MyCAT+MySQL 搭建高可用企业级数据库集群——第2章 MyCat入门

• 2-1 章节综述
• 2-2 什么是MyCat
• 2-3 什么是数据库中间层
• 2-4 MyCat的主要作用
• 2-5 MyCat基本元素
• 2-6 MyCat的安装

2-1 章节综述

1、掌握Mycat的基础概念、功能及适用场景；

2、掌握Mycat的安装和启动；

2-2 什么是MyCat

1、不同的工种对Mycat的不同理解；

• 研发人员；

• 架构师；

2、实现“读写分离”的两种方式；

• 从程序的角度实现，配置两套数据源；
• 通过中间件的角度实现，比如Mycat；

2-3 什么是数据库中间层

1、数据库中间层初识；

2-4 MyCat的主要作用

1、作为分布式数据库中间层使用（关系型与菲关系型均可）；

2、实现后端数据库的读写分离及负载均衡；

3、在数据库中，一般读请求操作远高于写请求操作；

4、改下图所示的，仅适用于“一主一从”的MySQL数据库架构；

5、实现“一主多从”的MySQL高可用，需要通过MHA或者3M的方式实现；

6、对业务数据库进行垂直切分；

7、使用Mycat的好处，将后端对应的真实数据库，作为一个“逻辑库”；

8、对业务数据库进行水平切分（分库分表）；

9、切分逻辑，通过Mycat；

10、控制数据库连接的数量；

• 当连接数占满后，所有新请求将无法再连接，影响业务；
• 通过Mycat中间件，建立一个公共的“数据库连接池”；

2-5 MyCat基本元素

1、逻辑库&逻辑表概念回顾；

2、逻辑表的分类；

• 分片表
• 全局表
• ER关系表

2-6 MyCat的安装

1、下载并解压Mycat；

wget http://dl.mycat.io/1.6.5/Mycat-server-1.6.5-release-20180122220033-linux.tar.gz

2、安装JAVA运行环境JDK1.7或之上版本；

wget http://download.oracle.com/otn/java/jdk/7u80-b15/jdk-7u80-linux-x64.tar.gz?AuthParam=1527933488_83c1bdc9836fadfe600eceed8afc9a1c

3、新建Mycat运行系统账号；

useradd mycat

chown -R mycat:mycat /usr/local/mycat

4、配置系统环境变量；

vim /etc/profile#修改系统环境变量；

export MyCAT_HOME=/usr/local/mycat
export JAVA_HOME=/usr/local/jdk1.7.0_80
export CLASSPATH=$JAVA_HOME/lib/tools.jar:$JAVA_HOME/lib/dt.jar:$JAVA_HOME/lib
export PATH=$MyCAT_HOME/bin:$JAVA_HOME/bin:$PATH

source /etc/profile

5、修改mycat启动参数；

vim /usr/local/mycat/conf/wrapper.conf#调整mycat内存大小；

日志：

[BEGIN] 2018/6/2 17:55:10
[root@iZqmo9i3j77p7eZ ~]# cd /usr/local/src/
[root@iZqmo9i3j77p7eZ src]# wget http://dl.mycat.io/1.6.5/Mycat-server-1.6.5-release-20180122220033-linux.tar.gz
--2018-06-02 17:55:20--  http://dl.mycat.io/1.6.5/Mycat-server-1.6.5-release-20180122220033-linux.tar.gz
Resolving dl.mycat.io (dl.mycat.io)... 210.51.26.184
Connecting to dl.mycat.io (dl.mycat.io)|210.51.26.184|:80... connected.
HTTP request sent, awaiting response... 200 OK
Length: 17480035 (17M) [application/octet-stream]
Saving to: ‘Mycat-server-1.6.5-release-20180122220033-linux.tar.gz’

100%[====================================================================================================================================================================================================================================>] 17,480,035   507KB/s   in 34s    

2018-06-02 17:55:55 (502 KB/s) - ‘Mycat-server-1.6.5-release-20180122220033-linux.tar.gz’ saved [17480035/17480035]
[root@iZqmo9i3j77p7eZ src]# wget http://download.oracle.com/otn/java/jdk/7u80-b15/jdk-7u80-linux-x64.tar.gz?AuthParam=1527933488_83c1bdc9836fadfe600eceed8afc9a1c
--2018-06-02 17:56:35--  http://download.oracle.com/otn/java/jdk/7u80-b15/jdk-7u80-linux-x64.tar.gz?AuthParam=1527933488_83c1bdc9836fadfe600eceed8afc9a1c
Resolving download.oracle.com (download.oracle.com)... 23.218.25.93
Connecting to download.oracle.com (download.oracle.com)|23.218.25.93|:80... connected.
HTTP request sent, awaiting response... 200 OK
Length: 153530841 (146M) [application/x-gzip]
Saving to: ‘jdk-7u80-linux-x64.tar.gz?AuthParam=1527933488_83c1bdc9836fadfe600eceed8afc9a1c’

