[
https://issues.apache.org/jira/browse/RATIS-1674?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17610759#comment-17610759
]
Song Ziyang commented on RATIS-1674:
------------------------------------
After changes, cluster still met OutOfDirectMemoryError. However, this time
there were no inconsistent AppendEntries (a great step!).
I checked recent issues in gRPC community, and discovered a new memory leak
issue: [https://github.com/grpc/grpc-java/issues/9563] . It looks like the leak
related to retry mechanism is not fully fixed. gRPC community provides a
workaround by disabling retry. I added .disableRetry() to AppendEntries channel
in
[https://github.com/apache/ratis/blob/c4448bfb3ec2032475cc105a19caa60c4d244632/ratis-grpc/src/main/java/org/apache/ratis/grpc/server/GrpcServerProtocolClient.java#L105]
and tested again. This time, the OutOfDirectMemoryError didn't appear! We can
conclude.
# minWaitTime can fix inconsistent AppendEntries without big impacts on
throughput & latency.
# OOM is caused by gRPC and we can wait for its update.
BTW, retry is enabled by default, maybe we can disable retry for appendEntries
by default, since it is already a timely-scheduled task?
> Frequent inconsistency entries during normal operations
> -------------------------------------------------------
>
> Key: RATIS-1674
> URL: https://issues.apache.org/jira/browse/RATIS-1674
> Project: Ratis
> Issue Type: Bug
> Reporter: Song Ziyang
> Priority: Major
> Attachments: RATIS-1674_idea.patch, RATIS-1674_idea2.patch,
> ratis-waitMin-experiment.pdf
>
>
> *After grpc 1.48.1 release, we packaged ratis with master branch and
> thirdparty 1.0.2 and test whether out of direct memory issue is fixed.
> Unfortunately, this error is again reproduced.*
> *See the error stack:*
> 2022-08-16 15:28:45,962
> [172.20.70.24_40010@group-000100000001->172.20.70.23_40010-GrpcLogAppender-LogAppenderDaemon]
> ERROR o.a.r.s.l.LogAppenderDaemon:86 -
> 172.20.70.24_40010@group-000100000001->172.20.70.23_40010-GrpcLogAppender-LogAppenderDaemon
> failed
> org.apache.ratis.thirdparty.io.netty.util.internal.OutOfDirectMemoryError:
> failed to allocate 2097152 byte(s) of direct memory (used: 17177772311, max:
> 17179869184)
> at
> org.apache.ratis.thirdparty.io.netty.util.internal.PlatformDependent.incrementMemoryCounter(PlatformDependent.java:806)
> at
> org.apache.ratis.thirdparty.io.netty.util.internal.PlatformDependent.allocateDirectNoCleaner(PlatformDependent.java:735)
> at
> org.apache.ratis.thirdparty.io.netty.buffer.PoolArena$DirectArena.allocateDirect(PoolArena.java:649)
> at
> org.apache.ratis.thirdparty.io.netty.buffer.PoolArena$DirectArena.newChunk(PoolArena.java:624)
> at
> org.apache.ratis.thirdparty.io.netty.buffer.PoolArena.allocateNormal(PoolArena.java:203)
> at
> org.apache.ratis.thirdparty.io.netty.buffer.PoolArena.tcacheAllocateNormal(PoolArena.java:187)
> at
> org.apache.ratis.thirdparty.io.netty.buffer.PoolArena.allocate(PoolArena.java:136)
> at
> org.apache.ratis.thirdparty.io.netty.buffer.PoolArena.allocate(PoolArena.java:126)
