Em dom., 13 de fev. de 2022 às 18:43, Andres Freund <andres@anarazel.de> escreveu:
Hi,
On 2022-02-13 18:21:38 -0300, Ranier Vilela wrote: > Why open and lock the table Extended Statistics if it is not the owner. > Check and return to avoid this.
I was about to say that this opens up time-to-check-time-to-use type issues. But it's the wrong thing to lock to prevent those.
Having looked briefly at it, I don't understand what the locking scheme is? Shouldn't there be at least some locking against concurrent ALTERs and between ALTER and ANALYZE etc?
I checked the pg_statistics_object_ownercheck function and I think the patch is wrong. It seems to me that when using SearchSysCache1, it is necessary to open and lock the table.