> Wei,
>
> > Does it make a performance difference if I use a char(20) or a char(36)
> > as the primary key? My thought is no, but I would like to hear more
> > opinions.
>
> Yes, it does, though probably minor unless you have millions of records. CHAR
> is padded out to the specified length. Therefore the index on a char(36)
> column will be a little larger, and thus a little slower, than the char(20).
>
Really? According to this url (search for "Tip") there is no performance
difference just a space difference. I don't know for sure either way, but
if there is a difference the manual needs updating.
http://www.postgresql.org/idocs/index.php?datatype-character.html
-philip