Francois Visconte created KAFKA-16511:
-----------------------------------------
Summary: Leaking tiered segments
Key: KAFKA-16511
URL: https://issues.apache.org/jira/browse/KAFKA-16511
Project: Kafka
Issue Type: Bug
Components: Tiered-Storage
Affects Versions: 3.7.0
Reporter: Francois Visconte
I have some topics there were not written since a few days (having 12h
retention) where some data remains on tiered storage (in our case S3) and they
are never deleted.
Looking at the log history, it appears that we never even tried to delete these
segments:
When looking at one of the non-leaking segment, I get the following interesting
messages:
```
"2024-04-02T10:30:45.265Z","""kafka""","""10039""","[RemoteLogManager=10039
partition=5G8Ai8kBSwmQ3Ln4QRY5rA:topic1_3543-764] Deleted remote log segment
RemoteLogSegmentId\{topicIdPartition=5G8Ai8kBSwmQ3Ln4QRY5rA:topic1_3543-764,
id=fqGng3UURCG3-v4lETeLKQ} due to leader-epoch-cache truncation. Current
earliest-epoch-entry: EpochEntry(epoch=8, startOffset=2980106),
segment-end-offset: 2976819 and segment-epochs: [5]"
"2024-04-02T10:30:45.242Z","""kafka""","""10039""","Deleting log segment data
for completed successfully
RemoteLogSegmentMetadata\{remoteLogSegmentId=RemoteLogSegmentId{topicIdPartition=5G8Ai8kBSwmQ3Ln4QRY5rA:topic1_3543-764,
id=fqGng3UURCG3-v4lETeLKQ}, startOffset=2968418, endOffset=2976819,
brokerId=10029, maxTimestampMs=1712009754536, eventTimestampMs=1712013411147,
segmentLeaderEpochs=\{5=2968418}, segmentSizeInBytes=536351075,
customMetadata=Optional.empty, state=COPY_SEGMENT_FINISHED}"
"2024-04-02T10:30:45.144Z","""kafka""","""10039""","Deleting log segment data
for
RemoteLogSegmentMetadata\{remoteLogSegmentId=RemoteLogSegmentId{topicIdPartition=5G8Ai8kBSwmQ3Ln4QRY5rA:topic1_3543-764,
id=fqGng3UURCG3-v4lETeLKQ}, startOffset=2968418, endOffset=2976819,
brokerId=10029, maxTimestampMs=1712009754536, eventTimestampMs=1712013411147,
segmentLeaderEpochs=\{5=2968418}, segmentSizeInBytes=536351075,
customMetadata=Optional.empty, state=COPY_SEGMENT_FINISHED}"
"2024-04-01T23:16:51.157Z","""kafka""","""10029""","[RemoteLogManager=10029
partition=5G8Ai8kBSwmQ3Ln4QRY5rA:topic1_3543-764] Copied
00000000000002968418.log to remote storage with segment-id:
RemoteLogSegmentId\{topicIdPartition=5G8Ai8kBSwmQ3Ln4QRY5rA:topic1_3543-764,
id=fqGng3UURCG3-v4lETeLKQ}"
"2024-04-01T23:16:51.147Z","""kafka""","""10029""","Copying log segment data
completed successfully, metadata:
RemoteLogSegmentMetadata\{remoteLogSegmentId=RemoteLogSegmentId{topicIdPartition=5G8Ai8kBSwmQ3Ln4QRY5rA:topic1_3543-764,
id=fqGng3UURCG3-v4lETeLKQ}, startOffset=2968418, endOffset=2976819,
brokerId=10029, maxTimestampMs=1712009754536, eventTimestampMs=1712013397319,
segmentLeaderEpochs=\{5=2968418}, segmentSizeInBytes=536351075,
customMetadata=Optional.empty, state=COPY_SEGMENT_STARTED}"
"2024-04-01T23:16:37.328Z","""kafka""","""10029""","Copying log segment data,
metadata:
RemoteLogSegmentMetadata\{remoteLogSegmentId=RemoteLogSegmentId{topicIdPartition=5G8Ai8kBSwmQ3Ln4QRY5rA:topic1_3543-764,
id=fqGng3UURCG3-v4lETeLKQ}, startOffset=2968418, endOffset=2976819,
brokerId=10029, maxTimestampMs=1712009754536, eventTimestampMs=1712013397319,
segmentLeaderEpochs=\{5=2968418}, segmentSizeInBytes=536351075,
customMetadata=Optional.empty, state=COPY_SEGMENT_STARTED}"
```
Which looks right because we can see logs from both the plugin and remote log
manager indicating that the remote log segment was removed.
Now if I look on one of the leaked segment, here is what I see
```
"2024-04-02T00:43:33.834Z","""kafka""","""10001""","[RemoteLogManager=10001
partition=5G8Ai8kBSwmQ3Ln4QRY5rA:topic1_3543-765] Copied
00000000000002971163.log to remote storage with segment-id:
RemoteLogSegmentId\{topicIdPartition=5G8Ai8kBSwmQ3Ln4QRY5rA:topic1_3543-765,
id=8dP13VDYSaiFlubl9SNBTQ}"
"2024-04-02T00:43:33.822Z","""kafka""","""10001""","Copying log segment data
completed successfully, metadata:
RemoteLogSegmentMetadata\{remoteLogSegmentId=RemoteLogSegmentId{topicIdPartition=5G8Ai8kBSwmQ3Ln4QRY5rA:topic1_3543-765,
id=8dP13VDYSaiFlubl9SNBTQ}, startOffset=2971163, endOffset=2978396,
brokerId=10001, maxTimestampMs=1712010648756, eventTimestampMs=1712018599981,
segmentLeaderEpochs=\{7=2971163}, segmentSizeInBytes=459778940,
customMetadata=Optional.empty, state=COPY_SEGMENT_STARTED}"
"2024-04-02T00:43:20.003Z","""kafka""","""10001""","Copying log segment data,
metadata:
RemoteLogSegmentMetadata\{remoteLogSegmentId=RemoteLogSegmentId{topicIdPartition=5G8Ai8kBSwmQ3Ln4QRY5rA:topic1_3543-765,
id=8dP13VDYSaiFlubl9SNBTQ}, startOffset=2971163, endOffset=2978396,
brokerId=10001, maxTimestampMs=1712010648756, eventTimestampMs=1712018599981,
segmentLeaderEpochs=\{7=2971163}, segmentSizeInBytes=459778940,
customMetadata=Optional.empty, state=COPY_SEGMENT_STARTED}"
```
I have no errors whatsoever indicating that the remote log deletion was
actually triggered and failed.
I tried rolling restarting my cluster to see if refreshing remote log metadata
from fresh state would help but that did not help
Now if I use offset shell to get earliest and latest offsets for both partitions
```
$ /opt/kafka-3.7.0/bin/kafka-get-offsets.sh --bootstrap-server
$KAFKA_CONNECT_STR --topic topic1 --partitions 764,765 -
-time -2
raw_spans_datadog_3543:764:2980106
raw_spans_datadog_3543:765:2976337
$ $ /opt/kafka-3.7.0/bin/kafka-get-offsets.sh --bootstrap-server
$KAFKA_CONNECT_STR --topic topic1 --partitions 764,765 --time -1
raw_spans_datadog_3543:764:2980106
raw_spans_datadog_3543:765:2978397
```
We can see that despite the retention period being largely exceeded, there are
2060 offsets that are never expiring.
One thing that might have triggered this bug was the fact that some nodes were
replaced with fresh disk in between the segment creation and their expiration.
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