[jira] [Created] (JENA-447) SDB - SQLException duplicate key value in model.commit when transaction isolation > TRANSACTION_READ_COMMITED

["Dave Lebling (JIRA)" <ji...@apache.org>]

Dave Lebling created JENA-447:
---------------------------------

             Summary: SDB - SQLException duplicate key value in model.commit when transaction isolation > TRANSACTION_READ_COMMITED 
                 Key: JENA-447
                 URL: https://issues.apache.org/jira/browse/JENA-447
             Project: Apache Jena
          Issue Type: Bug
          Components: SDB
    Affects Versions: SDB 1.3.5
         Environment: Windows 7, Ubuntu Linux
            Reporter: Dave Lebling


Using transaction isolation settings of TRANSACTION_REPEATABLE_READ or TRANSACTION_SERIALIZABLE to improve concurrency safety with multiple readers and writers in different JVMs eventually produces the following warning and then error from an SQLException:

WARN [tomcat-http--10] (SDBConnection.java:338) - execUpdate: SQLException
ERROR: duplicate key value violates unique constraint "nodes_pkey"
  Detail: Key (hash)=(-8555076428185164481) already exists.
LOCK TABLE Nodes; INSERT INTO Nodes (hash, lex, lang, datatype, type) SELECT NNodeQuads1740763164.n0 , NNodeQuads1740763164.n1 , NNodeQuads1740763164.n2 , NNodeQuads1740763164.n3 , NNodeQuads1740763164.n4 FROM NNodeQuads1740763164 LEFT JOIN Nodes ON (NNodeQuads1740763164.n0=Nodes.hash)
WHERE Nodes.hash IS NULL

ERROR [tomcat-http--10] (xxx.java:237) - lp:PI2 comp:PIS id:12 action:exception msg:submitExternalRequest
com.hp.hpl.jena.sdb.SDBException: Exception flushing
	at com.hp.hpl.jena.sdb.layout2.TupleLoaderBase.flush(TupleLoaderBase.java:234)
	at com.hp.hpl.jena.sdb.layout2.TupleLoaderBase.finish(TupleLoaderBase.java:169)
	at com.hp.hpl.jena.sdb.layout2.LoaderTuplesNodes.commitTuples(LoaderTuplesNodes.java:306)
	at com.hp.hpl.jena.sdb.layout2.LoaderTuplesNodes.flushTriples(LoaderTuplesNodes.java:235)
	at com.hp.hpl.jena.sdb.layout2.LoaderTuplesNodes.finishBulkUpdate(LoaderTuplesNodes.java:90)
	at com.hp.hpl.jena.sdb.graph.GraphSDB.finishBulkUpdate(GraphSDB.java:310)
	at com.hp.hpl.jena.sdb.graph.EventManagerSDB.notifyEvent(EventManagerSDB.java:41)
	at com.hp.hpl.jena.rdf.model.impl.ModelCom.notifyEvent(ModelCom.java:1543)

Further details on request, but the setup is large and complex, so it would be very hard to produce a "simple, repeatable case."

Andy Seabourne commented when this was first reported:

> Seeing that error message makes it a bit clearer to me. It's something 
> to do with the bulk loader (NNodeQuads1740763164) and some othe 
> raction has already inserted a node.  As the possible values for a row in the node table are fixed for a given primary key, I wonder if it's possible to insert but ignore duplicates (which won't an a different duplicate).
>  And maybe the  LOCK TABLE needs to be further out.
> (/me hopes Damian has better insight here)

Dave Lebling




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