[HDFS-4213] When the client calls hsync, allows the client to update the file length in the NameNode

• Type: New Feature
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 2.0.3-alpha
• Component/s: hdfs-client, namenode
• Hadoop Flags: Reviewed
• Assignee: Jing Zhao
• Reporter: Jing Zhao
• Created: 20/Nov/12 19:29
• Updated: 27/Mar/19 06:42
• Resolved: 30/Nov/12 19:31

Description

As per discussion in HDFS-3960 and HDFS-2802, when clients that need strong consistency update the file length at the NameNode, a special sync/flush is required for getting the length of the being written files when snapshots are taken for these files. This jira implements this sync-with-updating-length by 1) calling ClientProtocol#fsync(), and 2) adding a new field to ClientProtocol#fsync() to indicate the length information.

Issue Links

• is duplicated by: HDFS-5478 File size reports as zero after writing and calling FSDataOutputStream#hsync()
• is related to: HDFS-5478 File size reports as zero after writing and calling FSDataOutputStream#hsync()
• is related to: FLINK-12022 Enable StreamWriter to update file length on sync flush
• relates to: HDFS-3960 Snapshot of Being Written Files
• relates to: HDFS-2802 Support for RW/RO snapshots in HDFS