[HDFS-13227] Add a method to calculate cumulative diff over multiple snapshots in DirectoryDiffList

• Type: Improvement
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Fix Version/s: 3.1.0
• Component/s: snapshots
• Hadoop Flags: Reviewed
• Assignee: Shashikant Banerjee
• Reporter: Shashikant Banerjee
• Created: 05/Mar/18 11:58
• Updated: 19/Mar/18 18:31
• Resolved: 06/Mar/18 21:45

Description

This Jira proposes to add an API in DirectoryWithSnapshotFeature#f DirectoryDiffList which will return minimal list of diffs needed to combine to get the cumulative diff between two given snapshots. The same method will be made use while constructing the childrenList for a directory. DirectoryWithSnapshotFeature#getChildrenList and DirectoryWithSnapshotFeature#computeDiffBetweenSnapshots will make use of the same method to get the cumulative diff. When snapshotSkipList, with minimal set of diffs to combine in order to get the cumulative diff, the overall computation will be faster.

Issue Links

• is a child of: HDFS-11225 NameNode crashed because deleteSnapshot held FSNamesystem lock too long