13-MySQL分布式架構(gòu)

1. 結(jié)構(gòu)圖

image.png

2. MyCAT基礎(chǔ)架構(gòu)準(zhǔn)備

1.環(huán)境準(zhǔn)備:

兩臺(tái)虛擬機(jī) db01 db02
每臺(tái)創(chuàng)建四個(gè)mysql實(shí)例:3307 3308 3309 3310

2.節(jié)點(diǎn)主從規(guī)劃

箭頭指向誰(shuí)是主庫(kù)
以3307為主庫(kù),3309為從庫(kù),搭建主從復(fù)制關(guān)系
10.0.0.51:3307    <----->  10.0.0.52:3307
10.0.0.51:3309    ------>  10.0.0.51:3307
10.0.0.52:3309    ------>  10.0.0.52:3307

以3308為主庫(kù),3310為從庫(kù),搭建主從復(fù)制關(guān)系
10.0.0.52:3308  <----->    10.0.0.51:3308
10.0.0.52:3310  ----->     10.0.0.52:3308
10.0.0.51:3310  ----->     10.0.0.51:3308

3.分片規(guī)劃

shard1:
    Master:10.0.0.51:3307
    slave1:10.0.0.51:3309
    Standby Master:10.0.0.52:3307
    slave2:10.0.0.52:3309
shard2:
    Master:10.0.0.52:3308
    slave1:10.0.0.52:3310
    Standby Master:10.0.0.2. MyCAT基礎(chǔ)架構(gòu)準(zhǔn)備

4.開(kāi)始配置

shard1
  • 1.配置3307庫(kù)為雙主模式
10.0.0.51:3307 <-----> 10.0.0.52:3307
db02
mysql  -S /data/3307/mysql.sock -e "grant replication slave on *.* to repl@'10.0.0.%' identified by '123';"
mysql  -S /data/3307/mysql.sock -e "grant all  on *.* to root@'10.0.0.%' identified by '123'  with grant option;"
db01
mysql  -S /data/3307/mysql.sock -e "CHANGE MASTER TO MASTER_HOST='10.0.0.52', MASTER_PORT=3307, MASTER_AUTO_POSITION=1, MASTER_USER='repl', MASTER_PASSWORD='123';"
mysql  -S /data/3307/mysql.sock -e "start slave;"
mysql  -S /data/3307/mysql.sock -e "show slave status\G"
db02
mysql  -S /data/3307/mysql.sock -e "CHANGE MASTER TO MASTER_HOST='10.0.0.51', MASTER_PORT=3307, MASTER_AUTO_POSITION=1, MASTER_USER='repl', MASTER_PASSWORD='123';"
mysql  -S /data/3307/mysql.sock -e "start slave;"
mysql  -S /data/3307/mysql.sock -e "show slave status\G"
  • 2.配置db01的3309為3307的從庫(kù)
10.0.0.51:3309 ------> 10.0.0.51:3307
db01
mysql  -S /data/3309/mysql.sock  -e "CHANGE MASTER TO MASTER_HOST='10.0.0.51', MASTER_PORT=3307, MASTER_AUTO_POSITION=1, MASTER_USER='repl', MASTER_PASSWORD='123';"
mysql  -S /data/3309/mysql.sock  -e "start slave;"
mysql  -S /data/3309/mysql.sock  -e "show slave status\G"
  • 3.配置db02的3309為3307的從庫(kù)
10.0.0.52:3309 ------> 10.0.0.52:3307
db02
mysql  -S /data/3309/mysql.sock -e "CHANGE MASTER TO MASTER_HOST='10.0.0.52', MASTER_PORT=3307, MASTER_AUTO_POSITION=1, MASTER_USER='repl', MASTER_PASSWORD='123';"
mysql  -S /data/3309/mysql.sock -e "start slave;"
mysql  -S /data/3309/mysql.sock -e "show slave status\G"
shard2
  • 1.配置3308數(shù)據(jù)庫(kù)為雙主模式
10.0.0.52:3308 <-----> 10.0.0.51:3308
db01
mysql  -S /data/3308/mysql.sock -e "grant replication slave on *.* to repl@'10.0.0.%' identified by '123';"
mysql  -S /data/3308/mysql.sock -e "grant all  on *.* to root@'10.0.0.%' identified by '123'  with grant option;"
db02
mysql  -S /data/3308/mysql.sock -e "CHANGE MASTER TO MASTER_HOST='10.0.0.51', MASTER_PORT=3308, MASTER_AUTO_POSITION=1, MASTER_USER='repl', MASTER_PASSWORD='123';"
mysql  -S /data/3308/mysql.sock -e "start slave;"
mysql  -S /data/3308/mysql.sock -e "show slave status\G"
db01
mysql  -S /data/3308/mysql.sock -e "CHANGE MASTER TO MASTER_HOST='10.0.0.52', MASTER_PORT=3308, MASTER_AUTO_POSITION=1, MASTER_USER='repl', MASTER_PASSWORD='123';"
mysql  -S /data/3308/mysql.sock -e "start slave;"
mysql  -S /data/3308/mysql.sock -e "show slave status\G"
  • 2.配置db02的3310為3308的從庫(kù)
10.0.0.52:3310 -----> 10.0.0.52:3308
db02
mysql  -S /data/3310/mysql.sock -e "CHANGE MASTER TO MASTER_HOST='10.0.0.52', MASTER_PORT=3308, MASTER_AUTO_POSITION=1, MASTER_USER='repl', MASTER_PASSWORD='123';"
mysql  -S /data/3310/mysql.sock -e "start slave;"
mysql  -S /data/3310/mysql.sock -e "show slave status\G"
  • 3.配置db01的3310為3308的從庫(kù)
10.0.0.51:3310 -----> 10.0.0.51:3308
db01
mysql  -S /data/3310/mysql.sock -e "CHANGE MASTER TO MASTER_HOST='10.0.0.51', MASTER_PORT=3308, MASTER_AUTO_POSITION=1, MASTER_USER='repl', MASTER_PASSWORD='123';"
mysql  -S /data/3310/mysql.sock -e "start slave;"
mysql  -S /data/3310/mysql.sock -e "show slave status\G"

