We having scaling Apache Ignite grid where client nodes scale up and down based on load. Data nodes are our server nodes where continuous queries run. However this leads to unclean shutdown of some client nodes as we rely on SIGTERM for Ignite node shutdown.
Unclean shutdown of client nodes impacts excution of continuos query which starts giving "Possible starvation in striped pool" warning ultimately leading to Blocked system-critical threads.
We are currently working on ways to prevent striped pool stravation and have noticed 2 key issues around it:
Continuos query thread trying to connect to nodes which have shutdown but are still present in topology: We are planning to reduce the timeout so that client node is discarded early from grid.
Stacktrace:
Thread [name="sys-stripe-1-#2%App%", id=37, state=RUNNABLE, blockCnt=233817, waitCnt=3343945]
at sun.nio.ch.Net.poll(Native Method)
at sun.nio.ch.SocketChannelImpl.poll(SocketChannelImpl.java:954)
at sun.nio.ch.SocketAdaptor.connect(SocketAdaptor.java:110)
at o.a.i.spi.communication.tcp.TcpCommunicationSpi.createNioSession(TcpCommunicationSpi.java:3781)
at o.a.i.spi.communication.tcp.TcpCommunicationSpi.createTcpClient(TcpCommunicationSpi.java:3635)
at o.a.i.spi.communication.tcp.TcpCommunicationSpi.createCommunicationClient(TcpCommunicationSpi.java:3375)
at o.a.i.spi.communication.tcp.TcpCommunicationSpi.reserveClient(TcpCommunicationSpi.java:3180)
at o.a.i.spi.communication.tcp.TcpCommunicationSpi.sendMessage0(TcpCommunicationSpi.java:3013)
at o.a.i.spi.communication.tcp.TcpCommunicationSpi.sendMessage(TcpCommunicationSpi.java:2960)
at o.a.i.i.managers.communication.GridIoManager.send(GridIoManager.java:2100)
at o.a.i.i.managers.communication.GridIoManager.sendOrderedMessage(GridIoManager.java:2365)
at o.a.i.i.processors.continuous.GridContinuousProcessor.sendWithRetries(GridContinuousProcessor.java:1964)
at o.a.i.i.processors.continuous.GridContinuousProcessor.sendWithRetries(GridContinuousProcessor.java:1935)
at o.a.i.i.processors.continuous.GridContinuousProcessor.sendWithRetries(GridContinuousProcessor.java:1917)
at o.a.i.i.processors.continuous.GridContinuousProcessor.sendNotification(GridContinuousProcessor.java:1324)
at o.a.i.i.processors.continuous.GridContinuousProcessor.addNotification(GridContinuousProcessor.java:1261)
at o.a.i.i.processors.cache.query.continuous.CacheContinuousQueryHandler.onEntryUpdate(CacheContinuousQueryHandler.java:1059)
at o.a.i.i.processors.cache.query.continuous.CacheContinuousQueryHandler.access$600(CacheContinuousQueryHandler.java:90)
at o.a.i.i.processors.cache.query.continuous.CacheContinuousQueryHandler$2.onEntryUpdated(CacheContinuousQueryHandler.java:459)
at o.a.i.i.processors.cache.query.continuous.CacheContinuousQueryManager.onEntryUpdated(CacheContinuousQueryManager.java:447)
Continuos query threads waiting for read lock while trying to update the cache. This is generally comes up after retries for Client node connection are over.
Stacktrace:
Possible starvation in striped pool.
