On Sat, Apr 16, 2011 at 8:21 AM, Mark Kirkwood <mark.kirkw...@catalyst.net.nz> wrote: > > I guess you have answered my first question - i.e yes this should eat > massive amount of ram as written - however are you sure there is no memory > leaking going on here?
The planner doesn't try to free up memory while it's working, it generally assumes that producing a plan is a short process and when it's done it'll free the whole context and that's enough. The basic problem is that the number of possible plans blows up combinatorically. That is with 14 tables there are 14! possible join orderings and more something like 3^(14!) possible join strategies -- actually more if you include things like whether to materialize and which keys to use and so on. The planner uses various heuristics to avoid combinatoric growth wherever it can but there's no way to completely avoid it. -- greg -- Sent via pgsql-bugs mailing list (pgsql-bugs@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-bugs
