Horton

Re: 9.2beta1, parallel queries, ReleasePredicateLocks, CheckForSerializableConflictIn in the oprofile

Jeff Janes <jeff.janes@gmail.com>

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From: Jeff Janes <jeff.janes@gmail.com>
To: Sergey Koposov <koposov@ast.cam.ac.uk>
Cc: pgsql-hackers@postgresql.org
Date: 2012-05-24T18:02:15Z
Lists: pgsql-hackers

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  1. Improve bulk-insert performance by keeping the current target buffer pinned

On Thu, May 24, 2012 at 6:24 AM, Sergey Koposov <koposov@ast.cam.ac.uk> wrote:
> Hi,
>
> I've been running some tests on pg 9.2beta1 and in particular a set
> of queries like
...
>
> And I noticed than when I run the query like the one shown above in parallel
> (in multiple connections for ZZZ=0...8) the performance of each query drops
> down significantly (factor of 2)(despite the fact that during the execution
> of the query postgres is mostly CPU bound).

Is this a regression from previous versions (9.0, 9.1), or has the
slow down always been there?

Cheers,

Jeff