Re: RT3.4 query needed a lot more tuning with 9.2 than it did with 8.1

От: Christoph Berg
Тема: Re: RT3.4 query needed a lot more tuning with 9.2 than it did with 8.1
Дата: ,
Msg-id: 20130515064819.GD704@msgid.df7cb.de
(см: обсуждение, исходный текст)
Ответ на: Re: RT3.4 query needed a lot more tuning with 9.2 than it did with 8.1  (Tom Lane)
Список: pgsql-performance


Re: Tom Lane 2013-05-06 <>
> The newer rowcount estimates are much further away from reality:
>
> >  Unique  (cost=1117.67..1118.46 rows=9 width=1115) (actual time=82.646..85.695 rows=439 loops=1)
>
> >  Unique  (cost=784205.94..796940.08 rows=145533 width=1061) (actual time=9710.683..9713.175 rows=439 loops=1)
>
> Has the new DB been analyzed?  Maybe you had custom stats targets in
> the old DB that didn't get copied to the new one?

The new DB was analyzed with various stats targets, including values
that were higher that anything we would have used in 8.1. I don't
think we had per-table settings in there (the actual DB is now gone
for good).

Christoph
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