From: Josh Berkus <josh@agliodbs.com>
To: Robert Haas <robertmhaas@gmail.com>
Cc: Magnus Hagander <magnus@hagander.net>
Cc: Greg Smith <greg@2ndquadrant.com>
Cc: pgsql-hackers@postgresql.org
Subject: Re: auto-sizing wal_buffers
Date: Thu, 13 Jan 2011 15:20:00 -0800
Message-ID: <4D2F88A0.9010703@agliodbs.com> (raw)
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<AANLkTi=No26FrfqaNbB49JkYTUmsqnwteAkYGxaaENn4@mail.gmail.com>
Robert,
>> Unfortunately, we might still need a manual parameter for override
>> because of the interaction between wal_buffers and
>> synchronous_commit=off, since it sets the max size of the unflushed data
>> buffer. Discuss?
>
> Do we have any evidence there's actually a problem in that case, or
> that a larger value of wal_buffers solves it? I mean, the background
> writer is going to start a background flush as quickly as it can...
I don't think anyone has done any testing. However, the setting is
there and some users might be convinced that they need it.
>> And the "auto" setting should be -1, not 0kB. We use -1 for "use
>> default" for several other GUCs.
>
> No can do. Gotta have things in the same units.
That's certainly not true with, for example, log_temp_files.
--
-- Josh Berkus
PostgreSQL Experts Inc.
http://www.pgexperts.com
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To: pgsql-hackers@postgresql.org
Cc: josh@agliodbs.com, robertmhaas@gmail.com, magnus@hagander.net, greg@2ndquadrant.com
Subject: Re: auto-sizing wal_buffers
In-Reply-To: <4D2F88A0.9010703@agliodbs.com>
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