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https://issues.apache.org/jira/browse/KAFKA-7104?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16525759#comment-16525759
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ASF GitHub Bot commented on KAFKA-7104:
---------------------------------------
apovzner closed pull request #5302: KAFKA-7104: Handle leader's log start
offset beyond last fetched offset
URL: https://github.com/apache/kafka/pull/5302
This is a PR merged from a forked repository.
As GitHub hides the original diff on merge, it is displayed below for
the sake of provenance:
As this is a foreign pull request (from a fork), the diff is supplied
below (as it won't show otherwise due to GitHub magic):
diff --git a/core/src/main/scala/kafka/server/ReplicaAlterLogDirsThread.scala
b/core/src/main/scala/kafka/server/ReplicaAlterLogDirsThread.scala
index e46473b69e9..55bc384fa53 100644
--- a/core/src/main/scala/kafka/server/ReplicaAlterLogDirsThread.scala
+++ b/core/src/main/scala/kafka/server/ReplicaAlterLogDirsThread.scala
@@ -100,8 +100,9 @@ class ReplicaAlterLogDirsThread(name: String,
partition.appendRecordsToFollowerOrFutureReplica(records, isFuture = true)
val futureReplicaHighWatermark =
futureReplica.logEndOffset.messageOffset.min(partitionData.highWatermark)
+ val newLogStartOffset =
futureReplica.logEndOffset.messageOffset.min(partitionData.logStartOffset)
futureReplica.highWatermark = new
LogOffsetMetadata(futureReplicaHighWatermark)
- futureReplica.maybeIncrementLogStartOffset(partitionData.logStartOffset)
+ futureReplica.maybeIncrementLogStartOffset(newLogStartOffset)
if (partition.maybeReplaceCurrentWithFutureReplica())
removePartitions(Set(topicPartition))
diff --git a/core/src/main/scala/kafka/server/ReplicaFetcherThread.scala
b/core/src/main/scala/kafka/server/ReplicaFetcherThread.scala
index ce6e350d0bd..eb906c1f133 100644
--- a/core/src/main/scala/kafka/server/ReplicaFetcherThread.scala
+++ b/core/src/main/scala/kafka/server/ReplicaFetcherThread.scala
@@ -118,12 +118,15 @@ class ReplicaFetcherThread(name: String,
trace("Follower has replica log end offset %d after appending %d bytes
of messages for partition %s"
.format(replica.logEndOffset.messageOffset, records.sizeInBytes,
topicPartition))
val followerHighWatermark =
replica.logEndOffset.messageOffset.min(partitionData.highWatermark)
- val leaderLogStartOffset = partitionData.logStartOffset
+ // the fetch response from the leader may contain log start offset beyond
end offset of the
+ // fetched records, because log start offset may change on the leader
while the fetch
+ // response is being built. We don't move log start offset beyond LEO on
the follower,
+ val newLogStartOffset =
replica.logEndOffset.messageOffset.min(partitionData.logStartOffset)
// for the follower replica, we do not need to keep
// its segment base offset the physical position,
// these values will be computed upon making the leader
replica.highWatermark = new LogOffsetMetadata(followerHighWatermark)
- replica.maybeIncrementLogStartOffset(leaderLogStartOffset)
+ replica.maybeIncrementLogStartOffset(newLogStartOffset)
if (isTraceEnabled)
trace(s"Follower set replica high watermark for partition
$topicPartition to $followerHighWatermark")
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> ReplicaFetcher thread may die because of inconsistent log start offset in
> fetch response
> ----------------------------------------------------------------------------------------
>
> Key: KAFKA-7104
> URL: https://issues.apache.org/jira/browse/KAFKA-7104
> Project: Kafka
> Issue Type: Bug
> Affects Versions: 1.0.0, 1.1.0
> Reporter: Anna Povzner
> Assignee: Anna Povzner
> Priority: Major
>
> What we saw:
> The follower fetches offset 116617, which it was able successfully append.
> However, leader's log start offset in fetch request was 116753, which was
> higher than fetched offset 116617. When replica fetcher thread tried to
> increment log start offset to leader's log start offset, it failed with
> OffsetOutOfRangeException:
> [2018-06-23 00:45:37,409] ERROR Error due to
> (kafka.server.ReplicaFetcherThread)
> kafka.common.KafkaException: Error processing data for partition X-N offset
> 116617
> Caused by: org.apache.kafka.common.errors.OffsetOutOfRangeException: Cannot
> increment the log start offset to 116753 of partition X-N since it is larger
> than the high watermark 116619
>
> In leader's log, we see that log start offset was incremented almost at the
> same time (within one 100 ms or so).
> [2018-06-23 00:45:37,339] INFO Incrementing log start offset of partition X-N
> to 116753
>
> In leader's logic: ReplicaManager#ReplicaManager first calls
> readFromLocalLog() that reads from local log and returns LogReadResult that
> contains fetched data and leader's log start offset and HW. However, it then
> calls ReplicaManager#updateFollowerLogReadResults() which may move leader's
> log start offset and update leader's log start offset and HW in fetch
> response. If deleteRecords() happens in between, it is possible that log
> start offset may move beyond fetched offset. Or possibly, the leader moves
> log start offset because of deleting old log segments. Basically, the issue
> is that log start offset can move between records are read from the log and
> LogReadResult is updated with new log start offset. As a result, fetch
> response may contain fetched data but leader's log start offset in the
> response could be set beyond fetched offset (and indicate the state on leader
> that fetched data does not actually exist anymore on leader).
> When a follower receives such fetch response, it will first append, then move
> it's HW no further than its LEO, which maybe less than leader's log start
> offset in fetch response, and then call
> `replica.maybeIncrementLogStartOffset(leaderLogStartOffset)` which will throw
> OffsetOutOfRangeException exception causing the fetcher thread to stop.
> Note that this can happen if the follower is not in ISR, otherwise the leader
> will not move its log start offsets beyond follower's HW.
>
> *Suggested fix:*
> 1) Since ReplicaFetcher bounds follower's HW to follower's LEO, we should
> also bound follower's log start offset to its LEO. In this situation, the
> follower's log start offset will be updated to LEO.
> 2) In addition to #1, we could try to make sure that leader builds fetch
> response based on the state of the log as of time of reading data from
> replica (but including moving leader's HW based on the follower's fetch).
> That could be another JIRA potentially, since the fix could be more involved.
>
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