[HADOOP-3684] The data_join should allow the user to implement a customer cloning function

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 0.19.0
• Hadoop Flags: Reviewed
• Release Note: Allowed user to overwrite clone function in a subclass of TaggedMapOutput class.
• Assignee: Runping Qi
• Reporter: Runping Qi
• Created: 02/Jul/08 22:01
• Updated: 08/Jul/09 16:52
• Resolved: 10/Jul/08 22:16

Description

Currently, the framework uses serialization/deserialization to clone the values passed to the resuce function.
This amounts to a very heavy weight deep copy of the value objects.
That is way too expensive. Although that may be a generic way to work for all possible value classes, thus good as a default way,
the framework should allow the user to implemet an application specific yet efficient cloning function.