[SPARK-17417] Fix sorting of part files while reconstructing RDD/partition from checkpointed files.

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.6.0, 2.0.0
• Fix Version/s: 2.0.2, 2.1.0
• Component/s: Spark Core
• Assignee: Dhruve Ashar
• Reporter: Dhruve Ashar
• Created: 06/Sep/16 19:19
• Updated: 10/Oct/16 15:57
• Resolved: 10/Oct/16 15:57

Description

Spark currently assumes # of partitions to be less than 100000 and uses %05d padding.

If we exceed this no., the sort logic in ReliableCheckpointRDD gets messed up and fails. This is because of part-files are sorted and compared as strings.

This leads filename order to be part-10000, part-100000, ... instead of part-10000, part-10001, ..., part-100000 and while reconstructing the checkpointed RDD the job fails.

Possible solutions:

• Bump the padding to allow more partitions or
• Sort the part files extracting a sub-portion as string and then verify the RDD

Issue Links

• links to: [Github] Pull Request #15370 (dhruve)