Blocked system-critical thread has been detected - ignite

Question

I'm using Ignite.NET 2.7.6. There is a configuration from one server and about 40 clients. After 8 hours of work, the server starts behaving strangely: clients cannot connect it, some queries have no result, etc.
On the server's side, the memory consumption is ok, the amount of threads is about 250 and all looks ok. I don't see any problems, so I decided to solve all the problems on the server's side that were marked as SEVERE.
The first one I encounter is:
Blocked system-critical thread has been detected. This can lead to cluster-wide undefined behaviour [threadName=tcp-comm-worker, blockedFor=13s]
So I want to understand the reason this happens.
Full server's log can be found here:
https://yadi.sk/d/LF03Vz5vz4tRcw
https://yadi.sk/d/MMe0xrgI3k6lkA
Added:
The issue doesn't seem to be innocuous, this message appears every second from various threads, the "blockedFor" value is increasing from seconds to hours.
The load on the server is low but as the servers' threads become locked, it stops responding and registering new clients.
Here are logs from the server:
https://yadi.sk/d/tc3g2hb9B0jtvg
https://yadi.sk/d/05YrlYXcp4xPqg
This is the log from one client:
https://yadi.sk/d/bcbQ7ee4PUzq2w
The client's log's last lines are at 19:03:52, when the server was restarted.

Answer 1

I see the following .NET specific exception among the others but it should be triggered by another issue. Anyway, this one is reported to the community.
class org.apache.ignite.IgniteException: Platform error:System.NullReferenceException: Ññûëêà íà îáúåêò íå óêàçûâàåò íà ýêçåìïëÿð îáúåêòà.
â Apache.Ignite.Core.Impl.Unmanaged.UnmanagedCallbacks.CacheEntryFilterApply(Int64 memPtr)
â Apache.Ignite.Core.Impl.Unmanaged.UnmanagedCallbacks.InLongOutLong(Int32 type, Int64 val)
at org.apache.ignite.internal.processors.platform.PlatformProcessorImpl.loggerLog(PlatformProcessorImpl.java:404)
at org.apache.ignite.internal.processors.platform.PlatformProcessorImpl.processInStreamOutLong(PlatformProcessorImpl.java:460)
at org.apache.ignite.internal.processors.platform.PlatformProcessorImpl.processInStreamOutLong(PlatformProcessorImpl.java:512)
at org.apache.ignite.internal.processors.platform.PlatformTargetProxyImpl.inStreamOutLong(PlatformTargetProxyImpl.java:67)
at org.apache.ignite.internal.processors.platform.callback.PlatformCallbackUtils.inLongOutLong(Native Method)
at org.apache.ignite.internal.processors.platform.callback.PlatformCallbackGateway.cacheEntryFilterApply(PlatformCallbackGateway.java:143)
at org.apache.ignite.internal.processors.platform.cache.PlatformCacheEntryFilterImpl.apply(PlatformCacheEntryFilterImpl.java:70)
at org.apache.ignite.internal.processors.cache.query.GridCacheQueryManager$InternalScanFilter.apply(GridCacheQueryManager.java:3139)
The very first exceptions are related to the communication issues at the networking level. See below:
java.io.IOException: Óäàëåííûé õîñò ïðèíóäèòåëüíî ðàçîðâàë ñóùåñòâóþùåå ïîäêëþ÷åíèå
at sun.nio.ch.SocketDispatcher.read0(Native Method)
at sun.nio.ch.SocketDispatcher.read(Unknown Source)
at sun.nio.ch.IOUtil.readIntoNativeBuffer(Unknown Source)
at sun.nio.ch.IOUtil.read(Unknown Source)
at sun.nio.ch.SocketChannelImpl.read(Unknown Source)
at org.apache.ignite.internal.util.nio.GridNioServer$DirectNioClientWorker.processRead(GridNioServer.java:1282)
at org.apache.ignite.internal.util.nio.GridNioServer$AbstractNioClientWorker.processSelectedKeysOptimized(GridNioServer.java:2386)
at org.apache.ignite.internal.util.nio.GridNioServer$AbstractNioClientWorker.bodyInternal(GridNioServer.java:2153)
at org.apache.ignite.internal.util.nio.GridNioServer$AbstractNioClientWorker.body(GridNioServer.java:1794)
at org.apache.ignite.internal.util.worker.GridWorker.run(GridWorker.java:120)
at java.lang.Thread.run(Unknown Source)
[18:46:12,846][WARNING][grid-nio-worker-tcp-comm-0-#48][TcpCommunicationSpi] Closing NIO session because of unhandled exception [cls=class o.a.i.i.util.nio.GridNioException, msg=Óäàëåííûé õîñò ïðèíóäèòåëüíî ðàçîðâàë ñóùåñòâóþùåå ïîäêëþ÷åíèå]
[18:46:13,861][WARNING][tcp-comm-worker-#1][TcpCommunicationSpi] Connect timed out (consider increasing 'failureDetectionTimeout' configuration property) [addr=/127.0.0.1:47101, failureDetectionTimeout=10000]
[18:46:14,893][WARNING][tcp-comm-worker-#1][TcpCommunicationSpi] Connect timed out (consider increasing 'failureDetectionTimeout' configuration property) [addr=BB-SRV-DELTA/169.254.40.231:47101, failureDetectionTimeout=10000]
It looks like that either the server or some clients don't react to heartbeats or to other networking requests within 10 seconds. Check the logs of the client nodes as well. You might need to scale out your cluster adding more servers for the sake of load balancing or adjust the failureDetectionTimeou.
The Blocked system-critical thread has been detected... error message is innocuous but confusing. I've restarted the following conversation.

