[JENA-120] Query objects with aggregators cannot be reused

• Type: Bug
• Status: Closed
• Priority: Minor
• Resolution: Done
• Fix Version/s: Jena 2.11.0
• Component/s: ARQ
• Assignee: Andy Seaborne
• Reporter: Stephen Allen
• Created: 20/Sep/11 15:53
• Updated: 01/Feb/15 19:11
• Resolved: 01/Feb/15 19:11

Description

Query objects that contain aggregators (Group By) cannot be reused by different threads because the internal state is mutable. Even reusing a query object in the same thread has problems, because it creates a new Aggregator object each time you execute the query. Users may want to reuse Query objects to save having to reparse the query string.

I believe the solution is to copy the aggregators when compiling the query. I've attached a patch that does that in the AlgebraGenerator.compileModifiers() method.

See the thread at [1] for more discussion.

[1] http://mail-archives.apache.org/mod_mbox/incubator-jena-users/201109.mbox/[e-mail]%3E

Issue Links

• relates to: JENA-121 Improvements to Bindings