Re: Assertion failure with LEFT JOINs among >500 relations

I wrote:
> David Rowley <dgrowleyml(at)gmail(dot)com> writes:
>> I've ended up leaving the NaN checks in the join costing functions.
>> There was no case mentioned in [1] that showed how we hit that
>> reported test case, so I'm not really confident enough to know I'm not
>> just reintroducing the same problem again by removing that. The path
>> row estimate that had the NaN might not have been through
>> clamp_row_est(). Many don't.

> Hmm, I will try to find some time tomorrow to reconstruct that.

I'm confused now, because the v2 patch does remove those isnan calls?

I rechecked the archives, and I agree that there's no data about
exactly how we could have gotten a NaN here. My guess though is
infinity-times-zero in some earlier relation size estimate. So
hopefully the clamp to 1e100 will make that impossible, or if it
doesn't then clamp_row_est() should still prevent a NaN from
propagating to the next level up.

I'm good with the v2 patch.

regards, tom lane