Re: Unexpected "shared memory block is still in use"

Noah Misch <noah@leadboat.com> writes:
> Looks good.  That is basically a defect in commit c09850992; the race passed
> from irrelevance to relevance when that commit subjected more segments to the
> test.  Thanks for diagnosing it.

The bug's far older than that, surely, since before c09850992 we treated
*any* shmat failure as meaning we'd better fail.  I think you're right
that c09850992 might've made it slightly more probable, but most likely
the bottom line here is just that we haven't been doing parallel
check-worlds a lot until relatively recently.  The buildfarm would be
kind of unlikely to hit this I think --- AFAIK it doesn't launch multiple
postmasters using the same port number concurrently.  But parallel
invocation of TAP test scripts makes the hazard real.

Will go fix/backpatch in a minute.

            regards, tom lane