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James Cheng edited comment on KAFKA-3955 at 12/15/17 9:45 PM: -------------------------------------------------------------- [~ijuma], I said in my comment above that: {quote} Note that it is only safe to do this if the partition is online (being lead by someone other than the affected broker). If the partition is offline and the preferred replica for it is the one with this problem, then deleting the log directory on the leader will cause https://issues.apache.org/jira/browse/KAFKA-3410 to happen (because the leader will now have no data, but followers do have data, and so follower will be ahead of leader). {quote} If this happens on the offline partition leader, then what are my options? I think that I will need to first, delete all the logs for this partition from the offline partition leader's log.dir, and then I think I will need to turn on unclean.leader.election for that topic (in order to prevent KAFKA-3410) Does that sound right? was (Author: wushujames): [~ijuma], I said in my comment that: {quote} Note that it is only safe to do this if the partition is online (being lead by someone other than the affected broker). If the partition is offline and the preferred replica for it is the one with this problem, then deleting the log directory on the leader will cause https://issues.apache.org/jira/browse/KAFKA-3410 to happen (because the leader will now have no data, but followers do have data, and so follower will be ahead of leader). {quote} If this happens on the offline partition leader, then what are my options? I think that I will need to first, delete all the logs for this partition from the offline partition leader's log.dir, and then I think I will need to turn on unclean.leader.election for that topic (in order to prevent KAFKA-3410) Does that sound right? > Kafka log recovery doesn't truncate logs on non-monotonic offsets, leading to > failed broker boot > ------------------------------------------------------------------------------------------------ > > Key: KAFKA-3955 > URL: https://issues.apache.org/jira/browse/KAFKA-3955 > Project: Kafka > Issue Type: Bug > Affects Versions: 0.10.0.0, 0.10.1.1, 0.11.0.0, 1.0.0 > Reporter: Tom Crayford > Assignee: Ismael Juma > Priority: Critical > Labels: reliability > Fix For: 1.1.0 > > > Hi, > I've found a bug impacting kafka brokers on startup after an unclean > shutdown. If a log segment is corrupt and has non-monotonic offsets (see the > appendix of this bug for a sample output from {{DumpLogSegments}}), then > {{LogSegment.recover}} throws an {{InvalidOffsetException}} error: > https://github.com/apache/kafka/blob/trunk/core/src/main/scala/kafka/log/OffsetIndex.scala#L218 > That code is called by {{LogSegment.recover}}: > https://github.com/apache/kafka/blob/trunk/core/src/main/scala/kafka/log/LogSegment.scala#L191 > Which is called in several places in {{Log.scala}}. Notably it's called four > times during recovery: > Thrice in Log.loadSegments > https://github.com/apache/kafka/blob/trunk/core/src/main/scala/kafka/log/Log.scala#L199 > https://github.com/apache/kafka/blob/trunk/core/src/main/scala/kafka/log/Log.scala#L204 > https://github.com/apache/kafka/blob/trunk/core/src/main/scala/kafka/log/Log.scala#L226 > and once in Log.recoverLog > https://github.com/apache/kafka/blob/trunk/core/src/main/scala/kafka/log/Log.scala#L268 > Of these, only the very last one has a {{catch}} for > {{InvalidOffsetException}}. When that catches the issue, it truncates the > whole log (not just this segment): > https://github.com/apache/kafka/blob/trunk/core/src/main/scala/kafka/log/Log.scala#L274 > to the start segment of the bad log segment. > However, this code can't be hit on recovery, because of the code paths in > {{loadSegments}} - they mean we'll never hit truncation here, as we always > throw this exception and that goes all the way to the toplevel exception > handler and crashes the JVM. > As {{Log.recoverLog}} is always called during recovery, I *think* a fix for > this is to move this crash recovery/truncate code inside a new method in > {{Log.scala}}, and call that instead of {{LogSegment.recover}} in each place. > That code should return the number of {{truncatedBytes}} like we do in > {{Log.recoverLog}} and then truncate