Bill Schneider wrote:
> Does the PostgreSQL JDBC driver/protocol perform any optimization for
> repeated values created by joins?
No. The existing protocol is documented at
http://www.postgresql.org/docs/8.0/static/protocol.html
> Has anyone else thought about this, or does it just not affect
> performance enough to matter?
pgsql-hackers is probably the place to discuss it.
> select a.id, a.longText, b.id
> from a join b on b.a_id = a.id
> order by a.id;
In this case, you could of course turn it into two separate queries when
you know the characteristics of the query make that a win. It seems like
a lot of work for marginal benefit to try to do some sort of
duplicate-elimination automatically in the protocol.
-O