数据库垂直拆分，水平拆分利器，cobar升级版mycat

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本文原文连接: http://blog.csdn.net/freewebsys/article/details/44046365 转载请注明出处！

1，关于Mycat

Mycat情报
基于阿里的开源cobar ，可以用于生产系统中，目前在做如下的一些改进：
非阻塞IO的实现，相对于目前的cobar，并发性能大大提升，而且不会陷入假死状态
优化线程池的分配，目前cobar的线程池分配效率不高
修复cobar一些ＢＵＧ
参考impala中的impala front部分的Java代码，实现高效的Map-Reduce，能够处理上亿的大数据量
实现自动分片特性，目前cobar需要手工分片，并有一定的编程限制
官方网站：
https://github.com/MyCATApache/
好多文档，大多数都是word的，写的非常详细。
https://github.com/MyCATApache/Mycat-doc
Mycat是cobar重新优化开发的版本，和cobar的很多配置都类似。
可以参考之前写的cobar安装：
http://blog.csdn.net/freewebsys/article/details/44022421

2，安装Mycat服务

下载二进制安装文件
https://github.com/MyCATApache/Mycat-download
解压缩到/usr/local/mycat
修改配置文件：

<?xml version="1.0"?><!DOCTYPE mycat:schema SYSTEM "schema.dtd"><mycat:schema xmlns:mycat="http://org.opencloudb/">    #数据库名称是TESTDB，sqlMaxLimit设置limit防止错误sql查询大量数据    <schema name="TESTDB" checkSQLschema="false" sqlMaxLimit="100">        #自动分库规则        <!-- auto sharding by id (long) -->        <table name="travelrecord" dataNode="dn1,dn2,dn3" rule="auto-sharding-long" />        #全局配置表，所有数据均同步到每个数据库。        <!-- 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" />        #关联子表配置，不太明白        <table name="customer" primaryKey="ID" dataNode="dn1,dn2"            rule="sharding-by-intfile">            <childTable name="orders" primaryKey="ID" joinKey="customer_id"                parentKey="id">                <childTable name="order_items" joinKey="order_id"                    parentKey="id" />            </childTable>            <childTable name="customer_addr" primaryKey="ID" joinKey="customer_id"                parentKey="id" />        </table>    </schema>    #配置多个dataNode，制定dataHost和数据库名称。    <dataNode name="dn1" dataHost="localhost1" database="db1" />    <dataNode name="dn2" dataHost="localhost1" database="db2" />    <dataNode name="dn3" dataHost="localhost1" database="db3" />    #配置dataHost的读写分配。同时mysql也要配置好，Master-Slave或Master-Master    <dataHost name="localhost1" maxCon="1000" minCon="10" balance="0"        writeType="0" dbType="mysql" dbDriver="native">        <heartbeat>select user()</heartbeat>        <!-- can have multi write hosts -->        <writeHost host="hostM1" url="localhost:3306" user="root"            password="123456">            <!-- can have multi read hosts -->            <!-- <readHost host="hostS1" url="localhost:3306" user="root" password="123456"                 /> -->        </writeHost>        <!-- <writeHost host="hostM2" url="localhost:3316" user="root" password="123456"/> -->    </dataHost></mycat:schema>

wrapper.conf是mycat的配置文件启动参数等
rule.xml 是配置规则xml
还有几个配置文件慢慢研究
创建数据库

CREATE DATABASE db1 DEFAULT CHARACTER SET utf8 COLLATE utf8_general_ci;CREATE DATABASE db2 DEFAULT CHARACTER SET utf8 COLLATE utf8_general_ci;CREATE DATABASE db3 DEFAULT CHARACTER SET utf8 COLLATE utf8_general_ci;

