From: | Stefan Kaltenbrunner <stefan(at)kaltenbrunner(dot)cc> |
---|---|
To: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
Cc: | pgsql-hackers(at)postgresql(dot)org |
Subject: | Re: Changes improve the performance of INSERT and UPDATE |
Date: | 2005-08-13 18:22:20 |
Message-ID: | 42FE3A5C.4000605@kaltenbrunner.cc |
Views: | Raw Message | Whole Thread | Download mbox | Resend email |
Thread: | |
Lists: | pgsql-hackers |
Tom Lane wrote:
> Hiroki Kataoka <kataoka(at)interwiz(dot)jp> writes:
>
>>>>This small patch improves the performance of INSERT and UPDATE. By my
>>>>machine, these changes raised the performance about 5%~10% in pgbench.
>>>
>>>BTW, in profiling the backend I've never seen PageAddItem take more than
>>>about 1% of the runtime, and in pgbench in particular it seems to be
>>>down around 0.1% ... so the above seems a bit optimistic ...
>
>
>>I have the nearly same result, but pgbench says different. I don't know
>>why my test generates 5~10% performance improvement. Therefore, I want
>>to take a benchmark in a reliable environment.
>
>
> I've been testing this patch a bit, and I'm unable to measure any
> consistent improvement in pgbench times (sometimes it seems to win,
> and some other times it doesn't). And gprof still swears up and down
> that PageAddItem is only about 0.1% of the runtime, which would make
> it impossible to obtain more than an 0.1% speedup. I'm inclined to
> write off your result as measurement error --- it's notoriously hard
> to get reproducible results out of pgbench.
I played with the patch two weeks ago (pgbench and some bulkloading of
production data as well as restores from large dumps) - afair I have
been unable to measure any noticable real-life improvement.
Trusting pgbench is quite difficult for such tests - I can get easily up
to 15% variation on consecutive runs on my boxes here ...
Stefan
From | Date | Subject | |
---|---|---|---|
Next Message | Andrew Dunstan | 2005-08-13 18:24:02 | distributed performance testing |
Previous Message | Tom Lane | 2005-08-13 17:57:05 | Re: psql SET/RESET/SHOW tab completion |