Mycat实战之主键数据库自增方式
创建一个 person表，主键为Id，hash方式分片，主键自增（采用数据库方式）
#person表结构如下
Id，主键，Mycat自增主键
name,字符串，16字节最长
school,毕业学校，数字，1-1000范围，是学校编号
age，年龄，18-60
addr,地址，32字节，建议为 gz-tianhe（城市-地区两级 枚举的仿真数据）
zcode,邮编，
birth，生日，为日期类型， 1980到2010年之间随机的日期
score，得分，0-100分
1. 机器环境
192.168.2.136 mycat1
192.168.2.135 mysql
192.168.2.134 test
2. mycat参数文件配置
编辑server.xml
[root@localhost conf]# more /usr/local/mycat/conf/server.xml |grep sequnceHandlerType
<!--<property name="sequnceHandlerType">0</property>-->
#0 代表文件方式，
#1 代表数据库方式
#2 代表本地时间戳方式
重启mycat生效 登陆管理端口验证
[root@localhost conf]# mycat restart
Stopping Mycat-server...
Stopped Mycat-server.
Starting Mycat-server...
3.数据库配置，创建 sequence 相关的表以及 function
#所有操作都在 db1 上
#创建 MYCAT_SEQUENCE 表
DROP TABLE IF EXISTS MYCAT_SEQUENCE;
– name sequence 名称
– current_value 当前 value
– increment 增长步长! mycat在数据库中一次读取多少个sequence
CREATE TABLE MYCAT_SEQUENCE (name VARCHAR(50) NOT NULL,current_value INT
NOT NULL,increment INT NOT NULL DEFAULT 100, PRIMARY KEY(name))
ENGINE=InnoDB;
#插入一条 sequence
INSERT INTO MYCAT_SEQUENCE(name,current_value,increment) VALUES (‘PERSON’,
100000, 100);
#创建相关 function
#获取当前 sequence 的值 (返回当前值,增量)
DROP FUNCTION IF EXISTS mycat_seq_currval;
DELIMITER ;;
CREATE DEFINER=`root`@`%` FUNCTION `mycat_seq_currval`(seq_name VARCHAR(50))
RETURNS VARCHAR(64) charset utf8
DETERMINISTIC
BEGIN
DECLARE retval VARCHAR(64);
SET retval="-999999999,null";
SELECT CONCAT(CAST(current_value AS CHAR),",",CAST(increment AS
CHAR) ) INTO retval
FROM MYCAT_SEQUENCE WHERE NAME = seq_name;
RETURN retval ;
END
;;
DELIMITER ;
#设置 sequence 值
DROP FUNCTION IF EXISTS mycat_seq_setval;
DELIMITER ;;
CREATE DEFINER=`root`@`%` FUNCTION mycat_seq_setval(seq_name VARCHAR(50),value INTEGER)
RETURNS varchar(64) CHARSET utf8
DETERMINISTIC
BEGIN
UPDATE MYCAT_SEQUENCE
SET current_value = value
WHERE name = seq_name;
RETURN mycat_seq_currval(seq_name);
END ;;
DELIMITER ;
#获取下一个 sequence 值
DROP FUNCTION IF EXISTS `mycat_seq_nextval`;
DELIMITER ;;
CREATE DEFINER=`root`@`%` FUNCTION `mycat_seq_nextval`(seq_name VARCHAR(50))
RETURNS VARCHAR(64)CHARSET utf8
DETERMINISTIC
BEGIN
UPDATE MYCAT_SEQUENCE SET current_value = current_value + increment
WHERE NAME = seq_name;
RETURN mycat_seq_currval(seq_name);
END;;
DELIMITER ;
4.修改mycat 相关配置
sequence_db_conf.properties
[root@mysqldb conf]# vi sequence_db_conf.properties
#sequence stored in datanode
GLOBAL=dn1
COMPANY=dn1
CUSTOMER=dn1
ORDERS=dn1
PERSON=dn1
配置schema.xml
<!DOCTYPE mycat:schema SYSTEM "schema.dtd">
<mycat:schema xmlns:mycat="http://org.opencloudb/">
<schema name="TESTDB" checkSQLschema="false" sqlMaxLimit="100">
<table name="person" primaryKey="id" autoIncrement="true"
dataNode="dn1,dn2,dn3" rule="sharding-by-murmurperson" />
</schema>
<dataNode name="dn1" dataHost="mysqlserver" database="db1" />
<dataNode name="dn2" dataHost="mysqlserver" database="db2" />
<dataNode name="dn3" dataHost="mysqlserver" database="db3" />
<!--######### TESTDB ########-->
<dataHost name="mysqlserver" maxCon="1000" minCon="10" balance="0"
writeType="0" dbType="mysql" dbDriver="native" switchType="1" slaveThreshold="100">
<heartbeat>select user()</heartbeat>
<writeHost host="hostM1" url="192.168.2.135:3306" user="root" password="root123">
</writeHost>
</dataHost>
</mycat:schema>
配置rule.xml
<function name="murmur"
class="org.opencloudb.route.function.PartitionByMurmurHash">
<property name="seed">0</property><!-- 默认是0 -->
<property name="count">2</property><!-- 要分片的数据库节点数量，必须指定，否则没法分片 -->
<property name="virtualBucketTimes">160</property><!-- 一个实际的数据库节点被映射为这么多虚拟节点，默认是160倍，也就是虚拟节点数是物理节点数的160倍 -->
<!-- <property name="weightMapFile">weightMapFile</property> 节点的权重，没有指定权重的节点默认是1。以properties文件的格式填写，以从0开始到count-1的整数值也就是节点索引为key，以节点权重值为值。所有权重值必须是正整数，否则以1代替 -->
<!-- <property name="bucketMapPath">/etc/mycat/bucketMapPath</property>
用于测试时观察各物理节点与虚拟节点的分布情况，如果指定了这个属性，会把虚拟节点的murmur hash值与物理节点的映射按行输出到这个文件，没有默认值，如果不指定，就不会输出任何东西 -->
</function>
重启mycat
[root@mycat conf]# mycat restart
Stopping Mycat-server...
Mycat-server was not running.
[mysql@mycat ~]$ mysql -utest -ptest -h192.168.2.136 -P8066
Warning: Using a password on the command line interface can be insecure.
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 4
Server version: 5.5.8-mycat-1.5.1-RELEASE-20161130213509 MyCat Server (OpenCloundDB)
Copyright (c) 2000, 2017, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql>
mysql>
mysql> use TESTDB;
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A
Database changed
mysql> show tables;
+------------------+
| Tables in TESTDB |
+------------------+
| person |
+------------------+
1 row in set (0.00 sec)
5 mycat中创建person表并插入数据验证
#创建 person 表:
CREATE TABLE person(id INT AUTO_INCREMENT PRIMARY KEY,NAME VARCHAR(16),school INT,
age INT, addr VARCHAR(32),zcode VARCHAR(6),birth DATETIME,score INT) ;
#插入数据
insert into person(id,name, school, age, addr, zcode, birth, score)
values(NEXT VALUE FOR MYCATSEQ_PERSON,'xiaoxu', 100, 30,
'shanghai-jiuting','072450','1987-02-01',100);
插入成功！！！
