Release Notes - Kafka - Version 2.4.1

Below is a summary of the JIRA issues addressed in the 2.4.1 release of Kafka. For full documentation of the release, a guide to get started, and information about the project, see the Kafka project site.

Note about upgrades: Please carefully review the upgrade documentation for this release thoroughly before upgrading your cluster. The upgrade notes discuss any critical information about incompatibilities and breaking changes, performance changes, and any other changes that might impact your production deployment of Kafka.

The documentation for the most recent release can be found at https://kafka.apache.org/documentation.html.

Improvement

• [KAFKA-7052] - ExtractField SMT throws NPE - needs clearer error message
• [KAFKA-9011] - Add KStream#flatTransform and KStream#flatTransformValues to Scala API
• [KAFKA-9515] - Upgrade ZooKeeper to 3.5.7

Bug

• [KAFKA-6266] - Kafka 1.0.0 : Repeated occurrence of WARN Resetting first dirty offset of __consumer_offsets-xx to log start offset 203569 since the checkpointed offset 120955 is invalid. (kafka.log.LogCleanerManager$)
• [KAFKA-8025] - Flaky Test RocksDBGenericOptionsToDbOptionsColumnFamilyOptionsAdapterTest#shouldForwardAllDbOptionsCalls
• [KAFKA-8705] - NullPointerException was thrown by topology optimization when two MergeNodes have common KeyChaingingNode
• [KAFKA-8764] - LogCleanerManager endless loop while compacting/cleaning segments
• [KAFKA-8933] - An unhandled SSL handshake exception in polling event - needed a retry logic
• [KAFKA-9024] - org.apache.kafka.connect.transforms.ValueToKey throws NPE
• [KAFKA-9051] - Source task source offset reads can block graceful shutdown
• [KAFKA-9065] - Loading offsets and group metadata loops forever
• [KAFKA-9068] - Fix incorrect JavaDocs for `Stores.xxxSessionStore(...)`
• [KAFKA-9074] - Connect's Values class does not parse time or timestamp values from string literals
• [KAFKA-9083] - Various parsing issues in Values class
• [KAFKA-9143] - DistributedHerder misleadingly log error on connector task reconfiguration
• [KAFKA-9144] - Early expiration of producer state can cause coordinator epoch to regress
• [KAFKA-9192] - NullPointerException if field in schema not present in value
• [KAFKA-9204] - ReplaceField transformation fails when encountering tombstone event
• [KAFKA-9232] - Coordinator new member heartbeat completion does not work for JoinGroup v3
• [KAFKA-9235] - Transaction state not cleaned up following StopReplica request
• [KAFKA-9254] - Updating Kafka Broker configuration dynamically twice reverts log configuration to default
• [KAFKA-9293] - NPE in DumpLogSegments with --offsets-decoder
• [KAFKA-9306] - Kafka Consumer does not clean up all metrics after shutdown
• [KAFKA-9307] - Transaction coordinator could be left in unknown state after ZK session timeout
• [KAFKA-9310] - StreamThread may die from recoverable UnknownProducerId exception
• [KAFKA-9335] - java.lang.IllegalArgumentException: Number of partitions must be at least 1.
• [KAFKA-9390] - Non-key joining of KTable not compatible with confluent avro serdes
• [KAFKA-9449] - Producer's BufferPool may block the producer from closing.
• [KAFKA-9491] - Fast election during reassignment can lead to replica fetcher failures
• [KAFKA-9492] - ProducerResponse with record-level errors throw NPE with older client version
• [KAFKA-9500] - Foreign-Key Join creates an invalid topology
• [KAFKA-9503] - TopologyTestDriver processes intermediate results in the wrong order
• [KAFKA-9507] - AdminClient should check for missing committed offsets
• [KAFKA-9517] - KTable Joins Without Materialized Argument Yield Results That Further Joins NPE On
• [KAFKA-9535] - Metadata not updated when consumer encounters FENCED_LEADER_EPOCH
• [KAFKA-9540] - Application getting "Could not find the standby task 0_4 while closing it" error
• [KAFKA-9599] - create unique sensor to record group rebalance
• [KAFKA-9601] - Workers log raw connector configs, including values