[TAJO-614] Explaning a logical node should use ExplainLogicalPlanVisitor.

• Type: Improvement
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Fix Version/s: 0.8.0, 0.9.0
• Component/s: Planner/Optimizer
• Assignee: Hyunsik Choi
• Reporter: Hyunsik Choi
• Created: 20/Feb/14 08:10
• Updated: 21/Feb/14 07:03
• Resolved: 21/Feb/14 06:26

Description

Currently, many parts use LogicalNode::toString() for explaning plans. But, we already have ExplainLogicalPlanVisitor class to generate pretty print strings.

This patch improves logical planning related parts to use ExplainLogicalPlanVisitor instead of toString().

For this, I added PlannerUtil::buildExplainString for generating pretty print explain strings and simplified obsolete toString() methods of all LogicalNodes.

It much improves the readability of explain string. I expect that it would be helpful for debugging and users' understanding of query plans.