Re: Testing LISTEN/NOTIFY more effectively

On Sat, Jul 27, 2019 at 12:39 PM Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> Unfortunately, I just found out that on a slow enough machine
> (prairiedog's host) there *is* some variation in when that test's
> notices come out. I am unsure whether that's to be expected or
> whether there's something wrong there --- Peter, any thoughts?

I don't know why this happens, but it's worth noting that the plpgsql
function that raises these notices ("blurt_and_lock()") is marked
IMMUTABLE (not sure if you noticed that already). This is a deliberate
misrepresentation which is needed to acquire advisory locks at just
the right points during execution.

If I had to guess, I'd guess that it had something to do with that. I
might be able to come up with a better explanation if I saw the diff.

--
Peter Geoghegan