Query Execution Plan (QEP)

Summary

A Query Execution Plan (QEP) is represented as a tree of operators. Each operator performs a specific task (e.g., pattern matching, filtering, projection) and produces a result set that feeds into its parent operator.

Overview of Query Execution Plan

1. Tree Structure:

• The QEP is a tree where:
  • Leaf nodes represent data sources (e.g., Holon retrieval or RelationshipMap traversal).
  • Intermediate nodes perform operations (e.g., filtering, joins).
  • Root node represents the final output operator (e.g., RETURN in OpenCypher).

2. Execution:

• The query is executed via a post-order traversal of the tree:
  • Start at the leaves.
  • Compute intermediate results by combining results from child nodes.
  • Finish at the root to produce the final output.

3. Operator Types:

• Operators encapsulate logic for graph query operations such as pattern matching, projection, filtering, aggregation, and joins.

Operand Design

Operator Design