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Dong Lin updated KAFKA-6774: ---------------------------- Fix Version/s: 2.1.0 > Improve default groupId behavior in consumer > -------------------------------------------- > > Key: KAFKA-6774 > URL: https://issues.apache.org/jira/browse/KAFKA-6774 > Project: Kafka > Issue Type: Improvement > Components: consumer > Reporter: Jason Gustafson > Assignee: Vahid Hashemian > Priority: Major > Labels: needs-kip > Fix For: 2.1.0 > > > At the moment, the default groupId in the consumer is "". If you try to use > this to subscribe() to a topic, the broker will reject the group as invalid. > On the other hand, if you use it with assign(), then the user will be able to > fetch and commit offsets using the empty groupId. Probably 99% of the time, > this is not what the user expects. Instead you would probably expect that if > no groupId is provided, then no committed offsets will be fetched at all and > we'll just use the auto reset behavior if we don't have a current position. > Here are two potential solutions (both requiring a KIP): > 1. Change the default to null. We will preserve the current behavior for > subscribe(). When using assign(), we will not bother fetching committed > offsets for the null groupId, and any attempt to commit offsets will raise an > error. The user can still use the empty groupId, but they have to specify it > explicitly. > 2. Keep the current default, but change the consumer to treat this value as > if it were null as described in option 1. The argument for this behavior is > that using the empty groupId to commit offsets is inherently a dangerous > practice and should not be permitted. We'd have to convince ourselves that > we're fine not needing to allow the empty groupId for backwards compatibility > though. -- This message was sent by Atlassian JIRA (v7.6.3#76005)