Re: temp table "on commit delete rows": transaction overhead - Mailing list pgsql-performance

From Bruce Momjian
Subject Re: temp table "on commit delete rows": transaction overhead
Date
Msg-id 201004010044.o310iPU08826@momjian.us
Whole thread Raw
In response to Re: temp table "on commit delete rows": transaction overhead  (Tom Lane <tgl@sss.pgh.pa.us>)
Responses Re: temp table "on commit delete rows": transaction overhead  (Artiom Makarov <artiom.makarov@gmail.com>)
List pgsql-performance
Tom Lane wrote:
> Artiom Makarov <artiom.makarov@gmail.com> writes:
> > When temp tables with "on commit delete rows" exists, I can see a
> > strange delay at any �begin� and �commit�.
>
> A delay at commit is hardly surprising, because each such temp table
> requires filesystem operations at commit (basically an "ftruncate").
> I don't recall any operations at transaction start for such tables,
> but there may be some.

I think one of the problems is that we do the truncate even if the table
has not be touched by the query, which is poor behavior.

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

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