Answer 2

As Denis described, there are a lot of network communication issues.
In general, a client would like to perform some cache operation, but a server thread from the striped pool is blocked for a long time. I don't think it relates to the .NET part.
You can see following messages:
[18:53:04,385][SEVERE][tcp-disco-msg-worker-#2][G] Blocked system-critical thread has been detected. This can lead to cluster-wide undefined behaviour [threadName=sys-stripe-7, blockedFor=13s]
If you take a look at the thread:
hread [name="sys-stripe-7-#8", id=28, state=WAITING, blockCnt=51, waitCnt=3424]
at sun.misc.Unsafe.park(Native Method)
at java.util.concurrent.locks.LockSupport.park(Unknown Source)
at o.a.i.i.util.future.GridFutureAdapter.get0(GridFutureAdapter.java:178)
at o.a.i.i.util.future.GridFutureAdapter.get(GridFutureAdapter.java:141)
at o.a.i.spi.communication.tcp.TcpCommunicationSpi.reserveClient(TcpCommunicationSpi.java:2911)
at o.a.i.spi.communication.tcp.TcpCommunicationSpi.sendMessage0(TcpCommunicationSpi.java:2713)
at o.a.i.spi.communication.tcp.TcpCommunicationSpi.sendMessage(TcpCommunicationSpi.java:2672)
at o.a.i.i.managers.communication.GridIoManager.send(GridIoManager.java:1656)
at o.a.i.i.managers.communication.GridIoManager.sendOrderedMessage(GridIoManager.java:1879)
at o.a.i.i.processors.continuous.GridContinuousProcessor.sendWithRetries(GridContinuousProcessor.java:1904)
at o.a.i.i.processors.continuous.GridContinuousProcessor.sendWithRetries(GridContinuousProcessor.java:1875)
at o.a.i.i.processors.continuous.GridContinuousProcessor.sendWithRetries(GridContinuousProcessor.java:1857)
at o.a.i.i.processors.continuous.GridContinuousProcessor.sendNotification(GridContinuousProcessor.java:1275)
at o.a.i.i.processors.continuous.GridContinuousProcessor.addNotification(GridContinuousProcessor.java:1212)
The thread is trying to send a Continuous Query callback but is failing to establish a connection to a client node. This causes the thread to be blocked and it can not serve other cache API requests that require the same partition.
At first glance, you could try to reduce #clientFailureDetectionTimeout, default is 30sec. But this won't fix the network issues completely.