owlim-discussion  

Re: [Owlim-discussion] BigOWLIM configuration

Ivan Peikov
Fri, 28 May 2010 02:07:30 -0700

Hi Peter,

When working heavily with context it helps if the context index is built and 
maintained (this is the build-pcsot parameter in the BigOWLIM configuration).

Do you have such an index in your setup?


Cheers,
Ivan

On Thursday 27 May 2010 13:15:23 Peter Kostelnik, PhD. wrote:
> hi there, barry,
>
> thats ok .. thanks for your support ..
>
> btw, meanwhile, some new stuff arised :) .. there is some time problems
> when BigOWLIM deletes the triples from specified context, e.g.
> connection.clear(contextURI)
>
> we are doing quite heavy post-processing above cca. 80-100 milions of
> statements.. in our case, we are aggregating the snippets of data and
> putting them together into specific contexts (to be able to retrieve them
> fast) .. and in most cases, we have to replace the data in more contexts
> .. logs of the process say, that removing the context data using
> connection.clear(ctx) is fatally slow .. in some cases  it takes more that
> hour(s) .. please, do you have some idea, how to deal with this?
>
> thanks in advance, cheers,
>                                Peter K.
>
> > Hello Peter,
> >
> > Sorry for the delay in answering your email. We have had a number of
> > urgent tasks and holidays in the last few days.
> >
> > Nevertheless, we will discuss your tuning requirements today and come up
> > with some suggestions.
> >
> > Thanks for your patience,
> > barry
> >
> > On 21/05/2010 16:03, Peter Kostelnik, PhD. wrote:
> >> hi there ..
> >>
> >> I'd like to ask for the hints, how to configure BigOWLIM for the best
> >> possible performance in run-time ..
> >>
> >> there is a couple of parameters which (I believe) can improve the
> >> triple-store performance, so my question is, how to set them to achieve
> >> the best ..
> >>
> >> our setup is as follows:
> >> ---
> >> approx. number of statements: for sure more than 100 millions (pls, how
> >> affect the copying the same graphs of statements into more different
> >> context? are they copied to as different squads or there is just the
> >> kind
> >> of association of same statements to the different context URIs?)
> >>
> >> we are about to use the RDFS reasoning, but in most of cases (in this
> >> moment - in all cases) for now we don't use the reasoning at all yet..
> >>
> >> right now we don't use the rules
> >>
> >> we are firing the SPARQL queries, we are also using the
> >> RepositoryConnection instances to retrieve the data ..
> >>
> >>
> >> we are running the two different scenarios:
> >> ---
> >> scenario 1: off-line load of all data
> >> this is done only once - the very first load of the data into
> >> triplestore ..
> >> we are using two instances of Repository, first for loading the data,
> >> second for post-processing ..
> >> first instance is initialized, all data are loaded into the triple-store
> >> in a single transaction commited after the load is finished .. when
> >> loading, the snippets of data are parsed and stored into more separate
> >> contexts ..
> >> after the loading is finished, there comes the huge post-processing ..
> >> so
> >> first repository is shutted down, and post-processing repository is
> >> initialized .. it does the work and it is shutted down - data are in
> >> triple-store ..
> >> loaded data are moved to the production system (running as BigOWLIM
> >> under
> >> sesame server) ..
> >>
> >> scenario 2: run-time
> >> ---
> >> BigOWLIM is accessible remotely using HTTPRepository, handling the lots
> >> of
> >> queries and searches ..
> >>
> >> pls, do you have some hints, how to squeeze the best from BigOWLIM?
> >> if talking about the RAM, can you, pls - if possible - draw possible
> >> alternatives for several setups (<- just curious what effect has this
> >> parameter (sure, I know - the more the best :) ))?
> >>
> >> thanks a lot in advance, cheers,
> >>                                  Peter K.
> >>
> >>
> >>
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