Re: [PATCH] Fix for infinite signal loop in parallel scan

> On 18. Sep 2018, at 03:18, Thomas Munro <thomas(dot)munro(at)enterprisedb(dot)com> wrote:
>
> On Tue, Sep 18, 2018 at 1:15 AM Chris Travers <chris(dot)travers(at)adjust(dot)com> wrote:
>> On Mon, Sep 17, 2018 at 2:59 PM Oleksii Kliukin <alexk(at)hintbits(dot)com> wrote:
>>> With the patch applied, the posix_fallocate loop terminated right away (because
>>> of QueryCancelPending flag set to true) and the backend went through the
>>> cleanup, showing an ERROR of cancelling due to the conflict with recovery.
>>> Without the patch, it looped indefinitely in the dsm_impl_posix_resize, while
>>> the startup process were looping forever, trying to send SIGUSR1.
>
> Thanks for testing!
>
>>> One thing I’m wondering is whether we could do the same by just blocking SIGUSR1
>>> for the duration of posix_fallocate?
>>
>> If we were to do that, I would say we should mask all signals we can mask during the call.
>>
>> I don't have a problem going down that road instead if people think it is better.
>
> We discussed that when adding posix_fallocate() and decided that
> retrying is better:
>
> https://www.postgresql.org/message-id/20170628230458.n5ehizmvhoerr5yq%40alap3.anarazel.de
>
> Here is a patch that I propose to commit and back-patch to 9.4. I
> just wrote a suitable commit message, edited the comments lightly and
> fixed some whitespace.

Thanks!

Apart from the fact that the reviewer's name is “Murat Kabilov” and
not “Murak Kabilov” the back-patch looks good to me.

Cheers,
Oleksii Kliukin