On Fri, Jun 06, 2025 at 03:37:45PM -0400, Andres Freund wrote: > On 2025-06-06 15:21:13 -0400, Tom Lane wrote: > > So it's our code that is busted. No doubt, what is happening is > > that process A is fetching two fields, modifying one of them, > > and storing the word back (with the observed value of the other > > field) concurrently with some other process trying to update > > the other field. So the other process's update is lost. > > There shouldn't be any concurrent accesses here, so I don't really see > how the above would explain the problem (the IO can only ever be > modified by one backend, initially the "owning backend", then, when > submitted, by the IO worker, and then again by the backend).
No concurrent accesses, not from threads anyways, but not even from kernel subsystems nor from signal handlers?
