Purge / Empty / Drain a Kafka Topic in Oracle Event Hub Service (or any other Kafka broker)

I did not find this solution myself, but I am also not sure where I discovered it. Just a note to myself.

Actually it is becomes useful once you enabled client access to your Oracle Event Hub Cloud Service, since the web based console itself does not implement every functionality that is provided by Kafka.

# PURGE topic
# we drain the topic by expiring the messages

./kafka-topics --zookeeper ZKADR --alter --topic topic_name --config retention.ms=1000
./kafka-topics --zookeeper ZKADR --alter --topic topic_name --delete-config retention.ms

On another thought: what if the Event Hub Console implemented draining a topic in the web console? And maybe it could also display the number of messages stored in topic.