Re: PostgreSQL as a local in-memory cache - Mailing list pgsql-performance

From Bruce Momjian
Subject Re: PostgreSQL as a local in-memory cache
Date
Msg-id 201006232027.o5NKReE29495@momjian.us
Whole thread Raw
In response to Re: PostgreSQL as a local in-memory cache  (Robert Haas <robertmhaas@gmail.com>)
List pgsql-performance
Robert Haas wrote:
> On Wed, Jun 23, 2010 at 3:37 PM, Bruce Momjian <bruce@momjian.us> wrote:
> > Tom Lane wrote:
> >> Dimitri Fontaine <dfontaine@hi-media.com> writes:
> >> > Josh Berkus <josh@agliodbs.com> writes:
> >> >> a) Eliminate WAL logging entirely
> >
> > If we elimiate WAL logging, that means a reinstall is required for even
> > a postmaster crash, which is a new non-durable behavior.
> >
> > Also, we just added wal_level = minimal, which might end up being a poor
> > name choice of we want wal_level = off in PG 9.1. ?Perhaps we should
> > have used wal_level = crash_safe in 9.0.
> >
> > I have added the following TODO:
> >
> > ? ? ? ?Consider a non-crash-safe wal_level that eliminates WAL activity
> >
> > ? ? ? ? ? ?* http://archives.postgresql.org/pgsql-performance/2010-06/msg00300.php
>
> 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.

Uh, will we have some global unlogged setting, like for the system
tables and stuff?  It seems like an heavy burden to tell people they
have to create ever object as unlogged, and we would still generate log
for things like transaction commits.

--
  Bruce Momjian  <bruce@momjian.us>        http://momjian.us
  EnterpriseDB                             http://enterprisedb.com

  + None of us is going to be here forever. +

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