5.檢測(cè)主從狀態(tài)

mysql -S /data/3307/mysql.sock -e "show slave status\G"|grep Yes
mysql -S /data/3308/mysql.sock -e "show slave status\G"|grep Yes
mysql -S /data/3309/mysql.sock -e "show slave status\G"|grep Yes
mysql -S /data/3310/mysql.sock -e "show slave status\G"|grep Yes

注:如果中間出現(xiàn)錯(cuò)誤,執(zhí)行以下命令,重新配置主從關(guān)系
mysql -S /data/3307/mysql.sock -e "stop slave; reset slave all;"
mysql -S /data/3308/mysql.sock -e "stop slave; reset slave all;"
mysql -S /data/3309/mysql.sock -e "stop slave; reset slave all;"
mysql -S /data/3310/mysql.sock -e "stop slave; reset slave all;"

3. MyCAT安裝

1.預(yù)先安裝Java運(yùn)行環(huán)境
yum install -y java
2.下載

軟件包名稱: Mycat-server-xxxxx.linux.tar.gz
下載地址: http://mycat.io/

3.解壓文件
tar xf Mycat-server-1.6.5-release-20180122220033-linux.tar.gz
mv mycat/ /usr/local/
4.軟件目錄結(jié)構(gòu)
[root@db01 mycat]# ls
bin  catlet  conf  lib  logs  version.txt
5.啟動(dòng)和連接
  • 配置環(huán)境變量
vim /etc/profile
export PATH=/usr/local/mycat/bin:$PATH
source /etc/profile
  • 啟動(dòng)
mycat start
  • 連接mycat
mysql -uroot -p123456 -h 127.0.0.1 -P8066

