[Sugar-devel] new journal and datastore maintainer

[Tomeu Vizoso]

On Fri, Sep 18, 2009 at 02:10, James Cameron <quozl at laptop.org> wrote:
> On Thu, Sep 17, 2009 at 04:51:47PM +0200, Martin Langhoff wrote:
>> So I am strictly looking forward -- and wondering if we can help these
>> users of 0.82 now.
>
> By branching at the 0.82 point as deployed, determining from evidence
> (those renamed DS directories you have been unable to obtain) what the
> likely problem is, and then making a minor change to prevent or handle
> it.
>
> The authors of the 0.82 DS or the 0.84 DS might also use their knowledge
> of the code to  comment on the likely causes so that the investigation
> can be refined.

Sure, we are here available for help.

> It's not impossible, just more difficult than a rewrite.  Maintenance
> programming is like that; more difficult.

True, but there's several times more developers downstream that
upstream. There's also a big investment going in support personnel,
and there's also the lost learning opportunities because of bugs, and
also the duplicated efforts in each deployment. I think that when the
Sugar ecosystem matures further, we'll reach much bigger efficiency in
development and maintenance.

Maintenance is also less shiny and interesting to newcomers, so I
would avoid relying only on volunteers for that.

> If the current writers are unable to dedicate that extra time, then an
> upgrade becomes the only option they will encourage.
>
> git://git.sugarlabs.org/sugar-datastore/mainline.git
>
> I've reviewed the changes just now from 0.82 to 0.84.  It was certainly
> an entire rewrite, so what you are in effect asking is for someone to
> support the 0.82 DS to fix a problem that is not yet well defined.  Is
> Benjamin Saller available?  ;-)

Perhaps we could ask?

> You've said that coincident with total datastore loss you've also
> observed the datastore directory is renamed and journal items are no
> longer listed.  I've looked for this code, but have not found it.  Can
> anyone tell me where in the sugar or sugar-datastore code this rename
> decision is made?
>
>> And how we'll handle similar issues when 0.84 is deployed and if
>> dataloss bugs are reported.
>
> There is no evidence yet to suggest that the same bugs will be reported,
> and since the datastore code is entirely different I think it is
> unlikely that you'll get the same bugs.

Also: the new DS was designed to avoid the causes of data loss that we
knew about (chiefly, index corruption), and is also designed to
automatically repair the index when that happens.

> Have there been any instances of entire datastore loss on 0.84 or 0.86?

Daniel reported some cases in which the index wasn't correctly
autorebuilt and those got fixed.

> The saved datastore and the logs will be very pertinent to the problem.
> So that's the first way to handle it ... gather the critical problem
> data.

Yes, I also look forward to that.

Thanks for your interest,

Tomeu

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«Sugar Labs is anyone who participates in improving and using Sugar.
What Sugar Labs does is determined by the participants.» - David
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