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Sönke Liebau commented on KAFKA-8246: ------------------------------------- I believe that used to be a regular expression but was changed for better performance, see this [pull request|https://github.com/apache/kafka/pull/3234]. > refactor topic/group instance id validation condition > ----------------------------------------------------- > > Key: KAFKA-8246 > URL: https://issues.apache.org/jira/browse/KAFKA-8246 > Project: Kafka > Issue Type: Improvement > Reporter: Boyang Chen > Assignee: Boyang Chen > Priority: Major > -- This message was sent by Atlassian JIRA (v7.6.3#76005)