Habits of Effective Sqoop Users
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This document provides tips for troubleshooting common issues with Sqoop. It discusses how to effectively provide debugging information when seeking help, addresses specific problems with MySQL connections and importing to Hive, Oracle case-sensitive errors and export failures, and recommends best practices like using separate tables for import and export and specifying options correctly.
Habits of Effective Sqoop Users
- 1. Habits of Effective Sqoop Users Kate Ting, Customer Operations Engineer kate@cloudera.com
- 2. Halp! Sqoop doesn't work! Now what? 2
- 3. Agenda • First Things First • Common Problems • MySQL – Connection Failure – Importing into Hive • Oracle – Case-Sensitive Catalog Query Errors – Sqoop Export Failing • Effective Sqoop Habits 3
- 4. Agenda • First Things First • Common Problems • MySQL – Connection Failure – Importing into Hive • Oracle – Case-Sensitive Catalog Query Errors – Sqoop Export Failing • Effective Sqoop Habits 4
- 5. First Things First Save time by providing this upfront: • Versions: Sqoop, Hadoop, OS, JDBC • Run with --verbose flag then attach log • Sqoop command including options-file • Expected output vs. actual output • Table definition • Input data set that triggers problem • Hadoop task logs • Check permissions on input files • Divide and conquer – e.g. Import that creates and populates a Hive table is failing • First, do the import alone • Second, create a Hive table without the import using the create-hive- table tool 5
- 7. Agenda • First Things First • Common Problems • MySQL – Connection Failure – Importing into Hive • Oracle – Case-Sensitive Catalog Query Errors – Sqoop Export Failing • Effective Sqoop Habits 7
- 8. MySQL: Connection Failure java.lang.RuntimeException: java.lang.RuntimeException: com.mysql.jdbc.exceptions.jdbc4 .CommunicationsException: Communications link failure The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server. at com.cloudera.sqoop.mapreduce.db.DBInputFormat.setConf(DBInputFormat.java:164 ) at org.apache.hadoop.util.ReflectionUtils.setConf(ReflectionUtils.java:62) at org.apache.hadoop.util.ReflectionUtils.newInstance(ReflectionUtils.java:117) at org.apache.hadoop.mapred.MapTask.runNewMapper(MapTask.java:606) at org.apache.hadoop.mapred.MapTask.run(MapTask.java:323) at org.apache.hadoop.mapred.Child$4.run(Child.java:270) at java.security.AccessController.doPrivileged(Native Method) at javax.security.auth.Subject.doAs(Subject.java:396) at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.ja va:1127) at org.apache.hadoop.mapred.Child.main(Child.java:264) 8
- 9. MySQL: Connection Failure • Problem: Communications Link Failure caused by incorrect permissions. • Solution: – Verify that you can connect to the database from the node where you are running Sqoop: • $ mysql --host=<IP Address> --database=test --user=<username> -- password=<password> – Add the network port for the server to your my.cnf file – Set up a user account to connect via Sqoop. Grant permissions to the user to access the database over the network: • Log into MySQL as root mysql -u root -p<ThisIsMyPassword> • Issue the following command: mysql> grant all privileges on test.* to 'testuser'@'%' identified by 'testpassword' 9
- 10. MySQL: Importing into Hive • Troubleshooting tips: – Look at /tmp/${user}/hive.log • Identifies exceptions during the load – Look at /user/hive/warehouse • View contents of the imported data 10
- 11. Agenda • First Things First • Common Problems • MySQL – Connection Failure – Importing into Hive • Oracle – Case-Sensitive Catalog Query Errors – Sqoop Export Failing • Effective Sqoop Habits 11
- 12. Oracle: Case-Sensitive Catalog Query Errors INFO manager.OracleManager: Time zone has been set to GMT DEBUG manager.SqlManager: Using fetchSize for next query: 1000 INFO manager.SqlManager: Executing SQL statement: SELECT t.* FROM addlabel_pris t WHERE 1=0 DEBUG manager.OracleManager$ConnCache: Caching released connection for jdbc:oracle:thin: ERROR sqoop.Sqoop: Got exception running Sqoop: java.lang.NullPointerException java.lang.NullPointerException at com.cloudera.sqoop.hive.TableDefWriter.getCreateTableStmt(TableDefWriter.java:148) at com.cloudera.sqoop.hive.HiveImport.importTable(HiveImport.java:187) at com.cloudera.sqoop.tool.ImportTool.importTable(ImportTool.java:362) at com.cloudera.sqoop.tool.ImportTool.run(ImportTool.java:423) at com.cloudera.sqoop.Sqoop.run(Sqoop.java:144) at org.apache.hadoop.util.ToolRunner.run(ToolRunner.java:65) at com.cloudera.sqoop.Sqoop.runSqoop(Sqoop.java:180) at com.cloudera.sqoop.Sqoop.runTool(Sqoop.java:219) at com.cloudera.sqoop.Sqoop.runTool(Sqoop.java:228) at com.cloudera.sqoop.Sqoop.main(Sqoop.java:237) 12
- 13. Oracle: Case-Sensitive Catalog Query Errors • Problem: NPE caused by using the wrong case for the user name and table name. • Solution: Always specify the user and table names in upper case (unless it was created with mixed/lower case within quotes). 13
- 14. Oracle: Sqoop Export Failing INFO mapred.JobClient: Running job: job_201109231340_0785 INFO mapred.JobClient: map 0% reduce 0% INFO mapred.JobClient: Task Id : attempt_201109231340_0785_m_000000_0, Status : FAILED java.lang.NullPointerException at com.cloudera.sqoop.mapreduce.db.DataDrivenDBRecordReader.getSe lectQuery(DataDrivenDBRecordReader.java:87) at com.cloudera.sqoop.mapreduce.db.DBRecordReader.nextKeyValue (DBRecordReader.java:225) at org.apache.hadoop.mapred.MapTask $NewTrackingRecordReader.nextKeyValue(MapTask.java:455) at org.apache.hadoop.mapreduce.MapContext.nextKeyValue (MapContext.java:67) 14
- 15. Oracle: Sqoop Export Failing • Problem: IllegalArgumentException caused by not non-owner trying to connect to the table. • Solution: Prefix the table name with the schema, for example SchemaName.OracleTableName. 15
- 16. Agenda • First Things First • Common Problems • MySQL – Connection Failure – Importing into Hive • Oracle – Case-Sensitive Catalog Query Errors – Sqoop Export Failing • Effective Sqoop Habits 16
- 17. Effective Sqoop Habits • Do create an empty export table. • Don’t use the same table for both import and export. 17
- 18. Effective Sqoop Habits • Do use --escaped-by option during import and --input-escaped-by during export. • Do use fields-terminated-by during import and input-fields-terminated-by during export. • Don’t reverse them. 18
- 19. Effective Sqoop Habits • Do specify the direct mode option (-- direct), if you use the direct connector. • Don’t specify the query, if you use the direct connector. 19
- 20. How Do You Eat an Elephant? • One bite at a time – Versions – Verbose flag – Console log – Exact command, etc • Sqoop Troubleshooting Guide – http://archive.cloudera.com/cdh/3/sqoop/ SqoopUserGuide.html#_troubleshooting 20