IBM Websphere 7.1线程转储

Question

I am trying to understand the concurreny anaylysis logged in thread dumps.. 1) Say i have two threads A and B, If thread A hs lock on few rows (oracle 10g) and my thread B is trying to update same ROw soo ideally in my thread dumps i should get Thread B waiting for thread A Second Senario Now suppose Thread A is locking on a block of code and Thread B tries to enter and i take thread dumps soo in my dumos i should again see Thread B trying to get a monitor held by thread A..

My question is from Thread Dumps how can i verify if thread A is waiting for a something that is held by thread A is at Code level or query level????

Second Question .... in "LOCKS subcomponent dump routine"

I see many many locks but i couln'd see which thread is holding this resource
ie it should say like Own by thread 10 but its saying "unowned"

Third Question

for reference please refer below sample

3XMTHREADINFO "Multicast Heartbeat Receiver Thread" J9VMThread:0x0000000033896700, j9thread_t:0x00000001217D9FC0, java/lang/Thread:0x000000004E017320, state:CW, prio=5 3XMTHREADINFO1 (native thread ID:0x5CD0E2B, native priority:0x5, native policy:UNKNOWN) 3XMTHREADINFO3 Java callstack: 4XESTACKTRACE at java/net/PlainDatagramSocketImpl.receive0(Native Method) 4XESTACKTRACE at java/net/PlainDatagramSocketImpl.receive(PlainDatagramSocketImpl.java:164(Compiled Code)) 4XESTACKTRACE at java/net/DatagramSocket.receive(DatagramSocket.java:721(Compiled Code)) 4XESTACKTRACE at net/sf/ehcache/distribution/MulticastKeepaliveHeartbeatReceiver$MulticastReceiverThread.run(MulticastKeepaliveHeartbeatReceiver.java:124) 3XMTHREADINFO3 Native callstack: 4XENATIVESTACK _event_wait+0x344 (0x09000000007AD9C8 [libpthreads.a+0x169c8]) 4XENATIVESTACK _cond_wait_local+0x4dc (0x09000000007BBBA0 [libpthreads.a+0x24ba0]) 4XENATIVESTACK _cond_wait+0xc8 (0x09000000007BC18C [libpthreads.a+0x2518c]) 4XENATIVESTACK pth read_cond_wait+0x19c (0x09000000007BCDE0 [libpthreads.a+0x25de0]) 4XENATIVESTACK (0x090000004BD4FB64 [libj9thr24.so+0x4b64])

Now its in Conditional Wait , But how can i proceed the reason for conditional wait.,. coz i can't see any thing like waiting on something curretnly owned is some thing else??

Answer 1

You have to monitor the lock on resource, and see if the threads blocked waiting for a condition remain the same during time (possible deadlock) or dynamically change

I strongly advise you to take three java cores with an interval of some minute and then open them with Thread Analyzer

https://www.ibm.com/developerworks/community/groups/service/html/communityview?communityUuid=2245aa39-fa5c-4475-b891-14c205f7333c

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