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mycat實驗之主從配置讀寫分離和分表
1.實驗環境：
vmware虛機3個 （虛機太少了，電腦有點吃力，3個虛機只能達到基本的測試）
系統centos7 （實驗是關閉防火墻和selinux做的）
mysql版本5.7
mycat版本1.6
虛機名字和ip：
mysql1 192.168.211.138
mysql2 192.168.211.139
mysql3 192.168.211.142
mycat安裝在mysql1(192.168.211.138)
這臺主機須能夠解析mysql2,mysql3的地址。
可通過/etc/hosts 手動添加解析
2.實驗目的
實現mycat讀寫分離和分表的功能。
3.實驗思路
在mycat創建一個邏輯庫：hello。
創建四個表格：
t1 這個表格用來分片，用枚舉的規則分片。
t2 這個表格做全局表。
t3 這個表格做普通表，定義它放到其中一個datanode,放到mysql1
t4 這個表格做普通表，定義它放到其中一個datanode,放到mysql3
虛機的分配：
mysql1 和mysql2做主從配置，其中mysql1為主，mysql2為從,其中mysql1用來寫，mysql2用來讀。
mysql3 就是個單獨的datanode
實際我們只有兩個datanode，mysql1,mysql3。
4.實驗步驟
分別在虛機安裝mysql5.7，步驟略。
設置mysql用戶，步驟略。請注意，必須設置一個用戶允許內網地址連接或者干脆是允許任何地方連接。比如設置'root'@'%'。
安裝mycat。步驟略。
配置mysql1和mysql2主從，步驟略。
以上都是些常用配置，懶得特意記錄了。
以上的環境都配置好了，就可以開始我們實驗核心步驟mycat的配置了
現在開始整個過程的配置。
1.在mysql1（192.168.211.138）里創建一個db1.
mysql> create database db1; Query OK, 1 row affected (0.01 sec)
檢查mysql2（192.168.211.139）里是不是同步了？
mysql> show databases; +--------------------+ | Database | +--------------------+ | information_schema | | db1 | | logs | | mysql | | performance_schema | | sys | | wordpress | +--------------------+ 7 rows in set (0.00 sec)
同步了。
2.在mysql3（192.168.211.142）里創建db2。
mysql> show databases; +--------------------+ | Database | +--------------------+ | information_schema | | db2 | | logs | | mysql | | performance_schema | | sys | | wordpress | +--------------------+ 7 rows in set (0.01 sec)
3.在mysql1里配置mycat，我的mycat安裝在mysql1。
我的配置文件路徑：
[root@mysql1 conf]# pwd /usr/local/mycat/conf
主要配置文件有：
[root@mysql1 conf]# ls autopartition-long.txt log4j2.xml schema.xml.bk server.xml.bk auto-sharding-long.txt migrateTables.properties schema.xml.bk2 sharding-by-enum.txt auto-sharding-rang-mod.txt myid.properties sequence_conf.properties wrapper.conf cacheservice.properties partition-hash-int.txt sequence_db_conf.properties zkconf dnindex.properties partition-range-mod.txt sequence_distributed_conf.properties zkdownload ehcache.xml rule.xml sequence_time_conf.properties index_to_charset.properties schema.xml server.xml [root@mysql1 conf]#
需要用到的是:schema.xml ##這個文件配置分表讀寫分離策略
rule.xml ##這是分表規則的定義
server.xml ##登錄mycat的賬戶密碼和防火墻的設置
4.首先配置：schema.xml
備份下原配置文件：
[root@mysql1 conf]# cp schema.xml schema.xml.bk3
清空配置文件：
[root@mysql1 conf]# echo " " >schema.xml
重新配置schema.xml，如下是我的配置文件整個內容:
