"Unable to create execution plan" with simple BIND

Support Bug
1

(this is on 5.3.1)
The following (at end) very basic query gives an “Internal server error” (it would be nice if Stardog Studio were more helpful than leaving one to trawl through pages of log). I did start off with a more sophisticated BIND expression but narrowed it down to even the basic BIND functionality failing.
[I’ve also been getting a lot of inferencing weirdness and will try to construct some cases. Already raised one bug here]

The log was as follows:
ERROR 2018-07-10 21:38:12,527 [stardog-user-12] com.complexible.stardog.protocol
s.http.server.StardogHttpServiceLoader:accept(229): An unexpected exception was
handled by the server
org.openrdf.query.QueryEvaluationException: com.complexible.stardog.plan.eval.Ex
ecutionException: Could not create execution plan for query
at com.complexible.stardog.query.DefaultQueryFactory$TupleQuery.execute(
DefaultQueryFactory.java:207) ~[stardog-5.3.1.jar:?]
at com.complexible.stardog.query.DefaultQueryFactory$TupleQuery.execute(
DefaultQueryFactory.java:190) ~[stardog-5.3.1.jar:?]

Here is the very simple query:

select * from repos:fibo where {
?element a owl:Class.
BIND ((?element) as ?exp).
}

If I remove the BIND it works fine.

3

FWIW running the same command using the same Stardog server with a different database does not hit the problem. What could it be about the specific database? One difference is that the failing one has reasoning_schema set, but reasoning is not turned on for this SPARQL.

4

Hi Pete,

Can you please check if there’s further information in the log? Seeing the full stack trace would help a lot.

Thanks,
Pavel

5

Here is the stack trace.
Pete

log.log (4.0 KB)

6

Thanks for the plan. Indeed it appears to be a bug but so far I cannot reproduce. Any chance you can share the database on which the query fails? If not, the query plan might help too.

Best,
Pavel

7

I can share the database privately - how can I best get it to you?