100%[====================================================================================================================================================================================================================================>] 153,530,841 5.96MB/s   in 24s    

2018-06-02 17:57:00 (6.08 MB/s) - ‘jdk-7u80-linux-x64.tar.gz?AuthParam=1527933488_83c1bdc9836fadfe600eceed8afc9a1c’ saved [153530841/153530841]

[root@iZqmo9i3j77p7eZ src]# rpm -qa|grep java
[root@iZqmo9i3j77p7eZ src]# ll
total 167008
-rw-r--r-- 1 root root 153530841 Jul  8  2015 jdk-7u80-linux-x64.tar.gz?AuthParam=1527933488_83c1bdc9836fadfe600eceed8afc9a1c
-rw-r--r-- 1 root root  17480035 Jan 22 22:07 Mycat-server-1.6.5-release-20180122220033-linux.tar.gz
[root@iZqmo9i3j77p7eZ src]# mv jdk-7u80-linux-x64.tar.gz\?AuthParam\=1527933488_83c1bdc9836fadfe600eceed8afc9a1c jdk-7u80-linux-x64.tar.gz
[root@iZqmo9i3j77p7eZ src]# tar zxf jdk-7u80-linux-x64.tar.gz -C /usr/local/
[root@iZqmo9i3j77p7eZ src]# vim /etc/profile
[root@iZqmo9i3j77p7eZ src]# source /etc/profile
[root@iZqmo9i3j77p7eZ src]# java
Usage: java [-options] class [args...]
           (to execute a class)
   or  java [-options] -jar jarfile [args...]
           (to execute a jar file)
where options include:
    -d32      use a 32-bit data model if available
    -d64      use a 64-bit data model if available
    -server      to select the "server" VM
                  The default VM is server.

    -cp <class search path of directories and zip/jar files>
    -classpath <class search path of directories and zip/jar files>
                  A : separated list of directories, JAR archives,
                  and ZIP archives to search for class files.
    -D<name>=<value>
                  set a system property
    -verbose:[class|gc|jni]
                  enable verbose output
    -version      print product version and exit
    -version:<value>
                  require the specified version to run
    -showversion  print product version and continue
    -jre-restrict-search | -no-jre-restrict-search
                  include/exclude user private JREs in the version search
    -? -help      print this help message
    -X            print help on non-standard options
    -ea[:<packagename>...|:<classname>]
    -enableassertions[:<packagename>...|:<classname>]
                  enable assertions with specified granularity
    -da[:<packagename>...|:<classname>]
    -disableassertions[:<packagename>...|:<classname>]
                  disable assertions with specified granularity
    -esa | -enablesystemassertions
                  enable system assertions
    -dsa | -disablesystemassertions
                  disable system assertions
    -agentlib:<libname>[=<options>]
                  load native agent library <libname>, e.g. -agentlib:hprof
                  see also, -agentlib:jdwp=help and -agentlib:hprof=help
    -agentpath:<pathname>[=<options>]
                  load native agent library by full pathname
    -javaagent:<jarpath>[=<options>]
                  load Java programming language agent, see java.lang.instrument
    -splash:<imagepath>
                  show splash screen with specified image
See http://www.oracle.com/technetwork/java/javase/documentation/index.html for more details.
[root@iZqmo9i3j77p7eZ src]# javac
Usage: javac <options> <source files>
where possible options include:
  -g                         Generate all debugging info
  -g:none                    Generate no debugging info
  -g:{lines,vars,source}     Generate only some debugging info
  -nowarn                    Generate no warnings
  -verbose                   Output messages about what the compiler is doing
  -deprecation               Output source locations where deprecated APIs are used
  -classpath <path>          Specify where to find user class files and annotation processors
  -cp <path>                 Specify where to find user class files and annotation processors
  -sourcepath <path>         Specify where to find input source files
  -bootclasspath <path>      Override location of bootstrap class files
  -extdirs <dirs>            Override location of installed extensions
  -endorseddirs <dirs>       Override location of endorsed standards path
  -proc:{none,only}          Control whether annotation processing and/or compilation is done.
  -processor <class1>[,<class2>,<class3>...] Names of the annotation processors to run; bypasses default discovery process
  -processorpath <path>      Specify where to find annotation processors
  -d <directory>             Specify where to place generated class files
  -s <directory>             Specify where to place generated source files
  -implicit:{none,class}     Specify whether or not to generate class files for implicitly referenced files
  -encoding <encoding>       Specify character encoding used by source files
  -source <release>          Provide source compatibility with specified release
  -target <release>          Generate class files for specific VM version
  -version                   Version information
  -help                      Print a synopsis of standard options
  -Akey[=value]              Options to pass to annotation processors
  -X                         Print a synopsis of nonstandard options
  -J<flag>                   Pass <flag> directly to the runtime system
  -Werror                    Terminate compilation if warnings occur
  @<filename>                Read options and filenames from file

