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mycat读写分离与主从切换

1，分库分表的优缺点、以及为什么分表方式无法成为主流？

分表：在台server上，长处是易维护，相似表分区。缺点是在一台dbserver上。无法分担IO、负载集中。

分库：在多台server上，长处是分担IO、负载均衡，缺点是较不易维护、数据统计以及jion操作有些难度。

数据库切分的目的是为了分担IO、负载均衡，分表无法达到最佳的要求。所以无法成为主流。

2，准备主库

tar -xvf mysql-5.6.12.tar.gz
cd mysql-5.6.12

time cmake . -DCMAKE_INSTALL_PREFIX=/usr/local/mysql56m1 -DMYSQL_DATADIR=/home/data/mysql56m1/data -DWITH_INNOBASE_STORAGE_ENGINE=1 -DMYSQL_UNIX_ADDR==/usr/local/mysql56m1/mysql.sock -DMYSQL_USER=mysql -DDEFAULT_CHARSET=utf8 -DDEFAULT_COLLATION=utf8_general_ci

time make
time make install 

 chown -R mysql /home/data/
 chgrp -R mysql /home/data/
 chown -R mysql /usr/local/mysql

 chown -R mysql /usr/local/mysql56m1
 chgrp -R mysql /usr/local/mysql

 chgrp -R mysql /usr/local/mysql56m1/
 mkdir -p /home/data/mysql56m1/binlog/
 chown -R mysql.mysql /home/data/mysql56m1/binlog/
 mkdir -p /home/data/mysql5610/binlog/
 chown -R mysql.mysql /home/data/

cd /usr/local/mysql56m1
time scripts/mysql_install_db  --user=mysql --basedir=/usr/local/mysql56m1 --datadir=/home/data/mysql56m1/data --defaults-file=/usr/local/mysql56m1/my.cnf

cp support-files/mysql.server /etc/init.d/mysql56m1
chmod 700 /etc/init.d/mysql56m1
echo "export PATH=$PATH:/usr/local/mysql56m1/bin">>/etc/profile 
source /etc/profile
chkconfig --add mysql56m1

service mysql56m1 start

3。准备备库

tar -xvf mysql-5.6.12.tar.gz
cd mysql-5.6.12

time cmake . -DCMAKE_INSTALL_PREFIX=/usr/local/mysql56s1 -DMYSQL_DATADIR=/home/data/mysql56s1/data -DWITH_INNOBASE_STORAGE_ENGINE=1 -DMYSQL_UNIX_ADDR==/usr/local/mysql56s1/mysql.sock -DMYSQL_USER=mysql -DDEFAULT_CHARSET=utf8 -DDEFAULT_COLLATION=utf8_general_ci

time make
time make install 


 chown -R mysql /home/data/
 chgrp -R mysql /home/data/
 chown -R mysql /usr/local/mysql

 chown -R mysql /usr/local/mysql56s1
 chgrp -R mysql /usr/local/mysql

 chgrp -R mysql /usr/local/mysql56s1/
 mkdir -p /home/data/mysql56s1/binlog/
 chown -R mysql.mysql /home/data/mysql56s1/binlog/
 mkdir -p /home/data/mysql5610/binlog/
 chown -R mysql.mysql /home/data/


cd /usr/local/mysql56s1
time scripts/mysql_install_db  --user=mysql --basedir=/usr/local/mysql56s1 --datadir=/home/data/mysql56s1/data --defaults-file=/usr/local/mysql56s1/my.cnf

cp support-files/mysql.server /etc/init.d/mysql56s1
chmod 700 /etc/init.d/mysql56s1
echo "export PATH=$PATH:/usr/local/mysql56s1/bin">>/etc/profile 
source /etc/profile
chkconfig --add mysql56s1
service mysql56s1 start

4，搭建主从环境

在一台server。主3317端口，从3327端口。
主库备库上，加入复制帐号：

GRANT REPLICATION SLAVE ON . TO ‘repl’@’10.254.%’ IDENTIFIED BY ‘mycatms’;

在备库上3327端口上设置复制：

stop slave;
reset slave;
change master to master_user='repl', master_password='mycatms', master_host='127.0.0.1',master_port=3317, master_log_file='mysql-bin.000003',master_log_pos=840;
start slave;
show slave statusG;

