From: Rob Wultsch <wultsch@gmail.com>
To: Joachim Worringen <joachim.worringen@iathh.de>
Cc: pgsql-performance@postgresql.org
Subject: Re: performance of temporary vs. regular tables
Date: Fri, 28 May 2010 10:07:42 -0700
Message-ID: <AANLkTinmMF0ZXWYmfIuIx4BESK7-RvvjOSDu0dchkeM7@mail.gmail.com> (raw)
In-Reply-To: <4BFFA32D.8010009@iathh.de>
References: <4BFB837C.6010005@iathh.de>
<AANLkTik4_exB6U3GlfLMNIgPSk0G3RVQ8fWBTzwekrke@mail.gmail.com>
<4BFB91A8.20805@iathh.de>
<201005251241.59605.andres@anarazel.de>
<4BFD4643.9010901@iathh.de>
<4BFFA32D.8010009@iathh.de>
On Fri, May 28, 2010 at 4:04 AM, Joachim Worringen
<joachim.worringen@iathh.de> wrote:
> On 05/26/2010 06:03 PM, Joachim Worringen wrote:
>>
>> Am 25.05.2010 12:41, schrieb Andres Freund:
>>>
>>> On Tuesday 25 May 2010 11:00:24 Joachim Worringen wrote:
>>>>
>>>> Thanks. So, the Write-Ahead-Logging (being used or not) does not matter?
>>>
>>> It does matter quite significantly in my experience. Both from an io
>>> and a cpu
>>> overhead perspective.
>>
>> O.k., looks as if I have to make my own experience... I'll let you know
>> if possible.
>
> As promised, I did a tiny benchmark - basically, 8 empty tables are filled
> with 100k rows each within 8 transactions (somewhat typically for my
> application). The test machine has 4 cores, 64G RAM and RAID1 10k drives for
> data.
>
> # INSERTs into a TEMPORARY table:
> [joachim@testsrv scaling]$ time pb query -d scaling_qry_1.xml
>
> real 3m18.242s
> user 1m59.074s
> sys 1m51.001s
>
> # INSERTs into a standard table:
> [joachim@testsrv scaling]$ time pb query -d scaling_qry_1.xml
>
> real 3m35.090s
> user 2m5.295s
> sys 2m2.307s
>
> Thus, there is a slight hit of about 10% (which may even be within
> meausrement variations) - your milage will vary.
>
> Joachim
>
>
> --
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>
I think it would be interesting to create a ram disk and insert into
it. In the MySQL community even thought MyISAM has fallen out of use
the Memory table (based on MyISAM) is still somewhat used.
--
Rob Wultsch
wultsch@gmail.com
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To: pgsql-performance@postgresql.org
Cc: wultsch@gmail.com, joachim.worringen@iathh.de
Subject: Re: performance of temporary vs. regular tables
In-Reply-To: <AANLkTinmMF0ZXWYmfIuIx4BESK7-RvvjOSDu0dchkeM7@mail.gmail.com>
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