Re: Select performance vs. mssql

От: Bruno Wolff III
Тема: Re: Select performance vs. mssql
Дата: ,
Msg-id: 20050524172713.GC8129@wolff.to
(см: обсуждение, исходный текст)
Ответ на: Re: Select performance vs. mssql  (mark durrant)
Ответы: Re: Select performance vs. mssql  (Alex Turner)
Re: Select performance vs. mssql  (Enrico Weigelt)
Список: pgsql-performance

Скрыть дерево обсуждения

Select performance vs. mssql  (mark durrant, )
 Re: Select performance vs. mssql  (Christopher Kings-Lynne, )
 Re: Select performance vs. mssql  (mark durrant, )
  Re: Select performance vs. mssql  (Neil Conway, )
  Re: Select performance vs. mssql  ("Harald Lau (Sector-X)", )
 Re: Select performance vs. mssql  (mark durrant, )
  Re: Select performance vs. mssql  (Bruno Wolff III, )
   Re: Select performance vs. mssql  (Alex Turner, )
   Re: Select performance vs. mssql  (Enrico Weigelt, )
    Re: Select performance vs. mssql  (Jochem van Dieten, )
  Re: Select performance vs. mssql  (Christopher Kings-Lynne, )
   Re: Select performance vs. mssql  ("Jim C. Nasby", )
 Re: Select performance vs. mssql  (mark durrant, )
  Re: Select performance vs. mssql  (Josh Berkus, )
   Re: Select performance vs. mssql  (PFC, )
   Re: Select performance vs. mssql  (Michael Stone, )
    Re: Select performance vs. mssql  (John A Meinel, )

On Tue, May 24, 2005 at 08:36:36 -0700,
  mark durrant <> wrote:
>
> --MSSQL's ability to hit the index only and not having
> to go to the table itself results in a _big_
> performance/efficiency gain. If someone who's in
> development wants to pass this along, it would be a
> nice addition to PostgreSQL sometime in the future.
> I'd suspect that as well as making one query faster,
> it would make everything else faster/more scalable as
> the server load is so much less.

This gets brought up a lot. The problem is that the index doesn't include
information about whether the current transaction can see the referenced
row. Putting this information in the index will add significant overhead
to every update and the opinion of the developers is that this would be
a net loss overall.


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