From: Joachim Worringen <joachim.worringen@iathh.de>
To: pgsql-performance@postgresql.org
Subject: Re: performance of temporary vs. regular tables
Date: Fri, 28 May 2010 13:04:13 +0200
Message-ID: <4BFFA32D.8010009@iathh.de> (raw)
In-Reply-To: <4BFD4643.9010901@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>
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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To: pgsql-performance@postgresql.org
Cc: joachim.worringen@iathh.de
Subject: Re: performance of temporary vs. regular tables
In-Reply-To: <4BFFA32D.8010009@iathh.de>
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