Curtis Allen created STORM-399:
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Summary: Kafka Spout defaulting to latest offset when current offset is older
then 100k
Key: STORM-399
URL: https://issues.apache.org/jira/browse/STORM-399
Project: Apache Storm (Incubating)
Issue Type: Bug
Affects Versions: 0.9.2-incubating
Reporter: Curtis Allen
Priority: Minor
Using storm and storm-kafka 0.9.2-incubating
In the storm kafka spout the default for maxOffsetBehind is 100000
see https://github.com/apache/incubator-storm/blob/v0.9.2-incubating/external/storm-kafka/src/jvm/storm/kafka/KafkaConfig.java#L38
This default is too low and causes the kafka spout to start from the latest offset instead
of the last committed offset without warning.
see https://github.com/apache/incubator-storm/blob/v0.9.2-incubating/external/storm-kafka/src/jvm/storm/kafka/PartitionManager.java#L95
Producing the following log output from the storm worker processes
2014-07-09 18:02:15 s.k.PartitionManager [INFO] Read last commit
offset from zookeeper: 15266940; old topology_id:
ef3f1f89-f64c-4947-b6eb-0c7fb9adb9ea - new topology_id:
5747dba6-c947-4c4f-af4a-4f50a84817bf
2014-07-09 18:02:15 s.k.PartitionManager [INFO] Last commit offset
from zookeeper: 15266940
2014-07-09 18:02:15 s.k.PartitionManager [INFO] Commit offset 22092614
is more than 100000 behind, resetting to startOffsetTime=-2
2014-07-09 18:02:15 s.k.PartitionManager [INFO] Starting Kafka
prd-use1c-pr-08-kafka-kamq-0004:4 from offset 22092614
To fix this problem I ended up setting spout config in my topology like so
spoutConf.maxOffsetBehind = Long.MAX_VALUE;
Why would the kafka spout skip to the latest offset if the current offset
is more then 100000 behind by default?
This seems like a bad default value, the spout literally skipped over
months of data without any warning.
Are the core contributors open to accepting a pull request that would set
the default to Long.MAX_VALUE?
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