Re: benchmarking the query planner - Mailing list pgsql-hackers

From Simon Riggs
Subject Re: benchmarking the query planner
Date
Msg-id 1229106140.8673.80.camel@ebony.2ndQuadrant
Whole thread Raw
In response to Re: benchmarking the query planner  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-hackers
On Fri, 2008-12-12 at 13:10 -0500, Tom Lane wrote:

> If we don't
> have at least ballpark-correct figures for cost and number of output
> rows, we'll start making mistakes at higher plan levels.

That's definitely where we are now. 

Had a call with a customer today where I said "it's OK, its only out by
3 orders of magnitude, it gets worse than that". 9 hour query, with
substantially incorrect EXPLAIN.

I don't claim to have any/all of the answers myself, but this needs
attention very badly.

-- Simon Riggs           www.2ndQuadrant.comPostgreSQL Training, Services and Support



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