[PIG-812] COUNT(*) does not work

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 0.2.0
• Fix Version/s: 0.2.0
• Component/s: impl
• Assignee: Benjamin Reed
• Reporter: Viraj Bhat
• Created: 20/May/09 01:45
• Updated: 24/Mar/10 22:04
• Resolved: 21/Aug/09 18:35

Description

Pig script to count the number of rows in a studenttab10k file which contains 10k records.

studenttab = LOAD 'studenttab10k' AS (name:chararray, age:int,gpa:float);

X2 = GROUP studenttab ALL;

describe X2;

Y2 = FOREACH X2 GENERATE COUNT(*);

explain Y2;

DUMP Y2;

returns the following error
================================================================
ERROR org.apache.pig.tools.grunt.Grunt - ERROR 1066: Unable to open iterator for alias Y2
Details at logfile: /homes/viraj/pig-svn/trunk/pig_1242783700970.log
================================================================

If you look at the log file:
================================================================
Caused by: java.lang.ClassCastException
at org.apache.pig.builtin.COUNT$Initial.exec(COUNT.java:76)
at org.apache.pig.builtin.COUNT$Initial.exec(COUNT.java:68)
at org.apache.pig.backend.hadoop.executionengine.physicalLayer.expressionOperators.POUserFunc.getNext(POUserFunc.java:201)
at org.apache.pig.backend.hadoop.executionengine.physicalLayer.expressionOperators.POUserFunc.getNext(POUserFunc.java:235)
at org.apache.pig.backend.hadoop.executionengine.physicalLayer.relationalOperators.POForEach.processPlan(POForEach.java:254)
at org.apache.pig.backend.hadoop.executionengine.physicalLayer.relationalOperators.POForEach.getNext(POForEach.java:204)
at org.apache.pig.backend.hadoop.executionengine.physicalLayer.PhysicalOperator.processInput(PhysicalOperator.java:231)
at org.apache.pig.backend.hadoop.executionengine.physicalLayer.relationalOperators.POLocalRearrange.getNext(POLocalRearrange.java:223)
at org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.PigMapBase.runPipeline(PigMapBase.java:245)
at org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.PigMapBase.map(PigMapBase.java:236)
at org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.PigMapReduce$Map.map(PigMapReduce.java:88)
at org.apache.hadoop.mapred.MapRunner.run(MapRunner.java:47)
at org.apache.hadoop.mapred.MapTask.run(MapTask.java:227)
================================================================

Issue Links

• incorporates: PIG-813 Semantics of * and count
• incorporates: PIG-822 Flatten semantics are unknown
• is cloned by: PIG-813 Semantics of * and count