On 19/09/14 19:24, Mkrtchyan, Tigran wrote:
----- Original Message -----
From: "Mark Kirkwood" <mark.kirkwood@xxxxxxxxxxxxxxx>
To: "Tigran Mkrtchyan" <tigran.mkrtchyan@xxxxxxx>
Cc: "Merlin Moncure" <mmoncure@xxxxxxxxx>, "postgres performance list" <pgsql-performance@xxxxxxxxxxxxxx>
Sent: Friday, September 19, 2014 8:26:27 AM
Subject: Re: postgres 9.3 vs. 9.4
On 19/09/14 17:53, Mkrtchyan, Tigran wrote:
----- Original Message -----
From: "Mark Kirkwood" <mark.kirkwood@xxxxxxxxxxxxxxx>
Further to the confusion, here's my 9.3 vs 9.4 on two M550 (one for 9.3
one for 9.4), see below for results.
I'm running xfs on them with trim/discard enabled:
$ mount|grep pg
/dev/sdd4 on /mnt/pg94 type xfs (rw,discard)
/dev/sdc4 on /mnt/pg93 type xfs (rw,discard)
I'm *not* seeing any significant difference between 9.3 and 9.4, and the
numbers are both about 2x your best number, which is food for thought
(those P320's should toast my M550 for write performance...).
cool! any details on OS and other options? I still get the same numbers
as before.
Sorry, Ubuntu 14.04 on a single socket i7 3.4 Ghz, 16G (i.e my workstation).
I saw the suggestion that Didier made to run 9.3 on the SSD that you
were using for 9.4, and see if it suddenly goes slow - then we'd know
it's something about the disk (or filesystem/mount options). Can you
test this?
swapping the disks did not change the results.
Nevertheless, I run the same test on my fedora20 laptop
8GB RAM, i7 2.2GHz and got 2600tps! I am totally
confused now! Is it kernel version? libc?
Well, that's progress anyway!
I guess you could try fedora 20 on the Dell server and see if that makes
any difference. But yes, confusing. Having been dealing with a high end
Dell server myself recently (R920), some re-reading of any manuals you
can find might be useful, we were continually surprised how easy it was
to have everything configured *slow*... and the detail in the
manuals...could be better!
Cheers
Mark
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