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Tom Lane replied: > If there are 100 or more histogram entries it'll do the estimation by > counting how many of the histogram entries match the pattern, rather > than using the prefix-range-based estimator (which is pretty much > all-fantasy anyway for a pattern with leading % :-(). > > http://archives.postgresql.org/pgsql-committers/2006-09/msg00331.php Ugh, that's some gotcha. Now that the patches are in place to fix the planner problems, can I strongly recommend that a 8.2.6 version be made? These are some serious planner problems, reported by real-world users, and the only other option may be to go back to 8.1. > I'm too lazy to go check, but I think the stats target is interpreted as > the number of histogram bins rather than values, which is why you'd see > the switchover at 99 not 100. Can we switch the default_statistics_target to a default of 100? Is there any reason not to do so at this point? Ten has always seemed very low to me, and the 98/99 gotcha only makes the case for at least 100 as the default stronger. - -- Greg Sabino Mullane [EMAIL PROTECTED] PGP Key: 0x14964AC8 200711132325 http://biglumber.com/x/web?pk=2529DF6AB8F79407E94445B4BC9B906714964AC8 -----BEGIN PGP SIGNATURE----- iD8DBQFHOnkKvJuQZxSWSsgRA9i/AJ4rN3BANdWKLmrscVpij0GiZ1i/lwCg4u4x 6U+7bTe2o60Kv44f+6n61Zc= =MSBf -----END PGP SIGNATURE----- ---------------------------(end of broadcast)--------------------------- TIP 6: explain analyze is your friend
