Message-ID: <4BFFA32D.8010009@iathh.de>
Date: Fri, 28 May 2010 13:04:13 +0200
From: Joachim Worringen <joachim.worringen@iathh.de>
Organization: IAT GmbH
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To: pgsql-performance@postgresql.org
Subject: Re: performance of temporary vs. regular tables
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	<AANLkTik4_exB6U3GlfLMNIgPSk0G3RVQ8fWBTzwekrke@mail.gmail.com>
	<4BFB91A8.20805@iathh.de> <201005251241.59605.andres@anarazel.de>
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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