[
https://issues.apache.org/jira/browse/KAFKA-17803?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Kevin Wu updated KAFKA-17803:
-----------------------------
Description:
Calling MockLog or KafkaMetadataLog's read method for a given startOffset
returns a LogOffsetMetadata object that contains an offset field. In the case
of MockLog, this offset field is the base offset of the record batch which
contains startOffset.
However, in KafkaMetadataLog, this offset field is set to the given
startOffset. If the given startOffset is in the middle of a batch, the returned
LogOffsetMetadata will have an offset that does not match the file position of
the returned batch. This makes the javadoc for LogSegment#read inaccurate in
this case since startOffset is not a lower bound (the base offset of the batch
containing startOffset is the lower bound).
The discussed approach was to change the UnifiedLog and LogSegment
implementation to return the offset at the start of the batch since that is the
offset that is located at the byte start position of the batch. This way
KafkaMetadataLog#read semantics match MockLog#read.
was:
Calling MockLog or KafkaMetadataLog's read method for a given startOffset
returns a LogOffsetMetadata object that contains an offset field. In the case
of MockLog, this offset field is the base offset of the record batch which
contains startOffset.
However, in KafkaMetadataLog, this offset field is set to the given
startOffset. If the given startOffset is in the middle of a batch, the returned
LogOffsetMetadata will have an offset that does not match the file position of
the returned batch. This makes the javadoc for LogSegment#read inaccurate in
this case since startOffset is not a lower bound (the base offset of the batch
containing startOffset is the lower bound).
The discussed approach was to change MockLog to behave the same way as
KafkaMetadataLog, since this would be safer than changing the semantics of the
read call in UnifiedLog.
> Reconcile Differences in MockLog and KafkaMetadataLog `read` Implementation
> ---------------------------------------------------------------------------
>
> Key: KAFKA-17803
> URL: https://issues.apache.org/jira/browse/KAFKA-17803
> Project: Kafka
> Issue Type: Improvement
> Reporter: Kevin Wu
> Assignee: Kevin Wu
> Priority: Major
>
> Calling MockLog or KafkaMetadataLog's read method for a given startOffset
> returns a LogOffsetMetadata object that contains an offset field. In the case
> of MockLog, this offset field is the base offset of the record batch which
> contains startOffset.
> However, in KafkaMetadataLog, this offset field is set to the given
> startOffset. If the given startOffset is in the middle of a batch, the
> returned LogOffsetMetadata will have an offset that does not match the file
> position of the returned batch. This makes the javadoc for LogSegment#read
> inaccurate in this case since startOffset is not a lower bound (the base
> offset of the batch containing startOffset is the lower bound).
> The discussed approach was to change the UnifiedLog and LogSegment
> implementation to return the offset at the start of the batch since that is
> the offset that is located at the byte start position of the batch. This way
> KafkaMetadataLog#read semantics match MockLog#read.
>
--
This message was sent by Atlassian Jira
(v8.20.10#820010)
