Thanks. Going back to my original loop with the limit changed to
running->xcnt makes sense.
On 2026-Sep-21 at 15:35 UTC, Alvaro Herrera wrote:
> I think we should just go up to running->xcnt
> only;
Yes, scanning the subxids was unnecessary. My previous explanation
addressed overflow, but waiting for the parent covers the children in
the non-overflow case too. A note on the top-level-first ordering in
RunningTransactionsData would make that dependency explicit.
> maybe we should add
> something in SnapBuildBuildSnapshot()
Agreed. The explanation of why historic snapshots need no wait for
transactions to finish belongs there. The comment in
SnapBuildInitialSnapshot() can then focus on why the conversion to a
normal MVCC snapshot needs the wait.
Regards,
Rui
