From: Tom Lane <tgl@sss.pgh.pa.us>
To: Dave Page <dpage@pgadmin.org>
Cc: Robert Haas <robertmhaas@gmail.com>
Cc: Bruce Momjian <bruce@momjian.us>
Cc: Dimitri Fontaine <dfontaine@hi-media.com>
Cc: Josh Berkus <josh@agliodbs.com>
Cc: postgres performance list <pgsql-performance@postgresql.org>
Subject: Re: PostgreSQL as a local in-memory cache
Date: Wed, 23 Jun 2010 16:43:06 -0400
Message-ID: <27712.1277325786@sss.pgh.pa.us> (raw)
In-Reply-To: <AANLkTimxDE1PRSaIhLFqRfaXoG7zxbDNH9mQO4aK4Kkt@mail.gmail.com>
References: <24597.1276803510@sss.pgh.pa.us>
<201006231937.o5NJbKp05127@momjian.us>
<AANLkTikTFG8-4sfJsQ16Fdu1TzZOh_zUtb-QuBPuo9jF@mail.gmail.com>
<AANLkTimxDE1PRSaIhLFqRfaXoG7zxbDNH9mQO4aK4Kkt@mail.gmail.com>
Dave Page <dpage@pgadmin.org> writes:
> On Wed, Jun 23, 2010 at 9:25 PM, Robert Haas <robertmhaas@gmail.com> wrote:
>> I don't think we need a system-wide setting for that. I believe that
>> the unlogged tables I'm working on will handle that case.
> Aren't they going to be truncated at startup? If the entire system is
> running without WAL, we would only need to do that in case of an
> unclean shutdown wouldn't we?
The problem with a system-wide no-WAL setting is it means you can't
trust the system catalogs after a crash. Which means you are forced to
use initdb to recover from any crash, in return for not a lot of savings
(for typical usages where there's not really much churn in the
catalogs). I tend to agree with Robert that a way to not log content
updates for individual user tables is likely to be much more useful in
practice.
regards, tom lane
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To: pgsql-performance@postgresql.org
Cc: tgl@sss.pgh.pa.us, dpage@pgadmin.org, robertmhaas@gmail.com, bruce@momjian.us, dfontaine@hi-media.com, josh@agliodbs.com
Subject: Re: PostgreSQL as a local in-memory cache
In-Reply-To: <27712.1277325786@sss.pgh.pa.us>
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