Re: New thoughts about indexing cross-type comparisons

Tom Lane wrote:
> 
> Dave Smith <dave.smith@candata.com> writes:
> > If this is only dealing with constants, why not just explicitly add a
> > cast to the constant of the column type at the planner level. It would
> > solve this problem as well ...
> 
> > create table test (f int2);
> > select * from test where f=cast('1981928928921' as int2);
> > ERROR:  pg_atoi: error reading "1981928928921": Numerical result out of
> > range
> 
> >   select * from test where f=1981928928921;
> >   f
> > ---
> > (0 rows)
> 
> Uh, your own example points out why we can't just insert a cast to int2
> --- it changes the results.  Or am I missing your point?

Because PG doesn't have the functionality to catch exceptions
until now, we can't call cast functions tentatively. But for
example, why should the pg_atoi error cause an unrecoverable
error immediately ? IMHO we should be able to call cast functions
internally without an anxiety to cause an unrecoverable error. 

regards,
Hiroshi Inouehttp://www.geocities.jp/inocchichichi/psqlodbc/