Greg Smith wrote: > Mladen Gogala wrote: > > Greg, how many questions about queries not using an index have you > > seen? There is a reason why people keep asking that. The sheer number > > of questions like that on this group should tell you that there is a > > problem there. There must be a relatively simple way of influencing > > optimizer decisions. > > I think that's not quite the right question. For every person like > yourself who is making an informed "the optimizer is really picking the > wrong index" request, I think there are more who are asking for that but > are not actually right that it will help. I think you would agree that > this area is hard to understand, and easy to make mistakes about, yes? > So the right question is "how many questions about queries not using an > index would have actually benefitted from the behavior they asked for?" > That's a much fuzzier and harder to answer question. Agreed. I created an FAQ entry years ago to explain this point and tell people how to test it: http://wiki.postgresql.org/wiki/FAQ#Why_are_my_queries_slow.3F_Why_don.27t_they_use_my_indexes.3F Once I added that FAQ we had many fewer email questions about index choice. > > With all due respect, I consider myself smarter than the optimizer. > > I'm 6'4", 235LBS so telling me that you disagree and that I am more > > stupid than a computer program, would not be a smart thing to do. > > Please, do not misunderestimate me. > > I remember when I used to only weigh that much. You are lucky to be > such a slim little guy! > > Oh, I guess I should add, :) Oh, wow, what a great retort. :-) -- Bruce Momjian <bruce@xxxxxxxxxx> http://momjian.us EnterpriseDB http://enterprisedb.com + It's impossible for everything to be true. + -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
