Re: Increasing WAL usage followed by sudden drop

From: delongboy <sdelong(at)saucontech(dot)com>
To: pgsql-performance(at)postgresql(dot)org
Subject: Re: Increasing WAL usage followed by sudden drop
Date: 2012-08-20 20:51:09
Message-ID: 1345495869310-5720492.post@n5.nabble.com
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Jeff Janes wrote
>
> Maybe there is an easier way, but one thing would be to compile a test
> server (of the same version as the production) with WAL_DEBUG defined
> in src/include/pg_config_manual.h, turn on the wal_debug guc, and
> crank up trace_recovery_messages. Then replay the WAL log files from
> production through this test server and see what it logs. That
> requires that you have
>
> Easier would to be turn on wal_debug and watch the server log as the
> WAL logs are generated, instead of recovered, but you probably don't
> want to do that on production. So you would need a workload generator
> that also exhibits the phenomenon of interest.
>

This sounds like it may help me see what is going on. However I am not
finding very much documentation as to how to do this exactly. What I have
is it seems this has to be set and postgres needs to be re-compiled to
enable it. Is this true? As that would not really be a viable option right
now. I am in position to set up a test server and run wal files through it.
But I am not sure how to accomplish this exactly? Is there somewhere you
anyone could point me to find documentation on how to do this?

Thanks a lot for everyone's input so far.

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