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.
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/
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