Archives of Support Questions (Read Only)

latorres · ‎01-05-2016

I'm trying to test Oozie's Sqoop action in the following environment:

HDP2.3.2
Sqoop 1.4.6
Oozie 4.2.0

Via the command line, the following sqoop command works:

sqoop import \
	-D mapred.task.timeout=0 \
	--connect jdbc:sqlserver://x.x.x.x:1433;database=CEMHistorical \
 	--table MsgCallArrival \
	--username hadoop \
	--password-file hdfs:///user/sqoop/.adg.password \
	--hive-import \
	--create-hive-table \
	--hive-table develop.oozie \
	--split-by TimeStamp \
	--map-column-hive Call_ID=STRING,Stream_ID=STRING

But when I try to execute the same command via Oozie, I'm running into java.io.IOException: No columns to generate for ClassWriter

Below are my `job.properties` and `workflow.xml`:

nameNode=hdfs://host.vitro.com:8020
jobTracker=host.vitro.com:8050
projectRoot=${nameNode}/user/${user.name}/tmp/sqoop-test/
oozie.use.system.libpath=true
oozie.wf.application.path=${projectRoot}



<workflow-app name="sqoop-test-wf" xmlns="uri:oozie:workflow:0.4">
    <start to="sqoop-import"/>

    <action name="sqoop-import" retry-max="10" retry-interval="1">
        <sqoop xmlns="uri:oozie:sqoop-action:0.2">
            <job-tracker>${jobTracker}</job-tracker>
            <name-node>${nameNode}</name-node>
        <command>import -D mapred.task.timeout=0 --connect jdbc:sqlserver://x.x.x.x:1433;database=CEMHistorical --table MsgCallArrival --username hadoop --password-file hdfs:///user/sqoop/.adg.password --hive-import --create-hive-table --hive-table develop.oozie --split-by TimeStamp --map-column-hive Call_ID=STRING,Stream_ID=STRING</command>
        </sqoop>
        <ok to="end"/>
        <error to="errorcleanup"/>
    </action>
    <kill name="errorcleanup">
      <message>Sqoop Test WF failed. [${wf:errorMessage(wf:lastErrorNode())}]</message>
    </kill>
    <end name ="end"/>
</workflow-app>

I've attached the full log, but here's an excerpt:

2016-01-05 11:29:21,415 ERROR [main] tool.ImportTool (ImportTool.java:run(613)) - Encountered IOException running import job: java.io.IOException: No columns to generate for ClassWriter
    at org.apache.sqoop.orm.ClassWriter.generate(ClassWriter.java:1651)
    at org.apache.sqoop.tool.CodeGenTool.generateORM(CodeGenTool.java:107)
    at org.apache.sqoop.tool.ImportTool.importTable(ImportTool.java:478)
    at org.apache.sqoop.tool.ImportTool.run(ImportTool.java:605)
    at org.apache.sqoop.Sqoop.run(Sqoop.java:148)
    at org.apache.hadoop.util.ToolRunner.run(ToolRunner.java:70)
    at org.apache.sqoop.Sqoop.runSqoop(Sqoop.java:184)
    at org.apache.sqoop.Sqoop.runTool(Sqoop.java:226)
    at org.apache.sqoop.Sqoop.runTool(Sqoop.java:235)
    at org.apache.sqoop.Sqoop.main(Sqoop.java:244)
    at org.apache.oozie.action.hadoop.SqoopMain.runSqoopJob(SqoopMain.java:197)
    at org.apache.oozie.action.hadoop.SqoopMain.run(SqoopMain.java:177)
    at org.apache.oozie.action.hadoop.LauncherMain.run(LauncherMain.java:47)
    at org.apache.oozie.action.hadoop.SqoopMain.main(SqoopMain.java:46)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:497)
    at org.apache.oozie.action.hadoop.LauncherMapper.map(LauncherMapper.java:236)
    at org.apache.hadoop.mapred.MapRunner.run(MapRunner.java:54)
    at org.apache.hadoop.mapred.MapTask.runOldMapper(MapTask.java:453)
    at org.apache.hadoop.mapred.MapTask.run(MapTask.java:343)
    at org.apache.hadoop.mapred.YarnChild$2.run(YarnChild.java:164)
    at java.security.AccessController.doPrivileged(Native Method)
    at javax.security.auth.Subject.doAs(Subject.java:422)
    at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1657)
    at org.apache.hadoop.mapred.YarnChild.main(YarnChild.java:158)

I've been struggling with this problem for quite some time now, any help would be greatly appreciated!

latorres · ‎02-03-2016

At the same time that I was getting this issue, I was also dealing with a network issue when trying to issue Sqoop commands via CLI. Although the network issue was resolved and I stopped seeing this IOException, I kept running into new errors that I never managed to resolve.

In the end, I decided to work around it by breaking the hive import into a 2-step workflow:

sqoop action to import into HDFS
hive action to load data from HDFS into hive

UPDATE:

It turns out that the "new errors" was because the "yarn" user doesn't belong to the "hdfs" group and so couldn't perform the hive-import part. Adding this use to the group allows me now to use hive-import in my worfklows instead of the 2-step workflow I used before.

View solution in original post

aervits · ‎02-03-2016

@Luis Antonio Torres I have a couple of examples with sqoop and hive. Here they are. Here's hcatalog example, so you can use either hive or pig script to execute hcat commands and here's a sqoop command in shell action, also can be mixed with hive actions.

roney_jose · ‎03-15-2016

The Sqoop error 'No columns to generate' could also occur if your sqoop job is unable to determine a driver to use for this job. Try adding --driver com.sqlserver.jdbc.Driver along with the rest of your sqoop import parameters. Hope this helps.

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Oozie Sqoop action throwing java.io.IOException: No columns to generate for ClassWriter