[IMPALA-3823] Add timer to measure Parquet footer reads

• Type: Improvement
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: Impala 2.6.0
• Fix Version/s: Impala 2.8.0
• Component/s: Backend
• Labels: parquet performance
• Target Version: Product Backlog
• Assignee: Sailesh Mukil
• Reporter: Sailesh Mukil
• Created: 05/Jul/16 19:43
• Updated: 31/Oct/16 17:09
• Resolved: 31/Oct/16 17:09

Description

It's been observed that Parquet footer reads perform poorly especially when reading from S3. It would be useful to add a timer to measure how much of the query time is spent in performing these footer reads.