On Fri, 9 Oct 2020 at 15:06, Tom Lane <t...@sss.pgh.pa.us> wrote: > I notice there are some other ad-hoc isnan() checks scattered > about costsize.c, too. Maybe we should indeed consider fixing > clamp_row_estimate to get rid of inf (and nan too, I suppose) > so that we'd not need those. I don't recall the exact cases > that made us introduce those checks, but they were for cases > a lot more easily reachable than this one, I believe.
Is there actually a case where nrows could be NaN? If not, then it seems like a wasted check. Wouldn't it take one of the input relations or the input rels to have an Inf row estimate (which won't happen after changing clamp_row_estimate()), or the selectivity estimate being NaN. David
