--- Tom Lane <tgl@xxxxxxxxxxxxx> wrote: > Hm. I should have realized why correlation wouldn't > be high for the > city name: given the ordering by zipcode, city name > values may be > pretty well clumped, but they aren't in any kind of > alphabetical > order --- and it's the overall ordering, not the > clumping, that > correlation measures. > Ah. Localized clumping != Overall ordering. Thanks for the clarification. > However, there is something absolutely wacko about > the stats collection > process here ... you've got fairly reasonable > looking results for > most-common-values of city name at the lower end of > the stats settings > (HOUSTON and DALLAS are the most common, sounds > about right) ... but at > the higher settings the ordering of most-common > entries just goes nuts. > We've got some kind of bug there. > I had noticed that as well but wasn't sure about the whether MCV really meant what I thought it did. > What exactly are you changing in the different cases > --- > default_statistics_target, or are you doing an ALTER > TABLE on some > of the columns (if so which)? I have a setting of 30 for default_statistics_target and I am manipulating the statistics target for city by alter table. > > It might be easier to debug this if you could send > me the test case. > Any problem with sending just the city name and > zipcode columns > of the table (offlist of course)? COPY TO with a > column list can > extract that for you. > I had already removed proprietary data to try and whittle down the number of columns I needed to demonstrate the weirdness so I can host a dump of the table. However, before I take that step I should mention that this is the native Windows port so if that changes anything let me know. Regards, Shelby Cain __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com ---------------------------(end of broadcast)--------------------------- TIP 5: Have you checked our extensive FAQ? http://www.postgresql.org/docs/faq
