Re: Tablespaces and query planning - Mailing list pgsql-performance

From Cédric Villemain
Subject Re: Tablespaces and query planning
Date
Msg-id 201206081236.08512.cedric@2ndquadrant.com
Whole thread Raw
In response to Tablespaces and query planning  ("Albe Laurenz" <laurenz.albe@wien.gv.at>)
Responses Re: Tablespaces and query planning
List pgsql-performance
> - The statistics gathered by ANALYZE are independent of the tablespace
>   containing the table.

yes.

> - The tablespace containing the table has no influence on query planning
>   unless seq_page_cost or random_page_cost has been set on the
> tablespace.

yes.

> - VACUUM ANALYZE does the same as VACUUM followed by ANALYZE.

no.
it is fine grained, but in the diffs there is:

 VACUUM and ANALYSE do not update pg_class the same way for the
reltuples/relpages: for ex VACUUM is accurate for index, and ANALYZE is fuzzy
so if you issue a vacuum you have exact values, if you then run ANALYZE you
may change them to be less precise.

--
Cédric Villemain +33 (0)6 20 30 22 52
http://2ndQuadrant.fr/
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