Josh Berkus wrote: > Mark, Stephen, etc: > > > > I can see your point, however I wonder if the issue is that the default > > > stats settings of '10' (3000 rows, 10 histogram buckets) is too low, and > > > maybe we should consider making a higher value (say '100') the default. > > > > Personally, I think that'd be reasonable. > > I don't really think that we want to increase sampling for *all* columns. > Each column that doesn't get queried but has increased stats adds the size of > the pg_stats table and the amount of vacuuming it needs, decreasing > performance of stats lookups. Especially when very large text and BYTEA > columns are involved. > > Neil and I talked about setting a seperate GUC, default_index_stats_target, > for 8.0 that would dramatically increase the stats sampling for indexed > columns only (say, to 250). Unfortunately, I was unable to come up with a > good test case for setting this value.
Is default_index_stats_target a TODO item? Seems we already have cases where our bucket size isn't large enough and this would help. -- Bruce Momjian | http://candle.pha.pa.us pgman@candle.pha.pa.us | (610) 359-1001 + If your life is a hard drive, | 13 Roberts Road + Christ can be your backup. | Newtown Square, Pennsylvania 19073 ---------------------------(end of broadcast)--------------------------- TIP 8: explain analyze is your friend