主库：3317端口
这里写图片描写叙述

从库：3327端口

这里写图片描写叙述

数据同步測试：
这里写图片描写叙述

5。数据同步測试：

配置schema.xml：
然后改动mycat的schema.xml：
balance为1：让所有的readHost及备用的writeHost參与select的负载均衡。

switchType为2：基于MySQL主从同步的状态决定是否切换。

heartbeat：主从切换的心跳语句必须为show slave status。
这里写图片描写叙述

5.0 数据录入：

mysql> explain create table company(id int not null primary key,name varchar(100));
+-----------+---------------------------------------------------------------------+
| DATA_NODE | SQL                                                                 |
+-----------+---------------------------------------------------------------------+
| dn1       | create table company(id int not null primary key,name varchar(100)) |
| dn2       | create table company(id int not null primary key,name varchar(100)) |
| dn3       | create table company(id int not null primary key,name varchar(100)) |
+-----------+---------------------------------------------------------------------+
3 rows in set (0.00 sec)

mysql> create table company(id int not null primary key,name varchar(100));
Query OK, 0 rows affected (0.01 sec)

mysql> explain  insert into company(id,name) values(1,'alibaba');
+-----------+--------------------------------------------------+
| DATA_NODE | SQL                                              |
+-----------+--------------------------------------------------+
| dn1       | insert into company(id,name) values(1,'alibaba') |
| dn2       | insert into company(id,name) values(1,'alibaba') |
| dn3       | insert into company(id,name) values(1,'alibaba') |
+-----------+--------------------------------------------------+
3 rows in set (0.10 sec)

mysql>  insert into company(id,name) values(1,'alibaba');
Query OK, 1 row affected (0.00 sec)

mysql>

5.1主库验证：

[root@wgq_idc_squid_1_11 logs]# /usr/local/mysql56m1/bin/mysql -uroot -p -P3317 --socket=/usr/local/mysql56m1/mysql.sock -e "select @@port;select * from db1.company";
Enter password: 
+--------+
| @@port |
+--------+
|   3317 |
+--------+
+----+---------+
| id | name    |
+----+---------+
|  1 | alibaba |
+----+---------+
[root@wgq_idc_squid_1_11 logs]#

5.2从库验证：

[root@wgq_idc_squid_1_11 logs]# /usr/local/mysql56s1/bin/mysql -uroot -p -P3327 --socket=/usr/local/mysql56s1/mysql.sock -e "select @@port;select * from db1.company";
Enter password: 
+--------+
| @@port |
+--------+
|   3327 |
+--------+
+----+---------+
| id | name    |
+----+---------+
|  1 | alibaba |
+----+---------+
[root@wgq_idc_squid_1_11 logs]#

这里写图片描写叙述

6，读写分离模式

6.1然后改动mycat的schema.xml：

balance为1：让所有的readHost及备用的writeHost參与select的负载均衡。

switchType为2：基于MySQL主从同步的状态决定是否切换。
heartbeat：主从切换的心跳语句必须为show slave status。

这里写图片描写叙述
有配置读节点：

6.2 打开debug模式

[root@wgq_idc_squid_1_11 conf]# vim log4j.xml
<level value="info" /> 变成  <level value="debug" />

6.3 运行查询读操作

在mycat窗体上运行select操作：

mysql> explain select * from company where id=1;
+-----------+----------------------------------------------+
| DATA_NODE | SQL                                          |
+-----------+----------------------------------------------+
| dn3       | SELECT * FROM company WHERE id = 1 LIMIT 100 |
+-----------+----------------------------------------------+
1 row in set (0.14 sec)

mysql> select * from company where id=1;
+----+---------+
| id | name    |
+----+---------+
|  1 | alibaba |
+----+---------+
1 row in set (0.01 sec)