> at
> org.apache.ratis.thirdparty.io.netty.buffer.PooledByteBufAllocator.newDirectBuffer(PooledByteBufAllocator.java:396)
> at
> org.apache.ratis.thirdparty.io.netty.buffer.AbstractByteBufAllocator.directBuffer(AbstractByteBufAllocator.java:188)
> at
> org.apache.ratis.thirdparty.io.netty.buffer.AbstractByteBufAllocator.buffer(AbstractByteBufAllocator.java:124)
> at
> org.apache.ratis.thirdparty.io.grpc.netty.NettyWritableBufferAllocator.allocate(NettyWritableBufferAllocator.java:51)
> at
> org.apache.ratis.thirdparty.io.grpc.internal.MessageFramer.writeRaw(MessageFramer.java:285)
> at
> org.apache.ratis.thirdparty.io.grpc.internal.MessageFramer.access$400(MessageFramer.java:43)
> at
> org.apache.ratis.thirdparty.io.grpc.internal.MessageFramer$OutputStreamAdapter.write(MessageFramer.java:375)
> at
> org.apache.ratis.thirdparty.com.google.protobuf.CodedOutputStream$OutputStreamEncoder.write(CodedOutputStream.java:3005)
> at
> org.apache.ratis.thirdparty.com.google.protobuf.CodedOutputStream$OutputStreamEncoder.writeLazy(CodedOutputStream.java:3013)
> at
> org.apache.ratis.thirdparty.com.google.protobuf.ByteString$LiteralByteString.writeTo(ByteString.java:1411)
> at
> org.apache.ratis.thirdparty.com.google.protobuf.CodedOutputStream$OutputStreamEncoder.writeBytesNoTag(CodedOutputStream.java:2801)
> at
> org.apache.ratis.thirdparty.com.google.protobuf.CodedOutputStream$OutputStreamEncoder.writeBytes(CodedOutputStream.java:2775)
> at
> org.apache.ratis.proto.RaftProtos$StateMachineLogEntryProto.writeTo(RaftProtos.java:7869)
> at
> org.apache.ratis.thirdparty.com.google.protobuf.CodedOutputStream$OutputStreamEncoder.writeMessageNoTag(CodedOutputStream.java:2855)
> at
> org.apache.ratis.thirdparty.com.google.protobuf.CodedOutputStream$OutputStreamEncoder.writeMessage(CodedOutputStream.java:2824)
> at
> org.apache.ratis.proto.RaftProtos$LogEntryProto.writeTo(RaftProtos.java:9503)
> at
> org.apache.ratis.thirdparty.com.google.protobuf.CodedOutputStream$OutputStreamEncoder.writeMessageNoTag(CodedOutputStream.java:2855)
> at
> org.apache.ratis.thirdparty.com.google.protobuf.CodedOutputStream$OutputStreamEncoder.writeMessage(CodedOutputStream.java:2824)
> at
> org.apache.ratis.proto.RaftProtos$AppendEntriesRequestProto.writeTo(RaftProtos.java:17799)
> at
> org.apache.ratis.thirdparty.com.google.protobuf.AbstractMessageLite.writeTo(AbstractMessageLite.java:83)
> at
> org.apache.ratis.thirdparty.io.grpc.protobuf.lite.ProtoInputStream.drainTo(ProtoInputStream.java:52)
> at
> org.apache.ratis.thirdparty.io.grpc.internal.MessageFramer.writeToOutputStream(MessageFramer.java:267)
> at
> org.apache.ratis.thirdparty.io.grpc.internal.MessageFramer.writeKnownLengthUncompressed(MessageFramer.java:229)
> at
> org.apache.ratis.thirdparty.io.grpc.internal.MessageFramer.writeUncompressed(MessageFramer.java:168)
> at
> org.apache.ratis.thirdparty.io.grpc.internal.MessageFramer.writePayload(MessageFramer.java:141)
> at
> org.apache.ratis.thirdparty.io.grpc.internal.AbstractStream.writeMessage(AbstractStream.java:65)
> at
