On Mon, Nov 29, 2010 at 10:09 PM, Jaime Casanova <ja...@2ndquadrant.com> wrote: > On Mon, Nov 29, 2010 at 9:55 PM, Daniel Loureiro <loureir...@gmail.com> wrote: >> good point. But when you use a LIMIT in a SELECT statement you WANT n RANDOM >> tuples > > no. at least IMHO the only sensible way that LIMIT is usefull is with > an ORDER BY clause with make the results very well defined...
That's not 100% true - it can sometimes be very useful when digging through a database to grab 50 rows from a table just to get a feel for what kind of stuff in there. Maybe it's stupid, but I find it handy. But even granting the premise, that's an argument for making DELETE support both ORDER BY and LIMIT, not for supporting neither of them. For example, suppose we're trying to govern an ancient Greek democracy: http://en.wikipedia.org/wiki/Ostracism DELETE FROM residents_of_athens ORDER BY ostracism_votes DESC LIMIT 1; I think the executor already pretty much knows how to do this. The planner might need some fiddling to hand over the correct instructions, not sure. But this might not even be super hard, though Daniel might want to pick something a little less ambitious for his very first project, because debugging planner and executor problems is not so easy. -- 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