mysql>

后台日志显示出仅仅在3327上运行：

01/18 01:35:01.536  DEBUG [$_NIOREACTOR-3-RW] (PhysicalDBPool.java:452) -select read source hostS2 for dataHost:wgq_idc_mon_1_11
01/18 01:35:01.537  DEBUG [$_NIOREACTOR-3-RW] (MySQLConnection.java:445) -con need syn ,total syn cmd 2 commands SET names latin1;SET SESSION TRANSACTION ISOLATION LEVEL REPEATABLE READ;schema change:false con:MySQLConnection [id=14, lastTime=1453052101537, user=root, schema=db1, old shema=db1, borrowed=true, fromSlaveDB=false, threadId=3326, charset=latin1, txIsolation=0, autocommit=true, attachment=dn1{SELECT *
FROM company
WHERE id = 1
LIMIT 100}, respHandler=SingleNodeHandler [node=dn1{SELECT *
FROM company
WHERE id = 1
LIMIT 100}, packetId=0], host=127.0.0.1, port=3327, statusSync=null, writeQueue=0, modifiedSQLExecuted=false]
01/18 01:35:01.546  DEBUG [$_NIOREACTOR-2-RW] (NonBlockingSession.java:229) -release connection MySQLConnection [id=14, lastTime=1453052101529, user=root, schema=db1, old shema=db1, borrowed=true, fromSlaveDB=false, threadId=3326, charset=latin1, txIsolation=3, autocommit=true, attachment=dn1{SELECT *
FROM company
WHERE id = 1
LIMIT 100}, respHandler=SingleNodeHandler [node=dn1{SELECT *
FROM company
WHERE id = 1
LIMIT 100}, packetId=5], host=127.0.0.1, port=3327, statusSync=org.opencloudb.mysql.nio.MySQLConnection$StatusSync@7fb43f0f, writeQueue=0, modifiedSQLExecuted=false]
01/18 01:35:01.547  DEBUG [$_NIOREACTOR-2-RW] (PhysicalDatasource.java:403) -release channel MySQLConnection [id=14, lastTime=1453052101529, user=root, schema=db1, old shema=db1, borrowed=true, fromSlaveDB=false, threadId=3326, charset=latin1, txIsolation=3, autocommit=true, attachment=null, respHandler=null, host=127.0.0.1, port=3327, statusSync=null, writeQueue=0, modifiedSQLExecuted=false]
^C

这里写图片描写叙述

6.4 运行写操作

Mycat窗体写操作：
这里写图片描写叙述

后台log显示写操作在3317上：
这里写图片描写叙述

01/18 01:39:54.550  DEBUG [$_NIOREACTOR-3-RW] (NonBlockingSession.java:229) -release connection MySQLConnection [id=7, lastTime=1453052394535, user=root, schema=db3, old shema=db3, borrowed=true, fromSlaveDB=false, threadId=163, charset=latin1, txIsolation=3, autocommit=true, attachment=dn3{insert into company values(3,'baidu')}, respHandler=org.opencloudb.mysql.nio.handler.MultiNodeQueryHandler@42bed1e7, host=127.0.0.1, port=3317, statusSync=null, writeQueue=0, modifiedSQLExecuted=true]
01/18 01:39:54.550  DEBUG [$_NIOREACTOR-3-RW] (PhysicalDatasource.java:403) -release channel MySQLConnection [id=7, lastTime=1453052394535, user=root, schema=db3, old shema=db3, borrowed=true, fromSlaveDB=false, threadId=163, charset=latin1, txIsolation=3, autocommit=true, attachment=null, respHandler=null, host=127.0.0.1, port=3317, statusSync=null, writeQueue=0, modifiedSQLExecuted=false]
01/18 01:39:54.550  DEBUG [$_NIOREACTOR-3-RW] (MultiNodeQueryHandler.java:171) -received ok response ,executeResponse:true from MySQLConnection [id=3, lastTime=1453052394535, user=root, schema=db2, old shema=db2, borrowed=true, fromSlaveDB=false, threadId=162, charset=latin1, txIsolation=3, autocommit=true, attachment=dn2{insert into company values(3,'baidu')}, respHandler=org.opencloudb.mysql.nio.handler.MultiNodeQueryHandler@42bed1e7, host=127.0.0.1, port=3317, statusSync=null, writeQueue=0, modifiedSQLExecuted=true]
01/18 01:39:54.551  DEBUG [$_NIOREACTOR-3-RW] (NonBlockingSession.java:229) -release connection MySQLConnection [id=3, lastTime=1453052394535, user=root, schema=db2, old shema=db2, borrowed=true, fromSlaveDB=false, threadId=162, charset=latin1, txIsolation=3, autocommit=true, attachment=dn2{insert into company values(3,'baidu')}, respHandler=org.opencloudb.mysql.nio.handler.MultiNodeQueryHandler@42bed1e7, host=127.0.0.1, port=3317, statusSync=null, writeQueue=0, modifiedSQLExecuted=true]
01/18 01:39:54.551  DEBUG [$_NIOREACTOR-3-RW] (PhysicalDatasource.java:403) -release channel MySQLConnection [id=3, lastTime=1453052394535, user=root, schema=db2, old shema=db2, borrowed=true, fromSlaveDB=false, threadId=162, charset=latin1, txIsolation=3, autocommit=true, attachment=null, respHandler=null, host=127.0.0.1, port=3317, statusSync=null, writeQueue=0, modifiedSQLExecuted=false]

