Robert Haas <robertmh...@gmail.com> writes: > On Fri, Feb 2, 2018 at 7:06 PM, Tom Lane <t...@sss.pgh.pa.us> wrote: >> I'm disinclined to monkey with the way this works without someone >> presenting hard evidence that it creates enough of a performance problem >> to be worth spending a significant amount of time changing it. Up to >> now I don't think I've ever noticed plancat.c being a large fraction >> of planner runtime, though of course that might depend on the test case.
> If we're going to have to change this at some point (and I bet we > are), I'd rather do it before people jam even more stuff into the > current system rather than wait until it gets totally out of hand. While I'm prepared to believe that this *could* be a problem, I repeat that you've offered no hard evidence that it actually *is* a problem, or might become one in the future. We could easily expend a significant amount of effort here for no real return. regards, tom lane