1、mycat介绍
- Mycat 是一个开源的分布式数据库系统,但是由于真正的数据库需要存储引擎,而 Mycat 并没有存 储引擎,所以并不是完全意义的分布式数据库系统。
- MyCat是目前最流行的基于Java语言编写的数据库中间件,也可以理解为是数据库代理。
- 在架构体系中是位于数据库和应用层之间的一个组件,并且对于应用层是透明的,即数据库 感受不到mycat的存在,认为是直接连接的mysql数据库(实际上是连接的mycat,mycat实现了mysql的原生协议)。
- MyCat是基于阿里开源的Cobar产品而研发,Cobar的稳定性、可靠性、优秀的架构和性能以及众多成熟的使用案例使得MyCat变得非常的强大。
- mycat的三大功能:分库分表、读写分离、主从切换
2、mycat配置
Mycat conf目录下有三个重要配置文件,分别是:
- schema.xml:定义逻辑库,表,分片节点等内容;
- rule.xml:定义分片规则;
- server.xml:定义用户以及系统相关变量;
schema.xml:
<?xml version="1.0"?>
<!DOCTYPE mycat:schema SYSTEM "schema.dtd">
<mycat:schema xmlns:mycat="http://io.mycat/"><!-- --><schema name="TESTDB" checkSQLschema="true" sqlMaxLimit="100" randomDataNode="dn1"><!-- auto sharding by id (long) --><!--splitTableNames 启用<table name 属性使用逗号分割配置多个表,即多个表使用这个配置--><table name="travelrecord,address" dataNode="dn1,dn2,dn3" rule="auto-sharding-long" splitTableNames ="true"/><!-- <table name="oc_call" primaryKey="ID" dataNode="dn1$0-743" rule="latest-month-calldate"/> --></schema><!-- 数据库节点 --><dataNode name="dn1" dataHost="localhost1" database="db1" /><dataNode name="dn2" dataHost="localhost1" database="db2" /><dataNode name="dn3" dataHost="localhost1" database="db3" /><!--<dataNode name="dn4" dataHost="sequoiadb1" database="SAMPLE" /><dataNode name="jdbc_dn1" dataHost="jdbchost" database="db1" /><dataNode name="jdbc_dn2" dataHost="jdbchost" database="db2" /><dataNode name="jdbc_dn3" dataHost="jdbchost" database="db3" /> --><dataHost name="localhost1" maxCon="1000" minCon="10" balance="0"writeType="0" dbType="mysql" dbDriver="native" switchType="1" slaveThreshold="100"><heartbeat>select user()</heartbeat><!-- 配置的写库 --><writeHost host="hostM1" url="localhost:3306" user="root"password="123456"></writeHost><!-- <writeHost host="hostM2" url="localhost:3316" user="root" password="123456"/> --></dataHost><!--<dataHost name="sequoiadb1" maxCon="1000" minCon="1" balance="0" dbType="sequoiadb" dbDriver="jdbc"><heartbeat> </heartbeat><writeHost host="hostM1" url="sequoiadb://1426587161.dbaas.sequoialab.net:11920/SAMPLE" user="jifeng" password="jifeng"></writeHost></dataHost><dataHost name="oracle1" maxCon="1000" minCon="1" balance="0" writeType="0" dbType="oracle" dbDriver="jdbc"> <heartbeat>select 1 from dual</heartbeat><connectionInitSql>alter session set nls_date_format='yyyy-mm-dd hh24:mi:ss'</connectionInitSql><writeHost host="hostM1" url="jdbc:oracle:thin:@127.0.0.1:1521:nange" user="base" password="123456" > </writeHost> </dataHost><dataHost name="jdbchost" maxCon="1000" minCon="1" balance="0" writeType="0" dbType="mongodb" dbDriver="jdbc"><heartbeat>select user()</heartbeat><writeHost host="hostM" url="mongodb://192.168.0.99/test" user="admin" password="123456" ></writeHost> </dataHost><dataHost name="sparksql" maxCon="1000" minCon="1" balance="0" dbType="spark" dbDriver="jdbc"><heartbeat> </heartbeat><writeHost host="hostM1" url="jdbc:hive2://feng01:10000" user="jifeng" password="jifeng"></writeHost> </dataHost> --><!-- <dataHost name="jdbchost" maxCon="1000" minCon="10" balance="0" dbType="mysql"dbDriver="jdbc"> <heartbeat>select user()</heartbeat> <writeHost host="hostM1"url="jdbc:mysql://localhost:3306" user="root" password="123456"> </writeHost></dataHost> -->
</mycat:schema>
rule.xml
<?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="sharding-by-date"><rule><columns>createTime</columns><algorithm>partbyday</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="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="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="mod-long" class="io.mycat.route.function.PartitionByMod"><!-- how many data nodes --><property name="count">3</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="partbyday"class="io.mycat.route.function.PartitionByDate"><property name="dateFormat">yyyy-MM-dd</property><property name="sNaturalDay">0</property><property name="sBeginDate">2014-01-01</property><property name="sEndDate">2014-01-31</property><property name="sPartionDay">10</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>
server.xml
<?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:server SYSTEM "server.dtd">
