From: Heikki Linnakangas <hlinnakangas@vmware.com>
To: Dong Ye <yed@vmware.com>
Cc: Claudio Freire <klaussfreire@gmail.com>
Cc: Ants Aasma <ants@cybertec.at>
Cc: pgsql-performance@postgresql.org <pgsql-performance@postgresql.org>
Subject: Re: dbt2 performance regresses from 9.1.6 to 9.2.1
Date: Wed, 07 Nov 2012 13:43:09 +0200
Message-ID: <509A494D.10607@vmware.com> (raw)
In-Reply-To: <CAGTBQpYYuHN8hoxjsWdbaVEqLLz0ns9XSATd80v4u=6SxQ-tBA@mail.gmail.com>
References: <03E840D17E263A48A5766AD576E0423A03DF0A266E@exch-mbx-111.vmware.com>
<CA+CSw_uPVRmWzRZL3PcLG6JZe4wOvTHBw6GhP=Eq-iKmgtCkAg@mail.gmail.com>
<03E840D17E263A48A5766AD576E0423A03DDC5BDE7@exch-mbx-111.vmware.com>
<CAGTBQpYYuHN8hoxjsWdbaVEqLLz0ns9XSATd80v4u=6SxQ-tBA@mail.gmail.com>
On 05.11.2012 16:32, Claudio Freire wrote:
> On Sun, Nov 4, 2012 at 7:23 PM, Dong Ye<yed@vmware.com> wrote:
>>> You are using prepared statements, this makes me think that this
>>> regression might be due to support for parameter specific plans for
>>> prepared statements. [1] Can you run the test on both versions without
>>> prepared statements and see if the regressions remains.
>>
>> Without prepare statement, we got 48837.33 avg notpm with 9.1.6 and 43264.54 avg notpm with 9.2.1.
>> notps over time shows the slowdown of 9.2.1 is evident during the entire course of the run.
>> Their profiles are posted on http://pgsql.privatepaste.com/b770f72967 (9.1.6) and http://pgsql.privatepaste.com/6fa8b7f174 (9.2.1).
>
> You know... it does look as if 9.2.1 is generating a lot more pressure
> into the memory allocator (AllocSetAlloc notably higher).
Did you check the access plans of the queries? 9.2 planner might choose
a slightly worse plan. Or perhaps index-only scans are hurting
performance with the DBT-2 queries.
- Heikki
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To: pgsql-performance@postgresql.org
Cc: hlinnakangas@vmware.com, yed@vmware.com, klaussfreire@gmail.com, ants@cybertec.at
Subject: Re: dbt2 performance regresses from 9.1.6 to 9.2.1
In-Reply-To: <509A494D.10607@vmware.com>
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