Named Subqueries

[JonasKress]

It would be nice if Named Subqueries would be supported, even though they are not part of the SPARQL spec:
https://wiki.blazegraph.com/wiki/index.php/NamedSubquery

[RubenVerborgh]

Thanks for the suggestion. Are these used often? I haven't encountered them myself.

[fnielsen]

We are using WITH quite often in Scholia: If the labeling SERVICE is included in the first SELECT we get a slow performance. It is possible that multiple selects perform just as well.

There are a few on this page, for instance: https://tools.wmflabs.org/scholia/organization/Q1137665

[lucaswerkmeister]

Yes, in general, named subqueries are a more reliable optimization than regular subqueries (BlazeGraph executes the named subqueries only once, before the rest of the query, whereas it sometimes seems to do strange things for regular subqueries).

[RubenVerborgh]

Thanks for the info. I'm reluctant to implement a non-standard feature, but I'll leave this issue open so it can be taken into consideration.

[JonasKress]

This is very important for us and I have seen that there are other non standard features already part of this library.

[RubenVerborgh]

The issue you linked to is about the non-standard feature DEFINE, which is not part of this library.

[RubenVerborgh]

That said, I'm willing to consider a pull request for named subqueries, on the condition that it is configurable and switched off by default.