[DRILL-6126] Allocate memory for value vectors upfront in flatten operator

• Type: Improvement
• Status: Resolved
• Priority: Critical
• Resolution: Fixed
• Fix Version/s: 1.13.0
• Labels: ready-to-commit
• Assignee: Padma Penumarthy
• Reporter: Padma Penumarthy
• Reviewer: Paul Rogers
• Created: 31/Jan/18 00:40
• Updated: 12/Mar/18 18:48
• Resolved: 08/Mar/18 02:57

Description

With recent changes to control batch size for flatten operator, we figure out row count in the output batch based on memory. Since we know how many rows we are going to include in the batch, we can also allocate the memory needed upfront instead of starting with initial value (4096) and doubling, copying every time we need more. 

Issue Links

• links to: GitHub Pull Request #1125