[TAJO-999] SequenceFile key class need to be compatible.

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 0.9.0
• Component/s: Storage
• Assignee: JaeHwa Jung
• Reporter: JaeHwa Jung
• Created: 07/Aug/14 10:27
• Updated: 11/Aug/14 03:54
• Resolved: 11/Aug/14 02:37

Description

Currently, tajo uses ByteWritable class for key class in SequenceFile. If we used ByteWritable class for key class, it is no problem. But if we use another class for key class, we must find IOException. For example, When I used LongWritable class for key class in TextSerde, I found error as follows:

ERROR org.apache.tajo.worker.Task: wrong key class: org.apache.hadoop.io.BytesWritable is not class org.apache.hadoop.io.LongWritable
java.io.IOException: wrong key class: org.apache.hadoop.io.BytesWritable is not class org.apache.hadoop.io.LongWritable
        at org.apache.hadoop.io.SequenceFile$Reader.next(SequenceFile.java:2251)
        at org.apache.tajo.storage.sequencefile.SequenceFileScanner.next(SequenceFileScanner.java:147)

Thus, we need to improve SequenceFileScanner and SequenceFileScannerAppender compatible for all writable classes.