Andrew Dunstan <andrew@dunslane.net> writes:
> On 10/12/2015 04:35 PM, Tom Lane wrote:
>> BTW, it appears from this that Cygwin builds have been broken right along
>> in a different way: according to the code in sysv_shmem's
>> PGSharedMemoryReAttach, Cygwin does cause a re-attach to occur, which we
>> were not undoing for putatively-not-connected-to-shmem child processes.
>> That's a robustness problem because it breaks the postmaster's expectation
>> that it's safe to not reinitialize shmem after a crash of one of those
>> processes. I believe this patch fixes that problem as well, though if
>> anyone can test it on Cygwin that wouldn't be a bad thing either.
> OK, I can test it. But it's not quite clear to me from your description
> how I should test Cygwin.
The point is that I think that right now, the logging collector subprocess
remains connected to shared memory, which it should not (and won't, if my
patch is doing the right thing). I do not know if there's an easy way to
inspect the process state to verify that on Windows.
If nothing else, you could put a bogus access to some shared-memory data
structure into the syslogger loop, and check that it succeeds now and
crashes after applying the patch ...
regards, tom lane