On Tue, Dec 3, 2024 at 10:34 PM Alvaro Herrera <alvhe...@alvh.no-ip.org> wrote: > > On 2024-Nov-29, Amit Kapila wrote: > > BTW it occurs to me that there might well be some sort of thundering > herd problem if every process needs to run the check_hook when a SIGHUP > is broadcast, and they'll all be waiting on that particular lwlock and > run the same validation locally again and again. I bet if you have a > few thousand backends (hi Jakub! [1]) it's problematic. >
The lock is taken in shared mode, so, ideally, it shouldn't create a problem but if it ever creates a problem, we can even skip that check during validation. The validation will anyway happen later during replication in StandbySlotsHaveCaughtup(). This check is mostly to detect the error in GUC early. > Maybe we need a > different way to validate the GUC, but I don't know what that might be; > but doing the validation once and storing the result in shmem might be > better. > What if that particular GUC changes again? We may need some additional invalidation mechanism. -- With Regards, Amit Kapila.
