02.11.2016, 13:08, Osma Suominen wrote:
It's possible that a MINUS expression could be used instead of FILTER
NOT EXISTS and perform better. I will have to test this. But other than
switching to MINUS, I can't think of any way to express this constraint
on collections without using some kind of double negation.
I played with MINUS, but it was no better than FILTER NOT EXISTS.
Osma - could you please try putting the VALUES in each arm of the UNION
which gets you to something like the first example.
I will try this as well.
This helped - a lot. The query time is practically the same now as it
was with Jena 3.1.0. Thanks!
The original query, though, has four UNION branches. It seems a bit
stupid to put the same VALUES statement (which may have 20 URIs or more)
in each of those arms, but I will do that if it's the only way to get
good performance with 3.1.1.
-Osma
--
Osma Suominen
D.Sc. (Tech), Information Systems Specialist
National Library of Finland
P.O. Box 26 (Kaikukatu 4)
00014 HELSINGIN YLIOPISTO
Tel. +358 50 3199529
osma.suomi...@helsinki.fi
http://www.nationallibrary.fi
