Maybe this article can help: http://wwwconference.org/www2008/papers/pdf/p595-stocker1.pdf
It's about BGPs not graph patterns, but I guess selectivity still applies. On Wed, 25 Oct 2017 at 03.17, Dimov, Stefan <[email protected]> wrote: > Let’s consider the following JOIN: > > SELECT $subj > FROM NAMED ng1 > FROM NAMED ng2 > { > GRAPH ng1 { $subj $pred0 $obj0 } > GRAPH ng2 { $subj $pred1 $obj1 } > } > > My question is: Does the order of the clauses affect the performance? > Let’s say that ng1 is much bigger than ng2. If SPARQL applies the first > clause first and then the second clause over the set result of the first > one, then it makes sense to exchange their places. > > Is that right? > > Regards, > Stefan >
