[Pellet-users] Pellet performance in TopBraid Composer

[Holger Knublauch]

This is in response to:

http://clarkparsia.com/pellet/faq/topbraid-composer/

Currently it says:

Why does Pellet run slowly in TopBraid Composer?

We don’t support TopBraid Composer or any TopQuadrant products. Often,  
Pellet appears to run slowly in TopBraid Composer due to the nature of  
the integration performed by TopQuadrant. If you are experiencing  
problems using Pellet via TopBraid Composer, we recommend trying  
Pellet directly before reporting an issue or bug.

The statement above is misleading. There is enough evidence on this  
mailing list these days [1,2] that the problem is not only "the  
integration performed by TopQuadrant". The flip side is the lack of  
optimizations in Pellet for the Jena query ontModel.listStatements().  
TBC in general uses this call for all provided inference engines, and  
none of them hang on this like Pellet does. Other ontology tools that  
appear to be faster simply don't do the complete set of inferences  
like TopBraid does.

However there are simple work-arounds already in TBC to make Pellet  
faster, and I suggest the page above be adjusted to the text below. I  
also mention them here for the mailing list archive and those  
searching for TopBraid and Pellet on Google.


Why does Pellet run slowly in TopBraid Composer?

When you hit the Run Inferences button in TopBraid Composer, Pellet  
may run slowly because Composer queries the complete list of inferred  
triples. Since this operation is hard to optimize in the general case,  
you may want to run only a subset of the inferences. For example, use  
"Inference > Run Superclass Inferences only" or "Consistency Checking  
only" to get much faster response times. Another mechanism is to  
activate inferencing in the SPARQL view and then run a SPARQL query on  
the kinds of query that you are interested in (e.g. via a library of  
stored CONSTRUCT queries). For the best fine-grained control, we  
recommend using the Pellet API directly. For further questions on  
TopBraid, please contact the TopBraid Composer mailing list.


Thanks
Holger

[1] http://lists.owldl.com/pipermail/pellet-users/2009-February/003347.html
[2] http://lists.owldl.com/pipermail/pellet-users/2009-February/003322.html
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