Connector periodically issues warnings: "Commit of offsets timed out"

[ngc4579]

We are in the process of evaluating and establishing a CDC system streaming change events from our databases into an Opensearch deployment.

The Opensearch connector eventually pushing aggregated topics into Opensearch periodically issues warnings like this:

...

2024-03-16 22:38:59,742 WARN [connector-opensearch|task-0] WorkerSinkTask{id=connector-opensearch-0} Commit of offsets timed out (org.apache.kafka.connect.runtime.WorkerSinkTask) [task-thread-connector-opensearch-0]

2024-03-16 22:40:01,936 WARN [connector-opensearch|task-0] WorkerSinkTask{id=connector-opensearch-0} Commit of offsets timed out (org.apache.kafka.connect.runtime.WorkerSinkTask) [task-thread-connector-opensearch-0]

2024-03-16 22:41:03,366 WARN [connector-opensearch|task-0] WorkerSinkTask{id=connector-opensearch-0} Commit of offsets timed out (org.apache.kafka.connect.runtime.WorkerSinkTask) [task-thread-connector-opensearch-0]

...

These messages occur roughly every minute.

Our connector config basically looks like this:

spec:
  class: io.aiven.kafka.connect.opensearch.OpensearchSinkConnector
  config:
    batch.size: 1000
    behavior.on.malformed.documents: warn
    behavior.on.null.values: delete
    behavior.on.version.conflict: warn
    connection.password: ${secrets:debezium/opensearch-credentials:password}
    connection.url: https://debezium-opensearch-nodes.debezium.svc:9200
    connection.username: ${secrets:debezium/opensearch-credentials:username}
    errors.deadletterqueue.context.headers.enable: true
    errors.deadletterqueue.topic.name: myjack.index.dl
    errors.deadletterqueue.topic.replication.factor: 3
    errors.tolerance: all
    flush.timeout.ms: 30000
    index.write.method: upsert
    key.converter: org.apache.kafka.connect.json.JsonConverter
    key.converter.schemas.enable: false
    key.ignore: false
    key.ignore.id.strategy: record.key
    max.buffered.records: 20000
    schema.ignore: "true"
    topics: <redacted>
    transforms: extractKey
    transforms.extractKey.field: id
    transforms.extractKey.type: org.apache.kafka.connect.transforms.ExtractField$Key
    type.name: _doc
    value.converter: org.apache.kafka.connect.json.JsonConverter
    value.converter.schemas.enable: false

Is this something noteworthy, does it indicate an issue? What causes these periodic messages?

[reta]

Seems to be Kafka related: https://github.com/confluentinc/kafka-connect-jdbc/issues/846

[ngc4579]

@reta Thanks for the hint. I've actually come across that issue before, yet disregarded it as it had been reported against a different connector and with ambiguous comments. I'll have an eye on that one anyway and meanwhile experiment with higher offset.flush.timeout.ms settings (currently at the default value).