[PIG-2411] AvroStorage UDF in PiggyBank fails to STORE a bag of single-field tuples as Avro arrays

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 0.9.0, 0.9.1, 0.9.2
• Fix Version/s: 0.10.0
• Component/s: piggybank
• Labels: patch

Environment

Mac OS X 10.6.8 in local mode

• Patch Info: Patch Available
• Hadoop Flags: Reviewed
• Tags: avro udf piggybank pig storage
• Assignee: Russell Jurney
• Reporter: Russell Jurney
• Created: 07/Dec/11 23:46
• Updated: 22/Jun/12 03:36
• Resolved: 17/Mar/12 01:19

Description

This patch is a fix for a bug for persisting bags of tuples via AvroStorage.

The script that alerted me to a bug is:

messages = LOAD '/tmp/messages.avro' USING AvroStorage();
user_groups = GROUP messages by user_id;
per_user = FOREACH user_groups

{ sorted = ORDER messages BY message_id DESC; GENERATE group AS user_id, sorted AS messages; }

DESCRIBE per_user
> per_user: {user_id: int,messages: {(message_id: int,topic: chararray,user_id: int)}}
STORE per_user INTO '/tmp/per_user.avro' USING AvroStorage();

The error is:

Pig Stack Trace
---------------
ERROR 1002: Unable to store alias per_user

org.apache.pig.impl.logicalLayer.FrontendException: ERROR 1002: Unable to store alias per_user
at org.apache.pig.PigServer$Graph.registerQuery(PigServer.java:1596)
at org.apache.pig.PigServer.registerQuery(PigServer.java:584)
at org.apache.pig.tools.grunt.GruntParser.processPig(GruntParser.java:942)
at org.apache.pig.tools.pigscript.parser.PigScriptParser.parse(PigScriptParser.java:386)
at org.apache.pig.tools.grunt.GruntParser.parseStopOnError(GruntParser.java:188)
at org.apache.pig.tools.grunt.GruntParser.parseStopOnError(GruntParser.java:164)
at org.apache.pig.tools.grunt.Grunt.run(Grunt.java:67)
at org.apache.pig.Main.run(Main.java:487)
at org.apache.pig.Main.main(Main.java:108)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.apache.hadoop.util.RunJar.main(RunJar.java:156)
Caused by: java.lang.NullPointerException
at org.apache.pig.piggybank.storage.avro.AvroStorageUtils.isTupleWrapper(AvroStorageUtils.java:327)
at org.apache.pig.piggybank.storage.avro.PigSchema2Avro.convert(PigSchema2Avro.java:82)
at org.apache.pig.piggybank.storage.avro.PigSchema2Avro.convert(PigSchema2Avro.java:105)
at org.apache.pig.piggybank.storage.avro.PigSchema2Avro.convertRecord(PigSchema2Avro.java:151)
at org.apache.pig.piggybank.storage.avro.PigSchema2Avro.convert(PigSchema2Avro.java:62)
at org.apache.pig.piggybank.storage.avro.AvroStorage.checkSchema(AvroStorage.java:502)
at org.apache.pig.newplan.logical.rules.InputOutputFileValidator$InputOutputFileVisitor.visit(InputOutputFileValidator.java:65)
at org.apache.pig.newplan.logical.relational.LOStore.accept(LOStore.java:77)
at org.apache.pig.newplan.DepthFirstWalker.depthFirst(DepthFirstWalker.java:64)
at org.apache.pig.newplan.DepthFirstWalker.depthFirst(DepthFirstWalker.java:66)
at org.apache.pig.newplan.DepthFirstWalker.depthFirst(DepthFirstWalker.java:66)
at org.apache.pig.newplan.DepthFirstWalker.depthFirst(DepthFirstWalker.java:66)
at org.apache.pig.newplan.DepthFirstWalker.depthFirst(DepthFirstWalker.java:66)
at org.apache.pig.newplan.DepthFirstWalker.walk(DepthFirstWalker.java:53)
at org.apache.pig.newplan.PlanVisitor.visit(PlanVisitor.java:50)
at org.apache.pig.newplan.logical.rules.InputOutputFileValidator.validate(InputOutputFileValidator.java:45)
at org.apache.pig.backend.hadoop.executionengine.HExecutionEngine.compile(HExecutionEngine.java:292)
at org.apache.pig.PigServer.compilePp(PigServer.java:1360)
at org.apache.pig.PigServer.executeCompiledLogicalPlan(PigServer.java:1297)
at org.apache.pig.PigServer.execute(PigServer.java:1286)
at org.apache.pig.PigServer.access$400(PigServer.java:125)
at org.apache.pig.PigServer$Graph.registerQuery(PigServer.java:1591)
... 13 more