[RATIS-1778] Fix NPE in ReadIndexHeartbeats

• Type: Sub-task
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 3.0.0, 2.5.0
• Component/s: Linearizable Read, server
• Assignee: Yaolong Liu
• Reporter: Yaolong Liu
• Created: 01/Feb/23 03:53
• Updated: 04/Aug/23 18:37
• Resolved: 01/Feb/23 13:19

Description

When a raft node fails to start, NPE will appear, and the error stack is as follows:

GrpcLogAppender - Failed onNext request=AppendEntriesRequest:cid=302,entriesCount=0,lastEntry=null, reply=VM-212-21-centos_19201<-VM-212-21-centos_19200#302:OK-t230,SUCCESS,nextIndex=76347,followerCommit=76346,matchIndex=-1
java.lang.NullPointerException
	at org.apache.ratis.server.impl.ReadIndexHeartbeats$AppendEntriesListener.lambda$receive$1(ReadIndexHeartbeats.java:104)
	at org.apache.ratis.server.impl.LeaderStateImpl.hasMajority(LeaderStateImpl.java:841)
	at org.apache.ratis.server.impl.LeaderStateImpl.hasMajority(LeaderStateImpl.java:822)
	at org.apache.ratis.server.impl.ReadIndexHeartbeats$AppendEntriesListener.receive(ReadIndexHeartbeats.java:104)
	at org.apache.ratis.server.impl.ReadIndexHeartbeats$AppendEntriesListeners.onAppendEntriesReply(ReadIndexHeartbeats.java:141)
	at org.apache.ratis.server.impl.ReadIndexHeartbeats.onAppendEntriesReply(ReadIndexHeartbeats.java:167)
	at org.apache.ratis.server.impl.LeaderStateImpl.onAppendEntriesReply(LeaderStateImpl.java:1122)
	at org.apache.ratis.grpc.server.GrpcLogAppender$AppendLogResponseHandler.onNextImpl(GrpcLogAppender.java:395)
	at org.apache.ratis.grpc.server.GrpcLogAppender$AppendLogResponseHandler.onNext(GrpcLogAppender.java:359)
	at org.apache.ratis.grpc.server.GrpcLogAppender$AppendLogResponseHandler.onNext(GrpcLogAppender.java:334)
	at org.apache.ratis.thirdparty.io.grpc.stub.ClientCalls$StreamObserverToCallListenerAdapter.onMessage(ClientCalls.java:474)
	at org.apache.ratis.thirdparty.io.grpc.internal.DelayedClientCall$DelayedListener.onMessage(DelayedClientCall.java:452)
	at org.apache.ratis.thirdparty.io.grpc.internal.ClientCallImpl$ClientStreamListenerImpl$1MessagesAvailable.runInternal(ClientCallImpl.java:661)
	at org.apache.ratis.thirdparty.io.grpc.internal.ClientCallImpl$ClientStreamListenerImpl$1MessagesAvailable.runInContext(ClientCallImpl.java:646)
	at org.apache.ratis.thirdparty.io.grpc.internal.ContextRunnable.run(ContextRunnable.java:37)
	at org.apache.ratis.thirdparty.io.grpc.internal.SerializingExecutor.run(SerializingExecutor.java:133)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
	at java.lang.Thread.run(Thread.java:750)

Issue Links

• links to: GitHub Pull Request #817
• links to: GitHub Pull Request #818
• links to: GitHub Pull Request #819