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 [MySQL][原创]MySQL的LIST分区体验与总结 
软件技术
lhwork 发表于 2008/3/13 22:06:47 |
| 终于有点空闲时间了，测试一下LIST分区，因为LIST在我们的开发中用到。他分区以后再补上。版本：Server version: 5.1.23a-maria-alpha-log MySQL Community Server [Maria] (GPL)一、讲在前面注意：1、ALTER TABLE也可以用于对带分区的表进行重新分区，所以不能在建表之后再用ALTER TABLE语法。2、如果你表中有KEY。用来分区的字段必须是KEY的一部份。3、现在的分区属于水平分区。（垂直分区我们可以自己模拟，这个以后再写）mysql> use t_girlDatabase changed先建立一个普通表mysql> create table category( cid int unsigned not null auto_increment primary key, cname varchar(64) not null, parent_id int not null);Query OK, 0 rows affected (0.00 sec)mysql> create table parent(parent_id int not null auto_increment primary key,pname varchar(64) not null);Query OK, 0 rows affected (0.00 sec)分区表mysql> create table category_part( cid int unsigned not null auto_increment,cname varchar(64) not null,parent_id int not null,primary key (cid,parent_id))partition by list(parent_id)(partition p1 values in (1,2,3,6,9),partition p2 values in (4,5,10,22,23),partition p3 values in (7,8,11,12,13),partition p4 values in (14,15,16,17,20),partition p5 values in (18,19,21,24,25));Query OK, 0 rows affected (0.01 sec)插入数据部分省略。。。建立索引。mysql> create index f_parent_id on category(parent_id);Query OK, 2048000 rows affected (17.61 sec)Records: 2048000 Duplicates: 0 Warnings: 0mysql> show index from category;+----------+------------+-------------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+| Table | Non_unique | Key_name | Seq_in_index | Column_name | Collation | Cardinality | Sub_part | Packed | Null | Index_type | Comment |+----------+------------+-------------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+| category | 0 | PRIMARY | 1 | cid | A | 2048000 | NULL | NULL | | BTREE | | | category | 1 | f_parent_id | 1 | parent_id | A | 25 | NULL | NULL | | BTREE | | +----------+------------+-------------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+2 rows in set (0.00 sec)mysql> create index f_parent_id on category_part(parent_id);Query OK, 2048000 rows affected (18.57 sec)Records: 2048000 Duplicates: 0 Warnings: 0mysql> show index from category_part;+---------------+------------+-------------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+| Table | Non_unique | Key_name | Seq_in_index | Column_name | Collation | Cardinality | Sub_part | Packed | Null | Index_type | Comment |+---------------+------------+-------------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+| category_part | 0 | PRIMARY | 1 | cid | A | 2048000 | NULL | NULL | | BTREE | | | category_part | 0 | PRIMARY | 2 | parent_id | A | 2048000 | NULL | NULL | | BTREE | | | category_part | 1 | f_parent_id | 1 | parent_id | A | 318 | NULL | NULL | | BTREE | | +---------------+------------+-------------+--------------+-------------+-----------+-------------+----------+--------+------+------------+---------+3 rows in set (0.01 sec)mysql> select count(*) from category;+----------+| count(*) |+----------+| 2048000 |+----------+1 row in set (0.00 sec)mysql> select count(*) from category_part;+----------+| count(*) |+----------+| 2048000 |+----------+1 row in set (0.00 sec)mysql> select count(*) from parent;+----------+| count(*) |+----------+| 25 |+----------+1 row in set (0.00 sec)二、具体测试1、我们来看一下查询性能比较：1)、单表查询mysql> select count(*) from category where parent_id in (22,20);+----------+| count(*) |+----------+| 17002 |+----------+1 row in set (0.03 sec)mysql> select count(*) from category_part where parent_id in (22,20);+----------+| count(*) |+----------+| 17002 |+----------+1 row in set (0.02 sec)分区表普通的做了索引的速度上快了一点，不过差别不是很大。mysql> explain select count(*) from category where parent_id in (22,20);+----+-------------+----------+-------+---------------+-------------+---------+------+-------+--------------------------+| id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra |+----+-------------+----------+-------+---------------+-------------+---------+------+-------+--------------------------+| 1 | SIMPLE | category | range | f_parent_id | f_parent_id | 4 | NULL | 14335 | Using where; Using index | +----+-------------+----------+-------+---------------+-------------+---------+------+-------+--------------------------+1 row in set (0.00 sec)mysql> explain partitions select count(*) from category_part where parent_id in (22,20);+----+-------------+---------------+------------+-------+---------------+-------------+---------+------+-------+--------------------------+| id | select_type | table | partitions | type | possible_keys | key | key_len | ref | rows | Extra |+----+-------------+---------------+------------+-------+---------------+-------------+---------+------+-------+--------------------------+| 1 | SIMPLE | category_part | p2,p4 | range | f_parent_id | f_parent_id | 4 | NULL | 16893 | Using where; Using index | +----+-------------+---------------+------------+-------+---------------+-------------+---------+------+-------+--------------------------+1 row in set (0.00 sec)mysql> select count(*) from category where parent_id = 25; +----------+| count(*) |+----------+| 2001 |+----------+1 row in set (0.01 sec)mysql> select count(*) from category_part where parent_id = 25;+----------+| count(*) |+----------+| 2001 |+----------+1 row in set (0.00 sec)mysql> explain select count(*) from category where parent_id = 25;+----+-------------+----------+------+---------------+-------------+---------+-------+-------+-------------+| id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra |+----+-------------+----------+------+---------------+-------------+---------+-------+-------+-------------+| 1 | SIMPLE | category | ref | f_parent_id | f_parent_id | 4 | const | 38240 | Using index | +----+-------------+----------+------+---------------+-------------+---------+-------+-------+-------------+1 row in set (0.00 sec)mysql> explain partitions select count(*) from category_part where parent_id = 25;+----+-------------+---------------+------------+------+---------------+-------------+---------+-------+------+-------------+| id | select_type | table | partitions | type | possible_keys | key | key_len | ref | rows | Extra |+----+-------------+---------------+------------+------+---------------+-------------+---------+-------+------+-------------+| 1 | SIMPLE | category_part | p5 | ref | f_parent_id | f_parent_id | 4 | const | 4647 | Using index | +----+-------------+---------------+------------+------+---------------+-------------+---------+-------+------+-------------+1 row in set (0.00 sec)可以看出，扫描的行数大幅度减少2)、多表内联性能mysql> select count(*) from category as a inner join parent as b using(parent_id); +----------+| count(*) |+----------+| 2048000 |+----------+1 row in set (0.84 sec)mysql> select count(*) from category_part as a inner join parent as b using(parent_id);+----------+| count(*) |+----------+| 2048000 |+----------+1 row in set (0.88 sec)mysql> explain select count(*) from category as a inner join parent as b using(parent_id);+----+-------------+-------+-------+---------------+-------------+---------+--------------------+-------+-------------+| id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra |+----+-------------+-------+-------+---------------+-------------+---------+--------------------+-------+-------------+| 1 | SIMPLE | b | index | PRIMARY | PRIMARY | 4 | NULL | 25 | Using index | | 1 | SIMPLE | a | ref | f_parent_id | f_parent_id | 4 | t_girl.b.parent_id | 81920 | Using index | +----+-------------+-------+-------+---------------+-------------+---------+--------------------+-------+-------------+2 rows in set (0.00 sec)mysql> explain partitions select count(*) from category_part as a inner join parent as b using(parent_id);+----+-------------+-------+----------------+-------+---------------+-------------+---------+--------------------+------+-------------+| id | select_type | table | partitions | type | possible_keys | key | key_len | ref | rows | Extra |+----+-------------+-------+----------------+-------+---------------+-------------+---------+--------------------+------+-------------+| 1 | SIMPLE | b | NULL | index | PRIMARY | PRIMARY | 4 | NULL | 25 | Using index | | 1 | SIMPLE | a | p1,p2,p3,p4,p5 | ref | f_parent_id | f_parent_id | 4 | t_girl.b.parent_id | 6421 | Using index | +----+-------------+-------+----------------+-------+---------------+-------------+---------+--------------------+------+-------------+2 rows in set (0.00 sec)可以看出，扫描的行数大幅度减少mysql> explain select count(*) from category as a inner join parent as b using(parent_id) where a.parent_id =19;+----+-------------+-------+-------+---------------+-------------+---------+-------+------+-------------+| id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra |+----+-------------+-------+-------+---------------+-------------+---------+-------+------+-------------+| 1 | SIMPLE | b | const | PRIMARY | PRIMARY | 4 | const | 1 | Using index | | 1 | SIMPLE | a | ref | f_parent_id | f_parent_id | 4 | const | 6746 | Using index | +----+-------------+-------+-------+---------------+-------------+---------+-------+------+-------------+2 rows in set (0.00 sec)mysql> explain partitions select count(*) from category_part as a inner join parent as b using(parent_id) where a.parent_id =19;+----+-------------+-------+------------+-------+---------------+-------------+---------+-------+------+-------------+| id | select_type | table | partitions | type | possible_keys | key | key_len | ref | rows | Extra |+----+-------------+-------+------------+-------+---------------+-------------+---------+-------+------+-------------+| 1 | SIMPLE | b | NULL | const | PRIMARY | PRIMARY | 4 | const | 1 | Using index | | 1 | SIMPLE | a | p5 | ref | f_parent_id | f_parent_id | 4 | const | 5203 | Using index | +----+-------------+-------+------------+-------+---------------+-------------+---------+-------+------+-------------+2 rows in set (0.00 sec)由以上数据可以看出，数据越大，查询性能提升的越明显！2、下来看看写性能mysql> insert into category(cname,parent_id) values ('Test',1);Query OK, 1 row affected (0.01 sec)mysql> insert into category_part(cname,parent_id) values ('Test',1);Query OK, 1 row affected (0.00 sec)mysql> select * from category into outfile '/tmp/a.txt';ERROR 1086 (HY000): File '/tmp/a.txt' already existsmysql> select * from category into outfile '/tmp/test.dat';Query OK, 2048005 rows affected (2.82 sec)mysql> truncate table category;Query OK, 0 rows affected (0.06 sec)mysql> truncate table category_part;Query OK, 2048005 rows affected (0.10 sec)mysql> load data infile '/tmp/test.dat' into table category;Query OK, 2048005 rows affected (17.67 sec)Records: 2048005 Deleted: 0 Skipped: 0 Warnings: 0mysql> load data infile '/tmp/test.dat' into table category_part;Query OK, 2048005 rows affected (21.62 sec)Records: 2048005 Deleted: 0 Skipped: 0 Warnings: 0可以看出，写性能损失不了多少。牺牲了少许写的性能却大幅度提高了查询的性能，这个是值得的。如果我有什么说的不对的地方，欢迎各位提意见！ |
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回复:[原创]MySQL的LIST分区体验与总结
软件技术
ymm(游客)发表评论于2009/6/15 15:03:39 |
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