4. 配置文件介紹

1.logs目錄
wrapper.log       ---->mycat啟動(dòng)日志
mycat.log         ---->mycat詳細(xì)工作日志
2.conf目錄
schema.xml      
主配置文件(讀寫(xiě)分離、高可用、分布式策略定制、節(jié)點(diǎn)控制)

server.xml
mycat軟件本身相關(guān)的配置

rule.xml 
分片規(guī)則配置文件,記錄分片規(guī)則列表、使用方法等

5.應(yīng)用前環(huán)境準(zhǔn)備

1.用戶創(chuàng)建及數(shù)據(jù)庫(kù)導(dǎo)入
db01:
mysql -S /data/3307/mysql.sock 
grant all on *.* to root@'10.0.0.%' identified by '123';
source /root/world.sql

mysql -S /data/3308/mysql.sock 
grant all on *.* to root@'10.0.0.%' identified by '123';
source /root/world.sql
2.配置文件處理
[root@db01 conf]# vim schema.xml 
<schema name="TESTDB"  dataNode="sh1"> 
</schema>  
        <dataNode name="sh1" dataHost="oldguo1" database= "world" />    
        <dataHost name="oldguo1"
        <writeHost host="db1" url="10.0.0.51:3307" user="root" password="123"> 
                        <readHost host="db2" url="10.0.0.51:3309" user="root" password="123" /> 
        </writeHost> 
        </dataHost>         
</mycat:schema>

6. 讀寫(xiě)分離結(jié)構(gòu)配置

  • 編寫(xiě)讀寫(xiě)分離配置文件
vim schema.xml 
<?xml version="1.0"?>
<!DOCTYPE mycat:schema SYSTEM "schema.dtd">  
<mycat:schema xmlns:mycat="http://io.mycat/">
<schema name="TESTDB" checkSQLschema="false" sqlMaxLimit="100" dataNode="sh1"> 
</schema>  
        <dataNode name="sh1" dataHost="oldguo1" database= "world" />         
        <dataHost name="oldguo1" maxCon="1000" minCon="10" balance="1"  writeType="0" dbType="mysql"  dbDriver="native" switchType="1">    
                <heartbeat>select user()</heartbeat>  
        <writeHost host="db1" url="10.0.0.51:3307" user="root" password="123"> 
                        <readHost host="db2" url="10.0.0.51:3309" user="root" password="123" /> 
        </writeHost> 
        </dataHost>  
</mycat:schema>

7.測(cè)試一主一從的讀寫(xiě)分離

1.重啟mycat
mycat restart
2.讀寫(xiě)分離測(cè)試
mysql -uroot -p -h 127.0.0.1 -P8066
select @@server_id;

begin;
select @@server_id;
commit;

總結(jié):
以上案例實(shí)現(xiàn)了1主1從的讀寫(xiě)分離功能,寫(xiě)操作落到主庫(kù),讀操作落到從庫(kù).如果主庫(kù)宕機(jī),從庫(kù)不能在繼續(xù)提供服務(wù)了

8. 配置讀寫(xiě)分離及高可用

1.編寫(xiě)讀寫(xiě)分離及高可用配置文件
[root@db01 conf]# vim schema.xml
<?xml version="1.0"?>  
<!DOCTYPE mycat:schema SYSTEM "schema.dtd">  
<mycat:schema xmlns:mycat="http://io.mycat/">
<schema name="TESTDB" checkSQLschema="false" sqlMaxLimit="100" dataNode="sh1"> 
</schema>  
    <dataNode name="sh1" dataHost="oldguo1" database= "world" />  
    <dataHost name="oldguo1" maxCon="1000" minCon="10" balance="1"  writeType="0" dbType="mysql"  dbDriver="native" switchType="1"> 
        <heartbeat>select user()</heartbeat>  
    <writeHost host="db1" url="10.0.0.51:3307" user="root" password="123"> 
            <readHost host="db2" url="10.0.0.51:3309" user="root" password="123" /> 
    </writeHost> 
    <writeHost host="db3" url="10.0.0.52:3307" user="root" password="123"> 
            <readHost host="db4" url="10.0.0.52:3309" user="root" password="123" /> 
    </writeHost>        
    </dataHost>  
</mycat:schema>
2.配置文件介紹

