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Edoardo Comar commented on KAFKA-16622: --------------------------------------- if after the consumer reaches 10000 and the 1st checkpoint is emitted, MM2 restarts before the other 10000 messages are produced, then bug https://issues.apache.org/jira/browse/KAFKA-15905 hits and we end up with just two checkpoints, at 10000 and 20000. > Mirromaker2 first Checkpoint not emitted until consumer group fully catches > up once > ----------------------------------------------------------------------------------- > > Key: KAFKA-16622 > URL: https://issues.apache.org/jira/browse/KAFKA-16622 > Project: Kafka > Issue Type: Bug > Components: mirrormaker > Affects Versions: 3.7.0, 3.6.2, 3.8.0 > Reporter: Edoardo Comar > Priority: Major > Attachments: connect.log.2024-04-26-10.zip, > edo-connect-mirror-maker-sourcetarget.properties > > > We observed an excessively delayed emission of the MM2 Checkpoint record. > It only gets created when the source consumer reaches the end of a topic. > This does not seem reasonable. > In a very simple setup : > Tested with a standalone single process MirrorMaker2 mirroring between two > single-node kafka clusters(mirromaker config attached) with quick refresh > intervals (eg 5 sec) and a small offset.lag.max (eg 10) > create a single topic in the source cluster > produce data to it (e.g. 10000 records) > start a slow consumer - e.g. fetching 50records/poll and pausing 1 sec > between polls which commits after each poll > watch the Checkpoint topic in the target cluster > bin/kafka-console-consumer.sh --bootstrap-server localhost:9192 \ > --topic source.checkpoints.internal \ > --formatter org.apache.kafka.connect.mirror.formatters.CheckpointFormatter \ > --from-beginning > -> no record appears in the checkpoint topic until the consumer reaches the > end of the topic (ie its consumer group lag gets down to 0). -- This message was sent by Atlassian Jira (v8.20.10#820010)