Richard Guo <guofenglinux@gmail.com> writes:
> +1. I'm kind of worried that the expansion of parallelization could
> lead to more instances of instability. Alexander mentioned one such
> case at [1]. I haven't looked into it though.
> [1] https://www.postgresql.org/message-id/cbf0156f-5aa1-91db-5802-82435dda03e6%40gmail.com
The mechanism there is pretty obvious: a plancache flush happened
at just the wrong (right?) time and caused the output to change,
as indeed the comment acknowledges:
-- currently, this fails due to cached plan for "r.f1 + 1" expression
-- (but if debug_discard_caches is on, it will succeed)
I wonder if we shouldn't just remove that test case as being
too unstable -- especially since it's not proving much anyway.
regards, tom lane