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From Minto van der Sluis <>
Subject Re: Some Questions regarding implementing fastlane
Date Mon, 06 May 2013 14:49:48 GMT
Thanks Reto,

This clarifies the difference between fast-lane and slow-lane.



Op 5-5-2013 19:37, Reto Bachmann-Gmür schreef:
> Hi Minto
> Great work updating the modules!
> Now to the questions.
>>> - Forward query to fast- or slowlane using the Preparerser Hasan recently
>>> implemented
>> Questions: Where is this decision taken? How to decide whether to use
>> QueryEngine of QueryableTcProvider ? Are these both fast-lane?
> (Deferring the where question to when I write the code.)
> The QueryEngine is the slow-lane it works on any set of TripleCollections.
> QueryableTcProvider is the FastLane in that it might benefit from any
> optimization the backend provides it can only be used if the query only
> affects TripleCollections that are all provided by the same TcProvider (and
> this implements QueryableTcProvider).
>> - Make TdbTcProvider implement QueryableTcProvider
>> Question: Why is this needed if JenaSparqlEngine (implementation of
>> previous bullet) already takes care of this?
> The JenaSparqleEngine works on any TripleCollections which are passed to
> Jena wrapped as Jena Graphs. JenaSparqlEngine can only access the data in
> these graphs via the provided filter method. The assumption is that TDB can
> handle (some) queries more efficiently by using its internal quad-store or
> other optimization techniques it could provide.
>> Of coarse I could wire Tdb*Providers to use JenaSparqlEngine. But I
>> don't see the point.
> This shouldn't be wired to JenaSparqlEngine (only probably reuse response
> wrapping code) but forward the query directly to Jena rather than wrapping
> JenaGraphs as TripleCollections in the Tdb*Provider and wrapping these back
> to Jena Graphs for querying in the JenaSparqlEngine.
> Hope this makes things clearer.
> Cheers,
> Reto

ir. ing. Minto van der Sluis
Software innovator / renovator
Xup BV

Mobiel: +31 (0) 626 014541

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