[HDFS-16845] Add configuration flag to enable observer reads on routers without using ObserverReadProxyProvider

• Type: Bug
• Status: Resolved
• Priority: Critical
• Resolution: Fixed
• Affects Version/s: 3.4.0
• Fix Version/s: 3.4.0
• Component/s: configuration
• Labels: pull-request-available
• Target Version/s: 3.4.0
• Hadoop Flags: Reviewed
• Assignee: Simbarashe Dzinamarira
• Reporter: Simbarashe Dzinamarira
• Created: 17/Nov/22 00:42
• Updated: 28/Jan/24 07:38
• Resolved: 29/Nov/22 00:51

Description

In order for clients to have routers forward their reads to observers, the clients must use a proxy with an alignment context. This is currently achieved by using the ObserverReadProxyProvider.

Using ObserverReadProxyProvider allows backward compatible for client configurations.
However, the ObserverReadProxyProvider forces an msync on initialization which is not required with routers.

Performing msync calls is more expensive with routers because the router fans out the cal to all namespaces, so we'd like to avoid this.

Issue Links

• links to: GitHub Pull Request #5142