Check下主从数据是否都已经写入了：
主库3317端口：
这里写图片描写叙述
从裤3327端口：

7，主从切换測试

7.1 mycat托管配置例如以下

     <dataHost name="wgq_idc_mon_1_11" maxCon="1000" minCon="10" balance="1"
                writeType="0" dbType="mysql" dbDriver="native" switchType="2"  slaveThreshold="100">
                <heartbeat>show slave status</heartbeat>
                <!-- can have multi write hosts -->
                <writeHost host="hostM1" url="127.0.0.1:3317" user="root" password="">
                        <readHost host="hostR1" url="127.0.0.1:3327" user="root" password=""/>
                </writeHost>
                <writeHost host="hostS2" url="127.0.0.1:3327" user="root" password="" />
        </dataHost>

7.2 关闭主库。写操作切换到从裤3327端口

关闭主库
这里写图片描写叙述

[root@wgq_idc_squid_1_11 conf]# service mysql56m1 stop
Shutting down MySQL....                                    [确定]
[root@wgq_idc_squid_1_11 conf]#

Mycat后台报错：

01/18 01:50:01.037   INFO [Timer0] (PhysicalDatasource.java:373) -not ilde connection in pool,create new connection for hostM1 of schema db1
01/18 01:50:01.038   INFO [$_NIOConnector] (AbstractConnection.java:458) -close connection,reason:java.net.ConnectException: 拒绝连接 ,MySQLConnection [id=0, lastTime=1453053001035, user=root, schema=db1, old shema=db1, borrowed=false, fromSlaveDB=false, threadId=0, charset=utf8, txIsolation=0, autocommit=true, attachment=null, respHandler=null, host=127.0.0.1, port=3317, statusSync=null, writeQueue=0, modifiedSQLExecuted=false]
01/18 01:50:01.038   INFO [$_NIOConnector] (SQLJob.java:111) -can't get connection for sql :show slave status
01/18 01:50:01.038   WARN [$_NIOREACTOR-1-RW] (MySQLDetector.java:139) -found MySQL master/slave Replication err !!! DBHostConfig [hostName=hostR1, url=127.0.0.1:3327]error reconnecting to master 'repl@127.0.0.1:3317' - retry-time: 60  retries: 1
0

看到主从失效，由于主down了。

由于我们通过mycat配置了主从切换模式，如今3317端口主库down了，那么写库应该自己主动切换到从裤3327上面，假设在mycat上面写入。就应该写到3327端口的从库了，验证例如以下：
（1）在mycat窗体录入数据：
这里写图片描写叙述
（2）在3327端口从裤验证数据：

看到3327端口的数据有新录入的4,meituan的数据。

表明验证成功。
(3) dnindex属性文件里writeHost已经变成了第二个了，例如以下所看到的：
这里写图片描写叙述

7.3 再启动原来的主库3317端口，在mycat上做写操作，后台mysql写库还是原来的从库3327端口：

这个时候就会报错，主从连接失败，原因是从库3327会再又一次从主库3317同步所有的数据，可是从库已经有了，所以就会报错，例如以下所看到的：
这里写图片描写叙述

我採用

stop slave;
 set global sql_slave_skip_counter=1;
 start slave;
 show slave statusG;

一个个忽略过后。就正常了。没有报错：
这里写图片描写叙述

可是这个时候假设再在mycat窗体上录入数据。debug分析面。还是会写入到3327里面去：
这里写图片描写叙述

后台debug日志：
这里写图片描写叙述

OK，至此。mycat主从切换成功。

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原文地址：https://www.cnblogs.com/mfmdaoyou/p/7274610.html

mycat读写分离与主从切换

1， 分库分表的优缺点、以及为什么分表方式无法成为主流？

2， 准备主库

3。 准备备库

4， 搭建主从环境

5。 数据同步測试：

5.0 数据录入：

5.1主库验证：

5.2从库验证：

6，读写分离模式

6.1然后改动mycat的schema.xml：

6.2 打开debug模式

6.3 运行查询读操作

6.4 运行写操作

7，主从切换測试

7.1 mycat托管配置例如以下

7.2 关闭主库。写操作切换到从裤3327端口

7.3 再启动原来的主库3317端口，在mycat上做写操作，后台mysql写库还是原来的从库3327端口：

1，分库分表的优缺点、以及为什么分表方式无法成为主流？

2，准备主库

3。准备备库

4，搭建主从环境

5。数据同步測试：