Andy,
Are you suggesting the use of
Connection.setTransactionIsolation(something-other-than-TRANSACTION_READ_COMMITTED),
which is the default? The SDB implementation already uses setAutoCommit, etc.
I tried all higher values for setTransactionIsolation() than the default, using
a freshly populated database, and the results are that at levels
Connection.TRANSACTION_REPEATABLE_READ and Connection.TRANSACTION_SERIALIZABLE
after a while the following exception is thrown:
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] (PlannerInterfaceServiceEndPointImpl.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)
In addition, these level settings had no impact on the error conditions I
highlighted in my original message.
Obviously I'm missing something here. Were you actually suggesting something
different?
Dave
-----Original Message-----
From: Andy Seaborne [mailto:[email protected]]
Sent: Monday, April 15, 2013 10:10 AM
To: [email protected]
Subject: Re: Concurrency in Jena/SDB
On 15/04/13 14:51, Lebling, David (US SSA) wrote:
> Andy,
>
> Which part of that document is the part that might help? My code
> already creates a new Store for each transaction. My code already uses
> begin/commit.
The fact you can manage the JDBC connection separately from the Store - that
can tie to receiving servlet requests quite well.
Andy
You asked:
> I was hoping you might have some guidance as to what you mean by "You
> need to control the JDBC transaction in your code to get isolation
> between JVMs."
>
> (I've read the document many times previously, by the way.)
>
> Dave L.
>
> -----Original Message----- From: Andy Seaborne
> [mailto:[email protected]] Sent: Monday, April 15, 2013 9:42 AM To:
> [email protected] Subject: Re: Concurrency in Jena/SDB
>
> This might help:
>
> http://jena.apache.org/documentation/sdb/javaapi.html#connection-manag
> ement
>
> Andy
