MyCAT實現MySQL讀寫分離實踐

MyCAT實現MySQL讀寫分離實踐

MyCAT是一個的資料庫中介軟體，基於阿里開源的cobar產品而研發，由幾個有志之士的牛人共同完成並開源。提供高可用性資料分區叢集，自動故障切換，高可用性 ，支援讀寫分離，支援MySQL雙主多從，以及一主多從的模式 ，支援全域表，資料自動分區到多個節點，用於高效表關聯查詢 ，支援專屬的基於E-R 關係的分區策略，實現了高效的表關聯查詢多平台支援，部署和實施簡單。

今天來實踐下用MyCAT實現MySQL的讀寫分離，1.配置MySQL端主從資料同步，2.用MyCAT實現讀寫分離,配置MySQL端主從資料同步不作講解，這裡詳細介紹下用MyCAT實現資料讀寫分離

建立資料庫讀庫和寫庫

分別在兩個不同主機下建立兩個大庫，讀庫r和寫庫w,在讀庫r下建立3個資料庫分區（db1,db2,db3），在寫庫w下也建立3個分區（db1,db2,db3）。

1.db1分區指令碼

/*
Navicat MySQL Data Transfer
Source Server        : mysql
Source Server Version : 50527
Source Host          : localhost:3306
Source Database      : db1
Target Server Type    : MYSQL
Target Server Version : 50527
File Encoding        : 65001
Date: 2016-01-27 15:48:40
*/
SET FOREIGN_KEY_CHECKS=0;
-- ----------------------------
-- Table structure for `company`
-- ----------------------------
DROP TABLE IF EXISTS `company`;
CREATE TABLE `company` (
  `ID` bigint(20) NOT NULL DEFAULT '0',
  PRIMARY KEY (`ID`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
-- ----------------------------
-- Records of company
-- ----------------------------
-- ----------------------------
-- Table structure for `customer`
-- ----------------------------
DROP TABLE IF EXISTS `customer`;
CREATE TABLE `customer` (
  `ID` bigint(20) NOT NULL DEFAULT '0',
  `sharding_id` bigint(20) DEFAULT NULL,
  PRIMARY KEY (`ID`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
-- ----------------------------
-- Records of customer
-- ----------------------------
INSERT INTO `customer` VALUES ('1', null);
INSERT INTO `customer` VALUES ('4', '10000');
-- ----------------------------
-- Table structure for `employee`
-- ----------------------------
DROP TABLE IF EXISTS `employee`;
CREATE TABLE `employee` (
  `ID` bigint(20) NOT NULL DEFAULT '0',
  PRIMARY KEY (`ID`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
-- ----------------------------
-- Records of employee
-- ----------------------------
-- ----------------------------
-- Table structure for `goods`
-- ----------------------------
DROP TABLE IF EXISTS `goods`;
CREATE TABLE `goods` (
  `ID` bigint(20) NOT NULL DEFAULT '0',
  PRIMARY KEY (`ID`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
-- ----------------------------
-- Records of goods
-- ----------------------------
INSERT INTO `goods` VALUES ('11');
-- ----------------------------
-- Table structure for `hotnews`
-- ----------------------------
DROP TABLE IF EXISTS `hotnews`;
CREATE TABLE `hotnews` (
  `ID` bigint(20) NOT NULL DEFAULT '0',
  PRIMARY KEY (`ID`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
-- ----------------------------
-- Records of hotnews
-- ----------------------------
-- ----------------------------
-- Table structure for `mycat_sequence`
-- ----------------------------
DROP TABLE IF EXISTS `mycat_sequence`;
CREATE TABLE `mycat_sequence` (
  `name` varchar(50) NOT NULL,
  `current_value` int(11) NOT NULL,
  `increment` int(11) NOT NULL DEFAULT '100',
  PRIMARY KEY (`name`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
-- ----------------------------
-- Records of mycat_sequence
-- ----------------------------
INSERT INTO `mycat_sequence` VALUES ('GLOBAL', '100400', '100');
-- ----------------------------
-- Table structure for `orders`
-- ----------------------------
DROP TABLE IF EXISTS `orders`;
CREATE TABLE `orders` (
  `ID` bigint(20) NOT NULL DEFAULT '0',
  `customer_id` bigint(20) DEFAULT NULL,
  PRIMARY KEY (`ID`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
-- ----------------------------
-- Records of orders
-- ----------------------------
INSERT INTO `orders` VALUES ('1', '1');
INSERT INTO `orders` VALUES ('4', '4');
-- ----------------------------
-- Table structure for `travelrecord`
-- ----------------------------
DROP TABLE IF EXISTS `travelrecord`;
CREATE TABLE `travelrecord` (
  `ID` bigint(20) NOT NULL DEFAULT '0',
  PRIMARY KEY (`ID`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
-- ----------------------------
-- Records of travelrecord
-- ----------------------------
INSERT INTO `travelrecord` VALUES ('1');
INSERT INTO `travelrecord` VALUES ('4');
INSERT INTO `travelrecord` VALUES ('10001');
INSERT INTO `travelrecord` VALUES ('100400');
-- ----------------------------
-- Function structure for `mycat_seq_currval`
-- ----------------------------
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 ;
-- ----------------------------
-- Function structure for `mycat_seq_nextval`
-- ----------------------------
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 ;
-- ----------------------------
-- Function structure for `mycat_seq_setval`
-- ----------------------------
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 ;