<?xml version="1.0"?> <!DOCTYPE mycat:schema SYSTEM "schema.dtd"> <mycat:schema xmlns:mycat="http://io.mycat/"> <schema name="hello" checkSQLschema="false" sqlMaxLimit="100"> <!-- auto sharding by id (long) --> <table name="t1" dataNode="dn1,dn2" rule="sharding-by-intfile" /> <!-- 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="t2" primaryKey="ID" type="global" dataNode="dn1,dn2" /> <table name="t3" dataNode="dn1" /> <table name="t4" dataNode="dn2" /> </schema> <!-- <dataNode name="dn1$0-743" dataHost="localhost1" database="db$0-743" /> --> <dataNode name="dn1" dataHost="mysql1" database="db1" /> <dataNode name="dn2" dataHost="mysql3" database="db2" /> <dataHost name="mysql1" maxCon="1000" minCon="10" balance="3" writeType="0" dbType="mysql" dbDriver="native" switchType="1" slaveThreshold="100"> <heartbeat>select user()</heartbeat> <!-- can have multi write hosts --> <writeHost host="hostM1" url="192.168.211.138:3306" user="root" password="Alex2010@"> <!-- can have multi read hosts --> <readHost host="hostS2" url="192.168.211.139:3306" user="root" password="Alex2010@"/> </writeHost> </dataHost> <dataHost name="mysql3" 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="hostM1" url="192.168.211.142:3306" user="root" password="Alex2010@"> <!-- can have multi read hosts --> <readHost host="hostS2" url="192.168.211.142:3306" user="root" password="Alex2010@"/> </writeHost> </dataHost> </mycat:schema>
這些字段的解釋，可以查看我前面分片規則里面的解析。
說明下datahost balance字段的意義
balance屬性
負載均衡類型，目前的取值有3種：
1. balance="0", 不開啟讀寫分離機制，所有讀操作都發送到當前可用的writeHost上。
2. balance="1"，全部的readHost與stand by writeHost參與select語句的負載均衡，簡單的說，當雙主雙從模式(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語句的負載均衡。
3. balance="2"，所有讀操作都隨機的在writeHost、readhost上分發。
4. balance="3"，所有讀請求隨機的分發到wiriterHost對應的readhost執行，writerHost不負擔讀壓
writeType屬性
負載均衡類型，目前的取值有3種：
1. writeType="0", 所有寫操作發送到配置的第一個writeHost，第一個掛了切到還生存的第二個writeHost，重新啟動后已切換后的為準，
切換記錄在配置文件中:dnindex.properties .
2. writeType="1"，所有寫操作都隨機的發送到配置的writeHost，1.5以后廢棄不推薦。
需要說明的是：
<dataHost name="mysql1" maxCon="1000" minCon="10" balance="3" writeType="0" dbType="mysql" dbDriver="native" switchType="1" slaveThreshold="100"> <heartbeat>select user()</heartbeat> <!-- can have multi write hosts --> <writeHost host="hostM1" url="192.168.211.138:3306" user="root" password="Alex2010@"> <!-- can have multi read hosts --> <readHost host="hostS2" url="192.168.211.139:3306" user="root" password="Alex2010@"/> </writeHost> </dataHost>
讀寫分離這里有兩種寫法：
除了上面的還可以寫下面這樣：
<dataHost name="mysql1" maxCon="1000" minCon="10" balance="3" writeType="0" dbType="mysql" dbDriver="native" switchType="1" slaveThreshold="100"> <heartbeat>select user()</heartbeat> <!-- can have multi write hosts --> <writeHost host="hostM1" url="192.168.211.138:3306" user="root" password="Alex2010@"> </writeHost> <writeHost host="hostM1" url="192.168.211.139:3306" user="root" password="Alex2010@"> </writeHost> </dataHost>
區別是上面的那種寫法，如果主服務器掛了，從服務器不能讀了。
下面的這種寫法，主服務器掛了，從服務器依然可以正常讀取。
