一、原架构图：
二、扩容
在HOST1上新增节点db_user2
在HOST2上新增节点db_user2
三、操作步骤
1、mycat 所在环境安装 mysql 客户端程序
2、mycat 的 lib 目录下添加 mysql 的 jdbc 驱动包
下载mysql-connect-jdbc-5.1.35.jar,下载地址：https://mvnrepository.com/artifact/mysql/mysql-connector-java/5.1.35
把下载的jar包放到mycat lib目录下：/root/data/program/mycat/lib
3、对扩容缩容的表所有节点数据进行备份，以便迁移失败后的数据恢复
4、编辑schema.xml 和 rule.xml
schema.xml
<table name="users" dataNode="db_user_dataNode$1-4" rule="mod-userID-long" primaryKey="userID" autoIncrement="true">
<childTable name="user_address" joinKey="userID" parentKey="userID" primaryKey="addressID"/>
</table>
<!-- db_user -->
<dataNode name="db_user_dataNode1" dataHost="db_userHOST1" database="db_user" />
<dataNode name="db_user_dataNode2" dataHost="db_userHOST2" database="db_user" />
<dataNode name="db_user_dataNode3" dataHost="db_userHOST1" database="db_user2" />
<dataNode name="db_user_dataNode4" dataHost="db_userHOST2" database="db_user2" />
<?xml version="1.0"?> <!DOCTYPE mycat:schema SYSTEM "schema.dtd"> <mycat:schema xmlns:mycat="http://io.mycat/"> <schema name="db_store" checkSQLschema="false" sqlMaxLimit="100"> <table name="store" dataNode="db_store_dataNode" primaryKey="storeID"/> <table name="employee" dataNode="db_store_dataNode" primaryKey="employeeID"/> </schema> <schema name="db_user" checkSQLschema="false" sqlMaxLimit="100"> <table name="data_dictionary" type="global" dataNode="db_user_dataNode1,db_user_dataNode2" primaryKey="dataDictionaryID"/> <table name="users" dataNode="db_user_dataNode$1-4" rule="mod-userID-long" primaryKey="userID" autoIncrement="true"> <childTable name="user_address" joinKey="userID" parentKey="userID" primaryKey="addressID"/> </table> <table name = "mycat_sequence" dataNode ="db_user_dataNode2" /> </schema> <!-- 节点配置 --> <!-- db_store --> <dataNode name="db_store_dataNode" dataHost="db_storeHOST" database="db_store" /> <!-- db_user --> <dataNode name="db_user_dataNode1" dataHost="db_userHOST1" database="db_user" /> <dataNode name="db_user_dataNode2" dataHost="db_userHOST2" database="db_user" /> <dataNode name="db_user_dataNode3" dataHost="db_userHOST1" database="db_user2" /> <dataNode name="db_user_dataNode4" dataHost="db_userHOST2" database="db_user2" /> <!-- 节点主机配置 --> <!-- 配置db_store的节点主机 --> <dataHost name="db_storeHOST" maxCon="1000" minCon="10" balance="1" writeType="0" dbType="mysql" dbDriver="native" switchType="1" slaveThreshold="100"> <heartbeat>select user()</heartbeat> <!-- can have multi write hosts --> <writeHost host="hostM1" url="192.168.189.130:3306" user="root" password="123456"> <!-- can have multi read hosts --> <readHost host="hostS1" url="192.168.189.131:3306" user="root" password="123456" /> </writeHost> </dataHost> <!-- 配置db_user的节点主机 --> <dataHost name="db_userHOST1" maxCon="1000" minCon="10" balance="0" writeType="0" dbType="mysql" dbDriver="native" switchType="1" slaveThreshold="100"> <heartbeat>select user()</heartbeat> <writeHost host="userHost1" url="192.168.189.130:3306" user="root" password="123456"> </writeHost> </dataHost> <dataHost name="db_userHOST2" maxCon="1000" minCon="10" balance="0" writeType="0" dbType="mysql" dbDriver="native" switchType="1" slaveThreshold="100"> <heartbeat>select user()</heartbeat> <!-- can have multi write hosts --> <writeHost host="userHost2" url="192.168.189.131:3306" user="root" password="123456"> </writeHost> </dataHost> </mycat:schema>
rule.xml
<function name="mod-long" class="io.mycat.route.function.PartitionByMod">
<!-- how many data nodes -->
<property name="count">4</property>
</function>
