Re: SQL-Invoked Procedures for 8.1

Hannu Krosing <hannu(at)tm(dot)ee> writes:
> IIRC support for returning multiple recordsets was removed from
> postgresql fe-be protocol years ago as "nobody ever needs it" ;)

The protocol can still do it, and so can the backend, but it will
certainly break most if not all clients. Here's an example:

regression=# create table surprise(f1 text);
CREATE TABLE
regression=# create rule r1 as on insert to surprise do
regression-# ( select 'hello' ; select 'how are you' );
CREATE RULE
regression=# insert into surprise values ('boo');
?column?
-------------
how are you
(1 row)

regression=#

The 'hello' result was in fact computed and sent by the backend, but it
was discarded in libpq (see the documentation about PQexec: only the
last resultset returned by a querystring is returned to the caller).
psql could have printed both results, but it would need to use
PQsendQuery/PQgetResult instead of PQexec.

regards, tom lane