[HADOOP-4988] An earlier fix, for HADOOP-4373, results in a problem with reclaiming capacity when one or more queues have a capacity equal to zero

• Type: Bug
• Status: Closed
• Priority: Blocker
• Resolution: Fixed
• Fix Version/s: 0.20.0
• Assignee: Vivek Ratan
• Reporter: Vivek Ratan
• Created: 07/Jan/09 11:25
• Updated: 08/Jul/09 16:40
• Resolved: 16/Jan/09 00:26

Description

HADOOP-4373 introduced a fix for queues with guaranteed capacity (gc) equal to zero. Part of the fix was in the queue comparator used to sort queues. Queues with gc=0 were placed at the end. This causes a problem with the code for reclaiming capacity, which assumes that queues are sorted based on free space available and that a queue with gc=0 is no different than a queue which is running at capacity. Because of this, the following problem can arise: if we have a system with at least one queue whose gc=0, we may fail to reclaim capacity for some queues.