Problem indexing on internal functions . . .

Hi,

I'm running Debian Linux 2.1 with PostgreSQL 6.4.2.

I want to index on a float4 value.  This however presents,
I have recently learned, with attempting to index because
the float4 is promoted to float8 in the WHERE clause.

To get around this, I attemped to make a function index
on float8, but this is what happens:

final99=> create index mx on psc using btree (float8(glat) float8_ops);
ERROR:  internal error: untrusted function not supported.

["psc" is my table and "glat" is a float4].

Any ideas how to do this?

--Martin

===========================================================================

Martin Weinberg                      Phone: (413) 545-3821
Dept. of Physics and Astronomy       FAX:   (413) 545-2117/0648
530 Graduate Research Tower
University of Massachusetts
Amherst, MA  01003-4525