On Fri, Oct 17, 2025, at 15:51, Álvaro Herrera wrote:
> I have the impression that this thread has lost focus on the idea of
> producing a backpatchable bugfix. The last proposed patch has a lot of
> new mechanism that doesn't seem suitable for backpatch. I could be
> wrong of course.
I've tried to create a minimal isolated fix, hopefully suitable for
backpatching, with no new mechanisms, other than the added
GetOldestQueuedNotifyXid used by vac_update_datfrozenxid.
It's based on the approach discussed earlier in this thread, that just
goes through the notification queue from QUEUE_TAIL to QUEUE_HEAD, to
find the oldestXid in the current database.
Implementation:
* Break out SLRU read page code from asyncQueueReadAllNotifications into
new helper-function asyncQueueReadPageToBuffer.
* Add GetOldestQueuedNotifyXid which uses the new helper-function
asyncQueueReadPageToBuffer.
It passes the 001_xid_freeze.pl test, not included in this patch.
/Joel
