[HADOOP-6307] Support reading on un-closed SequenceFile

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 0.21.0
• Component/s: io
• Hadoop Flags: Reviewed
• Assignee: Tsz-wo Sze
• Reporter: Tsz-wo Sze
• Created: 09/Oct/09 22:31
• Updated: 02/May/13 02:29
• Resolved: 01/Dec/09 23:29

Description

When a SequenceFile.Reader is constructed, it calls fs.getFileStatus(file).getLen(). However, fs.getFileStatus(file).getLen() does not return the hflushed length for un-closed file since the Namenode does not know the hflushed length. DFSClient have to ask a datanode for the length last block which is being written; see also HDFS-570.

Issue Links

• depends upon: HDFS-691 Limitation on java.io.InputStream.available()
• relates to: HDFS-570 When opening a file for read, make the file length avaliable to client.
• relates to: HDFS-814 Add an api to get the visible length of a DFSDataInputStream.