1. CPSC-608 Database Systems Fall 2011 Instructor: Jianer Chen Office: HRBB 315C Phone: 845-4259 Email: chen@cse.tamu.edu 1 Notes #9

2. Where we were: 2 SQL program SQL Compiler Logic query plan LQP Optimizer Improved logic query plan SELECT a1, b1, c1 FROM A, B, C WHERE a2=1 AND b2=2 AND c2=3 × A B C × σ π a1, b1, c1 a2=1, b2 =2, c2=3 × A B C × σ π a1, b1, c1 a2=1 σ σ b2 =2 c2=3

3. Construction of Physical Query Plan

4. Input: an optimized LQP T, and a main memory constraint M × ∩ π σ σ σ G F E D C B A

5. Construction of Physical Query Plan Input: an optimized LQP T, and a main memory constraint M 1.Replacing each leaf R of T by “scan(R)”; × ∩ π σ σ σ scan(G) scan(F) scan(E) scan(D) scan(C) scan(B) scan(A)

6. Construction of Physical Query Plan Input: an optimized LQP T, and a main memory constraint M 1.Replacing each leaf R of T by “scan(R)”; 2.Combining the “scan’s” with other operations; × ∩ π σ σ σ scan(G) scan(F) scan(E) scan(D) scan(C) scan(B) scan(A) index-scan

7. Construction of Physical Query Plan Input: an optimized LQP T, and a main memory constraint M 1.Replacing each leaf R of T by “scan(R)”; 2.Combining the “scan’s” with other operations; 3.Replacing each internal node v of T by a proper algorithm; × ∩ π σ σ σ scan(G) scan(F) scan(E) scan(D) scan(C) scan(B) scan(A) index-scan J2P J1P CJ I1P

8. Construction of Physical Query Plan Input: an optimized LQP T, and a main memory constraint M 1.Replacing each leaf R of T by “scan(R)”; 2.Combining the “scan’s” with other operations; 3.Replacing each internal node v of T by a proper algorithm; 4.For each edge e in T, decide if e should be “materialized”; × ∩ π σ σ σ scan(G) scan(F) scan(E) scan(D) scan(C) scan(B) scan(A) index-scan J2P J1P CJ I1P

9. Construction of Physical Query Plan Input: an optimized LQP T, and a main memory constraint M 1.Replacing each leaf R of T by “scan(R)”; 2.Combining the “scan’s” with other operations; 3.Replacing each internal node v of T by a proper algorithm; 4.For each edge e in T, decide if e should be “materialized”; × ∩ π σ σ σ scan(G) scan(F) scan(E) scan(D) scan(C) scan(B) scan(A) index-scan J2P J1P CJ I1P

10. Construction of Physical Query Plan Input: an optimized LQP T, and a main memory constraint M 1.Replacing each leaf R of T by “scan(R)”; 2.Combining the “scan’s” with other operations; 3.Replacing each internal node v of T by a proper algorithm; 4.For each edge e in T, decide if e should be “materialized”; 5.Cut all materialized edges; × ∩ π σ σ σ scan(G) scan(F) scan(E) scan(D) scan(C) scan(B) scan(A) index-scan J2P J1P CJ I1P

11. Construction of Physical Query Plan Input: an optimized LQP T, and a main memory constraint M 1.Replacing each leaf R of T by “scan(R)”; 2.Combining the “scan’s” with other operations; 3.Replacing each internal node v of T by a proper algorithm; 4.For each edge e in T, decide if e should be “materialized”; 5.Cut all materialized edges; 6.Each subtree is a call to the subroutine at the root of the subtree. The order of the calls follows the bottom-up order in the structure. × ∩ π σ σ σ scan(G) scan(F) scan(E) scan(D) scan(C) scan(B) scan(A) index-scan J2P J1P CJ I1P 1 2 3

12. Construction of Physical Query Plan Input: an optimized LQP T, and a main memory constraint M 1.Replacing each leaf R of T by “scan(R)”; 2.Combining the “scan’s” with other operations; 3.Replacing each internal node v of T by a proper algorithm; 4.For each edge e in T, decide if e should be “materialized”; 5.Cut all materialized edges; 6.Each subtree is a call to the subroutine at the root of the subtree. The order of the calls follows the bottom-up order in the structure. × ∩ π σ σ σ scan(G) scan(F) scan(E) scan(D) scan(C) scan(B) scan(A) index-scan J2P J1P CJ I1P 1 2 3 This produces an executable code for the input DB program

13. Physical Query Plan: Summary Replacing internal nodes of a LQP by proper algorithms; Deciding if a subroutine call should be pipelined or materialized; Many optimization techniques are involved here; In practice, heuristic optimization techniques are used to construct good physical query plans; The resulting physical query plan is an executable code.

14. secondary storage (disks) in tables (relations) database administrator DDL language database programmer DML (query) language DBMS file manager buffer manager main memory buffers index/file manager DML complier DDL complier query execution engine transaction manager concurrency control lock table logging & recovery graduate database

15. secondary storage (disks) in tables (relations) database administrator DDL language database programmer DML (query) language DBMS file manager buffer manager main memory buffers index/file manager DML complier DDL complier query execution engine transaction manager concurrency control lock table logging & recovery graduate database

16. secondary storage (disks) in tables (relations) database administrator DDL language database programmer DML (query) language DBMS file manager buffer manager main memory buffers index/file manager DML complier DDL complier query execution engine transaction manager concurrency control lock table logging & recovery graduate database What is still missing?

17. secondary storage (disks) in tables (relations) database administrator DDL language database programmer DML (query) language DBMS file manager buffer manager main memory buffers index/file manager DML complier DDL complier query execution engine transaction manager concurrency control lock table logging & recovery graduate database Efficient Algorithms for Relational algebriac operations

18. secondary storage (disks) in tables (relations) database administrator DDL language database programmer DML (query) language DBMS file manager buffer manager main memory buffers index/file manager DML complier DDL complier query execution engine transaction manager concurrency control lock table logging & recovery Efficient Algorithms for Relational algebriac operations graduate database

19. secondary storage (disks) in tables (relations) database administrator DDL language database programmer DML (query) language DBMS file manager buffer manager main memory buffers index/file manager DML complier DDL complier query execution engine transaction manager concurrency control lock table logging & recovery graduate database

20. secondary storage (disks) in tables (relations) database administrator DDL language database programmer DML (query) language DBMS file manager buffer manager main memory buffers index/file manager DML complier DDL complier query execution engine transaction manager concurrency control lock table logging & recovery graduate database