On Mon, Jun 6, 2016 at 11:50 AM, Tom Lane <t...@sss.pgh.pa.us> wrote: > Robert Haas <robertmh...@gmail.com> writes: >> On Mon, May 23, 2016 at 4:15 PM, Tom Lane <t...@sss.pgh.pa.us> wrote: >>> 2. Rewrite into LATERAL ROWS FROM (srf1(), srf2(), ...). This would >>> have the same behavior as before if the SRFs all return the same number >>> of rows, and otherwise would behave differently. > >> I thought the idea was to rewrite it as LATERAL ROWS FROM (srf1()), >> LATERAL ROWS FROM (srf2()), ... > > No, because then you get the cross-product of multiple SRFs, not the > run-in-lockstep behavior.
Oh. I assumed that was the expected behavior. But, ah, what do I know? >> The rewrite you propose here seems to NULL-pad rows after the first >> SRF is exhausted: > > Yes. That's why I said it's not compatible if the SRFs don't all return > the same number of rows. It seems like a reasonable definition to me > though, certainly much more reasonable than the current run-until-LCM > behavior. I can't argue with that. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
