[HBASE-4324] Single unassigned directory is very slow when there are many unassigned nodes

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Won't Fix
• Affects Version/s: 0.90.4
• Component/s: Zookeeper
• Assignee: Unassigned
• Reporter: Todd Lipcon
• Created: 01/Sep/11 23:33
• Updated: 12/Jun/22 19:16
• Resolved: 16/Nov/16 20:52

Description

Because we use a single znode for /unassigned, and we re-list it every time its contents change, assignment speed per region is O(number of unassigned regions) rather than O(1). Every time something changes about one unassigned region, the master has to re-list the entire contents of the directory inside of AssignmentManager.nodeChildrenChanged().