What is the default value for session.timeout.ms?

• A. 5 seconds
• B. 30 seconds
• C. 60 seconds
• D. 10 seconds

Answer: (D)

Session timeout controls how long the Kafka group coordinator waits for a consumer’s heartbeat before considering that member failed and triggering a rebalance. The typical default is 10000 milliseconds, which is 10 seconds, giving a balance between quick failure detection and avoiding unnecessary rebalances. Since heartbeats are sent regularly (heartbeat interval defaults to about 3 seconds), the session timeout should be longer than that interval. A shorter value, like 5 seconds, can cause false failure detections during temporary delays, while much longer values (30 or 60 seconds) delay recovery from a failed member.