[HBASE-15470] Add a setting for Priority queue length

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.2.0
• Fix Version/s: 1.3.0, 2.0.0
• Component/s: IPC/RPC, Region Assignment
• Hadoop Flags: Reviewed
• Assignee: Elliott Neil Clark
• Reporter: Elliott Neil Clark
• Created: 16/Mar/16 16:01
• Updated: 29/Mar/16 05:58
• Resolved: 16/Mar/16 23:53

Description

Meta can have very different request rates than any other region. We shouldn't use the same call queue length.

For example:
If a normal request takes 100ms ( long scan or large get )
but a call to meta is all in memory so it takes < 1ms

So a call queue length of 100 represents multiple seconds of work for normal requests, but less than a second for meta.