這里說一下，后面會做測試。
5.看看rule.xml里的配置
看分表t1的設置：
<table name="t1" dataNode="dn1,dn2" rule="sharding-by-intfile" />
分表規則是 sharding-by-intfile
看看這個的規則設置
<tableRule name="sharding-by-intfile"> <rule> <columns>city</columns> <algorithm>hash-int</algorithm> </rule> </tableRule>
為什么columns是city呢？
這個city是我設定的，計劃創建表格t1(id,name,bu,city)有這四個列。我準備用city來做分片的列。
繼續往下看
</function> <function name="hash-int" class="io.mycat.route.function.PartitionByFileMap"> <property name="mapFile">partition-hash-int.txt</property> <property name="type">1</property> <property name="defaultNode">0</property> </function>
這是用的hash-int函數的設置了。其中mpfile是指要讀取的配置文件。這是什么意思呢？
看看partition-hash-int.txt的內容
[root@mysql1 conf]# cat partition-hash-int.txt #10000=0 #10010=1 bj=0 gz=0 sz=1 [root@mysql1 conf]#
我計劃的表格t1 city列有三個值，bj gz sz ，這個設置的意思是：bj gz 的數據存儲到datanode1也就是mysql1，sz的數據存儲
到datanode2也就是mysql3。
<property name="type">1</property> <property name="defaultNode">0</property>
這兩條參數也必須要有，type默認的值是0，而0的格式是interger，注意我們分片的列是city是字符。
6.配置server.xml，參考下官方教程，很簡單。
7.到這里可以來啟動mycat，登錄進去創建表格，插入數據測試，是不是能夠達到我們的預期目標？
[root@mysql1 conf]# mysql -uroot -p123456 -P8066 -h 127.0.0.1 mysql: [Warning] 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 2 Server version: 5.6.29-mycat-1.6-RELEASE-20161028204710 MyCat Server (OpenCloundDB) Copyright (c) 2000, 2017, Oracle and/or its affiliates. All rights reserved. Oracle is a registered trademark of Oracle Corporation and/or its affiliates. Other names may be trademarks of their respective owners. Type 'help;' or '\h' for help. Type '\c' to clear the current input statement. mysql>
登錄進來了
mysql> show databases; +----------+ | DATABASE | +----------+ | hello | +----------+ 1 row in set (0.02 sec) mysql>
我們設置的邏輯庫hello
mysql> use hello; Reading table information for completion of table and column names You can turn off this feature to get a quicker startup with -A Database changed mysql> show tables; +-----------------+ | Tables in hello | +-----------------+ | t1 | | t2 | | t3 | | t4 | +-----------------+ 4 rows in set (0.01 sec) mysql> mysql> desc t1; ERROR 1146 (42S02): Table 'db1.t1' doesn't exist mysql>
注意這里有個問題，這些t1-t4的表格，看似是有，其實是假的。感覺像是BUG。表格需要我們手動創建。
創建表格：
mysql> create table t1 (id int not null,name varchar(15) not null,bu varchar(10) not null,city varchar(5) not null); Query OK, 0 rows affected (0.36 sec) mysql> create table t2 (id int not null,name varchar(15) not null); Query OK, 0 rows affected (0.10 sec) mysql> create table t3 (id int not null,gongzi int not null); Query OK, 0 rows affected (0.07 sec) mysql> create table t4 (id int not null,shui int not null); Query OK, 0 rows affected (0.07 sec)
看看創建的表格都放在哪?
