[HDFS-16876] Garbage collect map entries in shared RouterStateIdContext using information from namenodeResolver instead of the map of active connectionPools.

• Type: Bug
• Status: Resolved
• Priority: Critical
• Resolution: Fixed
• Affects Version/s: 3.4.0
• Fix Version/s: 3.4.0
• Component/s: rbf
• Labels: pull-request-available
• Target Version/s: 3.4.0
• Hadoop Flags: Reviewed
• Assignee: Simbarashe Dzinamarira
• Reporter: Simbarashe Dzinamarira
• Created: 21/Dec/22 19:20
• Updated: 28/Jan/24 07:30
• Resolved: 23/Jan/23 09:31

Description

An element in RouterStateIdContext#namespaceIdMap is deleted when there is no connectionPool referencing the namespace. This is done by a thread in ConnectionManager that cleans up stale connectionPools. I propose a less aggressive approach, that is, cleaning up an entry when the router cannot resolve a namenode belonging to the namespace.

Some benefits of this approach are:

• Even when there are no active connections, the router still tracks a recent state of the namenode. This will be beneficial for debugging.
• Simpler lifecycle for the map entries. The entries are long-lived.
• Few operations under the writeLock in ConnectionManager.

Issue Links

• links to: GitHub Pull Request #5282