[HDFS-570] When opening a file for read, make the file length avaliable to client.

• Type: Sub-task
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: Append Branch
• Fix Version/s: Append Branch
• Component/s: hdfs-client
• Hadoop Flags: Incompatible change, Reviewed
• Release Note: In order to support read consistency, get last block length from a data-node when opening a file being written to.
• Assignee: Tsz-wo Sze
• Reporter: Tsz-wo Sze
• Created: 26/Aug/09 00:34
• Updated: 14/Aug/13 04:44
• Resolved: 26/Sep/09 23:44

Description

In order to support read consistency, DFSClient needs the file length at the file opening time. In the current implmentation, DFSClient obtains the file length at the file opening time but the length is inaccurate if the file is being written.

For more details, see Section 4 in the append design doc.

Issue Links

• is related to: HDFS-735 TestReadWhileWriting has wrong line termination symbols
• is related to: HADOOP-6307 Support reading on un-closed SequenceFile