Query OptimizationYannis E. IoannidisComputer Sciences Department University of Wisconsin ppt

Query Parser
Query Optimizer
Interpreter
Query Processor
Query Language (SQL)
Record−at−a−time calls
Code Generator/
Relational Calculus
Relational & Physical Algebra
Rewriter
Algebraic
Space
Space
Cost Model
Size−Distribution
Estimator
Planner
Method−Structure
Rewriting Stage (Declarative)
Planning Stage (Procedural)
σ
π
sal>100K
σ

sal>100K
name,floor
π
name,floor
π
name,floor
π
ππ
dno,floorname,dno
name,sal,dno
σ
sal>100K
EMP EMP
EMP
DEPT
DEPT
DEPT
dno=dno
dno=dno
dno=dno
T1 T2 T3
EMP
EMP
DEPT DEPT
dno=dno
dno=dno
ano=ano
ano=ano
ACNT
ACNT EMP

DEPT
dno=dno
ano=ano
ACNT
T1 T2 T3
EMP
DEPT
dno=dno
ano=ano
ACNT
BANK
bno=bno
EMP
DEPT
dno=dno
ano=ano
ACNT
BANK
bno=bno
EMP
DEPT
dno=dno
ano=ano
BANK
bno=bno
ACNT
T1 T2
T3