Hi,
Our institution is hosting an sparql endpoint which was populated using
sponger feature. Due to this we have several named graphs (roughly 30-40).
Sometimes we aren't sure which graphs would be relevant for the query so we
list all the graphs in a one from clause. Something like this :
Select *
from <graph1>
from <graph2>
from <graph3>
...
....
30 such lines
where
{
few-simple-predicates
}
//////////////////////////
The predicates aren't too fancy simple relationship chain of size 2-3.
The problem is now is that virtuoso estimates the query time to be 551 secs
and doesn't execute the query.
Is there a simple fix for this problem.
Is it possible to query in two stages first finding the graphs where the
constants in predicate occurs and then running the original query only
those graphs.
P.S. I have tried using bit-map indices but it doesn't help with our query
significantly.
Appreciate any help in this regard.
Thanks
Sandeep