Thread name: sys-stripe-12-#13%App%
Queue: [Message closure [msg=GridIoMessage [plc=2, topic=TOPIC_CACHE, topicOrd=8, ordered=false, timeout=0, skipOnTimeout=false, msg=CacheContinuousQueryBatchAck [routineId=37b43550-d3a5-4518-8745-ece5dc06b1fd, updateCntrs=HashMap {2=7414, 5=8228, 7=7508, 13=7536, 525=7586, 14=7596, 527=7959, 533=7886, 534=7666, 539=9556, 547=7866, 36=8380, 549=8131, 38=7126, 39=7776, 46=7822, 52=7800, 54=8098, 567=7894, 569=7640, 60=7912, 62=8170, 63=7962, 64=8190, 65=7662, 72=7754, 585=7712, 81=8564, 594=8000, 82=7980, 83=7999, 595=7688, 596=7972, 85=7494, 597=7806, 601=7812, 89=7478, 602=7868, 603=7944, 604=7944, 93=7778, 96=8036, 99=7916, 102=7584, 618=7956, 107=7656, 111=7176, 112=8042, 116=7620, 125=7768, 637=7662, 130=7846, 642=7696, 134=11672, 138=7638, 651=7418, 652=7908, 140=7478, 654=9136, 655=8934, 144=8052, 145=7656, 147=7904, 663=7354, 153=7868, 667=8232, 669=7774, 157=7850, 160=8094, 673=8120, 682=7722, 172=7930, 689=7864, 180=8026, 692=7674, 184=7526, 699=7458, 191=8326, 193=7700, 195=7986, 197=8056, 713=7858, 716=7896, 719=7946, 210=7560, 725=7604, 214=7442, 727=7668, 729=7406, 731=7790, 219=7594, 733=7360, 225=7522, 737=7482, 227=7838, 744=8380, 234=7150, 237=7886, 750=7910, 239=8624... and 104 more}]]], Message closure [msg=GridIoMessage [plc=2, topic=TOPIC_CACHE, topicOrd=8, ordered=false, timeout=0, skipOnTimeout=false, msg=CacheContinuousQueryBatchAck [routineId=0e950ae5-1474-4488-9042-80dbddb2f09a, updateCntrs=HashMap {2=7414, 5=8228, 7=7508, 13=7536, 525=7586, 14=7596, 527=7959, 533=7886, 534=7666, 539=9556, 547=7866, 36=8380, 549=8131, 38=7126, 39=7776, 46=7822, 52=7800, 54=8098, 567=7894, 569=7640, 60=7912, 62=8170, 63=7962, 64=8190, 65=7662, 72=7754, 585=7712, 81=8564, 594=8000, 82=7980, 595=7688, 83=7999, 596=7972, 597=7806, 85=7494, 601=7812, 89=7478, 602=7868, 603=7944, 604=7944, 93=7778, 96=8036, 99=7916, 102=7584, 618=7956, 107=7656, 111=7176, 112=8042, 116=7620, 637=7662, 125=7768, 130=7846, 642=7696, 134=11672, 138=7638, 651=7418, 140=7478, 652=7908, 654=9136, 655=8934, 144=8052, 145=7656, 147=7904, 663=7354, 153=7868, 667=8232, 669=7774, 157=7850, 160=8094, 673=8120, 682=7722, 172=7930, 689=7864, 692=7674, 180=8026, 184=7526, 699=7458, 191=8326, 193=7700, 195=7986, 197=8056, 713=7858, 716=7896, 719=7946, 210=7560, 725=7604, 214=7442, 727=7668, 729=7406, 219=7594, 731=7790, 733=7360, 225=7522, 737=7482, 227=7838, 744=8380, 234=7150, 237=7886, 750=7910, 239=8624... and 104 more}]]]]
Deadlock: false
Completed: 3316358
Thread [name="sys-stripe-12-#13%App%", id=48, state=WAITING, blockCnt=106311, waitCnt=1659827]
Lock [object=java.util.concurrent.locks.ReentrantReadWriteLock$NonfairSync@5f611d9a, ownerName=exchange-worker-#71%App%, ownerId=138]
at sun.misc.Unsafe.park(Native Method)
at java.util.concurrent.locks.LockSupport.park(LockSupport.java:175)
at java.util.concurrent.locks.AbstractQueuedSynchronizer.parkAndCheckInterrupt(AbstractQueuedSynchronizer.java:836)
at java.util.concurrent.locks.AbstractQueuedSynchronizer.doAcquireShared(AbstractQueuedSynchronizer.java:967)
at java.util.concurrent.locks.AbstractQueuedSynchronizer.acquireShared(AbstractQueuedSynchronizer.java:1283)
at java.util.concurrent.locks.ReentrantReadWriteLock$ReadLock.lock(ReentrantReadWriteLock.java:727)
