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

From: Robert Haas <robertmhaas(at)gmail(dot)com>
To: Sergey Koposov <koposov(at)ast(dot)cam(dot)ac(dot)uk>
Cc: Merlin Moncure <mmoncure(at)gmail(dot)com>, pgsql-hackers(at)postgresql(dot)org
Subject: Re: 9.2beta1, parallel queries, ReleasePredicateLocks, CheckForSerializableConflictIn in the oprofile
Date: 2012-05-24 18:02:56
Message-ID: CA+TgmoaygNLisDLRT5nPK9oE_+qKOaW7ELGRV4NrZLJb+6V_Ow@mail.gmail.com
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On Thu, May 24, 2012 at 1:42 PM, Sergey Koposov <koposov(at)ast(dot)cam(dot)ac(dot)uk> wrote:
> I guess there is nothing catastrophically wrong with that, but still I'm
> very suprised that you get severe locking problems (factor of two slow-down)
> when running parallel read-only transactions.

Me, too. How many concurrent connections are you running, and does
your working set exceed shared_buffers? Can you provide a
self-contained reproducible test case?

--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company

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