[HDFS-4090] getFileChecksum() result incompatible when called against zero-byte files.

• Type: Bug
• Status: Closed
• Priority: Critical
• Resolution: Fixed
• Affects Version/s: 0.23.4, 2.0.2-alpha
• Fix Version/s: 2.0.3-alpha, 0.23.5
• Component/s: hdfs-client
• Target Version/s: 2.0.3-alpha, 0.23.5
• Hadoop Flags: Reviewed
• Assignee: Kihwal Lee
• Reporter: Kihwal Lee
• Created: 19/Oct/12 21:29
• Updated: 03/Sep/14 23:19
• Resolved: 23/Oct/12 15:37

Description

When getFileChecksum() is called against a zero-byte file, the branch-1 client returns MD5MD5CRC32FileChecksum with crcPerBlock=0, bytePerCrc=0 and md5=70bc8f4b72a86921468bf8e8441dce51, whereas a null is returned in trunk.

The null makes sense since there is no actual block checksums, but this breaks the compatibility when doing distCp and calling getFileChecksum() via webhdfs or hftp.

This JIRA is to make the client to return the same 'magic' value that the branch-1 and earlier clients return.