memSQL简介

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前言

由前Facebook工程师创办的MemSQL，号称世界上最快的分布式关系型数据库，兼容MySQL但快30倍，能实现每秒150万次事务。原理是仅用内存并将SQL预编译为C++。

MemSQL 提供免费的开发者版本（数据限制32G）和全功能试用版本（试用期30天）

MemSQL 架构：

MemSQL 生态系统：

入门使用

下载

http://developers.memsql.com/docs/1b/guides/starting.html

• 点击右上角的下载链接 http://www.memsql.com/#download ，它会要求你提供email等信息，提交后返回一个license key和下载链接，我们下载developer版的即可。

安装

$ tar -xzf memsqlbin_amd64.tar.gz $ cd memsqlbin 

启动

$ ./check_system $ ./memsqld 

注：

• check_system会告诉系统是否满足需求，比如内核版本，OS版本，64位 等等
• 启动的时候，要加 -u root，否则会报fatal错误；如果你已经有mysql在运行，那么可能需要更改默认启动端口3306为其他端口，比如 3307

./memsqld -u root --port 3307 

• 如果你的RAM没有8G，启动的时候会有警告，但可以忽略。

测试

$ mysql -u root -h 127.0.0.1 -P 3306 --prompt="memsql> " 

memsql> show databases; +--------------------+ | Database | +--------------------+ | information_schema | | memsql | +--------------------+ 2 rows in set (0.00 sec) 

建库：

memsql> create database chris001; Query OK, 0 rows affected (0.08 sec) memsql> show databases; +--------------------+ | Database | +--------------------+ | information_schema | | memsql | | chris001 | +--------------------+ 3 rows in set (0.00 sec) 

建表：

 memsql> use chris001; Database changed memsql> memsql> create table tab001 (id int primary key, name varchar(100), memo varchar(200),num int); Query OK, 0 rows affected (6.71 sec) memsql> memsql> memsql> show tables; +--------------------+ | Tables_in_chris001 | +--------------------+ | tab001 | +--------------------+ 1 row in set (0.00 sec) memsql> desc tab001; +-------+--------------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +-------+--------------+------+-----+---------+-------+ | id | int(11) | NO | PRI | NULL | | | name | varchar(100) | YES | | NULL | | | memo | varchar(200) | YES | | NULL | | | num | int(11) | YES | | NULL | | +-------+--------------+------+-----+---------+-------+ 4 rows in set (0.00 sec) 

插入数据后查询：

memsql> insert into tab001 values (1,'chris','xxx',100); Query OK, 1 row affected (1.82 sec) memsql> memsql> memsql> select * from tab001; +----+-------+------+------+ | id | name | memo | num | +----+-------+------+------+ | 1 | chris | xxx | 100 | +----+-------+------+------+ 1 row in set (0.71 sec) memsql> select * from tab001; +----+-------+------+------+ | id | name | memo | num | +----+-------+------+------+ | 1 | chris | xxx | 100 | +----+-------+------+------+ 1 row in set (0.00 sec) memsql> select * from tab001; +----+-------+------+------+ | id | name | memo | num | +----+-------+------+------+ | 1 | chris | xxx | 100 | +----+-------+------+------+ 1 row in set (0.00 sec) memsql> select * from tab001; +----+-------+------+------+ | id | name | memo | num | +----+-------+------+------+ | 1 | chris | xxx | 100 | +----+-------+------+------+ 1 row in set (0.00 sec) memsql> select count(0) from tab001; +----------+ | count(0) | +----------+ | 1 | +----------+ 1 row in set (0.63 sec) memsql> memsql> select count(0) from tab001; +----------+ | count(0) | +----------+ | 1 | +----------+ 1 row in set (0.00 sec) memsql> select count(0) from tab001; +----------+ | count(0) | +----------+ | 1 | +----------+ 1 row in set (0.00 sec) 

查询的时候，服务端会打出日志：

2012-06-19 10:02:31 INFO: Table chris001.tab001 compiled in 6709 miliseconds (3185 miliseconds for header)

2012-06-19 10:02:31 INFO: Table chris001.tab001 row size 80 bytes (base overhead 32 bytes, column id 4 bytes, column name 12 bytes, column memo 12 bytes, column num 8 bytes)

2012-06-19 10:03:21 INFO: Query chris001.‘insert into tab001 values (?,?,?,?)’ compiled in 1825 miliseconds

2012-06-19 10:03:29 INFO: Query chris001.‘select * from tab001’ compiled in 712 miliseconds

2012-06-19 10:04:58 INFO: Query chris001.‘select count(0) from tab001’ compiled in 632 miliseconds

从以上测试我们看到，两次查询的首次和之后时间对比：

select * from tab001; (0.71 sec) (0.00 sec)

select count(0) from tab001; (0.63 sec) (0.00 sec)

从日志可以知道，首次查询的耗时基本全都花在编译上了 。

关闭

$ killall memsqld