[HBASE-10660] MR over snapshots can OOM when alternative blockcache is enabled

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 0.98.0, 0.99.0
• Fix Version/s: 0.98.1, 0.99.0
• Component/s: mapreduce
• Hadoop Flags: Reviewed
• Assignee: Nick Dimiduk
• Reporter: Nick Dimiduk
• Created: 03/Mar/14 23:36
• Updated: 21/Feb/15 23:33
• Resolved: 08/Mar/14 00:36

Description

Running IntegrationTestTableSnapshotInputFormat with the BucketCache enabled results in OOM. The map task is running a sequential scan over the region region it opened, so probably it's not benefiting much from a blockcache. Just disable blockcache entirely for these scans because it's likely the cache config detected is designed for a RS running on a different class of hardware than that running the map task.