Re: YA race condition in 001_stream_rep.pl (was Re: pgsql: Allow using the updated tuple while moving it to a different par)

Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> writes:
> On Sat, Jul 14, 2018 at 11:46 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>> So the issue boils down to this: the test script is, effectively,
>> assuming that it's guaranteed that the walreceiver will send a feedback
>> message before it shuts down; but there is no such guarantee. Is this
>> a bug in the test script, or a bug in the walreceiver logic? I can
>> see the value of having such a guarantee, but I also think it would be
>> nigh impossible to make it a bulletproof guarantee. We could perhaps
>> add "XLogWalRcvSendHSFeedback(true)" somewhere closer to process exit,
>> but that might add more failure modes than it removes.
>>
>> Or we could change the test script to wait for feedback before it
>> issues the shutdown, but then I think the test is a bit pointless.

We've seen two more instances of this failure in the buildfarm since
this exchange (dragonet and flaviventris --- seems like Andres' menagerie
is particularly prone to it).

> Currently, neither the code nor our documentation suggests that we can
> expect HSFeedback before the shutdown, so it is better to adjust the
> test. If the sole purpose of the test is to test feedback after
> shutdown, then it is worth considering to remove the test altogether.

Hearing nobody speaking in favor of the other alternatives,
I've removed the test.

regards, tom lane