[infinispan-issues] [JBoss JIRA] (ISPN-4995) ClusteredGet served for non-member of CH

[Radim Vansa (JIRA)]

    [ https://issues.jboss.org/browse/ISPN-4995?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13022115#comment-13022115 ] 

Radim Vansa edited comment on ISPN-4995 at 11/21/14 7:07 PM:
-------------------------------------------------------------

You're right, my argumentation was flawed. I was also mixing PRAM and causality. We need to redefine the 'all processes see updates from one process in the same order as this has executed them' with version for non-atomic updates. My request is this:
* before update is finished, other processes can see both old and new value
* after the update is finished, other processes can see only the new value
* update can start only after previous update was finished

If you'd rather promote eventually consistent system, there should be a way how to find out whether given entry is convergent. Or we could define that each entry converges within some timeout.

Any documentation about cache consistency is missing.


was (Author: rvansa):
You're right, my argumentation was flawed. I was also mixing PRAM and causality. We need to redefine the 'all processes see updates from one process in the same order as this has executed them' with version for non-atomic updates. My request is this:
* before update is finished, other processes can see both old and new value
* after the update is finished, other processes can see only the new value
* update can start only after previous update was finished

If you'd rather promote eventually consistent system, there should be a way how to find out whether given entry is convergent. Or we could define that each entry converges within some timeout.

I think that the documentation about cache consistency is missing.