<?xml version="1.0" encoding="UTF-8"?> <!-- - - Licensed under the Apache License, Version 2.0 (the "License"); - you may not use this file except in compliance with the License. - You may obtain a copy of the License at - - http://www.apache.org/licenses/LICENSE-2.0 - - Unless required by applicable law or agreed to in writing, software - distributed under the License is distributed on an "AS IS" BASIS, - WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. - See the License for the specific language governing permissions and - limitations under the License. --> <!DOCTYPE mycat:rule SYSTEM "rule.dtd"> <mycat:rule xmlns:mycat="http://io.mycat/"> <tableRule name="rule1"> <rule> <columns>id</columns> <algorithm>func1</algorithm> </rule> </tableRule> <tableRule name="rule2"> <rule> <columns>user_id</columns> <algorithm>func1</algorithm> </rule> </tableRule> <tableRule name="sharding-by-intfile"> <rule> <columns>sharding_id</columns> <algorithm>hash-int</algorithm> </rule> </tableRule> <tableRule name="auto-sharding-long"> <rule> <columns>id</columns> <algorithm>rang-long</algorithm> </rule> </tableRule> <tableRule name="mod-long"> <rule> <columns>id</columns> <algorithm>mod-long</algorithm> </rule> </tableRule> <tableRule name="mod-userID-long"> <rule> <columns>userID</columns> <algorithm>mod-long</algorithm> </rule> </tableRule> <tableRule name="sharding-by-murmur"> <rule> <columns>id</columns> <algorithm>murmur</algorithm> </rule> </tableRule> <tableRule name="crc32slot"> <rule> <columns>id</columns> <algorithm>crc32slot</algorithm> </rule> </tableRule> <tableRule name="sharding-by-month"> <rule> <columns>create_time</columns> <algorithm>partbymonth</algorithm> </rule> </tableRule> <tableRule name="latest-month-calldate"> <rule> <columns>calldate</columns> <algorithm>latestMonth</algorithm> </rule> </tableRule> <tableRule name="auto-sharding-rang-mod"> <rule> <columns>id</columns> <algorithm>rang-mod</algorithm> </rule> </tableRule> <tableRule name="jch"> <rule> <columns>id</columns> <algorithm>jump-consistent-hash</algorithm> </rule> </tableRule> <function name="mod-long" class="io.mycat.route.function.PartitionByMod"> <!-- how many data nodes --> <property name="count">4</property> </function> <function name="murmur" class="io.mycat.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> <function name="crc32slot" class="io.mycat.route.function.PartitionByCRC32PreSlot"> <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 --> </function> <function name="hash-int" class="io.mycat.route.function.PartitionByFileMap"> <property name="mapFile">partition-hash-int.txt</property> </function> <function name="rang-long" class="io.mycat.route.function.AutoPartitionByLong"> <property name="mapFile">autopartition-long.txt</property> </function> <function name="func1" class="io.mycat.route.function.PartitionByLong"> <property name="partitionCount">8</property> <property name="partitionLength">128</property> </function> <function name="latestMonth" class="io.mycat.route.function.LatestMonthPartion"> <property name="splitOneDay">24</property> </function> <function name="partbymonth" class="io.mycat.route.function.PartitionByMonth"> <property name="dateFormat">yyyy-MM-dd</property> <property name="sBeginDate">2015-01-01</property> </function> <function name="rang-mod" class="io.mycat.route.function.PartitionByRangeMod"> <property name="mapFile">partition-range-mod.txt</property> </function> <function name="jump-consistent-hash" class="io.mycat.route.function.PartitionByJumpConsistentHash"> <property name="totalBuckets">3</property> </function> </mycat:rule>
5、配置conf/migrateTables.properties
migrateTables.properties
db_user=users
#schema1=tb1,tb2,...
#schema2=all（写all或者不写将对此schema下拆分节点变化的拆分表全部进行重新路由）
#...
#sample
#TESTDB=travelrecord,company,goods
#要扩容的逻辑库 对应的逻辑表
db_user=users
6、修改bin/dataMigrate.sh，执行dataMigrate.sh
指定临时文件路径
#临时文件路径,目录不存在将自动创建，不指定此目录则默认为mycat根下的temp目录
RUN_CMD="$RUN_CMD -tempFileDir=/root/data/program/mycat/temp"
指定为false可以查看此过程中产生的sql
#完成扩容缩容后是否删除临时文件 默认为true
RUN_CMD="$RUN_CMD -deleteTempFileDir=false"
通过命令"find / -name mysqldump"查找mysqldump路径为"/usr/bin/mysqldump"，指定#mysql bin路径为"/usr/bin/"
[root@localhost program]# cd mycat
[root@localhost mycat]# pwd
/root/data/program/mycat
[root@localhost mycat]# find / -name mysqldump
/usr/bin/mysqldump
[root@localhost mycat]# ^C
[root@localhost mycat]#
#mysql bin路径
RUN_CMD="$RUN_CMD -mysqlBin=/usr/bin/"
mycat bin目录下执行脚本"./dataMigrate.sh" 报错：
Error: JAVA_HOME environment variable is not set.
