[HDFS-7210] Avoid two separate RPC's namenode.append() and namenode.getFileInfo() for an append call from DFSClient

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 2.7.0
• Component/s: hdfs-client, namenode
• Hadoop Flags: Incompatible change, Reviewed
• Assignee: Vinayakumar B
• Reporter: Vinayakumar B
• Created: 08/Oct/14 09:47
• Updated: 23/Oct/15 21:50
• Resolved: 28/Nov/14 16:04

Description

Currently DFSClient does 2 RPCs to namenode for an append operation.

append() for re-opening the file and getting the last block,
getFileInfo() Another on to get HdfsFileState

If we can combine result of these 2 calls and make one RPC, then it can reduce load on NameNode.

For the backward compatibility we need to keep existing append() call as is

Issue Links

• breaks: HDFS-9290 DFSClient#callAppend() is not backward compatible for slightly older NameNodes
• is related to: HDFS-7203 Concurrent appending to the same file can cause data corruption