[root@iZqmo9i3j77p7eZ src]# java -version
java version "1.7.0_80"
Java(TM) SE Runtime Environment (build 1.7.0_80-b15)
Java HotSpot(TM) 64-Bit Server VM (build 24.80-b11, mixed mode)
[root@iZqmo9i3j77p7eZ src]# ll
total 167008
-rw-r--r-- 1 root root 153530841 Jul  8  2015 jdk-7u80-linux-x64.tar.gz
-rw-r--r-- 1 root root  17480035 Jan 22 22:07 Mycat-server-1.6.5-release-20180122220033-linux.tar.gz
[root@iZqmo9i3j77p7eZ src]# tar xf  Mycat-server-1.6.5-release-20180122220033-linux.tar.gz -C /usr/local/
[root@iZqmo9i3j77p7eZ src]# cd /usr/local/
[root@iZqmo9i3j77p7eZ local]# ls
aegis  bin  etc  games  include  jdk1.7.0_80  lib  lib64  libexec  mycat  sbin  share  src
[root@iZqmo9i3j77p7eZ local]# ll
total 52
drwxr-xr-x  6 root root 4096 May 30 10:25 aegis
drwxr-xr-x. 2 root root 4096 Nov  5  2016 bin
drwxr-xr-x. 2 root root 4096 Nov  5  2016 etc
drwxr-xr-x. 2 root root 4096 Nov  5  2016 games
drwxr-xr-x. 2 root root 4096 Nov  5  2016 include
drwxr-xr-x  8   10  143 4096 Apr 11  2015 jdk1.7.0_80
drwxr-xr-x. 2 root root 4096 Nov  5  2016 lib
drwxr-xr-x. 2 root root 4096 Nov  5  2016 lib64
drwxr-xr-x. 2 root root 4096 Nov  5  2016 libexec
drwxr-xr-x  7 root root 4096 Jun  2 17:58 mycat
drwxr-xr-x. 2 root root 4096 Nov  5  2016 sbin
drwxr-xr-x. 6 root root 4096 May 26 11:18 share
drwxr-xr-x. 2 root root 4096 Jun  2 17:57 src
[root@iZqmo9i3j77p7eZ local]# useradd mycat
[root@iZqmo9i3j77p7eZ local]# ll
total 52
drwxr-xr-x  6 root root 4096 May 30 10:25 aegis
drwxr-xr-x. 2 root root 4096 Nov  5  2016 bin
drwxr-xr-x. 2 root root 4096 Nov  5  2016 etc
drwxr-xr-x. 2 root root 4096 Nov  5  2016 games
drwxr-xr-x. 2 root root 4096 Nov  5  2016 include
drwxr-xr-x  8   10  143 4096 Apr 11  2015 jdk1.7.0_80
drwxr-xr-x. 2 root root 4096 Nov  5  2016 lib
drwxr-xr-x. 2 root root 4096 Nov  5  2016 lib64
drwxr-xr-x. 2 root root 4096 Nov  5  2016 libexec
drwxr-xr-x  7 root root 4096 Jun  2 17:58 mycat
drwxr-xr-x. 2 root root 4096 Nov  5  2016 sbin
drwxr-xr-x. 6 root root 4096 May 26 11:18 share
drwxr-xr-x. 2 root root 4096 Jun  2 17:57 src
[root@iZqmo9i3j77p7eZ local]# chown -R mycat:mycat mycat/
[root@iZqmo9i3j77p7eZ local]# cd mycat/
[root@iZqmo9i3j77p7eZ mycat]# ls -l
total 24
drwxr-xr-x 2 mycat mycat 4096 Jun  2 17:58 bin
drwxrwxrwx 2 mycat mycat 4096 Mar  1  2016 catlet
drwxrwxrwx 4 mycat mycat 4096 Jun  2 17:58 conf
drwxr-xr-x 2 mycat mycat 4096 Jun  2 17:58 lib
drwxrwxrwx 2 mycat mycat 4096 Jan 22 22:01 logs
