coreZkRegister thread

[Rallavagu <ra...@gmail.com>]

Solr 4.6.1, 4 node cloud with 3 zk

I see the following thread as blocked. Could somebody please help me 
understand what is going on here and how will it impact solr cloud? All 
four of these threads blocked. Thanks.

"coreZkRegister-1-thread-1" id=74 idx=0x108 tid=32162 prio=5 alive, 
parked, native_blocked
     -- Parking to wait for: 
java/util/concurrent/locks/AbstractQueuedSynchronizer$ConditionObject@0x11a61daf8
     at pthread_cond_wait@@GLIBC_2.3.2+202(:0)@0x3d4180b5ba
     at eventTimedWaitNoTransitionImpl+71(event.c:90)@0x7f41a970aba8
     at 
syncWaitForSignalNoTransition+65(synchronization.c:28)@0x7f41a989e0b2
     at syncWaitForSignal+189(synchronization.c:85)@0x7f41a989e20e
     at vmtPark+164(signaling.c:72)@0x7f41a987a165
     at jrockit/vm/Locks.park0(J)V(Native Method)
     at jrockit/vm/Locks.park(Locks.java:2230)
     at sun/misc/Unsafe.park(ZJ)V(Native Method)
     at java/util/concurrent/locks/LockSupport.park(LockSupport.java:156)
     at 
java/util/concurrent/locks/AbstractQueuedSynchronizer$ConditionObject.await(AbstractQueuedSynchronizer.java:1987)
     at 
java/util/concurrent/LinkedBlockingQueue.take(LinkedBlockingQueue.java:399)
     at 
java/util/concurrent/ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:957)
     at 
java/util/concurrent/ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:917)
     at java/lang/Thread.run(Thread.java:682)
     at jrockit/vm/RNI.c2java(JJJJJ)V(Native Method)