[ZOOKEEPER-1444] Idle session-less connections never time out

• Type: Bug
• Status: Resolved
• Priority: Critical
• Resolution: Duplicate
• Affects Version/s: 3.3.2, 3.4.3, 3.5.0
• Component/s: server
• Release Note: Expire idle connections.
• Assignee: Jay Shrauner
• Reporter: Jay Shrauner
• Created: 10/Apr/12 01:08
• Updated: 27/Jul/12 05:17
• Resolved: 27/Jul/12 05:17

Description

A socket connection to the server on which a session is not created will never time out. A misbehaving client that opens and leaks connections without creating sessions will hold open file descriptors on the server.

The existing timeout code is implemented at the session level, but the servers also should track and expire connections at the connection level. Proposed solution is to pull the timeout data structure handling code (hashmap of expiry time to sets of objects, simple monotonically incrementing nextExpirationTime) from SessionTrackerImpl into its own class in order to share it with connection level timeouts to be implemented in NIOServerCnxnFactory. Connections can be assigned a small initial timeout (proposing something small, like 3s) until a session is created, at which point the ServerCnxn session timeout can be used instead.