<mycat:server xmlns:mycat="http://io.mycat/"><system><property name="nonePasswordLogin">0</property> <!-- 0为需要密码登陆、1为不需要密码登陆 ,默认为0,设置为1则需要指定默认账户--><property name="ignoreUnknownCommand">0</property><!-- 0遇上没有实现的报文(Unknown command:),就会报错、1为忽略该报文,返回ok报文。在某些mysql客户端存在客户端已经登录的时候还会继续发送登录报文,mycat会报错,该设置可以绕过这个错误--><property name="useHandshakeV10">1</property><property name="removeGraveAccent">1</property><property name="useSqlStat">0</property> <!-- 1为开启实时统计、0为关闭 --><property name="useGlobleTableCheck">0</property> <!-- 1为开启全加班一致性检测、0为关闭 --><property name="sqlExecuteTimeout">300</property> <!-- SQL 执行超时 单位:秒--><property name="sequnceHandlerType">1</property><!--<property name="sequnceHandlerPattern">(?:(\s*next\s+value\s+for\s*MYCATSEQ_(\w+))(,|\)|\s)*)+</property>INSERT INTO `travelrecord` (`id`,user_id) VALUES ('next value for MYCATSEQ_GLOBAL',"xxx");--><!--必须带有MYCATSEQ_或者 mycatseq_进入序列匹配流程 注意MYCATSEQ_有空格的情况--><property name="sequnceHandlerPattern">(?:(\s*next\s+value\s+for\s*MYCATSEQ_(\w+))(,|\)|\s)*)+</property><property name="subqueryRelationshipCheck">false</property> <!-- 子查询中存在关联查询的情况下,检查关联字段中是否有分片字段 .默认 false --><property name="sequenceHanlderClass">io.mycat.route.sequence.handler.HttpIncrSequenceHandler</property><!-- <property name="useCompression">1</property>--> <!--1为开启mysql压缩协议--><!-- <property name="fakeMySQLVersion">5.6.20</property>--> <!--设置模拟的MySQL版本号--><!-- <property name="processorBufferChunk">40960</property> --><!-- <property name="processors">1</property> <property name="processorExecutor">32</property> --><!--默认为type 0: DirectByteBufferPool | type 1 ByteBufferArena | type 2 NettyBufferPool --><property name="processorBufferPoolType">0</property><!--默认是65535 64K 用于sql解析时最大文本长度 --><!--<property name="maxStringLiteralLength">65535</property>--><!--<property name="sequnceHandlerType">0</property>--><!--<property name="backSocketNoDelay">1</property>--><!--<property name="frontSocketNoDelay">1</property>--><!--<property name="processorExecutor">16</property>--><!--<property name="serverPort">8066</property> <property name="managerPort">9066</property> <property name="idleTimeout">300000</property> <property name="bindIp">0.0.0.0</property><property name="dataNodeIdleCheckPeriod">300000</property> 5 * 60 * 1000L; //连接空闲检查<property name="frontWriteQueueSize">4096</property> <property name="processors">32</property> --><!--分布式事务开关,0为不过滤分布式事务,1为过滤分布式事务(如果分布式事务内只涉及全局表,则不过滤),2为不过滤分布式事务,但是记录分布式事务日志--><property name="handleDistributedTransactions">0</property><!--off heap for merge/order/group/limit 1开启 0关闭--><property name="useOffHeapForMerge">0</property><!--单位为m--><property name="memoryPageSize">64k</property><!--单位为k--><property name="spillsFileBufferSize">1k</property><property name="useStreamOutput">0</property><!--单位为m--><property name="systemReserveMemorySize">384m</property><!--是否采用zookeeper协调切换 --><property name="useZKSwitch">false</property><!-- XA Recovery Log日志路径 --><!--<property name="XARecoveryLogBaseDir">./</property>--><!-- XA Recovery Log日志名称 --><!--<property name="XARecoveryLogBaseName">tmlog</property>--><!--如果为 true的话 严格遵守隔离级别,不会在仅仅只有select语句的时候在事务中切换连接--><property name="strictTxIsolation">false</property><property name="useZKSwitch">true</property><!--如果为0的话,涉及多个DataNode的catlet任务不会跨线程执行--><property name="parallExecute">0</property></system><!-- 全局SQL防火墙设置 --><!--白名单可以使用通配符%或着*--><!--例如<host host="127.0.0.*" user="root"/>--><!--例如<host host="127.0.*" user="root"/>--><!--例如<host host="127.*" user="root"/>--><!--例如<host host="1*7.*" user="root"/>--><!--这些配置情况下对于127.0.0.1都能以root账户登录--><!--<firewall><whitehost><host host="1*7.0.0.*" user="root"/></whitehost><blacklist check="false"></blacklist></firewall>--><user name="root" defaultAccount="true"><property name="password">123456</property><!-- schemas:配置连接的逻辑库 --><property name="schemas">TESTDB</property><property name="defaultSchema">TESTDB</property><!--No MyCAT Database selected 错误前会尝试使用该schema作为schema,不设置则为null,报错 --><!-- 表级 DML 权限设置 --><!-- <privileges check="false"><schema name="TESTDB" dml="0110" ><table name="tb01" dml="0000"></table><table name="tb02" dml="1111"></table></schema></privileges> --></user><user name="user"><property name="password">user</property><property name="schemas">TESTDB</property><property name="readOnly">true</property><property name="defaultSchema">TESTDB</property></user></mycat:server>
既然是直接当做数据库系统用,所以直接用navicat连接mycat即可。
3、mysql主从复制的原理
mysql自带的功能:主从复制是把一台主机的数据复制到其他一台或多台主机上;
主从复制原理:
- 主从同步过程中主服务器有一个工作线程I/O dump thread,从服务器有两个工作线程I/O thread和SQL thread。
- 主库把外界接收的SQL请求记录到自己的binlog日志中,从库的I/O thread去请求主库的binlog日志,并将binlog日志写到中继日志中,然后从库重做中继日志的SQL语句。主库通过I/O dump thread给从库I/O thread传送binlog日志。