[jira] [Created] (KAFKA-17801) RemoteLogManager may compute inaccurate upperBoundOffset for aborted txns

["Jun Rao (Jira)" <ji...@apache.org>]

Jun Rao created KAFKA-17801:
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             Summary: RemoteLogManager may compute inaccurate upperBoundOffset for aborted txns
                 Key: KAFKA-17801
                 URL: https://issues.apache.org/jira/browse/KAFKA-17801
             Project: Kafka
          Issue Type: Bug
          Components: core
    Affects Versions: 3.6.0
            Reporter: Jun Rao


In RemoteLogManager.read, we compute startPos as the following.
{code:java}
startPos = lookupPositionForOffset(remoteLogSegmentMetadata, offset);{code}
This is the position returned by the offset index. The actual position for the first batch being read happens in the following, but startPos is not updated accordingly.
{code:java}
firstBatch = findFirstBatch(remoteLogInputStream, offset);{code}
We then use the inaccurate startPos to create fetchDataInfo.
{code:java}
FetchDataInfo fetchDataInfo = new FetchDataInfo(
new LogOffsetMetadata(offset, remoteLogSegmentMetadata.startOffset(), startPos),
MemoryRecords.readableRecords(buffer));{code}
In addAbortedTransactions(), we use startPos to find the upperBoundOffset to retrieve the aborted txns.
{code:java}
long upperBoundOffset = offsetIndex.fetchUpperBoundOffset(startOffsetPosition, fetchSize)
.map(position -> position.offset).orElse(segmentMetadata.endOffset() + 1);{code}
The inaccurate startPos can lead to inaccurate upperBoundOffset, which leads to inaccurate aborted txns returned to the consumer.



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