Hi Dave, As you suggested, I have computed the closure in memory, totaling over 4 millions triples. trying to serialize it. Is there a direct API to serialize the whole model into TDB? Tried to serialize into file, keep getting memory issue. What's the typical resource need for this size of model? ________________________________________ From: Dave Reynolds [dave.e.reyno...@gmail.com] Sent: Thursday, July 21, 2016 9:09 AM To: users@jena.apache.org Subject: Re: TDB triple storage
On 21/07/16 13:45, Chao Wang wrote: > Thanks Dave, > So my fuseki has configuration using TDB with OWL reasoner. I preloaded the > TDB with tdbloader, then starts up fuseki. > My question is when fuseki starts up, does it load all triples including > inferred triples into memory? Yes. It's actually slightly worse than that. All the inferences will be in memory (including intermediate state) which will be bigger than than source data. But the data itself isn't loaded explicitly which means that the reasoner is going back to TDB for each query which is a further slow down. Using a lighter reasoner config (OWL Micro if you are not already using it) may help. Otherwise, if your data is stable, then as I say, compute the closure once in memory, off line. Store that in TDB. Then have your fuseki configuration use that precomputed closure with no runtime inference. Dave > I am experiencing hanging sparql query. works fine with a small dataset. I am > hoping reasoning is not done during query time... > ________________________________________ > From: Dave Reynolds [dave.e.reyno...@gmail.com] > Sent: Thursday, July 21, 2016 3:35 AM > To: users@jena.apache.org > Subject: Re: TDB triple storage > > On 21/07/16 02:09, Chao Wang wrote: >> A newbie question: >> Does jena store the inferred triples into tdb? If yes, when? > > No. The current reasoners operate in memory. > > If you wish you can take the results of inference (either the entire > closure or the results of some selective queries) and store those back > in TDB yourself. A common pattern would be use separate named graphs for > the original data and for the inference closure and use union-default. > All this under your control but is not automatically done for you. > > There is also some support for generating a partial RDFS inference > closure at the time you load TDB. > > Dave >