> org.apache.ratis.thirdparty.io.grpc.internal.ForwardingClientStream.writeMessage(ForwardingClientStream.java:37)
> at
> org.apache.ratis.thirdparty.io.grpc.internal.RetriableStream.sendMessage(RetriableStream.java:545)
> at
> org.apache.ratis.thirdparty.io.grpc.internal.ClientCallImpl.sendMessageInternal(ClientCallImpl.java:520)
> at
> org.apache.ratis.thirdparty.io.grpc.internal.ClientCallImpl.sendMessage(ClientCallImpl.java:506)
> at
> org.apache.ratis.thirdparty.io.grpc.stub.ClientCalls$CallToStreamObserverAdapter.onNext(ClientCalls.java:374)
> at
> org.apache.ratis.grpc.server.GrpcLogAppender$StreamObservers.onNext(GrpcLogAppender.java:236)
> at
> org.apache.ratis.grpc.server.GrpcLogAppender.lambda$sendRequest$1(GrpcLogAppender.java:285)
> at java.util.Optional.map(Optional.java:215)
> at
> org.apache.ratis.grpc.server.GrpcLogAppender.sendRequest(GrpcLogAppender.java:284)
> at
> org.apache.ratis.grpc.server.GrpcLogAppender.appendLog(GrpcLogAppender.java:276)
> at
> org.apache.ratis.grpc.server.GrpcLogAppender.run(GrpcLogAppender.java:160)
> at
> org.apache.ratis.server.leader.LogAppenderDaemon.run(LogAppenderDaemon.java:77)
> at java.lang.Thread.run(Thread.java:748)
> 2022-08-16 15:28:45,963 [grpc-default-executor-2] WARN
> o.a.ratis.util.LogUtils:122 -
> 172.20.70.24_40010@group-000100000001->172.20.70.23_40010-AppendLogResponseHandler:
> Failed appendEntries:
> org.apache.ratis.thirdparty.io.grpc.StatusRuntimeException: CANCELLED: Client
> sendMessage() failed with Error
> 2022-08-16 15:28:45,963
> [172.20.70.24_40010@group-000100000001->172.20.70.23_40010-GrpcLogAppender-LogAppenderDaemon]
> INFO o.a.r.s.i.LeaderStateImpl:531 -
> 172.20.70.24_40010@group-000100000001-LeaderStateImpl: Restarting
> GrpcLogAppender for 172.20.70.24_40010@group-000100000001->172.20.70.23_40010
>
> {color:#ff0000}*However, we discover some other abnormalities.* {color}
> *That is, one follower often report that it receives inconsistent
> AppendEntries from leader as the first entry in AE already exists locally.
> After some complaining on "inconsistent appendEntry", this follower can still
> write logs to RaftLog from time to time. The "inconsistent AE" and "success
> log write" are interleaved. See follower log:*
> 2022-08-16 15:25:43,253
> [172.20.70.23_40010@group-000100000001-SegmentedRaftLogWorker] INFO
> o.a.r.s.r.s.SegmentedRaftLogWorker$StartLogSegment:629 -
> 172.20.70.23_40010@group-000100000001-SegmentedRaftLogWorker: created new log
> segment
> /data/cluster/first-rest-test/DataNode/apache-iotdb/datanode/sbin/../data/consensus/data_region/47474747-4747-4747-4747-000100000001/current/log_inprogress_1376
> 2022-08-16 15:25:43,345 [172.20.70.23_40010-server-thread2] INFO
> o.a.r.s.i.RaftServerImpl:1475 - 172.20.70.23_40010@group-000100000001: Failed
> appendEntries as the first entry (index 1283) already exists (snapshotIndex:
> -1, commitIndex: 1393)
> 2022-08-16 15:25:43,345 [172.20.70.23_40010-server-thread2] INFO
> o.a.r.s.i.RaftServerImpl:1455 - 172.20.70.23_40010@group-000100000001:
> inconsistency entries.