mysql> explain create table t1 (id int not null,name varchar(15) not null,bu varchar(10) not null,city varchar(5) not null); +-----------+--------------------------------------------------------------------------------------------------------------+ | DATA_NODE | SQL | +-----------+--------------------------------------------------------------------------------------------------------------+ | dn1 | create table t1 (id int not null,name varchar(15) not null,bu varchar(10) not null,city varchar(5) not null) | | dn2 | create table t1 (id int not null,name varchar(15) not null,bu varchar(10) not null,city varchar(5) not null) | +-----------+--------------------------------------------------------------------------------------------------------------+ 2 rows in set (0.00 sec) mysql>
這是分片表，dn1,dn2都有
mysql> explain create table t2 (id int not null,name varchar(15) not null); +-----------+-------------------------------------------------------------+ | DATA_NODE | SQL | +-----------+-------------------------------------------------------------+ | dn1 | create table t2 (id int not null,name varchar(15) not null) | | dn2 | create table t2 (id int not null,name varchar(15) not null) | +-----------+-------------------------------------------------------------+ 2 rows in set (0.00 sec) mysql>
這是全局表，dn1,dn2都有，全局表的意思是，每個dn節點都有的表而且數據保持一致。
mysql> explain create table t3 (id int not null,gongzi int not null); +-----------+-------------------------------------------------------+ | DATA_NODE | SQL | +-----------+-------------------------------------------------------+ | dn1 | create table t3 (id int not null,gongzi int not null) | +-----------+-------------------------------------------------------+ 1 row in set (0.00 sec) mysql>
普通表，預設就是放在dn1，正常
mysql> explain create table t4 (id int not null,shui int not null); +-----------+------------------------------------------------------+ | DATA_NODE | SQL | +-----------+------------------------------------------------------+ | dn2 | create table t4 (id int not null,shui int not null) | +-----------+------------------------------------------------------+ 1 row in set (0.00 sec) mysql>
普通表，預設就是放在dn2，正常
看看從庫的情況：
mysql> show tables; +---------------+ | Tables_in_db1 | +---------------+ | t1 | | t2 | | t3 | +---------------+ 3 rows in set (0.00 sec) mysql>
除了t4沒有，其他都有，正常。
插入數據：
插入t1
mysql> insert into t1(id,name,bu,city)values(1,'am1','sy','bj'); Query OK, 1 row affected (0.38 sec) mysql> insert into t1(id,name,bu,city)values(2,'am2','cs','gz'); Query OK, 1 row affected (0.03 sec) mysql> insert into t1(id,name,bu,city)values(3,'am3','net','sz'); Query OK, 1 row affected (0.08 sec) mysql>
插入t2
mysql> insert into t2(id,name)value(4,'am4'),(5,'am5'); Query OK, 2 rows affected (0.11 sec) Records: 2 Duplicates: 0 Warnings: 0
插入t3
mysql> insert into t3(id,gongzi)values(6,1000),(7,1200); Query OK, 2 rows affected (0.02 sec) Records: 2 Duplicates: 0 Warnings: 0
插入t4
mysql> insert into t4(id,shui)values(8,10),(9,8); Query OK, 2 rows affected (0.04 sec) Records: 2 Duplicates: 0 Warnings: 0
基礎架構和環境以及達成，現在來測試：
首先，t1根據預設的目的，bj和gz的數據存放在dn1(mysql1),sz的數據存放在dn2(mysql3)
mysql> select * from t1 where city='bj' or city='gz'; +----+------+----+------+ | id | name | bu | city | +----+------+----+------+ | 1 | am1 | sy | bj | | 2 | am2 | cs | gz | +----+------+----+------+ 2 rows in set (0.10 sec) mysql> explain select * from t1 where city='bj' or city='gz'; +-----------+--------------------------------------------------------------+ | DATA_NODE | SQL | +-----------+--------------------------------------------------------------+ | dn1 | SELECT * FROM t1 WHERE city = 'bj' OR city = 'gz' LIMIT 100 | +-----------+--------------------------------------------------------------+ 1 row in set (0.00 sec) mysql> mysql> explain select * from t1 where city='sz'; +-----------+----------------------------------------------+ | DATA_NODE | SQL | +-----------+----------------------------------------------+ | dn2 | SELECT * FROM t1 WHERE city = 'sz' LIMIT 100 | +-----------+----------------------------------------------+ 1 row in set (0.02 sec) mysql>
