What are the objects underlying col1, col2, and col3? You can only use the set of objects Pig understands (so, String, various Number derivatives, DataByteArray, Map<String, Object> , Tuple, DataBag)
-D On Tue, Oct 12, 2010 at 12:37 PM, Christian Decker < [email protected]> wrote: > Hi, > > I'm currently working on a simple Cassandra Loader that reads an index and > then works on that data. Now whenever I try to work on the retrieved data I > get a strange error: > > java.io.IOException: Type mismatch in key from map: expected > > org.apache.pig.impl.io.NullableBytesWritable, recieved > > org.apache.pig.impl.io.NullableText > > at > > > org.apache.hadoop.mapred.MapTask$MapOutputBuffer.collect(MapTask.java:845) > > at > > > org.apache.hadoop.mapred.MapTask$NewOutputCollector.write(MapTask.java:541) > > at > > > org.apache.hadoop.mapreduce.TaskInputOutputContext.write(TaskInputOutputContext.java:80) > > at > > > org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.PigMapReduce$Map.collect(PigMapReduce.java:115) > > at > > > org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.PigMapBase.runPipeline(PigMapBase.java:234) > > at > > > org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.PigMapBase.map(PigMapBase.java:227) > > at > > > org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.PigMapBase.map(PigMapBase.java:52) > > at org.apache.hadoop.mapreduce.Mapper.run(Mapper.java:144) > > at org.apache.hadoop.mapred.MapTask.runNewMapper(MapTask.java:621) > > at org.apache.hadoop.mapred.MapTask.run(MapTask.java:305) > > at > > org.apache.hadoop.mapred.LocalJobRunner$Job.run(LocalJobRunner.java:177) > > > > The script is pretty simple right now: > > rows = LOAD 'cassandra://localhost:9160/...' USING CassandraIndexReader() > as > > (col1, col2, col3); > > dump rows; > > grouped = GROUP rows BY col1; > > dump grouped; > > > > The first dump works fine,while the second just dies with the above error. > Strangely when I store it on disc and then load it with PigStorage() again > it just works as expected. > > Am I doing something wrong with my Custom Loader? > > Regards, > Chris >
