Re: benchmarking the query planner

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