Activities - Storing ResourceScoreCache in Nepomuk

Ivan Čukić ivan.cukic at kde.org
Wed May 22 11:41:37 UTC 2013


> Could you please point me to the relevant code?

Quick grep (don't know the code, it is Marco's)
  plasma-mobile/components/metadatamodel/metadatamodel.cpp:411

> Also, why duplicate the data in both the sqlite and nepomuk database?

For the speed issues.*

Storing and querying the desktop events proved to be by an order of magnitude 
slower in nepomuk (**for the type of queries that we need**). For that reason, 
the sqlite backend was introduced. It freed us from pushing a huge amount of 
(for the rest of the world unneeded) data into the database and having to 
query it every time the score is updated.

This way, we are having a private database for private things, and pushing 
only the important data to nepomuk to be accessible by other applications.
(as IMO it should be in other clients as well - not to abuse a rdf store as a 
kitchen-sink database)

Cheerio,
Ivan

* back then, there were also quite a few thread-safety related issues in 
soprano that kept kamd crashing. But that was not even considered as a reason 
for the switch - it was just a nice side-effect to have kamd more stable.

-- 
You know, there are many people in the country today who,
through no fault of their own, are sane. Some of them were born sane.
Some of them became sane later in their lives...
  -- Monty Python's Flying Circus



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