2.db2分區指令碼

/*
Navicat MySQL Data Transfer
Source Server        : mysql
Source Server Version : 50527
Source Host          : localhost:3306
Source Database      : db2
Target Server Type    : MYSQL
Target Server Version : 50527
File Encoding        : 65001
Date: 2016-01-27 15:48:50
*/
SET FOREIGN_KEY_CHECKS=0;
-- ----------------------------
-- Table structure for `company`
-- ----------------------------
DROP TABLE IF EXISTS `company`;
CREATE TABLE `company` (
  `ID` bigint(20) NOT NULL DEFAULT '0',
  PRIMARY KEY (`ID`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
-- ----------------------------
-- Records of company
-- ----------------------------
-- ----------------------------
-- Table structure for `customer`
-- ----------------------------
DROP TABLE IF EXISTS `customer`;
CREATE TABLE `customer` (
  `ID` bigint(20) NOT NULL DEFAULT '0',
  `sharding_id` bigint(20) DEFAULT NULL,
  PRIMARY KEY (`ID`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
-- ----------------------------
-- Records of customer
-- ----------------------------
INSERT INTO `customer` VALUES ('2', null);
INSERT INTO `customer` VALUES ('5', '10010');
-- ----------------------------
-- Table structure for `employee`
-- ----------------------------
DROP TABLE IF EXISTS `employee`;
CREATE TABLE `employee` (
  `ID` bigint(20) NOT NULL DEFAULT '0',
  PRIMARY KEY (`ID`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
-- ----------------------------
-- Records of employee
-- ----------------------------
-- ----------------------------
-- Table structure for `goods`
-- ----------------------------
DROP TABLE IF EXISTS `goods`;
CREATE TABLE `goods` (
  `ID` bigint(20) NOT NULL DEFAULT '0',
  PRIMARY KEY (`ID`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
-- ----------------------------
-- Records of goods
-- ----------------------------
INSERT INTO `goods` VALUES ('11');
-- ----------------------------
-- Table structure for `hotnews`
-- ----------------------------
DROP TABLE IF EXISTS `hotnews`;
CREATE TABLE `hotnews` (
  `ID` bigint(20) NOT NULL DEFAULT '0',
  PRIMARY KEY (`ID`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
-- ----------------------------
-- Records of hotnews
-- ----------------------------
INSERT INTO `hotnews` VALUES ('1');
-- ----------------------------
-- Table structure for `orders`
-- ----------------------------
DROP TABLE IF EXISTS `orders`;
CREATE TABLE `orders` (
  `ID` bigint(20) NOT NULL DEFAULT '0',
  `customer_id` bigint(20) DEFAULT NULL,
  PRIMARY KEY (`ID`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
-- ----------------------------
-- Records of orders
-- ----------------------------
INSERT INTO `orders` VALUES ('2', '2');
INSERT INTO `orders` VALUES ('5', '5');
-- ----------------------------
-- Table structure for `travelrecord`
-- ----------------------------
DROP TABLE IF EXISTS `travelrecord`;
CREATE TABLE `travelrecord` (
  `ID` bigint(20) NOT NULL DEFAULT '0',
  PRIMARY KEY (`ID`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
-- ----------------------------
-- Records of travelrecord
-- ----------------------------
INSERT INTO `travelrecord` VALUES ('2');

