On Fri, Dec 26, 2025, at 21:12, Joel Jacobson wrote: > On Tue, Nov 25, 2025, at 21:17, Tom Lane wrote: >> "Joel Jacobson" <[email protected]> writes: >>> It looks to me like it would be best with two boolean fields; one >>> boolean to stage the updates during PreCommit_Notify, that each >>> pendingActions could flip back and forth, and another boolean that >>> represents the current value, which we would overwrite with the staged >>> value during AtCommit_Notify. >> >> +1, I had a feeling that a single boolean wouldn't quite do it. >> (There are various ways we could define the states, but what >> you say above seems pretty reasonable.) > > I've implemented the two boolean approach and think it's good. > > The signals arrays are now preallocated during PreCommit_Notify. > > More details in the patch message under "Two-phase staging pattern".
New version with some fixes. I should have mentioned that v31 is based on v28 (v29 and v30 were discarded). Here is also a write-up of changes from v28 to v31: 0001: No changes. 0002: * To avoid post-commit OOM hazards, we now allocate hash table entries during PreCommit_Notify. Each listener entry has two boolean flags; staged and current. For each LISTEN/UNLISTEN action the staged flag is set/unset during PreCommit_Notify. The last action's staged value per channel is then copied from staged to current during AtCommit_Notify. * On abort, AtAbort_Notify reverts staged changes. * The signal arrays are now preallocated during PreCommit_Notify. * Renamed Exec_UnlistenAllCommit to CleanupListenersOnExit for the exit-handler path, since it has different semantics (unconditional removal rather than staged/current handling). In case someone has already started reviewing v31, these are the changes I made in v32: 0001: * Added test: Check UNLISTEN * cancels a LISTEN in the same transaction 0002: * Fixed initialization of QueueBackendStatus fields, corrected the LISTEN + UNLISTEN same-transaction case, restructured AtAbort_Notify to mirror AtCommit_Notify, and added a guard for OOM during staging. /Joel
0001-optimize_listen_notify-v32.patch
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0002-optimize_listen_notify-v32.patch
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