Re: Using a postgres table to maintain unique id?

Thomas Swan wrote:
> 
> At 11/13/2000 06:22 PM -0800, Michael Teter wrote:
> >
> > From what I can tell (both from docs and doing a
> > describe on sequences in my database), a postgresql
> > sequence is an int4, not an int8, and thus you are
> > limited to a max of 2.1 billion values.
> >
> > If you require an int8 sequence, you'll probably have
> > to manage your own and just use an int8 column.
> >
> I had originally started using int8 and creating custom sequences.   However,
> as mentioned in a previous post, there is an inherent performance penalty in
> using int8 over int4.   Tom Lane advised me that the int8 routines are an
> emulated or synthesized data type.  in the test I did on our 7.0.2 server I
> notice about a 25-30% decrease in performance when using complex joins on
> tables containing referential keys, primary keys all in the int8 data type.
> 
> This might be something to think about as well.

Thanks.  Because of these and other comments people have made, I've gone back
to using a flat_file-with-server approach instead of adding a table to my
postgres DB.  While an int4 *might* work, it doesn't handle the "worst-case"
scenario (which is up around 15 billion values).

Thanks to everyone for your comments and suggestions!

--
Steve Wampler-  SOLIS Project, National Solar Observatory
swampler@noao.edu