What does this stack trace indicate:
INFO [IOThread-6] 2021-02-13 19:10:03,154 RpcMethod.java:199 - Failed to execute method DseResourceManager.heartbeat
java.lang.RuntimeException: Failed to execute query
at com.datastax.bdp.router.InternalQueryRouter.withQueryExceptionsHandled(InternalQueryRouter.java:117)
at com.datastax.bdp.util.rpc.RpcMethod.execute(RpcMethod.java:173)
at com.datastax.bdp.cassandra.cql3.RpcCallStatement.execute(RpcCallStatement.java:107)
at org.apache.cassandra.cql3.QueryProcessor.lambda$processStatement$4(QueryProcessor.java:266)
at io.reactivex.internal.operators.single.SingleDefer.subscribeActual(SingleDefer.java:36)
at io.reactivex.Single.subscribe(Single.java:2700)
at org.apache.cassandra.utils.flow.RxThreads$1SubscribeOn.lambda$subscribeActual$0(RxThreads.java:50)
at org.apache.cassandra.concurrent.TPCRunnable.run(TPCRunnable.java:68)
at org.apache.cassandra.concurrent.IOScheduler$PooledTaskWorker.run(IOScheduler.java:319)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$201(ScheduledThreadPoolExecutor.java:180)
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:293)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30)
at java.lang.Thread.run(Thread.java:748)
Caused by: java.util.concurrent.ExecutionException: java.io.IOException: The channel has been terminated.
at java.util.concurrent.CompletableFuture.reportGet(CompletableFuture.java:357)
at java.util.concurrent.CompletableFuture.get(CompletableFuture.java:1928)
at com.datastax.bdp.util.rpc.RpcMethod.lambda$execute$8(RpcMethod.java:174)
at com.datastax.bdp.router.InternalQueryRouter.withQueryExceptionsHandled(InternalQueryRouter.java:94)
... 16 common frames omitted
Caused by: java.io.IOException: The channel has been terminated.
at com.datastax.bdp.node.transport.ClientServerConnection.terminatePendingRequests(ClientServerConnection.java:286)
at com.datastax.bdp.node.transport.ClientServerConnection.access$800(ClientServerConnection.java:60)
at com.datastax.bdp.node.transport.ClientServerConnection$ChannelStateHandler.channelInactive(ClientServerConnection.java:367)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelInactive(AbstractChannelHandlerContext.java:245)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelInactive(AbstractChannelHandlerContext.java:231)
at io.netty.channel.AbstractChannelHandlerContext.fireChannelInactive(AbstractChannelHandlerContext.java:224)
at io.netty.channel.DefaultChannelPipeline$HeadContext.channelInactive(DefaultChannelPipeline.java:1429)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelInactive(AbstractChannelHandlerContext.java:245)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelInactive(AbstractChannelHandlerContext.java:231)
at io.netty.channel.DefaultChannelPipeline.fireChannelInactive(DefaultChannelPipeline.java:947)
at io.netty.channel.AbstractChannel$AbstractUnsafe$8.run(AbstractChannel.java:839)
at io.netty.util.concurrent.AbstractEventExecutor.safeExecute(AbstractEventExecutor.java:163)
at io.netty.util.concurrent.SingleThreadEventExecutor.runAllTasks(SingleThreadEventExecutor.java:404)
at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:465)
at io.netty.util.concurrent.SingleThreadEventExecutor$5.run(SingleThreadEventExecutor.java:884)
... 2 common frames omitted
