[Nepomuk] Live Queries

[Peter Penz]

Hi Sebastian and Vishesh,

On 05/11/2012 09:26 AM, Sebastian Trüg wrote:
> On 05/11/2012 09:23 AM, Vishesh Handa wrote:
>>
[...]

>>      the simplest heuristic would be to check for ResourceTypeTerm in the
>>      main AndTerm (or as the only term) and then configure the RW
>>      accordingly.
>>      That might already take care of those main queries.
>>
>>
>> This seems like a good idea.
>>
>> Don't you think that sometimes one just might not need live queries?
>> Specially for the timeline stuff like "Yesterday". There is very little
>> chance of it changing.
>
> Yes, you are right. Let's do both.

I'm must admit that I'm not aware about the difference of a "live query" 
and a "default (?) query" ;-) Anyhow if there is a simple way for us 
application developers to have a gained performance by passing a kind of 
hint to Nepomuk, please just ping me and I'll adjust the code.

Thanks,
Peter

>>
>>      Cheers,
>>      Sebastian
>>
>>      On 05/11/2012 09:08 AM, Vishesh Handa wrote:
>>      >  Hey Sebastian and Peter
>>      >
>>      >  I've noticed that in the latest git version of Dolphin, the
>>      side-bar has
>>      >  been updated to show cool stuff like all your Documents, Music and
>>      even
>>      >  stuff from timeline.
>>      >
>>      >  Each of these runs by passing a query to the query service client,
>>      which
>>      >  in turn passes it the QueryService. The QueryService runs the
>>      query AND
>>      >  waits for changes to the Nepomuk repository. The moment it notices
>>      that
>>      >  the repository has changed, it re-runs ALL the queries.
>>      >
>>      >  This gives us absolutely horrible performance when listing a large
>>      >  number of files. A typical example is listing all the music files when
>>      >  stuff is being indexed. I have a small music collection, just around
>>      >  35,000 songs. Listing all them takes a lot out of Nepomuk and Dolphin.
>>      >  This will become an even more serious issue when the Telepathy-Nepomuk
>>      >  Service is shipped. It writes even the smallest change to Nepomuk, and
>>      >  that results in all the queries being re-run.
>>      >
>>      >  Is there any way we can improve this?
>>      >
>>      >  I was hoping for some kind of 'live query' boolean parameter. Only the
>>      >  queries with that parameter set will be re-run. For simple stuff like
>>      >  querying all the music files or documents (or even Timeline) we could
>>      >  use the ResourceWatcher.
>>      >
>>      >  What do you guys think?
>>      >
>>      >  --
>>      >  Vishesh Handa
>>      >
>>
>>
>>
>>
>> --
>> Vishesh Handa
>>