the log. The callers will have to be > notified "stop iterating over files in the directory", likely via a return > value of {{truncatedBytes}} like {{Log.recoverLog` does right now. > I'm happy working on a patch for this. I'm aware this recovery code is tricky > and important to get right. > I'm also curious (and currently don't have good theories as of yet) as to how > this log segment got into this state with non-monotonic offsets. This segment > is using gzip compression, and is under 0.9.0.1. The same bug with respect to > recovery exists in trunk, but I'm unsure if the new handling around > compressed messages (KIP-31) means the bug where non-monotonic offsets get > appended is still present in trunk. > As a production workaround, one can manually truncate that log folder > yourself (delete all .index/.log files including and after the one with the > bad offset). However, kafka should (and can) handle this case well - with > replication we can truncate in broker startup. > stacktrace and error message: > {code} > pri=WARN t=pool-3-thread-4 at=Log Found a corrupted index file, > /$DIRECTORY/$TOPIC-22/00000000000014306536.index, deleting and rebuilding > index... > pri=ERROR t=main at=LogManager There was an error in one of the threads > during logs loading: kafka.common.InvalidOffsetException: Attempt to append > an offset (15000337) to position 111719 no larger than the last offset > appended (15000337) to /$DIRECTORY/$TOPIC-8/00000000000014008931.index. > pri=FATAL t=main at=KafkaServer Fatal error during KafkaServer startup. > Prepare to shutdown kafka.common.InvalidOffsetException: Attempt to append an > offset (15000337) to position 111719 no larger than the last offset appended > (15000337) to /$DIRECTORY/$TOPIC-8/00000000000014008931.index. > at > kafka.log.OffsetIndex$$anonfun$append$1.apply$mcV$sp(OffsetIndex.scala:207) > at > kafka.log.OffsetIndex$$anonfun$append$1.apply(OffsetIndex.scala:197) > at > kafka.log.OffsetIndex$$anonfun$append$1.apply(OffsetIndex.scala:197) > at kafka.utils.CoreUtils$.inLock(CoreUtils.scala:262) > at kafka.log.OffsetIndex.append(OffsetIndex.scala:197) > at kafka.log.LogSegment.recover(LogSegment.scala:188) > at kafka.log.Log$$anonfun$loadSegments$4.apply(Log.scala:188) > at kafka.log.Log$$anonfun$loadSegments$4.apply(Log.scala:160) > at scala.collection.TraversableLike$With... > ...Filter$$anonfun$foreach$1.apply(TraversableLike.scala:778) > at > scala.collection.IndexedSeqOptimized$class.foreach(IndexedSeqOptimized.scala:33) > at scala.collection.mutable.ArrayOps$ofRef.foreach(ArrayOps.scala:186) > at > scala.collection.TraversableLike$WithFilter.foreach(TraversableLike.scala:777) > at kafka.log.Log.loadSegments(Log.scala:160) > at kafka.log.Log.<init>(Log.scala:90) > at > kafka.log.LogManager$$anonfun$loadLogs$2$$anonfun$3$$anonfun$apply$10$$anonfun$apply$1.apply$mcV$sp(LogManager.scala:150) > at kafka.utils.CoreUtils$$anon$1.run(CoreUtils.scala:60) > at > java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) > at java.util.concurrent.FutureTask.run(FutureTask.java:266) > at > java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) > at > java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) > at java.lang.Thread.run(Thread.java:745) > {code} > non-monotonic offsets from DumpLogSegments tool (with --deep-iteration) (they > go from 15000362 to 15000337): > {code} > offset: 15000361 position: 485145166 isvalid: true payloadsize: 1474 > magic: 0 compresscodec: NoCompressionCodec crc: 3958745838 keysize: 36 > offset: 15000362 position: 485145166 isvalid: true payloadsize: 1474 > magic: 0 compresscodec: NoCompressionCodec crc: 374463118 keysize: 36 > offset: 15000337 position: 485149591 isvalid: true payloadsize: 1474 > magic: 0 compresscodec: NoCompressionCodec crc: 3955938191 keysize: 36 > offset: 15000338 position: 485149591 isvalid: true payloadsize: 1474 > magic: 0 compresscodec: NoCompressionCodec crc: 4121377803 keysize: 36 > offset: 15000339 position: 485149591 isvalid: true payloadsize: 1474 > magic: 0 compresscodec: NoCompressionCodec crc: 372883992 keysize: 36 > offset: 15000340 position: 485149591 isvalid: true payloadsize: 1474 > magic: 0 compresscodec: NoCompressionCodec crc: 1294476491 keysize: 36 > {code} -- This message was sent by Atlassian JIRA (v6.4.14#64029)