服务启动:/bin/mycat start
/bin/mycat这个问题同时可以作为service，拷贝到/etc/init.d/目录下即可。

3，登陆mycat服务和管理端

登陆mycat服务：（端口8066）

# mysql -utest -ptest -h 127.0.0.1 -P8066Warning: USING a password ON the command line interface can be insecure.Welcome TO the MySQL monitor.  Commands END WITH ; OR \g.Your MySQL connection id IS 1Server version: 5.5.8-mycat-1.3 MyCat Server (OpenCloundDB)Copyright (c) 2000, 2015, Oracle AND/OR its affiliates. ALL rights reserved.Oracle IS a registered trademark OF Oracle Corporation AND/OR itsaffiliates. Other names may be trademarks OF their respectiveowners.TYPE 'help;' OR '\h' FOR help. TYPE '\c' TO clear the CURRENT INPUT statement.mysql> SHOW DATABASES;+----------+| DATABASE |+----------+| TESTDB   |+----------+1 ROW IN SET (0.02 sec)mysql> USE TESTDB;Reading TABLE information FOR completion OF TABLE AND COLUMN namesYou can turn off this feature TO GET a quicker startup WITH -ADATABASE changedmysql> SHOW TABLES;+------------------+| TABLES IN TESTDB |+------------------+| company          || customer         || customer_addr    || employee         || goods            || hotnews          || orders           || order_items      || travelrecord     |+------------------+9 ROWS IN SET (0.00 sec)mysql> CREATE TABLE company(id INT NOT NULL PRIMARY KEY,name VARCHAR(100));Query OK, 0 ROWS affected (0.05 sec)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 (0.01 sec)mysql> INSERT INTO company(id,name) VALUES(1,'hp'); INSERT INTO company(id,name) VALUES(2,'ibm'); INSERT INTO company(id,name) VALUES(3,'oracle');Query OK, 3 ROWS affected (0.37 sec)Query OK, 3 ROWS affected (0.01 sec)Query OK, 3 ROWS affected (0.00 sec)mysql> SELECT * FROM company ;+----+--------+| id | name   |+----+--------+|  1 | hp     ||  2 | ibm    ||  3 | oracle |+----+--------+3 ROWS IN SET (0.01 sec)

