Re: Temporary tables and disk activity

Tom Lane wrote:
> Bruce Momjian <pgman@candle.pha.pa.us> writes:
> > Tom Lane wrote:
> >> One of the things on the TODO list is making the size of temp-table
> >> buffers user-configurable.  (Temp table buffers are per-backend, they
> >> are not part of the shared buffer arena.)  With a large temp-table arena
> >> we'd never need to write to the kernel in the first place.  Right now
> >> you could manually increase the #define that sets it, but it would not
> >> pay to make it very large because the management algorithms are very
> >> stupid (linear scans).  That has to be fixed first :-(
>
> > I assume you mean your TODO list because the official one has no mention
> > of this.
>
> Doesn't it?  We've surely discussed the problem enough times, eg
> http://archives.postgresql.org/pgsql-hackers/2002-08/msg00380.php
> http://archives.postgresql.org/pgsql-hackers/2002-09/msg01368.php
> or for that matter here's Vadim complaining about it seven years ago:
> http://archives.postgresql.org/pgsql-hackers/1997-12/msg00215.php

OK, added:

* Allow the size of the buffer cache used by temporary objects to be
  specified as a GUC variable

  Larger local buffer cache sizes requires more efficient handling of
  local cache lookups.

--
  Bruce Momjian                        |  http://candle.pha.pa.us
  pgman@candle.pha.pa.us               |  (610) 359-1001
  +  If your life is a hard drive,     |  13 Roberts Road
  +  Christ can be your backup.        |  Newtown Square, Pennsylvania 19073