Re: when do I analyze after concurrent index creation? - Mailing list pgsql-general

From Tom Lane
Subject Re: when do I analyze after concurrent index creation?
Date
Msg-id 8902.1382110970@sss.pgh.pa.us
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In response to Re: when do I analyze after concurrent index creation?  (dinesh kumar <dineshkumar02@gmail.com>)
Responses Re: when do I analyze after concurrent index creation?
Re: when do I analyze after concurrent index creation?
List pgsql-general
dinesh kumar <dineshkumar02@gmail.com> writes:
> When we create an index, i believe the postgres engine it self update it's
> catalog about the index availability.

ANALYZE normally collects statistics about the contents of table columns.
Thus, adding (or removing) an index does not create any reason to
re-ANALYZE.

However ... if you have an index on an expression (not just a simple
column value), that cues ANALYZE to collect statistics about the values of
that expression.  So re-analyzing is useful after creating such an index,
to give the planner a better idea of when to use that index.

Whether you used CREATE INDEX CONCURRENTLY or some other way of creating
the index doesn't matter at all.

            regards, tom lane


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