Re: Blocking excessively in FOR UPDATE - Mailing list pgsql-performance

From Robert Haas
Subject Re: Blocking excessively in FOR UPDATE
Date
Msg-id CA+Tgmoasqd=pGy9FrE_PQH50rZi4d8nyZ1hMF3TKWpuBjO1sNg@mail.gmail.com
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In response to Re: Blocking excessively in FOR UPDATE  (Claudio Freire <klaussfreire@gmail.com>)
Responses Re: Blocking excessively in FOR UPDATE  (Claudio Freire <klaussfreire@gmail.com>)
List pgsql-performance
On Fri, Nov 4, 2011 at 2:45 PM, Claudio Freire <klaussfreire@gmail.com> wrote:
> I don't think 1 second can be such a big difference for the bgwriter,
> but I might be wrong.

Well, the default value is 200 ms.   And I've never before heard of
anyone tuning it up, except maybe to save on power consumption on a
system with very low utilization.  Nearly always you want to reduce
it.

> The wal_writer makes me doubt, though. If logged activity was higher
> than 8MB/s, then that setting would block it all.
> I guess I really should lower it.

Here again, you've set it to ten times the default value.  That
doesn't seem like a good idea.  I would start with the default and
tune down.

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

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