Re: IN subquery not using a hash

On Wed, Jul 20, 2005 at 08:11:46PM -0400, Paul Tillotson wrote:
> Tom Lane wrote:
> >Hardly likely, considering it's estimating only 296 rows in the subquery
> >output.  My bet is that you've chosen a datatype whose comparisons are
> >not hashable (like char(n)).  What is the datatype of parentid in these
> >tables, anyway?
> >
> I don't have access to the machine now, but my memory is that 
> parent.parentid is numeric(10,2) and child.parentid is int.

Numeric isn't hashable, but I don't know enough about the internals
to say why.  Tom?

Why different types, and why numeric for one of them?  Why not
integer for both?

-- 
Michael Fuhr
http://www.fuhr.org/~mfuhr/