encouraging index-only scans

От: Andrew Dunstan
Тема: encouraging index-only scans
Дата: ,
Msg-id: 50C8F1EC.9010801@dunslane.net
(см: обсуждение, исходный текст)
Ответы: Re: encouraging index-only scans  (Tom Lane)
Список: pgsql-performance

Скрыть дерево обсуждения

encouraging index-only scans  (Andrew Dunstan, )
 Re: encouraging index-only scans  (Andrew Dunstan, )
  Re: encouraging index-only scans  (Andrew Dunstan, )
 Re: encouraging index-only scans  (Tom Lane, )

A client is testing a migration from 9.1 to 9.2, and has found that a
large number of queries run much faster if they use index-only scans.
However, the only way he has found to get such a plan is by increasing
the seq_page_cost to insanely high levels (3.5). Is there any approved
way to encourage such scans that's a but less violent than this?

cheers

andrew



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