On Fri, Jan 27, 2023 at 9:30 AM Maxim Orlov <orlo...@gmail.com> wrote: > I thank you for your advices. I've dived deeper into the problem and I think > v2 patch is wrong.
Cool! > Accessing threshold_timestamp and threshold_xid in > TransactionIdLimitedForOldSnapshots > without lock would lead to an improper xlimit calculation. That would be a bummer. > So, my choice would be (3b). My goal is to optimize access to the > threshold_timestamp to avoid > multiple spinlock acquisition on read. In the same time, simultaneous access > to these variable > (threshold_timestamp and threshold_xid) should be protected with spinlock. > > I remove atomic for threshold_xid and add comments on mutex_threshold. PFA, > v3. I Interesting, but it's still not entirely clear to me from reading the comments why we should think that this is safe. -- Robert Haas EDB: http://www.enterprisedb.com
