Enis Soztutar created HBASE-14674:
-------------------------------------
Summary: Rpc handler / task monitoring seems to be broken after
0.98
Key: HBASE-14674
URL: https://issues.apache.org/jira/browse/HBASE-14674
Project: HBase
Issue Type: Bug
Reporter: Enis Soztutar
Fix For: 1.3.0, 1.2.1, 1.0.3, 1.1.4, 0.98.17
In 0.96, we have the RPC handlers listed as tasks and show them in the web UI
as well:
{code}
Tasks:
===========================================================
Task: RpcServer.handler=0,port=64231
Status: WAITING:Waiting for a call
Running for 932s
Task: RpcServer.handler=1,port=64231
Status: WAITING:Waiting for a call
Running for 932s
Task: RpcServer.handler=2,port=64231
Status: WAITING:Waiting for a call
Running for 932s
{code}
After pluggable RPC scheduler, the way the tasks work for the handlers got
changed. We no longer list idle RPC handlers in the tasks, but we register them
dynamically to {{TaskMonitor}} through {{CallRunner}}. However, the IPC readers
are still registered the old way (meaning that idle readers are listed as
tasks, but not idle handlers).
>From the javadoc of {{MonitoredRPCHandlerImpl}}, it seems that we are
>optimizing the allocation for the MonitoredTask anymore, but instead allocate
>one for every RPC call breaking the pattern (See CallRunner.getStatus()).
{code}
/**
* A MonitoredTask implementation designed for use with RPC Handlers
* handling frequent, short duration tasks. String concatenations and object
* allocations are avoided in methods that will be hit by every RPC call.
*/
@InterfaceAudience.Private
public class MonitoredRPCHandlerImpl extends MonitoredTaskImpl
{code}
There is also one more side affect that, since the CallRunner is a per-RPC
object and created in the RPC listener thread, the created task ends up having
a name "listener" although the actual processing happens in a handler thread.
This is obviously very confusing during debugging.
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