使用管理端登陆：（端口9066）

#  mysql -utest -ptest -h 127.0.0.1 -P9066Warning: USING a password ON the command line interface can be insecure.Welcome TO the MySQL monitor.  Commands END WITH ; OR \g.Your MySQL connection id IS 2Server version: 5.5.8-mycat-1.3 CobarManager@AlibabaCopyright (c) 2000, 2015, Oracle AND/OR its affiliates. ALL rights reserved.Oracle IS a registered trademark OF Oracle Corporation AND/OR itsaffiliates. Other names may be trademarks OF their respectiveowners.TYPE 'help;' OR '\h' FOR help. TYPE '\c' TO clear the CURRENT INPUT statement.mysql> SHOW @@help;+--------------------------------------+-----------------------------------+| STATEMENT                            | DESCRIPTION                       |+--------------------------------------+-----------------------------------+| clear @@slow WHERE datanode = ?      | Clear slow SQL BY datanode        || clear @@slow WHERE schema = ?        | Clear slow SQL BY schema          || KILL @@connection id1,id2,...        | KILL the specified connections    || offline                              | CHANGE MyCat STATUS TO OFF        || online                               | CHANGE MyCat STATUS TO ON         || reload @@config                      | Reload ALL config FROM file       || reload @@route                       | Reload route config FROM file     || reload @@USER                        | Reload USER config FROM file      || ROLLBACK @@config                    | ROLLBACK ALL config FROM memory   || ROLLBACK @@route                     | ROLLBACK route config FROM memory || ROLLBACK @@USER                      | ROLLBACK USER config FROM memory  || SHOW @@backend                       | Report backend connection STATUS  || SHOW @@cache                         | Report system cache usage         || SHOW @@command                       | Report commands STATUS            || SHOW @@connection                    | Report connection STATUS          || SHOW @@connection.SQL                | Report connection SQL             || SHOW @@DATABASE                      | Report DATABASES                  || SHOW @@datanode                      | Report dataNodes                  || SHOW @@datanode WHERE schema = ?     | Report dataNodes                  || SHOW @@datasource                    | Report dataSources                || SHOW @@datasource WHERE dataNode = ? | Report dataSources                || SHOW @@heartbeat                     | Report heartbeat STATUS           || SHOW @@parser                        | Report parser STATUS              || SHOW @@processor                     | Report processor STATUS           || SHOW @@router                        | Report router STATUS              || SHOW @@server                        | Report server STATUS              || SHOW @@SESSION                       | Report front SESSION details      || SHOW @@slow WHERE datanode = ?       | Report datanode slow SQL          || SHOW @@slow WHERE schema = ?         | Report schema slow SQL            || SHOW @@SQL WHERE id = ?              | Report specify SQL                || SHOW @@SQL.detail WHERE id = ?       | Report EXECUTE detail STATUS      || SHOW @@SQL.EXECUTE                   | Report EXECUTE STATUS             || SHOW @@SQL.slow                      | Report slow SQL                   || SHOW @@threadpool                    | Report threadPool STATUS          || SHOW @@TIME.CURRENT                  | Report CURRENT TIMESTAMP          || SHOW @@TIME.startup                  | Report startup TIMESTAMP          || SHOW @@version                       | Report Mycat Server version       || stop @@heartbeat name:TIME           | Pause dataNode heartbeat          || switch @@datasource name:INDEX       | Switch dataSource                 |+--------------------------------------+-----------------------------------+39 ROWS IN SET (0.03 sec)mysql> SHOW @@backend;+------------+------+---------+-----------------+------+--------+--------+---------+------+--------+----------+------------+--------+---------+------------+| processor  | id   | mysqlId | host            | port | l_port | net_in | net_out | life | closed | borrowed | SEND_QUEUE | schema | txlevel | autocommit |+------------+------+---------+-----------------+------+--------+--------+---------+------+--------+----------+------------+--------+---------+------------+| Processor0 |   12 |      33 | 127.0.0.1 | 3306 |  42505 |    596 |     501 | 3384 | FALSE  | FALSE    |          0 .......17 ROWS IN SET (0.03 sec)mysql> SHOW @@connection;+------------+------+-----------+------+------------+--------+---------+--------+---------+---------------+-------------+------------+---------+------------+| PROCESSOR  | ID   | HOST      | PORT | LOCAL_PORT | SCHEMA | CHARSET | NET_IN | NET_OUT | ALIVE_TIME(S) | RECV_BUFFER | SEND_QUEUE | txlevel | autocommit |+------------+------+-----------+------+------------+--------+---------+--------+---------+---------------+-------------+------------+---------+------------+| Processor0 |    2 | 127.0.0.1 | 9066 |      35952 | NULL   | utf8    |    156 |    4107 |            40 |        4096 |          0 | NULL    | NULL       || Processor0 |    1 | 127.0.0.1 | 8066 |      16525 | TESTDB | utf8    |   2005 |    5132 |          3461 |        4096 |          0 | 3       | TRUE       |+------------+------+-----------+------+------------+--------+---------+--------+---------+---------------+-------------+------------+---------+------------+2 ROWS IN SET (0.02 sec)mysql> SHOW @@heartbeat;+--------+-------+-----------------+------+---------+-------+--------+---------+--------------+---------------------+-------+| NAME   | TYPE  | HOST            | PORT | RS_CODE | RETRY | STATUS | TIMEOUT | EXECUTE_TIME | LAST_ACTIVE_TIME    | STOP  |+--------+-------+-----------------+------+---------+-------+--------+---------+--------------+---------------------+-------+| hostM1 | mysql | 127.0.0.1 | 3306 |       1 |     0 | idle   |   30000 | 0,0,0        | 2015-03-03 14:45:00 | FALSE |+--------+-------+-----------------+------+---------+-------+--------+---------+--------------+---------------------+-------+1 ROW IN SET (0.01 sec)mysql> SHOW @@datanode;+------+----------------+-------+-------+--------+------+------+---------+------------+----------+---------+---------------+| NAME | DATHOST        | INDEX | TYPE  | ACTIVE | IDLE | SIZE | EXECUTE | TOTAL_TIME | MAX_TIME | MAX_SQL | RECOVERY_TIME |+------+----------------+-------+-------+--------+------+------+---------+------------+----------+---------+---------------+| dn1  | localhost1/db1 |     0 | mysql |      0 |    9 |   50 |      27 |          0 |        0 |       0 |            -1 || dn2  | localhost1/db2 |     0 | mysql |      0 |    4 |   50 |      26 |          0 |        0 |       0 |            -1 || dn3  | localhost1/db3 |     0 | mysql |      0 |    3 |   50 |      17 |          0 |        0 |       0 |            -1 |+------+----------------+-------+-------+--------+------+------+---------+------------+----------+---------+---------------+3 ROWS IN SET (0.01 sec)mysql> SHOW @@cache;+-------------------------------------+-------+------+--------+------+------+---------------+---------------+| CACHE                               | MAX   | CUR  | ACCESS | HIT  | PUT  | LAST_ACCESS   | LAST_PUT      |+-------------------------------------+-------+------+--------+------+------+---------------+---------------+| SQLRouteCache                       | 10000 |    1 |      8 |    0 |    1 | 1425364473193 | 1425363891040 || TableID2DataNodeCache.TESTDB_ORDERS | 50000 |    0 |      0 |    0 |    0 |             0 |             0 || ER_SQL2PARENTID                     |  1000 |    0 |      0 |    0 |    0 |             0 |             0 |+-------------------------------------+-------+------+--------+------+------+---------------+---------------+3 ROWS IN SET (0.05 sec)

4，总结

初步安装测试了下mycat组件，还是非常不错的，确实比起cobar有不少的进步。
同时他们开发团队也说了，解决了cobar之前存在的问题。
有了全局表，这样可以使用join了，同时增加读写分离。
规则增加了不少，能满足大部分需求。
和cobar一样，mycat可以直接伪装成一个mysql服务器，对业务进行垂直拆分，水平拆分。平滑的进行数据扩展。
保证在原有系统上进行优化。接下来继续研究mycat，非常好的解决方案。

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