Hi Heikki, On Wed, Nov 12, 2025 at 07:16:38PM +0000, Heikki Linnakangas wrote: > Fix remaining race condition with CLOG truncation and LISTEN/NOTIFY > > Previous commit fixed a bug where VACUUM would truncate the CLOG > that's still needed to check the commit status of XIDs in the async > notify queue, but as mentioned in the commit message, it wasn't a full > fix. If a backend is executing asyncQueueReadAllNotifications() and > has just made a local copy of an async SLRU page which contains old > XIDs, vacuum can concurrently truncate the CLOG covering those XIDs, > and the backend still gets an error when it calls > TransactionIdDidCommit() on those XIDs in the local copy. This commit > fixes that race condition. > > To fix, hold the SLRU bank lock across the TransactionIdDidCommit() > calls in NOTIFY processing.
While reading through this set of changes, the addition of this commit across the v14~v16 range has made me smile: + * Now that we have let go of the SLRU bank lock, send the notifications + * to our backend SLRU bank locks have been introduced in v17 by Alvaro in 53c2a97a9266. Just noticed while going through. -- Michael
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