Jinghui Wang created HADOOP-11334: ------------------------------------- Summary: Mapreduce Job Failed due to failure fetching mapper output on the reduce side Key: HADOOP-11334 URL: https://issues.apache.org/jira/browse/HADOOP-11334 Project: Hadoop Common Issue Type: Bug Components: io Affects Versions: 2.4.1 Reporter: Jinghui Wang
Running terasort with the following options hadoop jar hadoop-mapreduce-examples.jar terasort *-Dio.native.lib.available=false -Dmapreduce.map.output.compress=true -Dmapreduce.map.output.compress.codec=org.apache.hadoop.io.compress.GzipCodec* /tmp/tera-in /tmp/tera-out The job failed with the reducer failed to fetching the output from mappers (see the following stacktrace). The problem is that in JIRA MAPREDUCE-1784, it added support to handle null compressors to default to non-compressed output. In this case, when the *io.native.lib.available* is set to true, the compressor will be null. However, the decompressor has a Java implementation, so when the reducer tries to read the mapper output, it uses the decompressor, but the output does not have the Gzip header. -- This message was sent by Atlassian JIRA (v6.3.4#6332)