Re: temp table "on commit delete rows": transaction overhead

От: Bruce Momjian
Тема: Re: temp table "on commit delete rows": transaction overhead
Дата: ,
Msg-id: 201004010044.o310iPU08826@momjian.us
(см: обсуждение, исходный текст)
Ответ на: Re: temp table "on commit delete rows": transaction overhead  (Tom Lane)
Ответы: Re: temp table "on commit delete rows": transaction overhead  (Artiom Makarov)
Список: pgsql-performance

Скрыть дерево обсуждения

temp table "on commit delete rows": transaction overhead  (Artiom Makarov, )
 Re: temp table "on commit delete rows": transaction overhead  (Tom Lane, )
  Re: temp table "on commit delete rows": transaction overhead  (Bruce Momjian, )
   Re: temp table "on commit delete rows": transaction overhead  (Artiom Makarov, )
  Re: temp table "on commit delete rows": transaction overhead  (Artiom Makarov, )

Tom Lane wrote:
> Artiom Makarov <> 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  <>        http://momjian.us
  EnterpriseDB                             http://enterprisedb.com


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