[Kde-pim] Nepomukfeeder updates almost ready

[Allen Winter]

On Wednesday 26 December 2012 04:44:53 PM Christian Mollekopf wrote:
> Hey,
> 
> I made another bunch of fixes, turned the finding of skipped items into a 
> recurring task, and turn the change-recorder off now if the feeder is disabled 
> entirely. In my testing so far this system behaves much better than what we 
> used to have.
> 
> I plan on committing this to 4.10 if noone objects within the next days. (I'll 
> write a mail to release-team first).
> 
> The code is here:
> http://quickgit.kde.org/?p=clones%2Fkdepim-
> runtime%2Fcmollekopf%2FpimRuntimeClone.git&a=shortlog&h=c2ca91566953c57af119634f65b5bd73bac7e7fa
> 
> Cheers,
> Christian
> 
> 
> On Sunday 23 December 2012 17.54:18 Christian Mollekopf wrote:
> > Heya,
> > 
> > To cut right to the chase; I revamped the feeders a bit, think it's much
> > better than what we had before, and would like to get it into 4.10. So feel
> > free to skip if you don't care.
> > 
> > I moved to a recurring, query based approach for the initial-indexing. That
> > means, instead of doing a single initial-indexing when the feeder is
> > executed the first time, and relying purely on updates from the
> > change-recorder afterwards, the initial-indexing is now more a maintenance
> > task (which is currently running on every start), and queries for all not
> > yet indexed items.
> > 
> > That is necessary, as the initial assumption that we can index items faster
> > than notifications come in didn't hold true, which resulted in the feeder
> > regularly being overloaded with stuff to index.
> > 
> > The initial query approach resulted in n queries for n items, which is way
> > too slow to be feasible for all items (it is taking ages, literally). The
> > only alternative approach I found is; we run two queries, one in akonadi
> > and one in nepomuk, each querying for *all* available items. Comparing the
> > two lists, results in the list of items which have not been indexed yet. Of
> > course, that misses any changes on items which have been indexed before,
> > but have been modified since then, so it's not ideal either.
> > These queries are fairly efficient as they result in a single sql query per
> > db (as opposed to n),  although with a huge result set. I could query my db
> > of ~100'000 items in ~20s (i7 processor).
> > 
> > Since I figured changes on emails, which are mostly just flags, are
> > negligible, I switched the email initial-indexing to that new approach.
> > 
> > Non-email items continue to be indexed as usual, meaning there is one query
> > per item, which allows us to detect modifications as well. That is slow as
> > usual, but since we usually have a lot more email items than non-email
> > items, it works well enough.
> > 
> > Another important advantage is that we can thus now also skip large batches
> > of new/changed items, knowing they will be picked up by the
> > initial-indexing eventually. That also allows us to turn off the
> > change-recorder when the feeder is turned off (which is another problem if
> > we rely on the change- recorder too much).
> > 
> > One remaining problem is that we get loads of notifications of changed/added
> > items, which I think are mostly due to sync-on-demand updates, updating the
> > cache (and not actual new emails or whatnot). I also often get flag change
> > notifications on my offline imap accounts, which I don't really know why
> > yet. That of course would lead to loads of items being indexed over and
> > over again, but that can be mitigated somewhat since we now can skip larger
> > batches of items.
> > 
> > Besides I made some performance improvements, such as the cache I mentioned
> > previously (200% performance boost), or that new items are now indexed
> > without any queries, which gives another boost of 10%-20% or so.
> > 
> > Overall, I think we should get this into 4.10 as fast as possible. The patch
> > is somewhat large (and way to late in the process), but IMO the previous
> > feeders are broken enough to justify this. So what do you think? Should I
> > commit this to 4.10 in a couple of commits, or only master and then
> > backport it for 4.10.1?
> > 

Are there any objections to getting this work committed for 4.10?
It's awfully late in the release cycle to be pushing for this, but I will
do so if I get warm-fuzzies from a couple more folks that we need it.

Anyone want to chime in here?
Please do so ASAP.

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