I'm trying to understand more about whether it makes sense for a DefaultConsistentHash to be created with a non-local owner specified in the DefaultConsistentHash constructor "segmentOwners" parameter.

During some AS7 cluster testing that I'm running on my machine, I'm seeing the test stall because we loop endlessly in KeyAffinityServiceImpl.getKeyForAddress(). We loop because KeyAffinityServiceImpl.generateKeys() doesn't add any keys. We don't generate any keys because DefaultConsistentHash.locatePrimaryOwnerForSegment() returns address "node-1/web" which never matches the local nodes filter (KeyAffinityServiceImpl.interestedInAddress() only filters for local owners via "node-0/web"). http://pastie.org/5027574 shows the call stack for the DefaultConsistentHash constructor that is the same instance that is used above. If you look at the call stack, it looks like the DefaultConsistentHash instance may of being serialized on the other node and sent over (which would explain why its owner is "node-1/web" but still not sure why/how it comes into play with local KeyAffinityServiceImpl.generateKeys()).

On 10/10/2012 06:47 AM, Dan Berindei wrote: > Hi Scott > > On Wed, Oct 10, 2012 at 6:20 AM, Scott Marlow <smarlow(a)redhat.com > <mailto:smarlow@redhat.com>> wrote: > > I'm trying to understand more about whether it makes sense for a > DefaultConsistentHash to be created with a non-local owner specified > in > the DefaultConsistentHash constructor "segmentOwners" parameter. > > > It definitely makes sense for such a DefaultConsistentHash to exist > while the cache is starting. But by the time the cache has started (i.e. > getCache() has returned), it should have been replaced with a > DefaultConsistentHash that contains the local node as well. > > During some AS7 cluster testing that I'm running on my machine, I'm > seeing the test stall because we loop endlessly in > KeyAffinityServiceImpl.**getKeyForAddress(). We loop because > KeyAffinityServiceImpl.**generateKeys() doesn't add any keys. > > We don't generate any keys because > DefaultConsistentHash.**locatePrimaryOwnerForSegment() returns > address > "node-1/web" which never matches the local nodes filter > (KeyAffinityServiceImpl.**interestedInAddress() only filters for > local > owners via "node-0/web"). > > http://pastie.org/5027574 shows the call stack for the > DefaultConsistentHash constructor that is the same instance that is > used > above. If you look at the call stack, it looks like the > DefaultConsistentHash instance may of being serialized on the other > node > and sent over (which would explain why its owner is "node-1/web" but > still not sure why/how it comes into play with local > KeyAffinityServiceImpl.**generateKeys()). > > > My guess is you're able to access the cache before it has finished > starting, and the KeyAffinityService doesn't know how to deal with a > cache that doesn't have any local state yet. Again, this should not > I instrumented the DefaultConsistentHash constructor to call thread.dumpStack() only if the owner is "node-1/web" (so I could track the origin of the wrong DefaultConsistentHash instance being used). Currently, I also have INFO level logging in the DefaultConsistentHash ctor that always shows: " DefaultConsistentHash ctor this=DefaultConsistentHash{**numSegments=1, numOwners=2, members=[node-1/web, node-0/web], segmentOwners={0: 0 1}system identityHashCode=108706475,**show segmentOwners[0 of 1] = [node-1/web, node-0/web] DefaultConsistentHash ctor numSegments=1, numOwners=2 DefaultConsistentHash ctor this.segmentOwners[0][0] = node-1/web "

Since this testing involves multiple tests (org.jboss.as.test.clustering.* *cluster.singleton.**SingletonTestCase,org.jboss.** as.test.clustering.cluster.**web.**ReplicationWebFailoverTestCase** ,org.jboss.as.test.clustering.**cluster.web.**GranularWebFailoverTestCase, **org.jboss.as.test.clustering.**cluster.web.passivation.** SessionBasedSessionPassivation**TestCase,org.jboss.as.test.** clustering.cluster.web.**passivation.**AttributeBasedSessionPassivati** onTestCase,org.jboss.as.test.**clustering.cluster.web.** DistributionWebFailoverTestCas**e), its not surprising to see that we reach the DefaultConsistentHash constructor 12 times. The segment owners for the 12 constructors are in the following: 1. [node-0/web] 2. [node-0/web] 3. [node-0/web, node-1/web] 4. [node-0/web, node-1/web] 5. [node-1/web] 6. [node-1/web] 7. [node-1/web] 8. [node-1/web, node-0/web] 9. [node-1/web, node-0/web] 10. [node-1/web, node-0/web] (we use this one when stuck in a loop) 11. [node-0/web] 12. [node-0/web] We are using the #10 DefaultConsistentHash constructed instance from above for several minutes to an hour (if I let the test run that long while the KeyAffinityServiceImpl.**getKeyForAddress() continues in the loop). Could there be a problem with the ordering of the segment owners? or is it more that we never switch to use #11/#12 that is likely to be the timing problem?

happen - getCache() should not return that soon - but it could be that > it does happen when multiple threads try to start the same cache in > parallel. Can you post logs with TRACE enabled for org.infinispan and/or > a link to your test code? > > Sure, I can enable TRACE for Infinispan and attach the logs to the ISPN-2376 jira. I'll add links to the test code there as well (as comments). Also, KeyAffinityServiceImpl.**generateKeys() contains: " // if we had too many misses, just release the lock and try again if (missCount < maxMisses) { " I tried changing the above to a ">=" check and also tried removing the check (just did the keyProducerStartLatch.close()) neither of which had direct impact on the current problem.