MySQL Range Optimization and Multipart index
Hi i'm newbie to MySQL World.
When i read about MySQL Range Optimization some of question were raised related to multipart index.
MySQL 5.7 Doc
(http://jorgenloland.blogspot.com/2011/08/mysql-range-access-method-explained.html)
Question 1 :
What is the meaning of single and continuous intervals ?
Question 2 :
Related to Multipart index and keylen
Table Structure
Create table orders(customer_id int,value int,name varchar(20),primary key(customer_id,value)) ;
A)
mysql> explain select * from orders where customer_id <= 2 and value = 1;
+----+-------------+--------+------------+-------+---------------+---------+---------+------+------+----------+-------------+
| id | select_type | table | partitions | type | possible_keys | key | key_len | ref | rows | filtered | Extra |
+----+-------------+--------+------------+-------+---------------+---------+---------+------+------+----------+-------------+
| 1 | SIMPLE | orders | NULL | range | PRIMARY | PRIMARY | 8 | NULL | 4 | 25.00 | Using where |
+----+-------------+--------+------------+-------+---------------+---------+---------+------+------+----------+-------------+
B)
mysql> explain select * from orders where customer_id < 2 and value = 1;
+----+-------------+--------+------------+-------+---------------+---------+---------+------+------+----------+-------------+
| id | select_type | table | partitions | type | possible_keys | key | key_len | ref | rows | filtered | Extra |
+----+-------------+--------+------------+-------+---------------+---------+---------+------+------+----------+-------------+
| 1 | SIMPLE | orders | NULL | range | PRIMARY | PRIMARY | 4 | NULL | 4 | 25.00 | Using where |
+----+-------------+--------+------------+-------+---------------+---------+---------+------+------+----------+-------------+
why explain statement (A) shows keylen as 8 but (B) shows keylen as 4
mysql database mysql-5.7 mysql-5.6 mysql-5.5
add a comment |
Hi i'm newbie to MySQL World.
When i read about MySQL Range Optimization some of question were raised related to multipart index.
MySQL 5.7 Doc
(http://jorgenloland.blogspot.com/2011/08/mysql-range-access-method-explained.html)
Question 1 :
What is the meaning of single and continuous intervals ?
Question 2 :
Related to Multipart index and keylen
Table Structure
Create table orders(customer_id int,value int,name varchar(20),primary key(customer_id,value)) ;
A)
mysql> explain select * from orders where customer_id <= 2 and value = 1;
+----+-------------+--------+------------+-------+---------------+---------+---------+------+------+----------+-------------+
| id | select_type | table | partitions | type | possible_keys | key | key_len | ref | rows | filtered | Extra |
+----+-------------+--------+------------+-------+---------------+---------+---------+------+------+----------+-------------+
| 1 | SIMPLE | orders | NULL | range | PRIMARY | PRIMARY | 8 | NULL | 4 | 25.00 | Using where |
+----+-------------+--------+------------+-------+---------------+---------+---------+------+------+----------+-------------+
B)
mysql> explain select * from orders where customer_id < 2 and value = 1;
+----+-------------+--------+------------+-------+---------------+---------+---------+------+------+----------+-------------+
| id | select_type | table | partitions | type | possible_keys | key | key_len | ref | rows | filtered | Extra |
+----+-------------+--------+------------+-------+---------------+---------+---------+------+------+----------+-------------+
| 1 | SIMPLE | orders | NULL | range | PRIMARY | PRIMARY | 4 | NULL | 4 | 25.00 | Using where |
+----+-------------+--------+------------+-------+---------------+---------+---------+------+------+----------+-------------+
why explain statement (A) shows keylen as 8 but (B) shows keylen as 4
mysql database mysql-5.7 mysql-5.6 mysql-5.5
add a comment |
Hi i'm newbie to MySQL World.
When i read about MySQL Range Optimization some of question were raised related to multipart index.
MySQL 5.7 Doc
(http://jorgenloland.blogspot.com/2011/08/mysql-range-access-method-explained.html)
Question 1 :
What is the meaning of single and continuous intervals ?
Question 2 :
Related to Multipart index and keylen
Table Structure
Create table orders(customer_id int,value int,name varchar(20),primary key(customer_id,value)) ;
A)
mysql> explain select * from orders where customer_id <= 2 and value = 1;
+----+-------------+--------+------------+-------+---------------+---------+---------+------+------+----------+-------------+
| id | select_type | table | partitions | type | possible_keys | key | key_len | ref | rows | filtered | Extra |
+----+-------------+--------+------------+-------+---------------+---------+---------+------+------+----------+-------------+
| 1 | SIMPLE | orders | NULL | range | PRIMARY | PRIMARY | 8 | NULL | 4 | 25.00 | Using where |
+----+-------------+--------+------------+-------+---------------+---------+---------+------+------+----------+-------------+
B)
mysql> explain select * from orders where customer_id < 2 and value = 1;
+----+-------------+--------+------------+-------+---------------+---------+---------+------+------+----------+-------------+
| id | select_type | table | partitions | type | possible_keys | key | key_len | ref | rows | filtered | Extra |
+----+-------------+--------+------------+-------+---------------+---------+---------+------+------+----------+-------------+
| 1 | SIMPLE | orders | NULL | range | PRIMARY | PRIMARY | 4 | NULL | 4 | 25.00 | Using where |
+----+-------------+--------+------------+-------+---------------+---------+---------+------+------+----------+-------------+
why explain statement (A) shows keylen as 8 but (B) shows keylen as 4
mysql database mysql-5.7 mysql-5.6 mysql-5.5
Hi i'm newbie to MySQL World.
When i read about MySQL Range Optimization some of question were raised related to multipart index.
MySQL 5.7 Doc
(http://jorgenloland.blogspot.com/2011/08/mysql-range-access-method-explained.html)
Question 1 :
What is the meaning of single and continuous intervals ?
Question 2 :
Related to Multipart index and keylen
Table Structure
Create table orders(customer_id int,value int,name varchar(20),primary key(customer_id,value)) ;
A)
mysql> explain select * from orders where customer_id <= 2 and value = 1;
+----+-------------+--------+------------+-------+---------------+---------+---------+------+------+----------+-------------+
| id | select_type | table | partitions | type | possible_keys | key | key_len | ref | rows | filtered | Extra |
+----+-------------+--------+------------+-------+---------------+---------+---------+------+------+----------+-------------+
| 1 | SIMPLE | orders | NULL | range | PRIMARY | PRIMARY | 8 | NULL | 4 | 25.00 | Using where |
+----+-------------+--------+------------+-------+---------------+---------+---------+------+------+----------+-------------+
B)
mysql> explain select * from orders where customer_id < 2 and value = 1;
+----+-------------+--------+------------+-------+---------------+---------+---------+------+------+----------+-------------+
| id | select_type | table | partitions | type | possible_keys | key | key_len | ref | rows | filtered | Extra |
+----+-------------+--------+------------+-------+---------------+---------+---------+------+------+----------+-------------+
| 1 | SIMPLE | orders | NULL | range | PRIMARY | PRIMARY | 4 | NULL | 4 | 25.00 | Using where |
+----+-------------+--------+------------+-------+---------------+---------+---------+------+------+----------+-------------+
why explain statement (A) shows keylen as 8 but (B) shows keylen as 4
mysql database mysql-5.7 mysql-5.6 mysql-5.5
mysql database mysql-5.7 mysql-5.6 mysql-5.5
edited Nov 23 '18 at 13:57
RKs
asked Nov 19 '18 at 16:16
RKsRKs
63
63
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