[Catalog-sig] Request: Interface to index of package-metadata

mereandor at gmail.com mereandor at gmail.com
Fri Mar 21 23:49:27 CET 2008


Am Freitag, 21. März 2008 21:39:01 schrieb Martin v. Löwis: 
> Thanks for the explicit scenario; it is fortunately not the
> case that you would have to download all package and version
> information each weak.
> 
> Instead, I recommend to use the changelog method, to find out
> all changes since the last week.
> 
> > I hope this clears things up a bit.
> 
> Indeed it does. For synchronization, you shouldn't at all
> consider downloading all information again repeatedly. Instead,
> try using incremental update methods as much as possible.
> 
> With the changelog method, daily updates become much more
> reasonable; some sites query the changelog every minute
> (and it is then typically empty).
> 
> Regards,
> Martin

I would still prefer the full dump for several reasons:
* changelog would only give me the information what package has changed, I still would have to use release_data to get the new data
* the benefits of changelog decrease the longer the update interval is (and it's typically longer than a day; sometimes several months - depends on the user)
* getting a dump of all data is not that expensive as search({'name':''}) takes about 5 seconds including the time for the data-transfer and displaying all the data
* the problem of the first sync remains (at least once for each system installation/user)

Incremental updates add a certain amount of complexity:
* I need to be sure that the data is sane before the sync so that I can be sure that it is sane after it
* I need to know the exact time of the last sync
* The algorithm for an incremental sync is considerably more complex

Regards, 
Roman


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