PG Bug reporting form <noreply(at)postgresql(dot)org> writes:
> SELECT pg_cancel_backend(130342);
> ...
> 2020-12-01 14:26:02.337 JST [130270] LOG: background worker "parallel
> worker" (PID 130342) was terminated by signal 11: Segmentation fault
> 2020-12-01 14:26:02.337 JST [130270] DETAIL: Failed process was running:
> EXPLAIN ANALYZE SELECT * FROM data1 d1, data1 d2;
FWIW, I failed to reproduce any crash here, using RHEL8 (llvm-10.0.1).
I don't see any plausibly-related commits since 13.1, so it's not
something we recently fixed. I wonder if this is an LLVM bug fixed
since the 7.1 release you have.
regards, tom lane