[HADOOP-1774] Remove use of INode.parent in Block CRC upgrade

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 0.15.0
• Assignee: Raghu Angadi
• Reporter: Raghu Angadi
• Created: 23/Aug/07 23:18
• Updated: 08/Jul/09 16:42
• Resolved: 13/Sep/07 20:49

Description

HADOOP-1687 proposes various reductions in Namenode memory. One of the 'cuts' is to remove 'parent' field in INodes (8 bytes per file). HADOOP-1743 already deprecates INode.getAbsoluteName() method.

Block CRC Upgrade code still requires this field (blockID -> fileName -> parent -> INode for .crc file). If we don't want to use parent, we need to build INode-to-parent map at the beginning of the upgrade. Note this would increase memory required during upgrade by 50 bytes for each of non-crc files (50% of files). I would estimate this to be around 5% more memory.