[Buildbot-devel] p4poller.py changes detection since last sync

[Yasser LEBON]

I totally agree with you that the response is too vague. My impression is
that they don't know exactly where the performance differences comes from
but they suspects the db queries .

In any case, using the head changelist number instead of @NOW improves
definitively the hit on our server.

Yasser


2013/10/28 William Deegan <bill at baddogconsulting.com>

> Yasser,
>
>
> On Oct 28, 2013, at 12:03 PM, Yasser LEBON <yasser.lebon at gmail.com> wrote:
>
> After clarification with team responsible of Perforce in my company it
> seems that using @HEAD or @NOW the scanning occurs at the level of the
> db.rev instead of db.change that gives differents impacts on Perforce
> server. I contacted Perforce and here is their answer:
> "The difference has to do with the query being different since you are
> using different arguments. The result may be the same but dealing with the
> internals is very different, if you are familiar with relational database
> you know that the way you construct your query has a lot to do with the
> performance.
>
>
> That's kind of a vague response from Perforce.
> Did they say which one is better?
>
>
> Actually, I made a patch to change the p4poller.py behaviour. I used "p4
> changes -m1" to have the last revision and use the result output  to get
> the changelists range "p4 changes @%d, @%d" % (lastChange, headRevision)
>
>
> Does this improve the hit on your server?
>
> Thanks,
> Bill
>
>
> Regards
> Yasser
>
>
>
> 2013/9/27 William Deegan <bill at baddogconsulting.com>
>
>> Yasser,
>> On Sep 19, 2013, at 2:14 PM, Yasser LEBON <yasser.lebon at gmail.com> wrote:
>>
>> >
>> > Hello,
>> >
>> > I noticed that buildbot use the following command to get perforce depot
>> list of changes since last sync:
>> >
>> > 'p4 changes %s...@%d,now' % (self.p4base, self.last_change+1)
>> >
>> > Is there any reason why we use 'now' instead of '#head'? Thanks
>>
>> I'm not sure why the previous maintainer used ,now, but the result should
>> be the same.
>>
>> From p4 docs:
>> * The datespec @now can be used as a synonym for the current date
>> and time.
>> * file#head The head revision (latest version) of file. Except where
>> explicitly
>> noted, this is equivalent to referring to the file without a revision
>> specifier.
>>
>> Are you aware of any functional difference?
>> -Bill
>
>
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://buildbot.net/pipermail/devel/attachments/20131028/9f80c8b7/attachment.html>