-rwxrwxrwx 1 mycat mycat  219 Jan 22 22:00 version.txt
[root@iZqmo9i3j77p7eZ mycat]# cd bin/
[root@iZqmo9i3j77p7eZ bin]# ls
dataMigrate.sh  init_zk_data.sh  mycat  rehash.sh  startup_nowrap.sh  wrapper-linux-ppc-64  wrapper-linux-x86-32  wrapper-linux-x86-64
[root@iZqmo9i3j77p7eZ bin]# cd /usr/local/mycat/conf/
[root@iZqmo9i3j77p7eZ conf]# ls -l
total 108
-rwxrwxrwx 1 mycat mycat   88 Jan 22 22:00 autopartition-long.txt
-rwxrwxrwx 1 mycat mycat   48 Jan 22 22:00 auto-sharding-long.txt
-rwxrwxrwx 1 mycat mycat   62 Jan 22 22:00 auto-sharding-rang-mod.txt
-rwxrwxrwx 1 mycat mycat  334 Jan 22 22:00 cacheservice.properties
-rwxrwxrwx 1 mycat mycat 3244 Jan 22 22:00 dbseq.sql
-rwxrwxrwx 1 mycat mycat  439 Jan 22 22:00 ehcache.xml
-rwxrwxrwx 1 mycat mycat 2132 Jan 22 22:00 index_to_charset.properties
-rwxrwxrwx 1 mycat mycat 1253 Dec  1  2016 log4j2.xml
-rwxrwxrwx 1 mycat mycat  178 Jan 22 22:00 migrateTables.properties
-rwxrwxrwx 1 mycat mycat  262 Jan 22 22:00 myid.properties
-rwxrwxrwx 1 mycat mycat   15 Jan 22 22:00 partition-hash-int.txt
-rwxrwxrwx 1 mycat mycat  102 Jan 22 22:00 partition-range-mod.txt
-rwxrwxrwx 1 mycat mycat 4794 Jan 22 22:00 rule.xml
-rwxrwxrwx 1 mycat mycat 4219 Jan 22 22:00 schema.xml
-rwxrwxrwx 1 mycat mycat  413 Jan 22 22:00 sequence_conf.properties
-rwxrwxrwx 1 mycat mycat   75 Jan 22 22:00 sequence_db_conf.properties
-rwxrwxrwx 1 mycat mycat   27 Jan 22 22:00 sequence_distributed_conf.properties
-rwxrwxrwx 1 mycat mycat   51 Jan 22 22:00 sequence_time_conf.properties
-rwxrwxrwx 1 mycat mycat 4623 Jan 22 22:00 server.xml
-rwxrwxrwx 1 mycat mycat   16 Jan 22 22:00 sharding-by-enum.txt
-rwxrwxrwx 1 mycat mycat 4186 Jan 22 22:05 wrapper.conf
drwxrwxrwx 2 mycat mycat 4096 Jun  2 17:58 zkconf
drwxrwxrwx 2 mycat mycat 4096 Jun  2 17:58 zkdownload
[root@iZqmo9i3j77p7eZ conf]# vim wrapper.conf
-rwxrwxrwx 1 mycat mycat 4623 Jan 22 22:00 server.xml
-rwxrwxrwx 1 mycat mycat   16 Jan 22 22:00 sharding-by-enum.txt
-rwxrwxrwx 1 mycat mycat 4186 Jan 22 22:05 wrapper.conf
drwxrwxrwx 2 mycat mycat 4096 Jun  2 17:58 zkconf
drwxrwxrwx 2 mycat mycat 4096 Jun  2 17:58 zkdownload
[root@iZqmo9i3j77p7eZ bin]# vim /etc/profile
[root@iZqmo9i3j77p7eZ bin]# source /etc/profile
[root@iZqmo9i3j77p7eZ bin]# mycat
Usage: /usr/local/mycat/bin/mycat { console | start | stop | restart | status | dump }
[root@iZqmo9i3j77p7eZ bin]# mycat status
Mycat-server is not running.
[root@iZqmo9i3j77p7eZ bin]# mycat start
Starting Mycat-server...