Query Processing and Optimization

Question 1

Query Tree

Answer 1

Internal representation of query

Question 2

Logical plan

Answer 2

o Based on relational algebra
o Level: Higher-level, algebraic
o Operators: Query language constructs
o Logical level optimization = aka heuristic optimization

Question 3

Physical plan

Answer 3

o Concrete algorithms
o Level: lower-level, operational
o Operators: “Access Methods”
o Physical level optimization = aka cost-based optimization

Question 4

Query Processing

Answer 4

1. • Query
2. • Parser
3. • Logical Plan
4. • Optimizer
5. • Physical Plan
6. • Evaluation Engine
7. • Query Output