Re: Relation of indices to ANALYZE

От: Tom Lane
Тема: Re: Relation of indices to ANALYZE
Дата: ,
Msg-id: 5740.1058466436@sss.pgh.pa.us
(см: обсуждение, исходный текст)
Ответ на: Relation of indices to ANALYZE  (Bill Moran)
Ответы: Re: Relation of indices to ANALYZE  (Bill Moran)
Список: pgsql-performance

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Relation of indices to ANALYZE  (Bill Moran, )
 Re: Relation of indices to ANALYZE  (Richard Huxton, )
 Re: Relation of indices to ANALYZE  (Tom Lane, )
  Re: Relation of indices to ANALYZE  (Bill Moran, )

Bill Moran <> writes:
> Specifically, I'm wondering if I should do
> the ANALYZE before or after I recreate the indexes, or whether it matters.

At the moment it does not matter --- ANALYZE computes statistics for
each column of a table regardless of what indexes exist.

There has been some talk of trying to compute statistics for the
contents of functional indexes.  Also, if we ever do anything about
computing multicolumn correlation statistics, we'd likely choose which
ones are worth computing based on the presence of multicolumn indexes.
So if you want to future-proof your code I'd recommend recreating the
indexes before you ANALYZE.

            regards, tom lane


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