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https://issues.apache.org/jira/browse/KAFKA-19200?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Gaurav Narula reassigned KAFKA-19200:
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Assignee: Gaurav Narula
> Indexes should be sanity checked on startup
> -------------------------------------------
>
> Key: KAFKA-19200
> URL: https://issues.apache.org/jira/browse/KAFKA-19200
> Project: Kafka
> Issue Type: Bug
> Affects Versions: 3.9.0, 4.0.0
> Reporter: Gaurav Narula
> Assignee: Gaurav Narula
> Priority: Major
>
> KAFKA-7283 removed sanity checks for indexes on broker startup as we
> thought it doesn't add much benefit. It turns out that log segment
> corruption may be independent of an index corruption.
> An index corruption when not caught early is quite tricky to debug. We
> observed the following in production:
> A corruption lead to a timeindex file on disk to be mostly filled with {{0}}s
> at the end. This file is then loaded in memory such that
> {{DirectByteBuffer}}'s {{position=limit=10485756}}. Note that this is 4 bytes
> short of 10MiB, the configured max index size.
> At this point, the log segment is eligible to be rolled as
> {{TimeIndex#isFull}} will return {{true}}. We observe that the roll is
> attempted from 2 code paths:
> 1. ReplicaFetcherThread attempts to roll the log segment as it tries to
> append records
> 2. LogCleanerThread attempts to roll the log segment as it tries to clean
> segments that breach retentionMs
> In both scenarios, {{LogSegment#onBecomeInactiveSegment}} is invoked which in
> turn invokes {{TimeIndex#maybeAppend(long timestamp, long offset, boolean
> skipFullCheck)}} with {{skipFullCheck=true}}, causing an append to an already
> full TimeIndex which fails by throwing a {{BufferOverException}}.
> For (1), the exception causes the partition to be marked as failed, thereby
> causing an under-replicated partition. For (2), the LogCleanerThread shuts
> down, potentially causing a leak as other segments which are eligible for
> cleanup aren't cleaned up.
> We should therefore reintroduce sanity checks on startup for indexes in
> {{LogSegment#sanityCheck}}, as that is invoked regardless of an unclean
> shutdown and it attempts to re-create the indexes if corruption is diagnosed.
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