这个问题折腾了好久，最后不用openjdk，下载jdk解压配置环境变量解决的参考文档：https://blog.csdn.net/Haiyang_Duan/article/details/62099225
继续执行 ./dataMigrate.sh，日志如下
[root@localhost bin]# ./dataMigrate.sh
"/usr/java/jdk1.8.0_191/bin/java" -DMYCAT_HOME="/root/data/program/mycat" -classpath "/root/data/program/mycat/conf:/root/data/program/mycat/lib/classes:/root/data/program/mycat/lib/asm-4.0.jar:/root/data/program/mycat/lib/commons-collections-3.2.1.jar:/root/data/program/mycat/lib/commons-lang-2.6.jar:/root/data/program/mycat/lib/curator-client-2.11.0.jar:/root/data/program/mycat/lib/curator-framework-2.11.0.jar:/root/data/program/mycat/lib/curator-recipes-2.11.0.jar:/root/data/program/mycat/lib/disruptor-3.3.4.jar:/root/data/program/mycat/lib/dom4j-1.6.1.jar:/root/data/program/mycat/lib/druid-1.0.26.jar:/root/data/program/mycat/lib/ehcache-core-2.6.11.jar:/root/data/program/mycat/lib/fastjson-1.2.12.jar:/root/data/program/mycat/lib/guava-19.0.jar:/root/data/program/mycat/lib/hamcrest-core-1.3.jar:/root/data/program/mycat/lib/hamcrest-library-1.3.jar:/root/data/program/mycat/lib/jline-0.9.94.jar:/root/data/program/mycat/lib/joda-time-2.9.3.jar:/root/data/program/mycat/lib/jsr305-2.0.3.jar:/root/data/program/mycat/lib/kryo-2.10.jar:/root/data/program/mycat/lib/leveldb-0.7.jar:/root/data/program/mycat/lib/leveldb-api-0.7.jar:/root/data/program/mycat/lib/log4j-1.2.17.jar:/root/data/program/mycat/lib/log4j-1.2-api-2.5.jar:/root/data/program/mycat/lib/log4j-api-2.5.jar:/root/data/program/mycat/lib/log4j-core-2.5.jar:/root/data/program/mycat/lib/log4j-slf4j-impl-2.5.jar:/root/data/program/mycat/lib/mapdb-1.0.7.jar:/root/data/program/mycat/lib/minlog-1.2.jar:/root/data/program/mycat/lib/mongo-java-driver-2.11.4.jar:/root/data/program/mycat/lib/Mycat-server-1.6-RELEASE.jar:/root/data/program/mycat/lib/mysql-binlog-connector-java-0.4.1.jar:/root/data/program/mycat/lib/mysql-connector-java-5.1.35.jar:/root/data/program/mycat/lib/netty-3.7.0.Final.jar:/root/data/program/mycat/lib/objenesis-1.2.jar:/root/data/program/mycat/lib/reflectasm-1.03.jar:/root/data/program/mycat/lib/sequoiadb-driver-1.12.jar:/root/data/program/mycat/lib/slf4j-api-1.6.1.jar:/root/data/program/mycat/lib/univocity-parsers-2.2.1.jar:/root/data/program/mycat/lib/velocity-1.7.jar:/root/data/program/mycat/lib/wrapper.jar:/root/data/program/mycat/lib/zookeeper-3.4.6.jar" -server -Xms2G -Xmx2G -XX:MaxPermSize=64M -XX:+AggressiveOpts -XX:MaxDirectMemorySize=2G io.mycat.util.dataMigrator.DataMigrator -tempFileDir=/root/data/program/mycat/temp -isAwaysUseMaster=true -mysqlBin=/usr/bin/ -cmdLength=110*1024 -charset=utf8 -deleteTempFileDir=false -threadCount= -delThreadCount= -queryPageSize=
Java HotSpot(TM) 64-Bit Server VM warning: ignoring option MaxPermSize=64M; support was removed in 8.0
2018-10-31 22:12:20:211 [1]-> creating migrator schedule and temp files for migrate...
+--------------------------------[db_user:users] migrate info---------------------------------+
|tableSize = 5 |
|migrate before = [db_user_dataNode1, db_user_dataNode2] |
|migrate after = [db_user_dataNode1, db_user_dataNode2, db_user_dataNode3, db_user_dataNode4]|
|rule function = PartitionByMod |
+---------------------------------------------------------------------------------------------+
+--[db_user:users] migrate schedule--+
|db_user_dataNode1[2] -> [0, 0, 1, 0]|
|db_user_dataNode2[3] -> [0, 0, 0, 1]|
+------------------------------------+
2018-10-31 22:12:21:911 [2]-> start migrate data...