> Reply:172.20.70.24_40010<-172.20.70.23_40010#2960:FAIL-t1,INCONSISTENCY,nextIndex=1394,followerCommit=1393,matchIndex=-1
> 2022-08-16 15:25:43,358 [172.20.70.23_40010-server-thread2] INFO
> o.a.r.s.i.RaftServerImpl:1475 - 172.20.70.23_40010@group-000100000001: Failed
> appendEntries as the first entry (index 1287) already exists (snapshotIndex:
> -1, commitIndex: 1393)
> 2022-08-16 15:25:43,359 [172.20.70.23_40010-server-thread2] INFO
> o.a.r.s.i.RaftServerImpl:1455 - 172.20.70.23_40010@group-000100000001:
> inconsistency entries.
> Reply:172.20.70.24_40010<-172.20.70.23_40010#2961:FAIL-t1,INCONSISTENCY,nextIndex=1394,followerCommit=1393,matchIndex=-1
> 2022-08-16 15:25:43,374 [172.20.70.23_40010-server-thread2] INFO
> o.a.r.s.i.RaftServerImpl:1475 - 172.20.70.23_40010@group-000100000001: Failed
> appendEntries as the first entry (index 1290) already exists (snapshotIndex:
> -1, commitIndex: 1393)
> 2022-08-16 15:25:43,374 [172.20.70.23_40010-server-thread2] INFO
> o.a.r.s.i.RaftServerImpl:1455 - 172.20.70.23_40010@group-000100000001:
> inconsistency entries.
> Reply:172.20.70.24_40010<-172.20.70.23_40010#2962:FAIL-t1,INCONSISTENCY,nextIndex=1394,followerCommit=1393,matchIndex=-1
> 2022-08-16 15:25:43,387 [172.20.70.23_40010-server-thread2] INFO
> o.a.r.s.i.RaftServerImpl:1475 - 172.20.70.23_40010@group-000100000001: Failed
> appendEntries as the first entry (index 1294) already exists (snapshotIndex:
> -1, commitIndex: 1393)
> 2022-08-16 15:25:43,387 [172.20.70.23_40010-server-thread2] INFO
> o.a.r.s.i.RaftServerImpl:1455 - 172.20.70.23_40010@group-000100000001:
> inconsistency entries.
> Reply:172.20.70.24_40010<-172.20.70.23_40010#2963:FAIL-t1,INCONSISTENCY,nextIndex=1394,followerCommit=1393,matchIndex=-1
> 2022-08-16 15:25:43,983 [172.20.70.23_40010-server-thread2] INFO
> o.a.r.s.i.RaftServerImpl:1475 - 172.20.70.23_40010@group-000100000001: Failed
> appendEntries as the first entry (index 1297) already exists (snapshotIndex:
> -1, commitIndex: 1393)
> 2022-08-16 15:25:43,984 [172.20.70.23_40010-server-thread2] INFO
> o.a.r.s.i.RaftServerImpl:1455 - 172.20.70.23_40010@group-000100000001:
> inconsistency entries.
