On Tue, Feb 2, 2010 at 7:14 PM, Tom Lane <t...@sss.pgh.pa.us> wrote: > "Davor J." <dav...@live.com> writes: > > Now, if one takes a subquery for "1", the optimizer evaluates it first > > (let's say to "1"), but then searches for it (sequentially) in every > > partition, which, for large partitions, can be very time-consuming and > goes > > beyond the point of partitioning. > > No, the optimizer doesn't "evaluate it first". Subqueries aren't ever > assumed to reduce to constants. (If you actually do have a constant > expression, why don't you just leave out the word SELECT?) > > regards, tom lane
If you don't have a constant expression then you can either explicitly loop in the calling code or a function or you could index the key in all the subtables. The index isn't really optimal but it gets the job done. Nik
