[MAPREDUCE-2584] Check for serializers early, and give out more information regarding missing serializers

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Not A Problem
• Affects Version/s: 0.20.2
• Component/s: task
• Labels: serializers tasks
• Tags: serializers
• Assignee: Harsh J
• Reporter: Harsh J
• Created: 11/Jun/11 18:54
• Updated: 26/Oct/16 14:54
• Resolved: 26/Oct/16 14:54

Description

As discussed on HADOOP-7328, MapReduce can handle serializers in a much better way in case of bad configuration, improper imports (Some odd Text class instead of the Writable Text set as key), etc..

This issue covers the MapReduce parts of the improvements (made to IFile, MapOutputBuffer, etc. and possible early-check of serializer availability pre-submit) that provide more information than just an NPE as is the current case.

Issue Links

• depends upon: HADOOP-7328 When a serializer class is missing, return null, not throw an NPE.
• is duplicated by: MAPREDUCE-5728 Check NPE for serializer/deserializer in MapTask
• is related to: HADOOP-8531 SequenceFile Writer can throw out a better error if a serializer or deserializer isn't available