> On Wed, May 13, 2026 at 07:56:43PM +0800, wenhui qiu wrote: > > I have an experimental patch to explore handling this situation. The patch > > adds a GUC, vacuum_freeze_terminate_blockers_pid, which allows VACUUM to > > terminate regular client backends whose transaction horizon blocks VACUUM > > from advancing its freeze cutoff. The intended targets are > > idle-in-transaction sessions and long-running active transactions that are > > holding an old xmin or assigned XID. > > Thanks for sharing. I certainly agree that this area has room for > improvement in Postgres.
My 2c. Using something like the proposed vacuum_freeze_terminate_blockers_pid (GUC name is misleading, since it's a bool ) seems backwards to me. It does not address the root cause, which is the long-running transaction, etc and attempts to deal with the symptom rather than the problem. This also means a poor configuration of this parameter will more likely lead to a system silently getting into wraparound, as a DBA may relax a bit on monitoring, maybe. I do think we need better visibility into what is blocking vacuum, which was discussed here [1], but ultimately it is up to the DBA to properly monitor and mitigate workloads that are impacting their vacuum. [1] https://www.postgresql.org/message-id/flat/CAOzEurSgy-gDtwFmEbj5%2BR9PL0_G3qYB6nnzJtNStyuf87VSVg%40mail.gmail.com -- Sami Imseih Amazon Web Services (AWS)
