[bind10-dev] some other details about differences

[JINMEI Tatuya / 神明達哉]

At Fri, 14 Oct 2011 22:17:29 +0200,
Michal 'vorner' Vaner <michal.vaner at nic.cz> wrote:

> The housekeeping process could run from time to time and check such conditions.
> Or maybe it could be asked in background after another update is created.
> 
> > One possible nice thing of the database approach is that it would be
> > relatively easy for the administrator to manually drop some older
> > versions of diffs, e.g., by 
> > selete from diffs where
> >   id <= (select id from diffs where version = X and
> >          operation = 1 (add)
> > 	 order by id desc limit 1);
> 
> I think we should provide our own tool for the admin. Even if he
> would need to run it from time to time by hand (which I don't think
> is the best approach).

I didn't mean we don't have to provide a dedicated tool.  My point is
that if the administrator wants they could directly fix the diff table
(at their own risk), while with the proprietary "journal file" format
it would be more difficult.

> Anyway, the tool should use some higher level API maybe? Should we have an API
> to delete diffs?

Ah, good point.  Since in our case different data sources will handle
diffs in different ways, we'll probably need to provide a higher level
unified API.

> Anyway, one more topic I was wondering about. Do we want to be able to create
> diffs from two versions (eg. user loads next version of zone file into the DB)?

Yes, this is necessary to implement "ixfr-from-differences".  But it's
more about how to calculate diffs from two different versions of
complete zone data, rather than how to manage the diffs.  So, while
this is a topic we should consider in terms of top level features,
it's outside the scope of this particular thread.

---
JINMEI, Tatuya
Internet Systems Consortium, Inc.