真正的 writehost:負(fù)責(zé)寫(xiě)操作的writehost
standby writeHost :和readhost一樣,只提供讀服務(wù)
當(dāng)寫(xiě)節(jié)點(diǎn)宕機(jī)后,后面跟的readhost也不提供服務(wù),這時(shí)候standby的writehost就提供寫(xiě)服務(wù),
后面跟的readhost提供讀服務(wù)

3.測(cè)試:
mycat restart
mysql -uroot -p123456 -h 127.0.0.1 -P 8066

讀寫(xiě)分離測(cè)試
mysql -uroot -p -h 127.0.0.1 -P8066
select @@server_id;

begin;
select @@server_id;
commit;

對(duì)db01 3307節(jié)點(diǎn)進(jìn)行關(guān)閉和啟動(dòng),測(cè)試讀寫(xiě)操作

9. 配置中的屬性介紹:

1.balance屬性

  • 負(fù)載均衡類型,目前的取值有3種:
    1.balance="0", 不開(kāi)啟讀寫(xiě)分離機(jī)制,所有讀操作都發(fā)送到當(dāng)前可用的writeHost上
    2.balance="1",全部的readHost與standby writeHost參與select語(yǔ)句的負(fù)載均衡,簡(jiǎn)單的說(shuō),當(dāng)雙主雙從模式(M1->S1,M2->S2,并且M1與 M2互為主備),正常情況下,M2,S1,S2都參與select語(yǔ)句的負(fù)載均衡
    3.balance="2",所有讀操作都隨機(jī)的在writeHost、readhost上分發(fā)

2.writeType屬性

  • 負(fù)載均衡類型,目前的取值有2種:
    1.writeType="0", 所有寫(xiě)操作發(fā)送到配置的第一個(gè)writeHost,第一個(gè)掛了切到還生存的第二個(gè)writeHost,重新啟動(dòng)后已切換后的為主,切換記錄在配置文件中:dnindex.properties
    2.writeType=“1”,所有寫(xiě)操作都隨機(jī)的發(fā)送到配置的writeHost,但不推薦使用

3.switchType屬性

-1   表示不自動(dòng)切換 
 1   默認(rèn)值,自動(dòng)切換 
 2   基于MySQL主從同步的狀態(tài)決定是否切換 ,心跳語(yǔ)句為 show slave status
  • datahost其他配置
<dataHost name="localhost1" maxCon="1000" minCon="10" balance="1"  writeType="0" dbType="mysql"  dbDriver="native" switchType="1"> 

maxCon="1000":最大的并發(fā)連接數(shù)
minCon="10" :mycat在啟動(dòng)之后,會(huì)在后端節(jié)點(diǎn)上自動(dòng)開(kāi)啟的連接線程

tempReadHostAvailable="1"
這個(gè)一主一從時(shí)(1個(gè)writehost,1個(gè)readhost時(shí)),可以開(kāi)啟這個(gè)參數(shù),如果2個(gè)writehost,2個(gè)readhost時(shí)
<heartbeat>select user()</heartbeat>  監(jiān)測(cè)心跳

10.垂直分表

  • 編寫(xiě)配置文件
vim schema.xml
<?xml version="1.0"?>
<!DOCTYPE mycat:schema SYSTEM "schema.dtd">
<mycat:schema xmlns:mycat="http://io.mycat/">
<schema name="TESTDB" checkSQLschema="false" sqlMaxLimit="100" dataNode="sh1">
        <table name="user" dataNode="sh1"/>
        <table name="order_t" dataNode="sh2"/>
</schema>
    <dataNode name="sh1" dataHost="oldguo1" database= "taobao" />
    <dataNode name="sh2" dataHost="oldguo2" database= "taobao" />
    
