Actually, after fixing a few dumb things I was doing, the speed has  
improved immensely.  In the end, I don't think supressing the spin  
model inferences really buys much since inferences are now running in  
under a second, even with those in.

Jeff

On Dec 18, 2009, at 12:24 PM, Holger Knublauch wrote:

>> Anyway, these rules take quite a long time (about 90 seconds) to  
>> execute on my OWL_MEM model, which isn't all that big at about 3000  
>> triples including all the imported models.  Does that sound  
>> plausible?  If so, I'm thinking I may need to add these inferences  
>> in a more targeted way.
>
> In general, as you certainly know, the performance of SPARQL queries  
> strongly depends on the implementation of the engine and whether (or  
> not) it re-orders clauses automatically. It is best to assume that  
> ARQ will execute the clauses (triple matches and filters) from top  
> to bottom, but looking at the SPARQL Debugger in TBC will help you  
> identify the real execution order. In particular FILTER clauses may  
> be re-ordered with significant performance penalty. There is a new  
> option in TBC on the SPARQL preferences tab to force ARQ to leave  
> the FILTER clauses in place, which is IMHO recommended.
>
> In SPIN in particular, other factors are important:
> - if a class has many subclasses with instances, then there might be  
> many individual SPARQL calls for each rule defined on the  
> superclasses.
> - Each iteration will have a clause to bind ?this with all instances  
> of a class.
>
> If these cause performance issues, you can bypass the binding of ? 
> this by either
> - making rules global (drop ?this and instead put them at owl:Thing  
> or rdfs:Resource) These global rules will be executed only once
> - use the new SPIN 1.1 property spin:thisUnbound to drop the ?this  
> rdf:type <class> clause, which may theoretically slow down
>
> After you run inferences in TBC, the Error Log will contain a list  
> of the slowest queries, together with benchmarks.
>
> I hope this helps... let me know if you have ideas on how to improve  
> performance tuning.
>
> Regards,
> Holger
>
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