Creating a topic will first check whether the topic already exists. The verification will read all topics under the namespace, and then traverse these topics to see if the topic already exists. When there are a large number of topics under the namespace(about 300,000 topics), less than 10 topics can be created in one second.
Without a distributed lock, this check is unreliable and costly. I tried to delete this check and write to ZooKeeper directly. If the znode already exists, it means the topic already exists. Then, I found this scenario in the unit test: The user already has a non-partitioned topic like `topic-name-partition-123` Then, he wants to create a partitioned topic like `topic-name`. It cannot be created successfully now. When traversing all topics, prefix matching is also performed. In order to solve this problem, I want to add a check for reserved words on the topic creation interface,and the topic name is not allowed to contain -partition-, but this may cause some compatibility problems. I want to hear your opinions. Is there a better way?
