On Mon Nov 10, 2025 at 9:29 AM -03, Smolkin Grigory wrote: > Hello, hackers! > > I`m currently investigating the case of one of our PostgreSQL instance > having started issuing error messages about missing clog segment: > ERROR: could not access status of transaction 1550558894 > DETAIL: Could not open file "pg_xact/05C6": No such file or directory. > Is this error happening with the LISTEN/NOTIFY? There is a discussion going on [1] that aims to fix this issue for the LISTEN/NOTIFY.
No, LISTEN/NOTIFY are not used.
So do you have a step by step to reproduce the issue?
Unfortunately, no.
Or at least some more information about what the server was running that caused the error?
By the looks of it, nothing special, really, just plain inserts and occasional index-scan reads (tuple (5456224,2) looks like it was read by index-scan, because it has HEAP_XMIN_COMMITTED stamped on). Instance wasn't subjected to power outages, kernel crashes or hardware issues.
On Mon Nov 10, 2025 at 9:29 AM -03, Smolkin Grigory wrote: > So is it possible that either all_frozen bit was set incorrectly or wansn't > unset when tuples were created? > I will be happy to provide any additional information if required. > PostgreSQL version: 15.6, data_checksums: on > Actually the 15.6 is quite old.
It is, but I didn't see any fixes that can possibly be related to this case, but maybe I've missed something.
I didn't find any specific release note about clog truncation but you are missing some important fixes though.
There is this fix [1] on 15.8 but I'm not sure if it's fully related with your issue faced here.
