Re: PostgreSQL as a local in-memory cache

From: Tom Lane
Subject: Re: PostgreSQL as a local in-memory cache
Date: ,
Msg-id: 27712.1277325786@sss.pgh.pa.us
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In response to: Re: PostgreSQL as a local in-memory cache  (Dave Page)
Responses: Re: PostgreSQL as a local in-memory cache  (Bruce Momjian)
Re: PostgreSQL as a local in-memory cache  (Dimitri Fontaine)
List: pgsql-performance

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PostgreSQL as a local in-memory cache  ("", )
 Re: PostgreSQL as a local in-memory cache  ("", )
  Re: PostgreSQL as a local in-memory cache  (Josh Berkus, )
   Re: PostgreSQL as a local in-memory cache  ("Pierre C", )
   Re: PostgreSQL as a local in-memory cache  (Dimitri Fontaine, )
    Re: PostgreSQL as a local in-memory cache  (Tom Lane, )
     Re: PostgreSQL as a local in-memory cache  (Bruce Momjian, )
      Re: PostgreSQL as a local in-memory cache  (Pavel Stehule, )
       Re: PostgreSQL as a local in-memory cache  (Bruce Momjian, )
      Re: PostgreSQL as a local in-memory cache  (Robert Haas, )
       Re: PostgreSQL as a local in-memory cache  (Dave Page, )
        Re: PostgreSQL as a local in-memory cache  (Tom Lane, )
         Re: PostgreSQL as a local in-memory cache  (Bruce Momjian, )
         Re: PostgreSQL as a local in-memory cache  (Dimitri Fontaine, )
       Re: PostgreSQL as a local in-memory cache  (Bruce Momjian, )
     Re: PostgreSQL as a local in-memory cache  (Bruce Momjian, )
      Re: PostgreSQL as a local in-memory cache  (Bruce Momjian, )
       Re: PostgreSQL as a local in-memory cache  (Robert Haas, )
        Re: PostgreSQL as a local in-memory cache  (Bruce Momjian, )
         Re: PostgreSQL as a local in-memory cache  ("Kevin Grittner", )
         Re: PostgreSQL as a local in-memory cache  (Robert Haas, )
          Re: PostgreSQL as a local in-memory cache  (Bruce Momjian, )
           Re: PostgreSQL as a local in-memory cache  (Tom Lane, )
            Re: PostgreSQL as a local in-memory cache  (Bruce Momjian, )
             Re: PostgreSQL as a local in-memory cache  (Jignesh Shah, )
              Re: PostgreSQL as a local in-memory cache  (Bruce Momjian, )
               Re: PostgreSQL as a local in-memory cache  (Brad Nicholson, )
                Re: PostgreSQL as a local in-memory cache  (Bruce Momjian, )
               Re: PostgreSQL as a local in-memory cache  (Jignesh Shah, )
                Re: PostgreSQL as a local in-memory cache  (Greg Smith, )
    Re: PostgreSQL as a local in-memory cache  ("Pierre C", )
     Re: PostgreSQL as a local in-memory cache  (Matthew Wakeling, )
      Re: PostgreSQL as a local in-memory cache  ("Pierre C", )
       Re: PostgreSQL as a local in-memory cache  (Josh Berkus, )
        Re: PostgreSQL as a local in-memory cache  (Rob Wultsch, )
         Re: PostgreSQL as a local in-memory cache  (Robert Haas, )
          Re: PostgreSQL as a local in-memory cache  (Josh Berkus, )
           Re: PostgreSQL as a local in-memory cache  (Pavel Stehule, )
            Re: PostgreSQL as a local in-memory cache  ("Joshua D. Drake", )
             Re: PostgreSQL as a local in-memory cache  (Pavel Stehule, )
              Re: PostgreSQL as a local in-memory cache  ("A.M.", )
               Re: PostgreSQL as a local in-memory cache  (Pavel Stehule, )
            Re: PostgreSQL as a local in-memory cache  (Josh Berkus, )
             Re: PostgreSQL as a local in-memory cache  (Pavel Stehule, )
            Re: PostgreSQL as a local in-memory cache  ("Joshua D. Drake", )
      Re: PostgreSQL as a local in-memory cache  (Josh Berkus, )
    Re: PostgreSQL as a local in-memory cache  (Josh Berkus, )
     Re: PostgreSQL as a local in-memory cache  (Tom Lane, )
   Re: PostgreSQL as a local in-memory cache  (Greg Smith, )
   Re: PostgreSQL as a local in-memory cache  (Robert Haas, )
 Re: PostgreSQL as a local in-memory cache  (Dave Crooke, )
  Re: PostgreSQL as a local in-memory cache  (Craig James, )

Dave Page <> writes:
> On Wed, Jun 23, 2010 at 9:25 PM, Robert Haas <> 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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From: Bruce Momjian
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Subject: Re: PostgreSQL as a local in-memory cache
From: Dimitri Fontaine
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Subject: Re: PostgreSQL as a local in-memory cache