[IMPALA-2937] Introduce sampled statistics

• Type: Sub-task
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: Impala 2.2
• Fix Version/s: Impala 2.12.0
• Component/s: Backend
• Labels: planner supportability
• Target Version: Product Backlog
• Assignee: Unassigned
• Reporter: Mostafa Mokhtar
• Created: 03/Feb/16 22:49
• Updated: 15/Jun/18 16:35
• Resolved: 15/Jun/18 16:35

Description

Stats computation can be expensive, introduce sampled scans for Parquet and text files to speedup stats computation.

Database will have a default sampling rate which can be overridden at table level.