[HIVE-6797] Add protection against divide by zero in stats annotation

• Type: Sub-task
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 0.13.0
• Fix Version/s: 0.13.0
• Component/s: Query Processor, Statistics
• Assignee: Prasanth Jayachandran
• Reporter: Prasanth Jayachandran
• Created: 31/Mar/14 23:08
• Updated: 01/Apr/14 21:31
• Resolved: 01/Apr/14 21:31

Description

In stats annotation, the denominator computation in join operator is not protected for divide by zero exception. It will be an issue when NDV (count distinct) updated by updateStats() becomes 0. This patch adds protection in updateStats() method to prevent divide-by-zero in downstream operators.