Re: pg_listener entries deleted under heavy NOTIFY load only on Windows

Marshall, Steve wrote:
> What's the timing of the errors? Is there a chance that we are sending
> the kill signal before the signal handling thread has actually started
> *and created the named pipe*?
>
> We set up the signal handling stuff pretty early, but we do seem to let
> the postmaster continue it's work before it's up...
>
> Under heavy load, a signal will typically be dropped within the first
> few minutes. However, it can sometimes take a little while before the
> problem happens. Thousands of the same signal to the same process may
> be properly handled before one is mishandled. This is not consistant
> with a problem with initial creation of the pipe.
>
> Going back to your tests, did it ever require more than one retry?
>
> Yes, but rarely. In a 90 hour stress test with code that allowed up to 5
> calls to CallNamedPipe, I found 760 signals that required a retry. Only
> one required two retries. That is why I set the number of retries to 2.
> The behavior might be different if the sleep interval between retries
> was changed. I used a 20 ms sleep interval between retries in all my
> tests, and in the patch I sent.

I have applied a modified version (no functional changes, just
stylistic) of this patch to head and backpatched to 8.2 which is as far
back as we support win32.

//Magnus