> Reply:172.20.70.24_40010<-172.20.70.23_40010#2964:FAIL-t1,INCONSISTENCY,nextIndex=1394,followerCommit=1393,matchIndex=-1
> {color:#0747a6}(successfully write after some inconsistency AE){color}
> {color:#0747a6}2022-08-16 15:25:44,011 [172.20.70.23_40010-server-thread2]
> INFO o.a.r.s.r.s.SegmentedRaftLogWorker:430 -
> 172.20.70.23_40010@group-000100000001-SegmentedRaftLogWorker: Rolling segment
> log-1376_1394 to index:1394{color}
> {color:#0747a6}2022-08-16 15:25:44,017
> [172.20.70.23_40010@group-000100000001-SegmentedRaftLogWorker] INFO
> o.a.r.s.r.s.SegmentedRaftLogWorker$FinalizeLogSegment:586 -
> 172.20.70.23_40010@group-000100000001-SegmentedRaftLogWorker: Rolled log
> segment from
> /data/cluster/first-rest-test/DataNode/apache-iotdb/datanode/sbin/../data/consensus/data_region/47474747-4747-4747-4747-000100000001/current/log_inprogress_1376
> to
> /data/cluster/first-rest-test/DataNode/apache-iotdb/datanode/sbin/../data/consensus/data_region/47474747-4747-4747-4747-000100000001/current/log_1376-1394{color}
> {color:#0747a6}2022-08-16 15:25:44,028
> [172.20.70.23_40010@group-000100000001-SegmentedRaftLogWorker] INFO
> o.a.r.s.r.s.SegmentedRaftLogWorker$StartLogSegment:629 -
> 172.20.70.23_40010@group-000100000001-SegmentedRaftLogWorker: created new log
> segment
> /data/cluster/first-rest-test/DataNode/apache-iotdb/datanode/sbin/../data/consensus/data_region/47474747-4747-4747-4747-000100000001/current/log_inprogress_1395{color}
> 2022-08-16 15:25:44,137 [172.20.70.23_40010-server-thread2] INFO
> o.a.r.s.i.RaftServerImpl:1475 - 172.20.70.23_40010@group-000100000001: Failed
> appendEntries as the first entry (index 1394) already exists (snapshotIndex:
> -1, commitIndex: 1395)
> 2022-08-16 15:25:44,137 [172.20.70.23_40010-server-thread2] INFO
> o.a.r.s.i.RaftServerImpl:1455 - 172.20.70.23_40010@group-000100000001:
> inconsistency entries.
> Reply:172.20.70.24_40010<-172.20.70.23_40010#2966:FAIL-t1,INCONSISTENCY,nextIndex=1396,followerCommit=1395,matchIndex=-1
> 2022-08-16 15:25:44,158 [172.20.70.23_40010-server-thread2] INFO
> o.a.r.s.i.RaftServerImpl:1475 - 172.20.70.23_40010@group-000100000001: Failed
> appendEntries as the first entry (index 1394) already exists (snapshotIndex:
> -1, commitIndex: 1395)
> 2022-08-16 15:25:44,158 [172.20.70.23_40010-server-thread2] INFO
> o.a.r.s.i.RaftServerImpl:1455 - 172.20.70.23_40010@group-000100000001:
> inconsistency entries.
> Reply:172.20.70.24_40010<-172.20.70.23_40010#2967:FAIL-t1,INCONSISTENCY,nextIndex=1396,followerCommit=1395,matchIndex=-1
> 2022-08-16 15:25:44,229 [172.20.70.23_40010-server-thread2] INFO
> o.a.r.s.r.s.SegmentedRaftLogWorker:430 -
> 172.20.70.23_40010@group-000100000001-SegmentedRaftLogWorker: Rolling segment
> log-1395_1411 to index:1411
> 2022-08-16 15:25:44,247 [172.20.70.23_40010-server-thread2] INFO
> o.a.r.s.i.RaftServerImpl:1475 - 172.20.70.23_40010@group-000100000001: Failed
> appendEntries as the first entry (index 1394) already exists (snapshotIndex:
> -1, commitIndex: 1403)
> 2022-08-16 15:25:44,248 [172.20.70.23_40010-server-thread2] INFO
> o.a.r.s.i.RaftServerImpl:1455 - 172.20.70.23_40010@group-000100000001:
> inconsistency entries.
