[HADOOP-10300] Allowed deferred sending of call responses

• Type: Sub-task
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.0.0-alpha, 3.0.0-alpha1
• Fix Version/s: 2.8.0, 2.7.4, 3.0.0-alpha1
• Component/s: ipc
• Labels: BB2015-05-TBR
• Target Version/s: 2.8.0
• Hadoop Flags: Reviewed
• Assignee: Daryn Sharp
• Reporter: Daryn Sharp
• Created: 28/Jan/14 19:29
• Updated: 02/Nov/16 05:25
• Resolved: 02/Nov/16 05:25

Description

RPC handlers currently do not return until the RPC call completes and response is sent, or a partially sent response has been queued for the responder. It would be useful for a proxy method to notify the handler to not yet the send the call's response.

An potential use case is a namespace handler in the NN might want to return before the edit log is synced so it can service more requests and allow increased batching of edits per sync. Background syncing could later trigger the sending of the call response to the client.

Issue Links

• is required by: HDFS-7964 Add support for async edit logging
• relates to: HADOOP-12483 Maintain wrapped SASL ordering for postponed IPC responses