Re: Wrong estimation of rows for hash join

Alban Hertroys <dalroi@solfertje.student.utwente.nl> writes:
> I'm also somewhat surprised to see an array of what appear to be
> integers be cast to bpchar[]. Did you define those coordinates(?) as
> character types? Numerical comparisons tend to be faster than string
> comparisons, which should make some difference on sequential scans.

Or, if the column can't be changed to an integer, at least consider
making it varchar not char.  The funny rules about trailing blanks
make char comparison a bit slower than varchar, IIRC.  They aren't
very conducive to fast hashing either ...

            regards, tom lane