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https://issues.apache.org/jira/browse/JENA-244?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Stephen Owens updated JENA-244:
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Attachment: JenaDeadLockTest.java
I've attached an update to the test case that shows all three potential work
arounds. All three seem to work. There are four tests in the attached, the
ignored test is the failure case that shows the deadlock, the other three all
succeed against the same thread use because they employ one of three work
around strategies for the bug.
1) Do a 'warmup' query on the model before accessing it from multiple threads.
This only works if you have a section of code that is thread safe running it
and only if you don't subsequently change the model. The warmup query itself
doesn't seem to matter. This has the advantage that you don't need to know if
the model is inferencing or not to run it.
2) Do a 'prepare' on the model before accessing it from multiple threads. This
also only works if you have a section of code that is thread safe running it
and only if you don't subsequently change the model. This requires you to test
the model to see if it is inferencing since the standard model interface
doesn't support the prepare method.
3) Use forward instead of backward chaining when you create the inference
model. Unless you need backward chaining for a specific reason this is the
number one choice. As far as I know it doesn't matter if you subsequently
change the model and this can be used without a thread safe starting point.
Perhaps this should become the default behaviour for the convenience method
that creates an RDFS model in the future?
> Deadlock during SPARQL execution on an inference model
> ------------------------------------------------------
>
> Key: JENA-244
> URL: https://issues.apache.org/jira/browse/JENA-244
> Project: Apache Jena
> Issue Type: Bug
> Components: Jena
> Reporter: Stephen Owens
> Attachments: JenaDeadLockTest.java, JenaDeadLockTest.java
>
>
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