2018-10-31 22:12:21,990 [INFO ][pool-3-thread-2] [db_user:users]/usr/bin/mysqldump -h192.168.189.131 -P3306 -uroot -p123456 db_user users --compact --no-create-info --default-character-set=utf8 --add-locks=false --where="USERID in (#)" --result-file="/root/data/program/mycat/temp/db_user-users/db_user_dataNode2(old)-db_user_dataNode4(new)/users.txt" (io.mycat.util.dataMigrator.dataIOImpl.MysqlDataIO:MysqlDataIO.java:103)
2018-10-31 22:12:21,990 [INFO ][pool-3-thread-1] [db_user:users]/usr/bin/mysqldump -h192.168.189.130 -P3306 -uroot -p123456 db_user users --compact --no-create-info --default-character-set=utf8 --add-locks=false --where="USERID in (#)" --result-file="/root/data/program/mycat/temp/db_user-users/db_user_dataNode1(old)-db_user_dataNode3(new)/users.txt" (io.mycat.util.dataMigrator.dataIOImpl.MysqlDataIO:MysqlDataIO.java:103)
2018-10-31 22:12:22,306 [INFO ][pool-3-thread-1] [db_user:users]/usr/bin/mysqldump -h192.168.189.130 -P3306 -uroot -p123456 db_user users --compact --no-create-info --default-character-set=utf8 --add-locks=false --where="USERID in (#)" --result-file="/root/data/program/mycat/temp/db_user-users/db_user_dataNode1(old)-db_user_dataNode3(new)/users.txt" exe info:mysqldump: [Warning] Using a password on the command line interface can be insecure. (io.mycat.util.dataMigrator.dataIOImpl.MysqlDataIO:MysqlDataIO.java:116)
2018-10-31 22:12:22,337 [INFO ][pool-3-thread-2] [db_user:users]/usr/bin/mysqldump -h192.168.189.131 -P3306 -uroot -p123456 db_user users --compact --no-create-info --default-character-set=utf8 --add-locks=false --where="USERID in (#)" --result-file="/root/data/program/mycat/temp/db_user-users/db_user_dataNode2(old)-db_user_dataNode4(new)/users.txt" exe info:mysqldump: [Warning] Using a password on the command line interface can be insecure. (io.mycat.util.dataMigrator.dataIOImpl.MysqlDataIO:MysqlDataIO.java:116)
2018-10-31 22:12:22,455 [INFO ][pool-3-thread-1] [db_user:users] /usr/bin/mysql -h192.168.189.130 -P3306 -uroot -p123456 -Ddb_user2 -f --default-character-set=utf8 -e "source /root/data/program/mycat/temp/db_user-users/db_user_dataNode1(old)-db_user_dataNode3(new)/users.sql" (io.mycat.util.dataMigrator.dataIOImpl.MysqlDataIO:MysqlDataIO.java:48)
2018-10-31 22:12:22,551 [INFO ][pool-3-thread-2] [db_user:users] /usr/bin/mysql -h192.168.189.131 -P3306 -uroot -p123456 -Ddb_user2 -f --default-character-set=utf8 -e "source /root/data/program/mycat/temp/db_user-users/db_user_dataNode2(old)-db_user_dataNode4(new)/users.sql" (io.mycat.util.dataMigrator.dataIOImpl.MysqlDataIO:MysqlDataIO.java:48)
[db_user:users] db_user_dataNode1->db_user_dataNode3 completed in 640ms
[db_user:users] db_user_dataNode2->db_user_dataNode4 completed in 660ms
2018-10-31 22:12:22:777 [3]-> cleaning redundant data...
[db_user:users] clean dataNode db_user_dataNode1 completed in 73ms
[db_user:users] clean dataNode db_user_dataNode2 completed in 137ms
2018-10-31 22:12:23:185 [4]-> validating tables migrate result...
+------migrate result------+
|[db_user:users] -> success|
+--------------------------+
2018-10-31 22:12:23:456 migrate data complete in 3247ms
[root@localhost bin]#
临时文件：/root/data/program/mycat/temp
7、扩容前、扩容后数据对比
扩容前：
扩容后：
五条数据所处位置：
1 192.168.189.131-slave db_user
2 192.168.189.130-master db_user2
3 192.168.189.131-slave db_user2
4 192.168.189.130-master db_user
5 192.168.189.131-slave db_user
8、特别注意
1，一旦执行数据是不可逆的
2，只能支持分片表的扩缩容
3，分片规则必须一致，只能节点扩或者缩
四、参考文档：
https://blog.csdn.net/wangshuang1631/article/details/69055958/
https://www.cnblogs.com/li3807/p/8461878.html
https://blog.csdn.net/Haiyang_Duan/article/details/62099225
https://blog.csdn.net/leisure_life/article/details/78612256?locationNum=3&fps=1