Re: cannot get stable function to use index

I wrote:
> This says there's only about a 25% runtime penalty for the partial match,
> at least on your example, compared to the planner's estimate of 2700x
> penalty :-(.  Definitely need to fix that.

I tried to reproduce this behavior with simple generated data, and could
not: the estimates seem to track the actual cost reasonably well.  So
it seems like you've got some weird data statistics that are causing a
misestimate.  Could we see the pg_stats row for that tsvector column?
Or maybe even the actual data?

            regards, tom lane