[HDFS-13947] Review of DirectoryScanner Class

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 3.2.0
• Fix Version/s: 3.3.0
• Component/s: datanode
• Hadoop Flags: Reviewed
• Flags: Patch
• Assignee: David Mollitor
• Reporter: David Mollitor
• Created: 01/Oct/18 03:39
• Updated: 04/Dec/21 06:38
• Resolved: 03/Oct/18 18:20

Description

Review of Directory Scanner. Replaced a lot of code with Guava MultiMap. Some general house cleaning and improved logging. For performance, using ArrayList instead of LinkedList where possible, especially since these lists can be quite large a LinkedList will consume a lot of memory and be slow to sort/iterate over.

https://stackoverflow.com/questions/322715/when-to-use-linkedlist-over-arraylist-in-java

Issue Links

• is related to: HDFS-13958 Miscellaneous Improvements for FsVolumeSpi