KAFKA-20310: Persist previousProducerId and nextProducerId in transaction log#21828
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haltandcatchwater wants to merge 1 commit intoapache:trunkfrom
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KAFKA-20310: Persist previousProducerId and nextProducerId in transaction log#21828haltandcatchwater wants to merge 1 commit intoapache:trunkfrom
haltandcatchwater wants to merge 1 commit intoapache:trunkfrom
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…tion log valueToBytes() was not setting PreviousProducerId or NextProducerId on the TransactionLogValue, causing these fields to reset to -1 (NO_PRODUCER_ID) after coordinator failover. The read path correctly deserializes both fields, so after a failover the transaction metadata loses track of which producer IDs were involved in epoch rotation. This causes two failure modes: - Coordinator failover during epoch exhaustion leaves the producer stuck at the exhausted epoch with no recovery path. - Client retry after epoch rotation gets PRODUCER_FENCED because the previous producer ID no longer matches. The fix sets both fields in valueToBytes, guarded by logValueVersion >= 1 since they are tagged fields only available in the flexible version.
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Summary
TransactionLog.valueToBytes()does not setPreviousProducerIdorNextProducerIdon theTransactionLogValuewhen serializing transaction metadata. Both fields exist in the schema (tagged fields at version 1+, tags 0 and 1) and are correctly read back byreadTxnRecord(), but because they are never written, they always deserialize as-1(NO_PRODUCER_ID) after coordinator failover.Impact
This causes two failure modes described in KAFKA-20310:
Coordinator failover during epoch exhaustion:
nextProducerIdis lost, soprepareComplete()cannot rotate to the new producer ID. The producer is stuck at the exhausted epoch with no recovery path.Client retry after epoch rotation failover:
prevProducerIdis lost, so the validation checkprevProducerId == expectedProducerIdfails. The client receivesPRODUCER_FENCED.Fix
Set both fields in
valueToBytes(), guarded bylogValueVersion >= 1since they are tagged fields only available in the flexible version (1+). At version 0, the fields are not set, preserving backward compatibility.Compatibility
These are tagged fields (tags 0 and 1) in the
TransactionLogValueschema. Tagged fields are forward/backward compatible by design:-1), which is the existing behavior.NextProducerEpoch(tag 3) was intentionally left out of this fix because the read path currently hardcodesRecordBatch.NO_PRODUCER_EPOCHrather than reading the field, making it a separate behavioral discussion.Tests
Two new tests added to
TransactionLogTest:shouldRoundTripPreviousAndNextProducerIds— verifies both fields survive serialization at version 1+shouldNotPersistProducerIdsAtVersion0— verifies version 0 serialization is unchanged (fields default toNO_PRODUCER_ID)All 16 existing tests continue to pass.