[HIVE-15723] Hive should report a warning about missing table/column statistics to user.

• Type: Bug
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Fix Version/s: 2.2.0
• Component/s: Query Processor
• Labels: TODOC2.2
• Target Version/s: 2.2.0
• Release Note: hive.cbo.show.warnings (default false) is added to control display of cost-based-optimizer compiler warnings, like missing stats.
• Assignee: Remus Rusanu
• Reporter: Remus Rusanu
• Created: 25/Jan/17 08:11
• Updated: 25/Jul/17 20:05
• Resolved: 01/Feb/17 21:02

Description

Many Hive performance issues are due to missing statistics. Either all, table or column statistics are missing. Potentially a new partition has been added and customer forgot to gather stats for that partition.
A simple warning about a table or column missing statistics can be very helpful and makes hive more user friendly. Hive already has this information, its a matter of printing it out.