Re: Proposal - improve eqsel estimates by including histogram bucket numdistinct statistics - Mailing list pgsql-hackers

From Andrew Dunstan
Subject Re: Proposal - improve eqsel estimates by including histogram bucket numdistinct statistics
Date
Msg-id 484F2D5B.7050508@dunslane.net
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In response to Re: Proposal - improve eqsel estimates by including histogram bucket numdistinct statistics  (Tom Lane <tgl@sss.pgh.pa.us>)
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Tom Lane wrote:
> This gets back to the discussions at PGCon about needing to have a more
> explicit representation of partitioning.  Right now, for a
> many-partition table we spend huge amounts of time deriving the expected
> behavior from first principles, each time we make a plan.  And even then
> we can only get it right for limited cases (eg, no parameterized
> queries).  If the planner actually understood that a set of tables
> formed a partitioned set then it'd be a lot easier and faster to get the
> desired behavior, not only with respect to the rowcount estimates but
> the plan's structure.
>
>             
>   

Even if this doesn't solve every problem, it's surely worth doing for 
those it will solve.

cheers

andrew


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