[HADOOP-947] isReplicationInProgress() is very heavyweight

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 0.12.0
• Assignee: Dhruba Borthakur
• Reporter: Dhruba Borthakur
• Created: 29/Jan/07 19:14
• Updated: 08/Jul/09 16:42
• Resolved: 16/Feb/07 22:23

Description

Suppose a decommission is in progress. The namenode receives a heartbeat from the being-decommissioned node and then invokes isReplicationInProgress() to determine if the decommissioned is complete. This method is very heavyweight and chews up plenty of CPU.

One option to fix this issue is to keep a counter to indicate how many blocks are pending replication. This could also help in showing a progress-status-indicator to display how far the decommissioning process is complete.