On Tue, May 16, 2006 at 09:33:14AM -0400, Tom Lane wrote: > Joachim Wieland <joe@xxxxxxxxxxx> writes: > > So irrespective of caching to prevent evaluation across statements, within a > > single statement, is there a strong reason why for example in > > WHERE col = f(const) with f() declared as immutable or stable and without an > > index on col, f() still gets called for every row? Or is this optimization > > just not done yet? > The above statement is not correct, at least not for immutable functions. So an immutable function gets evaluated once but a stable function still gets called for every row? Wouldn't it make sense to call a stable function only once as well? Joachim
