PG Bug reporting form <noreply@postgresql.org> writes:
> One of our customers recently experienced the following PANIC with
> PostgreSQL 11.5 on AIX:
> PANIC: cannot abort transaction 1234567890, it was already committed
That's probably just a side-effect of some other problem. There's
no strong reason to think that it's the same thing as #15727.
Can you provide a reproducer by any chance?
regards, tom lane