[IMPALA-7842] Refactor FrontEnd to make plan fragments available for testing

• Type: Improvement
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: Impala 3.0
• Fix Version/s: Impala 3.2.0
• Component/s: Frontend
• Epic Color: ghx-label-8
• Assignee: Paul Rogers
• Reporter: Paul Rogers
• Created: 11/Nov/18 00:24
• Updated: 14/Mar/19 14:54
• Resolved: 07/Feb/19 01:13

Description

Today, the FrontEnd class uses a functional model to generate a plan: pass in SQL text to the createExecRequest() method and get back a Thrift plan ready for serialization.

For unit testing, however, we need access to the intermediate plan fragments produced by the planner. Inspecting only the Thrift version results in loss of important details.

This ticket asks to create a new PlanCtx which can capture the details for testing.