On Wed, Apr 26, 2017 at 3:47 PM, Kyotaro HORIGUCHI
<horiguchi.kyotaro@lab.ntt.co.jp> wrote:
> At Wed, 26 Apr 2017 14:31:12 +0900, Masahiko Sawada <sawada.mshk@gmail.com> wrote in
<CAD21AoDMy8a6UwMrRh8pigQbDC+JAOQ4m_tXT41VRP4SYp23=w@mail.gmail.com>
>> On Wed, Apr 26, 2017 at 12:35 PM, Petr Jelinek
>> <petr.jelinek@2ndquadrant.com> wrote:
>> > On 26/04/17 01:01, Fujii Masao wrote:
>> >>>> However this is overkill for small gain and false wakeup of the
>> >>>> launcher is not so harmful (probably we can live with that), so
>> >>>> we do nothing here for this issue.
>> >>>
>> >>> I agree this as a whole. But I think that the main issue here is
>> >>> not false wakeups, but 'possible delay of launching new workers
>> >>> by 3 minutes at most' (this is centainly a kind of false wakeups,
>> >>> though). We can live with this failure when using two-paase
>> >>> commmit, but I think it shouldn't happen silently.
>> >>>
>> >>>
>> >>> How about providing AtPrepare_ApplyLauncher(void) like the
>> >>> follows and calling it in PrepareTransaction?
>> >>
>> >> Or we should apply the attached patch and handle the 2PC case properly?
>> >> I was thinking that it's overkill more than necessary, but that seems not true
>> >> as far as I implement that.
>> >>
>> > Looks like it does not even increase size of the 2pc file, +1 for this.
>>
>> In my honest opinion, I didn't have a big will that we should handle
>> even two-phase commit case, because this case is very rare (I could
>> not image such case) and doesn't mean to lead a harmful result such as
>> crash of server and returning inconsistent result. it just delays the
>> launching worker for at most 3 minutes. We also can deal with this for
>> example by making maximum nap time of apply launcher user-configurable
>> and document it.
>> But if we can deal with it by minimum changes like attached your patch I agree.
>
> This change looks reasonable to me, +1 from me to this.
>
> The patch reads on_commit_launcher_wakeup directly then updates
> it via ApplyALuncherWakeupAtCommit() but it's too much to add a
> function for the sake of this.
OK, so what about the attached patch? I replaced all the calls to
ApplyLauncherWakeupAtCommit() with the code "on_commit_launcher_wakeup = true".
Regards,
--
Fujii Masao
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