otar shavadze <oshavadze(at)gmail(dot)com> writes:
>> Hmmm ... actually, I wonder if maybe '@>' here is the contrib/intarray
>> operator not the core operator? The intarray operator didn't get plugged
>> into any real estimation logic until 9.6.
> So, you mean that better would be go to version 9.6 ?
If you are using that contrib module, and it's capturing this operator
reference, that would probably explain the bad estimate. You could
drop the extension if you're not depending on its other features, or you
could explicitly qualify the operator name ("operator(pg_catalog.@>)"),
or you could upgrade to 9.6 (don't forget to do ALTER EXTENSION ... UPDATE
afterwards).
regards, tom lane