3.db3分區指令碼

/*
Navicat MySQL Data Transfer
Source Server        : mysql
Source Server Version : 50527
Source Host          : localhost:3306
Source Database      : db3
Target Server Type    : MYSQL
Target Server Version : 50527
File Encoding        : 65001
Date: 2016-01-27 15:48:58
*/
SET FOREIGN_KEY_CHECKS=0;
-- ----------------------------
-- Table structure for `company`
-- ----------------------------
DROP TABLE IF EXISTS `company`;
CREATE TABLE `company` (
  `ID` bigint(20) NOT NULL DEFAULT '0',
  PRIMARY KEY (`ID`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
-- ----------------------------
-- Records of company
-- ----------------------------
-- ----------------------------
-- Table structure for `hotnews`
-- ----------------------------
DROP TABLE IF EXISTS `hotnews`;
CREATE TABLE `hotnews` (
  `ID` bigint(20) NOT NULL DEFAULT '0',
  PRIMARY KEY (`ID`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
-- ----------------------------
-- Records of hotnews
-- ----------------------------
INSERT INTO `hotnews` VALUES ('2');
-- ----------------------------
-- Table structure for `travelrecord`
-- ----------------------------
DROP TABLE IF EXISTS `travelrecord`;
CREATE TABLE `travelrecord` (
  `ID` bigint(20) NOT NULL DEFAULT '0',
  PRIMARY KEY (`ID`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
-- ----------------------------
-- Records of travelrecord
-- ----------------------------
INSERT INTO `travelrecord` VALUES ('3');
 

 

分別在兩個讀寫庫中建立三個分區
 
schema.xml中配置讀寫分離

<?xml version="1.0"?>
<!DOCTYPE mycat:schema SYSTEM "schema.dtd">
<mycat:schema xmlns:mycat="http://org.opencloudb/">
<schema name="TESTDB" checkSQLschema="false" sqlMaxLimit="100">
<!-- auto sharding by id (long) -->
<table name="travelrecord" dataNode="dn1,dn2,dn3" rule="auto-sharding-long" />
<!-- global table is auto cloned to all defined data nodes ,so can join
with any table whose sharding node is in the same data node -->
<table name="company" primaryKey="ID" type="global" dataNode="dn1,dn2,dn3" />
<table name="goods" primaryKey="ID" type="global" dataNode="dn1,dn2" />
<!-- random sharding using mod sharind rule -->
<table name="hotnews" primaryKey="ID" dataNode="dn1,dn2,dn3"
rule="mod-long" />
<table name="employee" primaryKey="ID" dataNode="dn1,dn2"
rule="sharding-by-intfile" />
<table name="customer" primaryKey="ID" dataNode="dn1,dn2"
rule="sharding-by-intfile">
<childTable name="orders" primaryKey="ID" joinKey="customer_id"
parentKey="id">
</childTable>
</table>
<table name="mycat_sequence" dataNode="dn1" />
</schema>
<dataNode name="dn1" dataHost="localhost1" database="db1" />
<dataNode name="dn2" dataHost="localhost1" database="db2" />
<dataNode name="dn3" dataHost="localhost1" database="db3" />
<dataHost name="localhost1" maxCon="1000" minCon="10" balance="3"
writeType="0" dbType="mysql" dbDriver="native" switchType="1"  slaveThreshold="100">
<heartbeat>select user()</heartbeat>
<!-- can have multi write hosts -->
<writeHost host="hostM1" url="ip1:3306" user="root" password="123456">
    <!-- can have multi read hosts -->
    <readHost host="hostS1" url="ip2:3306" user="root" password="123456" weight="1" />
</writeHost>
</dataHost>
</mycat:schema>
 

其中balance屬性

負載平衡類型，目前取值有3種： 1. balance="0", 開啟讀寫分離機制，所有讀操作都發送到當前可用的writeHost上。 2. balance="1"，全部的readHost和stand by writeHost參與select語句的負載平衡 3. balance="2"，所有讀操作都隨機在writeHost、readhost上分發。 4. balance="3"，所有讀請求隨機的分發到wiriterHost對應的readhost執行，writerHost不負擔讀壓力

以上ip1,ip2分別填寫真真實位址
 
測試讀寫分離

啟動mycat服務，

測試讀資料：select * from travelrecord

可見資料是從讀庫中讀取

測試寫資料：insert into travelrecord (ID) values(88)

查看讀庫，沒值，寫庫有一條88的記錄

MyCAT實現MySQL的讀寫分離 

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