JSR-352 with Liberty Profile - 'ORA-01002: fetch out of sequence' - websphere-liberty

Question

I am experimenting with the JSR-352 implementation in the Liberty Profile and have been stumped by an 'ORA-01002: fetch out of sequence' error after my reader processes the first 10 items of my JDBC ResultSet. My chunk size is set to 100.
Here is my reader:
#Dependent
#Named("myItemReader")
public class MyItemReader extends AbstractItemReader {
#Resource(name="jdbc/somedb",shareable=false)
private DataSource lavDb;
private PreparedStatement stmt;
private ResultSet rs;
#Override
public void open(Serializable checkpoint) throws Exception {
Connection con = lavDb.getConnection();
con.setAutoCommit(false);
stmt = con.prepareStatement("select id from sometable",
ResultSet.TYPE_FORWARD_ONLY, ResultSet.CONCUR_READ_ONLY);
rs = stmt.executeQuery();
}
#Override
public MyInputRecord readItem() throws Exception{
if(rs.next()){
return new MyInputRecord(rs.getInt(1));
}
return null;
}
#Override
public void close(){
try{
rs.close();
stmt.close();
}
catch(Exception e){
e.printStackTrace();
}
}
}
If the ResultSet processing occurs in the open() method then I do not encounter any errors.
Here is my batchPersistence configuration from my server.xml:
<dataSource id="oracle-wasadmin" jdbcDriverRef="wasoracledriver" jndiName="jdbc/wasoracledb" type="javax.sql.XADataSource">
<properties.oracle URL="${wasadmin.jdbcurl}" password="xxxxxx" user="yyyyyy"/>
<conionManager agedTimeout="1m" maxIdleTime="15m" maxPoolSize="25" minPoolSize="0"/>
</dataSource>
<jdbcDriver id="wasoracledriver" javax.sql.XADataSource="oracle.jdbc.xa.client.OracleXADataSource">
<library>
<fileset dir="${shared.resource.dir}/oracle" includes="*.jar"/>
</library>
</jdbcDriver>
Here is the error in the joblog:
com.ibm.jbatch.container.exception.BatchContainerRuntimeException: Failure in Read-Process-Write Loop
at com.ibm.jbatch.container.controller.impl.ChunkStepControllerImpl.invokeChunk(ChunkStepControllerImpl.java:702)
at com.ibm.jbatch.container.controller.impl.ChunkStepControllerImpl.invokeCoreStep(ChunkStepControllerImpl.java:792)
at com.ibm.jbatch.container.controller.impl.BaseStepControllerImpl.execute(BaseStepControllerImpl.java:292)
at com.ibm.jbatch.container.controller.impl.ExecutionTransitioner.doExecutionLoop(ExecutionTransitioner.java:118)
at com.ibm.jbatch.container.controller.impl.WorkUnitThreadControllerImpl.executeCoreTransitionLoop(WorkUnitThreadControllerImpl.java:94)
at com.ibm.jbatch.container.controller.impl.WorkUnitThreadControllerImpl.executeWorkUnit(WorkUnitThreadControllerImpl.java:155)
at com.ibm.jbatch.container.controller.impl.WorkUnitThreadControllerImpl$AbstractControllerHelper.runExecutionOnThread(WorkUnitThreadControllerImpl.java:480)
at com.ibm.jbatch.container.controller.impl.WorkUnitThreadControllerImpl.runExecutionOnThread(WorkUnitThreadControllerImpl.java:90)
at com.ibm.jbatch.container.util.BatchWorkUnit.run(BatchWorkUnit.java:117)
at com.ibm.ws.context.service.serializable.ContextualRunnable.run(ContextualRunnable.java:80)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471)
at java.util.concurrent.FutureTask.run(FutureTask.java:262)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at java.lang.Thread.run(Thread.java:745)
Caused by: com.ibm.jbatch.container.exception.BatchContainerRuntimeException: java.sql.SQLException: ORA-01002: fetch out of sequence
at com.ibm.jbatch.container.controller.impl.ChunkStepControllerImpl.readItem(ChunkStepControllerImpl.java:354)
at com.ibm.jbatch.container.controller.impl.ChunkStepControllerImpl.readAndProcess(ChunkStepControllerImpl.java:245)
at com.ibm.jbatch.container.controller.impl.ChunkStepControllerImpl.invokeChunk(ChunkStepControllerImpl.java:626)
... 14 more
Caused by: java.sql.SQLException: ORA-01002: fetch out of sequence
I have additional logs, etc, if they would be helpful. Thanks in advance.

Answer 1

Don't cache JDBC Statement or ResultSet instances across threads. The JDBC programming model does not support multi-threaded access, which is likely why you are running into this error. And also why it works fine from within the open method, which runs on a single thread. When using JDBC, it is okay to cache DataSource, but not Connection or anything beneath Connection. Let the application server manage pooling of Connections and Statements, which it does in a thread safe way.