[HDFS-13872] Only some protocol methods should perform msync wait

• Type: Sub-task
• Status: Resolved
• Priority: Major
• Resolution: Duplicate
• Target Version/s: HDFS-12943
• Assignee: Erik Krogen
• Reporter: Erik Krogen
• Created: 27/Aug/18 22:22
• Updated: 06/Sep/18 21:43
• Resolved: 06/Sep/18 21:43

Description

Currently the implementation of msync added in HDFS-13767 waits until the server has caught up to the client-specified transaction ID regardless of what the inbound RPC is. This particularly causes problems for ObserverReadProxyProvider (see HDFS-13779) when we try to fetch the state from an observer/standby; this should be a quick operation, but it has to wait for the node to catch up to the most current state. I initially thought all HAServiceProtocol methods should thus be excluded from the wait period, but actually I think the right approach is that only ClientProtocol methods should be subjected to the wait period. I propose that we can do this via an annotation on client protocol which can then be checked within ipc.Server.

Issue Links

• is duplicated by: HDFS-13880 Add mechanism to allow certain RPC calls to bypass sync