    <dataHost name="oldguo1" maxCon="1000" minCon="10" balance="1"  writeType="0" dbType="mysql"  dbDriver="native" switchType="1">
        <heartbeat>select user()</heartbeat>
    <writeHost host="db1" url="10.0.0.51:3307" user="root" password="123">
            <readHost host="db2" url="10.0.0.51:3309" user="root" password="123" />
    </writeHost>
    <writeHost host="db3" url="10.0.0.52:3307" user="root" password="123">
            <readHost host="db4" url="10.0.0.52:3309" user="root" password="123" />
    </writeHost>
    </dataHost>
    
    <dataHost name="oldguo2" maxCon="1000" minCon="10" balance="1"  writeType="0" dbType="mysql"  dbDriver="native" switchType="1">
        <heartbeat>select user()</heartbeat>
    <writeHost host="db1" url="10.0.0.51:3308" user="root" password="123">
            <readHost host="db2" url="10.0.0.51:3310" user="root" password="123" />
    </writeHost>
    <writeHost host="db3" url="10.0.0.52:3308" user="root" password="123">
            <readHost host="db4" url="10.0.0.52:3310" user="root" password="123" />
    </writeHost>
    </dataHost>
</mycat:schema>
  • 創(chuàng)建測(cè)試庫(kù)和表:
mysql -S /data/3307/mysql.sock -e "create database taobao charset utf8;"
mysql -S /data/3308/mysql.sock -e "create database taobao charset utf8;"
mysql -S /data/3307/mysql.sock -e "use taobao;create table user(id int,name varchar(20))";
mysql -S /data/3308/mysql.sock -e "use taobao;create table order_t(id int,name varchar(20))"
  • 重啟測(cè)試 :
mycat restart
mysql -uroot -p -h 127.0.0.1 -P8066

use  TESTDB ;
mysql> insert into order_t(id,name) values(1,'c');
mysql> insert into order_t(id,name) values(2,'d');
mysql> insert into user(id,name) values(1,'a');
mysql> insert into user(id,name) values(2,'b');
  • 分別登陸后端主節(jié)點(diǎn)查看數(shù)據(jù)
mysql -S /data/3307/mysql.sock -e "select * from taobao.user"
mysql -S /data/3308/mysql.sock -e "select * from taobao.order_t"

11. MyCAT核心特性——分片(水平拆分)

  • 分片:對(duì)一個(gè)"bigtable",比如說(shuō)t3表
    (1)行數(shù)非常多,800w
    (2)訪問(wèn)非常頻繁

  • 分片的目的:
    (1)將大數(shù)據(jù)量進(jìn)行分布存儲(chǔ)
    (2)提供均衡的訪問(wèn)路由

  • 分片策略:
    范圍 range
    取模 mod
    枚舉
    哈希 hash
    時(shí)間 流水

優(yōu)化關(guān)聯(lián)查詢
全局表
ER分片

12 .范圍分片

比如說(shuō)t3表
(1)行數(shù)非常多,2000w(1-1000w:sh1 1000w-2000w:sh2)
(2)訪問(wèn)非常頻繁,用戶訪問(wèn)較離散

1.修改配置文件

  • schema文件
vim schema.xml
<?xml version="1.0"?>
<!DOCTYPE mycat:schema SYSTEM "schema.dtd">
<mycat:schema xmlns:mycat="http://io.mycat/">
<schema name="TESTDB" checkSQLschema="false" sqlMaxLimit="100" dataNode="sh1">
    <table name="t3" dataNode="sh1,sh2" rule="auto-sharding-long" />
</schema>
    <dataNode name="sh1" dataHost="oldguo1" database= "taobao" />
    <dataNode name="sh2" dataHost="oldguo2" database= "taobao" />
    
    <dataHost name="oldguo1" maxCon="1000" minCon="10" balance="1"  writeType="0" dbType="mysql"  dbDriver="native" switchType="1">
        <heartbeat>select user()</heartbeat>
    <writeHost host="db1" url="10.0.0.51:3307" user="root" password="123">
            <readHost host="db2" url="10.0.0.51:3309" user="root" password="123" />
    </writeHost>
    <writeHost host="db3" url="10.0.0.52:3307" user="root" password="123">
            <readHost host="db4" url="10.0.0.52:3309" user="root" password="123" />
    </writeHost>
    </dataHost>
    
