[jira] [Created] (NIFI-4974) Uncaught AbstractMethodError when converting SQL results to Avro with JTDS driver

["Colin Dean (JIRA)" <ji...@apache.org>]

Colin Dean created NIFI-4974:
--------------------------------

             Summary: Uncaught AbstractMethodError when converting SQL results to Avro with JTDS driver
                 Key: NIFI-4974
                 URL: https://issues.apache.org/jira/browse/NIFI-4974
             Project: Apache NiFi
          Issue Type: Bug
          Components: Core Framework
    Affects Versions: 1.5.0
         Environment: Windows Server 2018, MS SQL Server
            Reporter: Colin Dean


I'm using the [jtds|https://jtds.sourceforge.net] driver to retrieve data from a Microsoft SQL Server installation. This is the first time I've come upon this kind of error while using JTDS so I'm not sure if it's a defect in JTDS or in NiFi.

{code:java}
java.lang.AbstractMethodError: null
    at net.sourceforge.jtds.jdbc.ClobImpl.free(ClobImpl.java:219)
    at org.apache.nifi.processors.standard.util.JdbcCommon.convertToAvroStream(JdbcCommon.java:288)
    at org.apache.nifi.processors.standard.ExecuteSQL$2.process(ExecuteSQL.java:230)
    at org.apache.nifi.controller.repository.StandardProcessSession.write(StandardProcessSession.java:2571)
    at org.apache.nifi.processors.standard.ExecuteSQL.onTrigger(ExecuteSQL.java:218)
    at org.apache.nifi.processor.AbstractProcessor.onTrigger(AbstractProcessor.java:27)
    at org.apache.nifi.controller.StandardProcessorNode.onTrigger(StandardProcessorNode.java:1122)
    at org.apache.nifi.controller.tasks.ContinuallyRunProcessorTask.call(ContinuallyRunProcessorTask.java:147)
    at org.apache.nifi.controller.tasks.ContinuallyRunProcessorTask.call(ContinuallyRunProcessorTask.java:47)
    at org.apache.nifi.controller.scheduling.TimerDrivenSchedulingAgent$1.run(TimerDrivenSchedulingAgent.java:128)
    at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
    at java.util.concurrent.FutureTask.runAndReset(FutureTask.java:308)
    at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$301(ScheduledThreadPoolExecutor.java:180)
    at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:294)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
    at java.lang.Thread.run(Thread.java:745)
{code}

Looking at the JTDS source code, provided that the Github repo I'm looking at it up to date with the SF repo, it appears that [this call to `free()`|https://github.com/milesibastos/jTDS/blob/master/src/main/net/sourceforge/jtds/jdbc/ClobImpl.java#L219] is intended to generate an error from JTDS:

{code}
/////// JDBC4 demarcation, do NOT put any JDBC3 code below this line ///////

    public void free() throws SQLException {
        // TODO Auto-generated method stub
        throw new AbstractMethodError();
    }
{code}

We're going to try to use the official MS SQL JDBC driver as a workaround. I minimally want to document this in case someone else encounters this problem or there's a way to workaround it within NiFi.





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