> ClusteredGet served for non-member of CH
> ----------------------------------------
>
>                 Key: ISPN-4995
>                 URL: https://issues.jboss.org/browse/ISPN-4995
>             Project: Infinispan
>          Issue Type: Bug
>          Components: Core, State Transfer
>            Reporter: Radim Vansa
>            Priority: Critical
>
> When nodes accept ClusteredGetCommand from node that is not member of CH, it can happen that when one thread does
> {code}
> put(K1, V1);
> put(K2, V2)
> {code}
> and another gets
> {code}
> get(K2) -> V2
> get(K1) -> V0 (some old value)
> {code}
> edg-perf01, 02 and 03 share this view and topology:
> {code}
> 04:40:08,714 TRACE [org.jgroups.protocols.FD_SOCK] (INT-8,edg-perf01-63779) edg-perf01-63779: i-have-sock: edg-perf02-45117 --> 172.18.1.3:37476 (cache is {edg-perf01-63779=172.18.1.1:40099, edg-perf02-45117=172.18.1.3:37476})
> 04:40:08,715 TRACE [org.infinispan.topology.ClusterTopologyManagerImpl] (transport-thread--p2-t6) Received new cluster view: 8, isCoordinator = true, becameCoordinator = false
> 04:40:11,203 DEBUG [org.infinispan.topology.LocalTopologyManagerImpl] (transport-thread--p2-t1) Updating local consistent hash(es) for cache testCache: new topology = CacheTopology{id=16, rebalanceId=4, currentC
> H=DefaultConsistentHash{ns = 512, owners = (3)[edg-perf02-45117: 171+170, edg-perf03-6264: 171+171, edg-perf01-63779: 170+171]}, pendingCH=null, unionCH=null, actualMembers=[edg-perf02-45117, edg-perf03-6264, edg-perf01-63779]}
> {code}
> Later, edg-perf02 and edg-perf03 get new view and install a new topology, where edg-perf01 does not exist:
> {code}
> 04:41:13,681 INFO [org.infinispan.remoting.transport.jgroups.JGroupsTransport] (Incoming-2,edg-perf03-6264) ISPN000093: Received new, MERGED cluster view for channel default: MergeView::[edg-perf02-45117|9] (3) [edg-perf02-45117, edg-perf03-6264, edg-perf04-10989], 1 subgroups: [edg-perf04-10989|7] (1) [edg-perf04-10989]
> 04:41:13,681 TRACE [org.infinispan.topology.ClusterTopologyManagerImpl] (transport-thread--p2-t22) Received new cluster view: 9, isCoordinator = false, becameCoordinator = false
> 04:41:13,760 TRACE [org.infinispan.remoting.transport.jgroups.CommandAwareRpcDispatcher] (remote-thread--p3-t32) Attempting to execute non-CacheRpcCommand command: CacheTopologyControlCommand{cache=testCache, type=CH_UPDATE, sender=edg-perf02-45117, joinInfo=null, topologyId=18, rebalanceId=4, currentCH=DefaultConsistentHash{ns = 512, owners = (2)[edg-perf02-45117: 256+85, edg-perf03-6264: 256+86]}, pendingCH=null, availabilityMode=AVAILABLE, actualMembers=[edg-perf02-45117, edg-perf03-6264], throwable=null, viewId=9}[sender=edg-perf02-45117]
> {code}
> After that, edg-perf04 writes to {{key_00000000000020DB}} which is currently owned only by edg-perf03 - this key servers as K1 in example above. It is not backed up to edg-perf01, but edg-perf01 still thinks it's an owner of this key as it did not get any new view (this is a log from edg-perf03) :
> {code}
> 04:41:30,884 TRACE [org.infinispan.remoting.rpc.RpcManagerImpl] (remote-thread--p3-t45) edg-perf03-6264 invoking PutKeyValueCommand{key=key_00000000000020DB, value=[33 #4: 0, 169, 284, 634, ], flags=[SKIP_CACHE_LOAD, SKIP_REMOTE_LOOKUP], putIfAbsent=false, valueMatcher=MATCH_ALWAYS,  metadata=EmbeddedMetadata{version=null}, successful=true} to recipient list [edg-perf03-6264] with options RpcOptions{timeout=60000, unit=MILLISECONDS, fifoOrder=true, totalOrder=false, responseFilter=null, responseMode=SYNCHRONOUS, skipReplicationQueue=false}
> {code}
> Later, edg-perf04 writes to another key {{stressor_33}} (K2 in the example) value with operationId=650 (previous value is 600) which is replicated to edg-perf02 and edg-perf03.
> Now a merge view with all 4 nodes is installed:
> {code}
> 04:41:31,258 INFO  [org.infinispan.remoting.transport.jgroups.JGroupsTransport] (Incoming-2,edg-perf01-63779) ISPN000093: Received new, MERGED cluster view for channel default: MergeView::[edg-perf01-63779|10] (4) [edg-perf01-63779, edg-perf03-6264, edg-perf02-45117, edg-perf04-10989], 6 subgroups: [edg-perf02-45117|7] (2) [edg-perf02-45117, edg-perf03-6264], [edg-perf01-63779|4] (2) [edg-perf01-63779, edg-perf02-45117], [edg-perf02-45117|9] (3) [edg-perf02-45117, edg-perf03-6264, edg-perf04-10989], [edg-perf03-6264|4] (2) [edg-perf03-6264, edg-perf04-10989], [edg-perf01-63779|8] (3) [edg-perf01-63779, edg-perf02-45117, edg-perf03-6264], [edg-perf01-63779|6] (1) [edg-perf01-63779]
> 04:41:31,258 TRACE [org.infinispan.topology.ClusterTopologyManagerImpl] (transport-thread--p2-t2) Received new cluster view: 10, isCoordinator = true, becameCoordinator = false
> {code}
> edg-perf01 now issues a remote get to edg-perf02 for key stressor_33 and receives the correct answer (operationId=650):
> {code}
> 04:41:32,494 TRACE [org.infinispan.remoting.rpc.RpcManagerImpl] (BackgroundOps-Checker-1) Response(s) to ClusteredGetCommand{key=stressor_33, flags=null} is {edg-perf02-45117=SuccessfulResponse{responseValue=ImmortalCacheValue {value=LastOperation{operationId=650, seed=0000A15A4C2DD25A}}} }
> {code}
> However, when edg-perf01 reads {{key_00000000000020DB}}, it loads the old value from local data container as no CH update/rebalance happened so far:
> {code}
> 04:41:32,496 TRACE [org.infinispan.partitionhandling.impl.PartitionHandlingManagerImpl] (BackgroundOps-Checker-1) Checking availability for key=key_00000000000020DB, status=AVAILABLE
> 04:41:32,497 ERROR [org.radargun.stages.cache.background.LogChecker] (BackgroundOps-Checker-1) Missing operation 634 for thread 33 on key 8411 (key_00000000000020DB) 
> 04:41:32,499 DEBUG [org.radargun.service.InfinispanDebugable] (BackgroundOps-Checker-1) Debug info for key testCache key_00000000000020DB: owners=edg-perf01-63779, edg-perf03-6264, local=true, uncertain=false, container.key_00000000000020DB=ImmortalCacheEntry[key=key_00000000000020DB, value=[33 #3: 0, 169, 284, ], created=-1, isCreated=false, lastUsed=-1, isChanged=false, expires=-1, isExpired=false, canExpire=false, isEvicted=true, isRemoved=false, isValid=false, lifespan=-1, maxIdle=-1], segmentId=173
> {code}
> Note that this was found on branch https://github.com/infinispan/infinispan/pull/3062/files trying to fix ISPN-4949.



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