测试表employees.t_emp水平分片，按照emp_no分片
配置mycat schema rule
1 [mycat@redis04 conf]$ cat schema.xml 2 <?xml version="1.0"?> 3 <!DOCTYPE mycat:schema SYSTEM "schema.dtd"> 4 <mycat:schema xmlns:mycat="http://io.mycat/"> 5 <schema name="employees" checkSQLschema="false" sqlMaxLimit="100" dataNode="dn2"> 6 <table name="t_emp" primaryKey="emp_no" dataNode="dn$1-2" rule="mod-long" /> 7 </schema> 8 9 <dataNode name="dn$1-2" dataHost="dh$1-2" database="employees" /> 10 <dataHost name="dh1" maxCon="1000" minCon="10" balance="1" writeType="1" dbType="mysql" dbDriver="native" switchType="1" slaveThreshold="100"> 11 <heartbeat>select user()</heartbeat> 12 <writeHost host="hostM1" url="192.168.20.201:3306" user="ht" password="ocm123" /> 13 </dataHost> 14 <dataHost name="dh2" maxCon="1000" minCon="10" balance="1" writeType="1" dbType="mysql" dbDriver="native" switchType="1" slaveThreshold="100"> 15 <heartbeat>select user()</heartbeat> 16 <writeHost host="hostM2" url="192.168.20.202:3306" user="ht" password="ocm123" /> 17 </dataHost> 18 19 </mycat:schema> 20 21 <tableRule name="mod-long"> 22 <rule> 23 <columns>emp_no</columns> 24 <algorithm>mod-long</algorithm> 25 </rule> 26 </tableRule> 27 28 <function name="mod-long" class="io.mycat.route.function.PartitionByMod"> 29 <!-- how many data nodes --> 30 <property name="count">2</property> 31 </function>
启动mycat，使用mycat explain查看路由
1 mysql> select count(1) from t_emp; 2 +--------+ 3 | COUNT0 | 4 +--------+ 5 | 1000 | 6 +--------+ 7 1 row in set (0.02 sec) 8 9 mysql> explain select count(1) from t_emp; 10 +-----------+------------------------------------------------+ 11 | DATA_NODE | SQL | 12 +-----------+------------------------------------------------+ 13 | dn1 | SELECT COUNT(1) AS COUNT0 FROM t_emp LIMIT 100 | 14 | dn2 | SELECT COUNT(1) AS COUNT0 FROM t_emp LIMIT 100 | 15 +-----------+------------------------------------------------+ 16 2 rows in set (0.00 sec)
如果后面业务量加大2台机器无法满足业务需求需要扩容，本次模拟hash水平拆分扩容扩容。
利用explain查看那些数据需要从redis01 redis02 的部分数据导入到redis03
1 mysql> explain select * from t_emp where emp_no=1002; 2 +-----------+---------------------------------------+ 3 | DATA_NODE | SQL | 4 +-----------+---------------------------------------+ 5 | dn1 | select * from t_emp where emp_no=1002 | 6 +-----------+---------------------------------------+ 7 1 row in set (0.01 sec) 8 9 mysql> explain select * from t_emp where emp_no=1003; 10 +-----------+---------------------------------------+ 11 | DATA_NODE | SQL | 12 +-----------+---------------------------------------+ 13 | dn2 | select * from t_emp where emp_no=1003 | 14 +-----------+---------------------------------------+ 15 1 row in set (0.00 sec) 16 17 mysql> explain select * from t_emp where emp_no=1004; 18 +-----------+---------------------------------------+ 19 | DATA_NODE | SQL | 20 +-----------+---------------------------------------+ 21 | dn3 | select * from t_emp where emp_no=1004 | 22 +-----------+---------------------------------------+ 23 1 row in set (0.01 sec) 24 25 mysql> select 1002%3 from dual; 26 +--------+ 27 | 1002%3 | 28 +--------+ 29 | 0 | 30 +--------+ 31 1 row in set (0.00 sec) 32 33 mysql> select 1003%3 from dual; 34 +--------+ 35 | 1003%3 | 36 +--------+ 37 | 1 | 38 +--------+ 39 1 row in set (0.00 sec) 40 41 mysql> select 1004%3 from dual; 42 +--------+ 43 | 1004%3 | 44 +--------+ 45 | 2 | 46 +--------+ 47 1 row in set (0.00 sec)
上面输出可得规律 emp_no%3=2数据应该放到redis03主机上。
在redis03上创建用户及授权及创建表