at o.a.i.i.processors.cache.distributed.dht.topology.GridDhtPartitionTopologyImpl.readLock(GridDhtPartitionTopologyImpl.java:256)
at o.a.i.i.processors.cache.distributed.dht.atomic.GridDhtAtomicCache.updateAllAsyncInternal0(GridDhtAtomicCache.java:1837)
at o.a.i.i.processors.cache.distributed.dht.atomic.GridDhtAtomicCache.updateAllAsyncInternal(GridDhtAtomicCache.java:1734)
at o.a.i.i.processors.cache.distributed.dht.atomic.GridDhtAtomicCache.processNearAtomicUpdateRequest(GridDhtAtomicCache.java:3322)
at o.a.i.i.processors.cache.distributed.dht.atomic.GridDhtAtomicCache.access$400(GridDhtAtomicCache.java:141)
at o.a.i.i.processors.cache.distributed.dht.atomic.GridDhtAtomicCache$5.apply(GridDhtAtomicCache.java:273)
at o.a.i.i.processors.cache.distributed.dht.atomic.GridDhtAtomicCache$5.apply(GridDhtAtomicCache.java:268)
at o.a.i.i.processors.cache.GridCacheIoManager.processMessage(GridCacheIoManager.java:1142)
at o.a.i.i.processors.cache.GridCacheIoManager.onMessage0(GridCacheIoManager.java:591)
at o.a.i.i.processors.cache.GridCacheIoManager.handleMessage(GridCacheIoManager.java:392)
at o.a.i.i.processors.cache.GridCacheIoManager.handleMessage(GridCacheIoManager.java:318)
at o.a.i.i.processors.cache.GridCacheIoManager.access$100(GridCacheIoManager.java:109)
at o.a.i.i.processors.cache.GridCacheIoManager$1.onMessage(GridCacheIoManager.java:308)
at o.a.i.i.managers.communication.GridIoManager.invokeListener(GridIoManager.java:1907)
at o.a.i.i.managers.communication.GridIoManager.processRegularMessage0(GridIoManager.java:1528)
at o.a.i.i.managers.communication.GridIoManager.access$5300(GridIoManager.java:241)
at o.a.i.i.managers.communication.GridIoManager$9.execute(GridIoManager.java:1421)
at o.a.i.i.managers.communication.TraceRunnable.run(TraceRunnable.java:55)
at o.a.i.i.util.StripedExecutor$Stripe.body(StripedExecutor.java:565)
at o.a.i.i.util.worker.GridWorker.run(GridWorker.java:120)
at java.lang.Thread.run(Thread.java:748)
Here we can see that lock is owned by "exchange-worker-#71%App%" which seems to be struck. In few cases we have seen that lock has no owner specific:
Thread [name="sys-stripe-2-#3%App%", id=43, state=WAITING, blockCnt=39097, waitCnt=394328]
Lock [object=java.util.concurrent.locks.ReentrantReadWriteLock$NonfairSync@667500d1, ownerName=null, ownerId=-1]
at sun.misc.Unsafe.park(Native Method)
at java.util.concurrent.locks.LockSupport.park(LockSupport.java:175)
at java.util.concurrent.locks.AbstractQueuedSynchronizer.parkAndCheckInterrupt(AbstractQueuedSynchronizer.java:836)
at java.util.concurrent.locks.AbstractQueuedSynchronizer.doAcquireShared(AbstractQueuedSynchronizer.java:967)
at java.util.concurrent.locks.AbstractQueuedSynchronizer.acquireShared(AbstractQueuedSynchronizer.java:1283)
at java.util.concurrent.locks.ReentrantReadWriteLock$ReadLock.lock(ReentrantReadWriteLock.java:727)
at o.a.i.i.processors.cache.persistence.GridCacheDatabaseSharedManager.checkpointReadLock(GridCacheDatabaseSharedManager.java:1663)
Continuos query runs on server nodes which are our data nodes and we do not expect data nodes to be impacted by client nodes like getting locked. Can someone advice on how we can avoid such locks given that nodes can have unclean shutdowns?
