Gaetano,
> don't you think the best statistic target for a boolean
> column is something like 2? Or in general the is useless
> have a statistics target > data type cardinality ?
It depends, really, on the proportionality of the boolean values; if they're
about equal, I certainly wouldn't raise Stats from the default of 10. If,
however, it's very dispraportionate -- like 2% true and 98% false -- then it
may pay to have better statistics so that the planner doesn't assume 50%
hits, which it otherwise might.
--
--Josh
Josh Berkus
Aglio Database Solutions
San Francisco