create user 'ht'@'192.%' identified by 'ocm123';
GRANT ALL ON employees.* TO 'ht'@'%';
修改mycat' schema rule，重启mycat
1 [mycat@redis04 conf]$ cat schema.xml 2 <?xml version="1.0"?> 3 <!DOCTYPE mycat:schema SYSTEM "schema.dtd"> 4 <mycat:schema xmlns:mycat="http://io.mycat/"> 5 <schema name="employees" checkSQLschema="false" sqlMaxLimit="100" dataNode="dn2"> 6 <table name="t_emp" primaryKey="emp_no" dataNode="dn$1-3" rule="mod-long" /> 7 </schema> 8 9 <dataNode name="dn$1-3" dataHost="dh$1-3" database="employees" /> 10 <dataHost name="dh1" maxCon="1000" minCon="10" balance="1" writeType="1" dbType="mysql" dbDriver="native" switchType="1" slaveThreshold="100"> 11 <heartbeat>select user()</heartbeat> 12 <writeHost host="hostM1" url="192.168.20.201:3306" user="ht" password="ocm123" /> 13 </dataHost> 14 <dataHost name="dh2" maxCon="1000" minCon="10" balance="1" writeType="1" dbType="mysql" dbDriver="native" switchType="1" slaveThreshold="100"> 15 <heartbeat>select user()</heartbeat> 16 <writeHost host="hostM2" url="192.168.20.202:3306" user="ht" password="ocm123" /> 17 </dataHost> 18 <dataHost name="dh3" maxCon="1000" minCon="10" balance="1" writeType="1" dbType="mysql" dbDriver="native" switchType="1" slaveThreshold="100"> 19 <heartbeat>select user()</heartbeat> 20 <writeHost host="hostM2" url="192.168.20.203:3306" user="ht" password="ocm123" /> 21 </dataHost> 22 23 </mycat:schema> 24 25 [mycat@redis04 conf]$ cat rule.xml 26 <?xml version="1.0" encoding="UTF-8"?> 27 <!-- - - Licensed under the Apache License, Version 2.0 (the "License"); 28 - you may not use this file except in compliance with the License. - You 29 may obtain a copy of the License at - - http://www.apache.org/licenses/LICENSE-2.0 30 - - Unless required by applicable law or agreed to in writing, software - 31 distributed under the License is distributed on an "AS IS" BASIS, - WITHOUT 32 WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. - See the 33 License for the specific language governing permissions and - limitations 34 under the License. --> 35 <!DOCTYPE mycat:rule SYSTEM "rule.dtd"> 36 <mycat:rule xmlns:mycat="http://io.mycat/"> 37 <tableRule name="mod-long"> 38 <rule> 39 <columns>emp_no</columns> 40 <algorithm>mod-long</algorithm> 41 </rule> 42 </tableRule> 43 44 <function name="mod-long" class="io.mycat.route.function.PartitionByMod"> 45 <!-- how many data nodes --> 46 <property name="count">3</property> 47 </function> 48 </mycat:rule>
导入导出数据及清理数据
1 redis01 2 select * into outfile '/home/mysql/t1.txt' from employees.t_emp where emp_no%3=2 ; 3 delete from employees.t_emp where emp_no%3=2; 4 redis02 5 select * into outfile '/home/mysql/t2.txt' from employees.t_emp where emp_no%3=2 ; 6 delete from employees.t_emp where emp_no%3=2; 7 redis03 8 load data infile '/home/mysql/t1.txt' into table employees.t_emp; 9 load data infile '/home/mysql/t2.txt' into table employees.t_emp;
这样扩容的话达到最小停机时间 不过在导入导出数据时，delete 、update、select语句时路由到dn3上没数据
查看扩容后的效果
1 mysql> explain select count(1) from t_emp; 2 +-----------+------------------------------------------------+ 3 | DATA_NODE | SQL | 4 +-----------+------------------------------------------------+ 5 | dn1 | SELECT COUNT(1) AS COUNT0 FROM t_emp LIMIT 100 | 6 | dn2 | SELECT COUNT(1) AS COUNT0 FROM t_emp LIMIT 100 | 7 | dn3 | SELECT COUNT(1) AS COUNT0 FROM t_emp LIMIT 100 | 8 +-----------+------------------------------------------------+ 9 3 rows in set (0.00 sec)