    <dataHost name="oldguo2" maxCon="1000" minCon="10" balance="1"  writeType="0" dbType="mysql"  dbDriver="native" switchType="1">
        <heartbeat>select user()</heartbeat>
    <writeHost host="db1" url="10.0.0.51:3308" user="root" password="123">
            <readHost host="db2" url="10.0.0.51:3310" user="root" password="123" />
    </writeHost>
    <writeHost host="db3" url="10.0.0.52:3308" user="root" password="123">
            <readHost host="db4" url="10.0.0.52:3310" user="root" password="123" />
    </writeHost>
    </dataHost>
</mycat:schema>
  • rule文件
vim rule.xml
<tableRule name="auto-sharding-long">
                <rule>
                        <columns>id</columns>
                        <algorithm>rang-long</algorithm>
                </rule>        

<function name="rang-long"
    class="io.mycat.route.function.AutoPartitionByLong">
    <property name="mapFile">autopartition-long.txt</property>
</function>
  • autopartition-long.txt文件
vim autopartition-long.txt
0-10=0
10-20=1

2.創(chuàng)建測(cè)試

mysql -S /data/3307/mysql.sock -e "use taobao;create table t3 (id int not null primary key auto_increment,name varchar(20) not null);"

mysql -S /data/3308/mysql.sock  -e "use taobao;create table t3 (id int not null primary key auto_increment,name varchar(20) not null);"

3.測(cè)試

重啟mycat
mycat restart
mysql -uroot -p123456 -h 127.0.0.1 -P 8066
insert into t3(id,name) values(1,'a');
insert into t3(id,name) values(2,'b');
insert into t3(id,name) values(3,'c');
insert into t3(id,name) values(4,'d');
insert into t3(id,name) values(11,'aa');
insert into t3(id,name) values(12,'bb');
insert into t3(id,name) values(13,'cc');
insert into t3(id,name) values(14,'dd');
insert into t3(id,name) values(10,'ddd');

分別登陸后端主節(jié)點(diǎn)查看數(shù)據(jù)

mysql -S /data/3307/mysql.sock -e "select * from taobao.t3"
mysql -S /data/3308/mysql.sock -e "select * from taobao.t3"

13. 取模分片(mod-long):

取余分片方式:分片鍵(一個(gè)列)與節(jié)點(diǎn)數(shù)量進(jìn)行取余,得到余數(shù),將數(shù)據(jù)寫(xiě)入對(duì)應(yīng)節(jié)點(diǎn)

修改配置文件

  • schema配置
vim schema.xml
<table name="t4" dataNode="sh1,sh2" rule="mod-long" />

rule配置

vim rule.xml
<property name="count">2</property>

準(zhǔn)備測(cè)試環(huán)境

  • 創(chuàng)建測(cè)試表
mysql -S /data/3307/mysql.sock -e "use taobao;create table t4 (id int not null primary key auto_increment,name varchar(20) not null);"
mysql -S /data/3308/mysql.sock -e "use taobao;create table t4 (id int not null primary key auto_increment,name varchar(20) not null);"
  • 重啟mycat
mycat restart 
  • 測(cè)試
mysql -uroot -p123456 -h10.0.0.52 -P8066

use TESTDB
insert into t4(id,name) values(1,'a');
insert into t4(id,name) values(2,'b');
insert into t4(id,name) values(3,'c');
insert into t4(id,name) values(4,'d');
  • 分別登錄后端節(jié)點(diǎn)查詢數(shù)據(jù)
mysql -S /data/3307/mysql.sock 
use taobao
select * from t4;

mysql -S /data/3308/mysql.sock 
use taobao
select * from t4;

14. 枚舉分片

t5 表
id name telnum
1 bj 1212
2 sh 22222
3 bj 3333
4 sh 44444
5 bj 5555

sharding-by-intfile

修改配置文件

  • schema配置
vim schema.xml
<table name="t5" dataNode="sh1,sh2" rule="sharding-by-intfile" />
  • rule配置
vim rule.xml
<tableRule name="sharding-by-intfile"> 
<rule> <columns>name</columns> 
<algorithm>hash-int</algorithm> 
</rule> 
</tableRule> 

