2

我正在 Liberty Profile 中试验 JSR-352 实现，并且在我的阅读器处理了我的 JDBC ResultSet 的前 10 个项目后，我被“ORA-01002: fetch out of sequence”错误所困扰。我的块大小设置为 100。

这是我的读者：

@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();
        }
    }
}

如果 ResultSet 处理发生在 open() 方法中，那么我不会遇到任何错误。

这是我的 server.xml 中的 batchPersistence 配置：

<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>

这是作业日志中的错误：

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

我有额外的日志等，如果它们有帮助的话。提前致谢。

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1 回答 1

2

不要跨线程缓存 JDBC Statement 或 ResultSet 实例。JDBC 编程模型不支持多线程访问，这可能是您遇到此错误的原因。以及为什么它在 open 方法中运行良好，该方法在单个线程上运行。使用 JDBC 时，可以缓存 DataSource，但不能缓存 Connection 或 Connection 下的任何内容。让应用程序服务器管理连接和语句的池，它以线程安全的方式进行。

于 2017-02-15T20:21:56.130 回答