The document discusses database indexing and optimization. It explains the concepts of primary keys, covering indexes, and read/write operations. It also provides examples of using indexes to optimize queries and discusses how MySQL handles read and write operations through its binary log and relay log.

1. 2011 3 4
2011 3 5

2. • DB
• Index
Index Covering Index Primary Key
Read Write
• MySQL
DB SQL
2011 3 5

3. •
→(10001,A)
※
•
Primary Key
→Primary Key
•
Primary Key
2011 3 5

4. •
ID
ID
1
1
2
2
2
2011 3 5

5. •
ID ID
1 10001
1 10002
2 10001
ID ID
1 10001 2 10002
1 10002
2 10001
2 10002 ID
10001
10002
2011 3 5

6. •
ID ID
1 101
2 102
ID ID 3 103
1 101 4 102
2 102
3 103
4 102 ID
101
102
103
2011 3 5

7. ALTER TABLE
•
• (ALTER TABLE)
→ALTER TABLE
•
•
→
2011 3 5

8. ID ID
1 1 101 1
1 2 234 2
1 3 553 3
1 4 232 4
2 1 102
2 2 271
2 3 952
ID
1 101 234 553 232 873 0 102 0
2 102 271 8652 98 0 234 202 0
3 103 952 76 765 872 45 0 0
4 102 197 2312 762 4 232 672 34
•
2011 3 5

9. Index
• WHERE Index Primary Key
WHERE user_id = 10001
→ user_id Index( Primary Key)
WHERE user_id = 10001 AND friend_id = 10002
→ (user_id, friend_id)
WHERE visiting_id = 10001 AND visited_id IN (1,2,3) AND action=2
→ (visiting_id,visited_id,action)
WHERE status = 2 ORDER BY start_time
→ (status,start_time)
2011 3 5

10. Index
• Index
WHERE start_time < 12345678 AND state = 2
→(start_time,state) (state,start_time)
• Index
WHERE visited_id = 10002 AND visiting_id = 10001 AND action=2
→ (visiting_id,visited_id,action)
• Index
WHERE visiting_id = 10001 AND action = 2 AND visited_id = 10002
→ (visiting_id,visited_id,action) Index visiting_id
2011 3 5

11. Covering Index
•
MySQL Covering Index - ( ∀ )o sasata299's blog
http://blog.livedoor.jp/sasata299/archives/51336006.html
•
Covering Index
→
2011 3 5

12. Primary Key id
• Primary Key
→ Primary Key MySQL id
Primary Key
MySQL :: MySQL 5.1 :: 13.5.13 InnoDB
http://dev.mysql.com/doc/refman/5.1/ja/innodb-table-and-index.html
• id WHERE id IN (a,b,c,d...)
• id
id
Primary Key ( Covering
Index )
2011 3 5

13. Primary Key
• id Primary Key
1
Primary Key
• id
• id Primary Key
(“WHERE user_id=10001” )
2011 3 5

14. auto_increment
•
ID
CREATE TABLE seq_history(
seq_id bigint unsigned not null
);
• auto_increment
MySQL5.1 DB
auto_increment
2011 3 5

15. Read Write
• Read(SELECT) DB
Write DB DB
• Write SELECT
• SELECT
• Read
Write
2011 3 5

16. • Read/Write SQL
•
IO
→
→
2011 3 5

17. MySQL
• DB DB
DB
DB DB
(3)Relay Log
(1) (INSERT,UPDATE )
SQL
Binary Log
SQL
IO
Binary Log
Relay Log
(2)IO Binary
Log
DB
2011 3 5

18. DB
• DB DB
→MySQL 1
•
→ SSD cf.
2011 3 5

19. •
NG
UPDATE history_tbl SET state = 2 WHERE state = 1 LIMIT 10
→state=1
UPDATE history_tbl SET state = 2 ORDER BY finish_time LIMIT 1
→ finish_time
• UPDATE WHERE Primary Key
2011 3 5