[infinispan-issues] [JBoss JIRA] (ISPN-4995) ClusteredGet served for non-member of CH
Dan Berindei (JIRA)
issues at jboss.org
Fri Nov 21 09:00:44 EST 2014
[ https://issues.jboss.org/browse/ISPN-4995?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13021937#comment-13021937 ]
Dan Berindei commented on ISPN-4995:
------------------------------------
We really don't want to install any topology that another member happens to have, just because its id is higher. If both partitions are in degraded mode and one's id is higher than the other's, we could end up installing the same topology on both partitions and losing the data in the partition with the smaller id.
I guess responding to a query from a node in another partition is still a problem if we have a more tricky scenario with the available partition evolving and moving keys while the degraded partition doesn't realize it should enter degraded mode. If that happens, the remote get might return null without the key being updated at all.
We might be able to work around this in JGroups by increasing the MERGE2/3 intervals so that it's very unlikely to install the merge view before every node detected the partition. We already have a retry algorithm in {{BaseDistributionInterceptor.retrieveFromRemoteSource()}} that assumes nodes that have the key do reply with the value to avoid blocking, so we can't throw an {{OutdatedTopologyException}} every time the topology id is different. But we could also throw an OutdatedTopologyException when the target is no longer an owner instead of returning a {{null}} and translate that to the user as an {{AvailabilityException}}.
> 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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