AdvancedAsyncCacheLoader.process() concurrency issues ----------------------------------------------------- Key: ISPN-3938 URL: https://issues.jboss.org/browse/ISPN-3938 Project: Infinispan Issue Type: Bug Components: Core, Loaders and Stores Affects Versions: 6.0.0.Final Reporter: Dan Berindei Assignee: William Burns Fix For: 8.0.0.Final {{AdvancedAsyncCacheLoader.process()}} calls {{advancedLoader().process()}} to collect all the keys in the store, but the HashSet used to collect the keys it not thread-safe. This can cause problems, e.g. during state transfer: {noformat} WARN cheTopologyControlCommand | ISPN000071: Caught exception when handling command CacheTopologyControlCommand{cache=sessions, type=CH_UPDATE, sender=alfie-lt-46127, joinInfo=null, topologyId=3, currentCH=DefaultConsistentHash{numSegments=60, numOwners=1, members=[alfie-lt-46127]}, pendingCH=null, throwable=null, viewId=1}java.util.ConcurrentModificationException at java.util.HashMap$HashIterator.nextEntry(HashMap.java:926) at java.util.HashMap$KeyIterator.next(HashMap.java:960) at org.infinispan.persistence.async.AdvancedAsyncCacheLoader.process(AdvancedAsyncCacheLoader.java:80) at org.infinispan.persistence.manager.PersistenceManagerImpl.processOnAllStores(PersistenceManagerImpl.java:414) at org.infinispan.statetransfer.StateConsumerImpl.invalidateSegments(StateConsumerImpl.java:910) at org.infinispan.statetransfer.StateConsumerImpl.onTopologyUpdate(StateConsumerImpl.java:393) at org.infinispan.statetransfer.StateTransferManagerImpl.doTopologyUpdate(StateTransferManagerImpl.java:178) at org.infinispan.statetransfer.StateTransferManagerImpl.access$000(StateTransferManagerImpl.java:38) at org.infinispan.statetransfer.StateTransferManagerImpl$1.updateConsistentHash(StateTransferManagerImpl.java:100) at org.infinispan.topology.LocalTopologyManagerImpl.handleConsistentHashUpdate(LocalTopologyManagerImpl.java:191) at org.infinispan.topology.CacheTopologyControlCommand.doPerform(CacheTopologyControlCommand.java:152) at org.infinispan.topology.CacheTopologyControlCommand.perform(CacheTopologyControlCommand.java:124) at org.infinispan.topology.ClusterTopologyManagerImpl$3.run(ClusterTopologyManagerImpl.java:606) at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471) at java.util.concurrent.FutureTask.run(FutureTask.java:262) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615) at java.lang.Thread.run(Thread.java:744) {noformat}