On 2017-09-08 20:18, Andy Seaborne wrote: > Yes, Chris - MultiUnion is linking with a distinguished that is updated. > (Changing that would be a BIG change!) > > Datasets like TIM (transactions in memory) and TDB can provide the union > graph of their named graphs and more efficiently than the general purpose > MultiUnion.
Previously I was using the "urn:x-arq:UnionGraph" named graph, but now I need to be less generic and only include some of them. This is why I have to work with the other options :( > Andy > > On 8 September 2017 at 13:52, Chris Dollin <[email protected]> > wrote: > >> On 8 September 2017 at 10:11, George News <[email protected]> wrote: >> >>> Hi, >>> >>> Is multiunion only linking the graphs or copying them in a new graph? >>> >>> I'm thinking on splitting a huge graph on many simple ones and them >>> making the union depending on the part of the main graph that has to be >>> requested, therefore limiting the scope of the sparql and speeding >>> things up. But if multiunion copies, then I don't think I will speed >>> things. >>> >> >> If things haven't changed too much ... >> >> (a) it links the graphs. They are not copied. Hooray! >> >> (b)ut when you run an operation over the graph that delivers >> a set of triples (which is how queries work over union graphs) >> it has to remember all the triples it has already seen so that it >> doesn't deliver duplicates. Hence (depending on the triple >> pattern being used) may mean lots of store being held onto. >> Alas! >> >> Chris >> >> -- >> "What I don't understand is this ..." Trevor Chaplin, /The Beiderbeck >> Affair/ >> >> Epimorphics Ltd, http://www.epimorphics.com >> Registered address: Court Lodge, 105 High Street, Portishead, Bristol BS20 >> 6PT >> Epimorphics Ltd. is a limited company registered in England (number >> 7016688) >> >
