Thanks Riccardo, but that's not the case. I checked and made sure it's collecting FooWritable. In fact, from the following thread:
http://www.nabble.com/Different-output-classes-from-map-and-reducer-td15728122.html My exception is the same as if map output value class was not set. - Chang On Mon, Mar 24, 2008 at 4:52 PM, Riccardo Boscolo <[EMAIL PROTECTED]> wrote: > From the exception stack it appears that the map output class is correctly > set to FooWritable.class but you are trying to collect BarWritable(s) in > your map tasks. > > Best, > > RB > > On Mon, Mar 24, 2008 at 1:22 PM, Chang Hu <[EMAIL PROTECTED]> wrote: > > > Hi, > > > > I have been unsuccessfully trying to set the map output value class > > different to the one reduce outputs (in 0.16.0). AFAIK the following > > should > > do the trick: > > > > conf.setMapOutputValueClass(FooWritable.class) > > conf.setOutputValueClass(BarWritable.class) > > > > However I kept getting exceptions saying BarWritable is not FooWritable. > > Both classes implements WritableComparable. > > > > java.io.IOException: wrong value class: test.BarWritable is not class > > test.FooWritable > > at org.apache.hadoop.io.SequenceFile$Writer.append(SequenceFile.java > > :952) > > at org.apache.hadoop.mapred.MapTask$MapOutputBuffer$2.collect( > > MapTask.java:489) > > at edu.umd.cs.hadoopImage.HadoopImg$InpaintReduceClass.reduce( > > HadoopImg.java:122) > > at edu.umd.cs.hadoopImage.HadoopImg$InpaintReduceClass.reduce( > > HadoopImg.java:1) > > at org.apache.hadoop.mapred.MapTask$MapOutputBuffer.combineAndSpill( > > MapTask.java:522) > > at > org.apache.hadoop.mapred.MapTask$MapOutputBuffer.sortAndSpillToDisk( > > MapTask.java:493) > > at org.apache.hadoop.mapred.MapTask$MapOutputBuffer.flush( > MapTask.java > > :713) > > at org.apache.hadoop.mapred.MapTask.run(MapTask.java:209) > > at org.apache.hadoop.mapred.TaskTracker$Child.main(TaskTracker.java > > :2071) > > > > > > Suggestions? Thanks. > > > > > > - Chang > > > > > > -- > > --------------- > > Überstehen ist alles. > > > > > > Chang Hu > > Ph.D. student > > Computer Science Department > > University of Maryland > > > > > > -- > ------------------------------- > Riccardo Boscolo, PhD > V.P. of Core Technology > Netseer Inc. > 11943 Montana Ave, Suite 200 > Los Angeles, CA 90049 > T: 310-597-4482 > F: 310-597-4489 > Email: [EMAIL PROTECTED] > ------------------------------- > -- --------------- Überstehen ist alles. Chang Hu Ph.D. student Computer Science Department University of Maryland
