Re: What constitutes "reproducible" numbers from pgbench? - Mailing list pgsql-general

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Subject Re: What constitutes "reproducible" numbers from pgbench?
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Msg-id C5DBACC6DCC7604C9E4875FD9C7968B112D918542F@ITXS01EVS.service.it.nrw.de
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In response to Re: What constitutes "reproducible" numbers from pgbench?  (Andy Colson <andy@squeakycode.net>)
Responses Re: What constitutes "reproducible" numbers from pgbench?
Re: What constitutes "reproducible" numbers from pgbench?
List pgsql-general
On Tuesday, April 21, 2015 7:43 PM, Andy Colson wrote:
> On 4/21/2015 9:21 AM, Holger.Friedrich-Fa-Trivadis@it.nrw.de wrote:
>> Exactly what constitutes "reproducible" values from pgbench?  I keep
>> getting a range between 340 tps and 440 tps or something like that
> I think its common to get different timings.  I think its ok because things are changing (files, caches, indexes,
etc).

As I found out, our test server is a virtual machine, so while I should be "alone" on that virtual machine, of course I
haveno idea what else might be going on on the physical server the virtual machine is running on.  That would explain
thesomewhat wide variations. 

Qingqing Zhou wrote that the range between 340 tps and 440 tps I keep getting is not ok and numbers should be the same
withinseveral per cent.  Of course, if other things are going on on the physical server, I can't always expect a close
match.

Since someone asked, the point of the exercise is to see if and how various configurations in postgresql.conf are
affectingperformance. 

Cheers,
Holger Friedrich


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