On Tue, 2010-05-04 at 07:13 -0400, Robert Haas wrote: > On Tue, May 4, 2010 at 4:37 AM, Simon Riggs <si...@2ndquadrant.com> wrote: > > option for them, especially for the stated reason. (My point about > > ndistinct: 99% of users have no idea that exists or when to use it, but > > it still exists as an option because it solves a known issue, just like > > this.) > > Slightly OT, but funnily enough, when I was up in New York a couple of > weeks ago with Bruce and a couple of other folks, I started talking > with a DBA up there about his frustrations with PostgreSQL, and - I'm > not making this up - the first example he gave me of something he > wished he could do in PG to improve query planning was manually > override ndistinct estimates. He was pleased to here that we'll have > that in 9.0 and I was pleased to be able to tell him it was my patch. > If you'd asked me what the odds that someone picking a missing feature > would have come up with that one were, I'd have said a billion-to-one > against. But I'm not making this up.
It matches my experience. I think its a testament to the expertise of our users as well to the hackers that have done so much to make that the top of user's lists for change. > To be honest, I am far from convinced that the existing behavior is a > good one and I'm in favor of modifying it or ripping it out altogether > if we can think of something better. But it has to really be better, > of course, not just trading one set of pain points for another. The only way I see as genuine better rather than just a different mix of trade-offs is to come up with ways where there are no conflicts. Hannu came up with one, using filesystem snapshots, but we haven't had time to implement that yet. -- Simon Riggs www.2ndQuadrant.com -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
