[pgpool-hackers: 2502] Re: wd_authkey bug (bug tracker #333)

[Tatsuo Ishii]

I think the restriction (to use watchdog clusters, each Pgpool-II
major/minor versions are exactly same) is not big deal for users.

So I prefer to go with the change Yugo proposed.

Best regards,
--
Tatsuo Ishii
SRA OSS, Inc. Japan
English: http://www.sraoss.co.jp/index_en.php
Japanese:http://www.sraoss.co.jp

> Hi Yugo Nagata,
> 
> Thanks for catching this, Since most of the time we test the watchdog by
> running multiple instances on same machine so this issue would never appear
> in our test environment,
> I believe you fix is spot on and unfortunately as far as I can think of
> there is not much we can do for backward compatibility and have to live
> with that to fix this issue.
> 
>  Thanks
> Best Regards
> Muhammad Usama
> 
> On Thu, Aug 24, 2017 at 12:33 PM, Yugo Nagata <nagata at sraoss.co.jp> wrote:
> 
>> On Thu, 24 Aug 2017 16:31:51 +0900
>> Yugo Nagata <nagata at sraoss.co.jp> wrote:
>>
>> Sorray, the previous attachment is incorrect.
>> I attached a revised one.
>>
>> > Hi Usama,
>> >
>> > There is the recent bug report about wd_authkey.
>> >
>> >  0000333: watchdog fails to add node to master when wd_authkey is not an
>> empty string; pgpool member shuts down
>> >  http://www.pgpool.net/mantisbt/view.php?id=333
>> >
>> > We have the same issue report recently from our client. In my analysis,
>> this is a bug
>> > due to the commit [1]. This changed the definition of tv_sec that is
>> used to check wd_authkey
>> > so that this was affected by the clock of OS. So, if there is a lag
>> between two nodes' clocks,
>> > the wd_authkey check fails.
>> >
>> > A simple solution is not to use tv_sec in the wd_authkey check as the
>> attached patch.
>> > However, one concern is that this is a specification change and that
>> this also will break
>> > back-compatibility. Of course, we can diallow watchdog cluster to have
>> Pgpool-II of different
>> > minor-versions. Although this is already implicit restriction of
>> watchdog, we can make this
>> > explicit restriction by checking other Pgpool-II node's version when
>> receiving watchdog
>> > packet.
>> >
>> > What do you think about it?
>> >
>> > [1] http://www.pgpool.net/pipermail/pgpool-committers/
>> 2017-April/003945.html
>> >
>> > --
>> > Yugo Nagata <nagata at sraoss.co.jp>
>>
>>
>> --
>> Yugo Nagata <nagata at sraoss.co.jp>
>>
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