[ARROW-17837] [C++] Create ExecPlan-owned QueryContext that will store a plan's shared data structures

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 11.0.0
• Component/s: C++
• Labels: pull-request-available
• External issue URL: https://github.com/apache/arrow/issues/33057
• Assignee: Sasha Krassovsky
• Reporter: Sasha Krassovsky
• Created: 24/Sep/22 02:41
• Updated: 11/Jan/23 11:56
• Resolved: 22/Dec/22 19:22

Description

As we begin to include more and more plan-global stuff (such as Scheduler, AsyncScheduler, IO thread pool, ExecContext), ExecPlan's definition is becoming cluttered. ExecPlan should store and organize nodes, and store these structures elsewhere. We thus introduce QueryContext which will store any information related to the currently executing plan.

An added bonus is that now more components can be decoupled from ExecPlan and rely only on QueryContext (useful for e.g. testing, or just reusing a component in a non-ExecPlan context).

Also, this QueryContext can introduce options for the query such as maximum memory used and this legacy batching thingy.

Issue Links

• links to: GitHub Pull Request #14227