[HBASE-3759] Eliminate use of ThreadLocals for CoprocessorEnvironment bypass() and complete()

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 0.92.0
• Component/s: Coprocessors
• Hadoop Flags: Reviewed
• Assignee: Gary Helmling
• Reporter: Gary Helmling
• Created: 08/Apr/11 22:18
• Updated: 20/Nov/15 12:42
• Resolved: 13/Apr/11 05:43

Description

In the current coprocessor framework, ThreadLocal objects are used for the bypass and complete booleans in CoprocessorEnvironment. This allows the *CoprocessorHost implementations to identify when to short-circuit processing the the preXXX and postXXX hook methods.

Profiling the region server, however, shows that these ThreadLocals can become a contention point when on a hot code path (such as prePut()). We should refactor the CoprocessorHost pre/post implementations to remove usage of the ThreadLocal variables and replace them with locally scoped variables to eliminate contention between handler threads.