Tom Lane wrote: > Bruce Momjian <br...@momjian.us> writes: > > Tom, you mentioned this should be a TODO item. Do we put it on our main > > TODO, and if so, in what section? > > Optimizer/executor I guess. It's a pretty vague TODO though. We need > some way to consider alternative join orders for joins that do not > semantically commute. When I wrote that CVS log entry I was thinking > in terms of fixing the executor so that the joins actually could > commute, which would involve some way of separating the > force-vars-to-null behavior of an outer join from the actual execution > of the join. I don't know how practical that really is though (and > also I've got a feeling it likely would fall foul of some patent or > other). Or maybe it could be solved entirely in the planner, but I > don't have an idea of what the planner's internal representation would > have to look like to do that.
Yea, this is beyond the detail we normally put in the TODO list. If we want to add this I am afraid we will need to document other optimizer items as well. -- Bruce Momjian <br...@momjian.us> http://momjian.us EnterpriseDB http://enterprisedb.com + If your life is a hard drive, Christ can be your backup. + -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
