guids / bytea and index use ?

Paul Newman wrote:

We are currently using a 32byte varchar for our primary keys. We tried
to reduce this down to 16 bytes but varchar didn't seem to store this
correctly.

In what way was it not stored "correctly"? The size limit should not
significantly affect varchar behavior, other than bounding its maximum
size of course.

I'd like to use bytea instead so we could use 16bytes, but are
indexes used properly ?

Sure.

Does anyone have any other suggestions on how to store guids ?

http://gborg.postgresql.org/project/pguuid/projdisplay.php

is out there; I haven't used it personally, though.

Is there a reason you can't use an int8?

-Neil