<function name="hash-int" class="org.opencloudb.route.function.PartitionByFileMap"> 
<property name="mapFile">partition-hash-int.txt</property> 
  <property name="type">1</property>
                <property name="defaultNode">0</property>
</function> 
  • partition-hash-int.txt 配置
bj=0 
sh=1
DEFAULT_NODE=1 

columns 標(biāo)識(shí)將要分片的表字段,algorithm 分片函數(shù), 其中分片函數(shù)配置中,mapFile標(biāo)識(shí)配置文件名稱

2.準(zhǔn)備測(cè)試環(huán)境

  • 準(zhǔn)備數(shù)據(jù)
mysql -S /data/3307/mysql.sock -e "use taobao;create table t5 (id int not null primary key auto_increment,name varchar(20) not null);"

mysql -S /data/3308/mysql.sock -e "use taobao;create table t5 (id int not null primary key auto_increment,name varchar(20) not null);"
  • 重啟mycat
mycat restart 
mysql -uroot -p123456 -h10.0.0.51 -P8066
use TESTDB
insert into t5(id,name) values(1,'bj');
insert into t5(id,name) values(2,'sh');
insert into t5(id,name) values(3,'bj');
insert into t5(id,name) values(4,'sh');
insert into t5(id,name) values(5,'tj');

15 . Mycat全局表

a b c d
join
t

select t1.name ,t.x from t1
join t
select t2.name ,t.x from t2
join t
select t3.name ,t.x from t3
join t

使用場(chǎng)景:
如果你的業(yè)務(wù)中有些數(shù)據(jù)類似于數(shù)據(jù)字典,比如配置文件的配置,
常用業(yè)務(wù)的配置或者數(shù)據(jù)量不大很少變動(dòng)的表,這些表往往不是特別大,
而且大部分的業(yè)務(wù)場(chǎng)景都會(huì)用到,那么這種表適合于Mycat全局表,無(wú)須對(duì)數(shù)據(jù)進(jìn)行切分,
要在所有的分片上保存一份數(shù)據(jù)即可,Mycat 在Join操作中,業(yè)務(wù)表與全局表進(jìn)行Join聚合會(huì)優(yōu)先選擇相同分片內(nèi)的全局表join,
避免跨庫(kù)Join,在進(jìn)行數(shù)據(jù)插入操作時(shí),mycat將把數(shù)據(jù)分發(fā)到全局表對(duì)應(yīng)的所有分片執(zhí)行,在進(jìn)行數(shù)據(jù)讀取時(shí)候?qū)?huì)隨機(jī)獲取一個(gè)節(jié)點(diǎn)讀取數(shù)據(jù)。

1.修改配置

vim schema.xml 
<table name="t_area" primaryKey="id"  type="global" dataNode="sh1,sh2" /> 

2.后端數(shù)據(jù)準(zhǔn)備

mysql -S /data/3307/mysql.sock 
use taobao
create table t_area (id int not null primary key auto_increment,name varchar(20) not null);

mysql -S /data/3308/mysql.sock 
use taobao
create table t_area  (id int not null primary key auto_increment,name varchar(20) not null);

3.重啟mycat

mycat restart 

4.測(cè)試

mysql -uroot -p123456 -h10.0.0.52 -P8066

use TESTDB
insert into t_area(id,name) values(1,'a');
insert into t_area(id,name) values(2,'b');
insert into t_area(id,name) values(3,'c');
insert into t_area(id,name) values(4,'d');

16. E-R分片

A
join
B
為了防止跨分片join,可以使用E-R模式
A join B
on a.xx=b.yy
join C
on A.id=C.id
<table name="A" dataNode="sh1,sh2" rule="mod-long">
<childTable name="B" joinKey="yy" parentKey="xx" />
</table>

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