I see the following exception in the karaf log:

2014-09-23 04:59:58,150 | WARN | ds-oper-thread-0 | StatisticsManagerImpl | 218 - org.opendaylight.controller.md.statistics-manager - 1.1.0.SNAPSHOT | Stat DataStore Operation executor fail!
java.lang.IllegalArgumentException: value already present: Uri [_value=5|8|9|8|64999|Match [_ethernetMatch=EthernetMatch [_ethernetType=EthernetType [_type=EtherType [_value=2048], augmentation=[]], augmentation=[]], _ipMatch=IpMatch [_ipProtocol=1, augmentation=[]], augmentation=[GeneralAugMatchNodesNodeTableFlow [_extensionList=[ExtensionList [_extension=Extension [augmentation=[NxAugMatchNodesNodeTableFlow [_nxmNxReg=NxmNxReg [_reg=class org.opendaylight.yang.gen.v1.urn.opendaylight.openflowjava.nx.match.rev140421.NxmNxReg0, _value=5, augmentation=[]]]]], _extensionKey=class org.opendaylight.yang.gen.v1.urn.opendaylight.openflowplugin.extension.nicira.match.rev140714.NxmNxReg0Key, _key=ExtensionListKey [_extensionKey=class org.opendaylight.yang.gen.v1.urn.opendaylight.openflowplugin.extension.nicira.match.rev140714.NxmNxReg0Key], augmentation=[]], ExtensionList [_extension=Extension [augmentation=[NxAugMatchNodesNodeTableFlow [_nxmNxReg=NxmNxReg [_reg=class org.opendaylight.yang.gen.v1.urn.opendaylight.openflowjava.nx.match.rev140421.NxmNxReg1, _value=8, augmentation=[]]]]], _extensionKey=class org.opendaylight.yang.gen.v1.urn.opendaylight.openflowplugin.extension.nicira.match.rev140714.NxmNxReg1Key, _key=ExtensionListKey [_extensionKey=class org.opendaylight.yang.gen.v1.urn.opendaylight.openflowplugin.extension.nicira.match.rev140714.NxmNxReg1Key], augmentation=[]], ExtensionList [_extension=Extension [augmentation=[NxAugMatchNodesNodeTableFlow [_nxmNxReg=NxmNxReg [_reg=class org.opendaylight.yang.gen.v1.urn.opendaylight.openflowjava.nx.match.rev140421.NxmNxReg2, _value=9, augmentation=[]]]]], _extensionKey=class org.opendaylight.yang.gen.v1.urn.opendaylight.openflowplugin.extension.nicira.match.rev140714.NxmNxReg2Key, _key=ExtensionListKey [_extensionKey=class org.opendaylight.yang.gen.v1.urn.opendaylight.openflowplugin.extension.nicira.match.rev140714.NxmNxReg2Key], augmentation=[]], ExtensionList [_extension=Extension [augmentation=[NxAugMatchNodesNodeTableFlow [_nxmNxReg=NxmNxReg [_reg=class org.opendaylight.yang.gen.v1.urn.opendaylight.openflowjava.nx.match.rev140421.NxmNxReg3, _value=8, augmentation=[]]]]], _extensionKey=class org.opendaylight.yang.gen.v1.urn.opendaylight.openflowplugin.extension.nicira.match.rev140714.NxmNxReg3Key, _key=ExtensionListKey [_extensionKey=class org.opendaylight.yang.gen.v1.urn.opendaylight.openflowplugin.extension.nicira.match.rev140714.NxmNxReg3Key], augmentation=[]]]]]]]
at com.google.common.collect.HashBiMap.put(HashBiMap.java:241)[78:com.google.guava:14.0.1]
at com.google.common.collect.HashBiMap.put(HashBiMap.java:218)[78:com.google.guava:14.0.1]
at org.opendaylight.controller.md.statistics.manager.impl.StatListenCommitFlow$TableFlowUpdateState.<init>(StatListenCommitFlow.java:305)[218:org.opendaylight.controller.md.statistics-manager:1.1.0.SNAPSHOT]
at org.opendaylight.controller.md.statistics.manager.impl.StatListenCommitFlow$NodeUpdateState.<init>(StatListenCommitFlow.java:269)[218:org.opendaylight.controller.md.statistics-manager:1.1.0.SNAPSHOT]
at org.opendaylight.controller.md.statistics.manager.impl.StatListenCommitFlow.statsFlowCommitAll(StatListenCommitFlow.java:219)[218:org.opendaylight.controller.md.statistics-manager:1.1.0.SNAPSHOT]
at org.opendaylight.controller.md.statistics.manager.impl.StatListenCommitFlow.access$100(StatListenCommitFlow.java:82)[218:org.opendaylight.controller.md.statistics-manager:1.1.0.SNAPSHOT]
at org.opendaylight.controller.md.statistics.manager.impl.StatListenCommitFlow$2.applyOperation(StatListenCommitFlow.java:194)[218:org.opendaylight.controller.md.statistics-manager:1.1.0.SNAPSHOT]
at org.opendaylight.controller.md.statistics.manager.impl.StatisticsManagerImpl.run(StatisticsManagerImpl.java:196)[218:org.opendaylight.controller.md.statistics-manager:1.1.0.SNAPSHOT]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)[:1.7.0_65]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)[:1.7.0_65]
at java.lang.Thread.run(Thread.java:745)[:1.7.0_65]

Thereafter, I see the following repeat over and over in the logs:

2014-09-23 05:00:28,123 | WARN | ds-oper-thread-0 | StatisticsManagerImpl | 218 - org.opendaylight.controller.md.statistics-manager - 1.1.0.SNAPSHOT | Stat DataStoreOperation unexpected State!
java.lang.IllegalStateException: Previous transaction DOM-OPER-621 is not ready yet
at com.google.common.base.Preconditions.checkState(Preconditions.java:176)[78:com.google.guava:14.0.1]
at org.opendaylight.controller.md.sal.dom.store.impl.InMemoryDOMDataStore$DOMStoreTransactionChainImpl.getSnapshot(InMemoryDOMDataStore.java:244)[166:org.opendaylight.controller.sal-inmemory-datastore:1.1.0.SNAPSHOT]
at org.opendaylight.controller.md.sal.dom.store.impl.InMemoryDOMDataStore$DOMStoreTransactionChainImpl.newReadWriteTransaction(InMemoryDOMDataStore.java:266)[166:org.opendaylight.controller.sal-inmemory-datastore:1.1.0.SNAPSHOT]
at org.opendaylight.controller.md.sal.dom.broker.impl.AbstractDOMForwardedTransactionFactory.newReadWriteTransaction(AbstractDOMForwardedTransactionFactory.java:183)[160:org.opendaylight.controller.sal-broker-impl:1.1.0.SNAPSHOT]
at org.opendaylight.controller.md.sal.binding.impl.BindingTranslatedTransactionChain.newReadWriteTransaction(BindingTranslatedTransactionChain.java:63)[163:org.opendaylight.controller.sal-binding-broker-impl:1.1.0.SNAPSHOT]
at org.opendaylight.controller.md.statistics.manager.impl.StatisticsManagerImpl.run(StatisticsManagerImpl.java:191)[218:org.opendaylight.controller.md.statistics-manager:1.1.0.SNAPSHOT]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)[:1.7.0_65]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)[:1.7.0_65]
at java.lang.Thread.run(Thread.java:745)[:1.7.0_65]