[ZOOKEEPER-3724] [Java Client] - Calculation of connectionTimeout needs improvement.

• Type: Bug
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Component/s: java client
• Assignee: Unassigned
• Reporter: Deepak Vilakkat
• Created: 13/Feb/20 06:01
• Updated: 13/Feb/20 06:01

Description

https://github.com/apache/zookeeper/blob/master/zookeeper-server/src/main/java/org/apache/zookeeper/ClientCnxn.java#L439

This makes scaling zookeeper an issue without notifying all clients that they need to increase the sessionTimeout to a large value. Already had a production outage when a client in an asia data-center was trying to write to a zookeeper server in america for cross-colo announcements. The session timeout was kept at 5000ms and was working all the while but the cluster size was increased which made this value less than 200ms. Since its technically impossible to connect with this value, we increased session timeout.

 

Shouldn't there be a floor value like 5 seconds, below which this value shouldn't drop. Theoretically this calculation can make connecting over Local network also timeout in some use cases.

 

This was also discussed in http://zookeeper-user.578899.n2.nabble.com/How-to-modify-Client-Connection-timer-td7583017.html#a7583019 and I am trying to understand if there is some other catch for this implementation.