Marinos Yannikos wrote:
> (what exactly does ANALYZE look at for text columns? in our case, about
> 7% of the rows match the index condition, so it seems that left-anchored
> regexp/like matches are not evaluated using the gathered
> most-common-value list at all)
oops, I think I gave myself the answer there. Of course the
most-common-value list will not help if all the values that match the
"bad" index condition exist only once, but have a common prefix...
Perhaps Postgres could sample the first few characters separately for
such queries, but it's probably not worth it.