Re: shm_mq fix for non-blocking mode

On Thu, Oct 22, 2015 at 4:45 PM, Robert Haas <robertmhaas(at)gmail(dot)com> wrote:
> On Fri, Oct 16, 2015 at 5:08 PM, Robert Haas <robertmhaas(at)gmail(dot)com> wrote:
>> The shm_mq code handles blocking mode and non-blocking mode
>> asymmetrically in a couple of places, with the unfortunate result that
>> if you are using non-blocking mode, and your counterparty dies before
>> attaching the queue, operations on the queue continue to return
>> SHM_MQ_WOULD_BLOCK instead of, as they should, returning
>> SHM_MQ_DETACHED. The attached patch fixes the problem. Thanks to my
>> colleague Rushabh Lathia for helping track this down.
>>
>> (There's are some further bugs in this area outside the shm_mq code
>> ... but I'm still trying to figure out exactly what they are and what
>> we should do about them. This much, however, seems clear-cut.)
>
> ...and so I've committed it and back-patched to 9.4.

Sigh. This was buggy; I have no idea how it survived my earlier testing.

I will go fix it. Sorry.

--
Robert Haas
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