> Reply:172.20.70.24_40010<-172.20.70.23_40010#2980:FAIL-t1,INCONSISTENCY,nextIndex=1404,followerCommit=1403,matchIndex=-1
>
> *Meanwhile, the leader keeps reporting changing this follower's nextIndex*
> 2022-08-16 15:25:43,291
> [172.20.70.24_40010@group-000100000001-SegmentedRaftLogWorker] INFO
> o.a.r.s.r.s.SegmentedRaftLogWorker$FinalizeLogSegment:586 -
> 172.20.70.24_40010@group-000100000001-SegmentedRaftLogWorker: Rolled log
> segment from
> /data/cluster/first-rest-test/DataNode/apache-iotdb/datanode/sbin/../data/consensus/data_region/47474747-4747-4747-4747-000100000001/current/log_inprogress_1430
> to
> /data/cluster/first-rest-test/DataNode/apache-iotdb/datanode/sbin/../data/consensus/data_region/47474747-4747-4747-4747-000100000001/current/log_1430-1444
> 2022-08-16 15:25:43,826
> [org.apache.ratis.util.JvmPauseMonitor$$Lambda$168/788892554@6273c5a4] WARN
> o.a.r.u.JvmPauseMonitor:124 - JvmPauseMonitor-172.20.70.24_40010: Detected
> pause in JVM or host machine (eg GC): pause of approximately 163309780ns.
> GC pool 'PS Scavenge' had collection(s): count=1 time=431ms
> 2022-08-16 15:25:43,826
> [org.apache.ratis.util.JvmPauseMonitor$$Lambda$168/788892554@756cf158] WARN
> o.a.r.u.JvmPauseMonitor:124 - JvmPauseMonitor-172.20.70.24_50010: Detected
> pause in JVM or host machine (eg GC): pause of approximately 163346070ns.
> GC pool 'PS Scavenge' had collection(s): count=1 time=431ms
> 2022-08-16 15:25:43,876 [grpc-default-executor-0] INFO
> o.a.r.s.i.FollowerInfoImpl:48 -
> 172.20.70.24_40010@group-000100000001->172.20.70.23_40010: nextIndex:
> updateUnconditionally 1299 -> 1394
> 2022-08-16 15:25:44,014 [grpc-default-executor-0] INFO
> o.a.r.s.i.FollowerInfoImpl:48 -
> 172.20.70.24_40010@group-000100000001->172.20.70.23_40010: nextIndex:
> updateUnconditionally 1396 -> 1394
> 2022-08-16 15:25:44,118 [grpc-default-executor-0] INFO
> o.a.r.s.i.FollowerInfoImpl:48 -
> 172.20.70.24_40010@group-000100000001->172.20.70.23_40010: nextIndex:
> updateUnconditionally 1396 -> 1394
> 2022-08-16 15:25:44,129 [grpc-default-executor-0] INFO
> o.a.r.s.i.FollowerInfoImpl:48 -
> 172.20.70.24_40010@group-000100000001->172.20.70.23_40010: nextIndex:
> updateUnconditionally 1422 -> 1394
> 2022-08-16 15:25:44,130 [grpc-default-executor-0] INFO
> o.a.r.s.i.FollowerInfoImpl:48 -
> 172.20.70.24_40010@group-000100000001->172.20.70.23_40010: nextIndex:
> updateUnconditionally 1396 -> 1394
> 2022-08-16 15:25:44,141 [grpc-default-executor-0] INFO
> o.a.r.s.i.FollowerInfoImpl:48 -
> 172.20.70.24_40010@group-000100000001->172.20.70.23_40010: nextIndex:
> updateUnconditionally 1418 -> 1396
> *{color:#ff0000}I looked back at previous directOOM logs and discovered this
> similar log pattern. Since these "inconsistent AppendEntries" are sent from
> leader almost with 0 waiting time (according to follower reply timestamp), I
> guess directOOM may related to continuous Leader "inconsistent
> AppendEntries", which consumes lots of direct memory for network
> transimission.{color}*
> {*}Through, I'm confused why a follower will report inconsistent from time to
> time while still can successfully append logs between these "inconsistent
> AppendEntries"{*}{*}, why leader keeps sending “inconsistent AE" with zero
> waiting time{*}{*}. There is no obvious network congestion.{*}
> *FYI, I've set RaftLog forceFlush to false. {color:#172b4d}I'm not sure
> whether this async disk flush strategy is the cause for above
> abnormalities.{color}*
> *{color:#172b4d}I'll be grateful if anyone can help me with this issue.
> Thanks in advance!{color}*
>
>
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