Em qui., 17 de jun. de 2021 às 22:08, Andres Freund <andres@anarazel.de> escreveu:
Hi,
On 2021-06-17 21:27:15 -0300, Ranier Vilela wrote: > While another long thread discusses the situation of old_snapshot_threshold, > I believe we can improve procarray.c by avoiding calling > MaintainOldSnapshotTimeMapping (src/backend/utils/time/snapmgr.c). > > There's a very explicit comment there, which says (line 1866): > "Never call this function when old snapshot checking is disabled." > > Well, assert should never be used to validate a condition that certainly > occurs at runtime.
I don't see how it can happen at runtime currently?
> Since old_snapshot_threshold is -1, it is disabled, so > MaintainOldSnapshotTimeMapping doesn't need to be run, right?
It *isn't* run, the caller checks OldSnapshotThresholdActive() first.
True. My mistake.
I didn't check GetSnapshotDataInitOldSnapshot correctly.