分表正常
測試讀寫分離
開啟debug日志
<asyncRoot level="debug" includeLocation="true"> ##默認level是info 改成debug后，重啟mycat服務。 <AppenderRef ref="Console" /> <AppenderRef ref="RollingFile"/> </asyncRoot>
檢索數據：
檢索t3的數據，t3只有mysql1有。
mysql> select * from t3; +----+--------+ | id | gongzi | +----+--------+ | 6 | 1000 | | 7 | 1200 | +----+--------+ 2 rows in set (0.02 sec)
以下是mycat.log日志，可以看到是從mysql2(192.168.211.139)讀取的數據
2017-12-15 01:47:23.280 DEBUG [$_NIOREACTOR-0-RW] (io.mycat.server.NonBlockingSession.releaseConnection(NonBlockingSession.java:341))
- release connection MySQLConnection [id=22, lastTime=1513320443251, user=root, schema=db1, old shema=db1, borrowed=true,
fromSlaveDB=true, threadId=33, charset=utf8, txIsolation=3, autocommit=true, attachment=dn1{SELECT *
FROM t3
LIMIT 100}, respHandler=SingleNodeHandler [node=dn1{SELECT *
FROM t3
LIMIT 100}, packetId=6], host=192.168.211.139, port=3306, statusSync=null, writeQueue=0, modifiedSQLExecuted=false]
2017-12-15 01:54:37.777 DEBUG [$_NIOREACTOR-0-RW] (io.mycat.server.NonBlockingSession.releaseConnection(NonBlockingSession.java:341))
- release connection MySQLConnection [id=26, lastTime=1513320877751, user=root, schema=db1, old shema=db1, borrowed=true, fromSlaveDB=true,
threadId=31, charset=utf8, txIsolation=3, autocommit=true, attachment=dn1{SELECT *
FROM t3
LIMIT 100}, respHandler=SingleNodeHandler [node=dn1{SELECT *
FROM t3
LIMIT 100}, packetId=6], host=192.168.211.139, port=3306, statusSync=null, writeQueue=0, modifiedSQLExecuted=false]mysql> select * from t1; +----+------+-----+------+ | id | name | bu | city | +----+------+-----+------+ | 3 | am3 | net | sz | | 1 | am1 | sy | bj | | 2 | am2 | cs | gz | +----+------+-----+------+ 3 rows in set (0.04 sec)
日志
2017-12-15 02:02:35.818 DEBUG [$_NIOREACTOR-0-RW] (io.mycat.backend.mysql.nio.MySQLConnection.synAndDoExecute(MySQLConnection.java:448))
- con need syn ,total syn cmd 1 commands SET names utf8;schema change:false con:MySQLConnection [id=29, lastTime=1513321355817, user=root,
schema=db1, old shema=db1, borrowed=true, fromSlaveDB=true, threadId=35, charset=utf8, txIsolation=3, autocommit=true, attachment=dn1{SELECT *
FROM t1
LIMIT 100}, respHandler=io.mycat.backend.mysql.nio.handler.MultiNodeQueryHandler@11eaaf37, host=192.168.211.139, port=3306, statusSync=null, writeQueue=0,
modifiedSQLExecuted=false]
2017-12-15 02:02:35.819 DEBUG [$_NIOREACTOR-0-RW] (io.mycat.backend.mysql.nio.MySQLConnection.synAndDoExecute(MySQLConnection.java:448))
- con need syn ,total syn cmd 1 commands SET names utf8;schema change:false con:MySQLConnection [id=20, lastTime=1513321355819, user=root,
schema=db2, old shema=db2, borrowed=true, fromSlaveDB=false, threadId=65, charset=utf8, txIsolation=3, autocommit=true, attachment=dn2{SELECT *
FROM t1
LIMIT 100}, respHandler=io.mycat.backend.mysql.nio.handler.MultiNodeQueryHandler@11eaaf37, host=192.168.211.142, port=3306, statusSync=null, writeQueue=0,
modifiedSQLExecuted=false]多執行幾次檢索存在dn1的數據，查看日志，可以確認，數據都是從mysql2(192.168.211.139)讀取。實現了讀寫分離。
8.讀寫兩種不同寫法的測試
前面有提到讀寫分離有兩種寫法，
<dataHost name="mysql1" maxCon="1000" minCon="10" balance="3" writeType="0" dbType="mysql" dbDriver="native" switchType="1" slaveThreshold="100"> <heartbeat>select user()</heartbeat> <!-- can have multi write hosts --> <writeHost host="hostM1" url="192.168.211.138:3306" user="root" password="Alex2010@"> <!-- can have multi read hosts --> <readHost host="hostS2" url="192.168.211.139:3306" user="root" password="Alex2010@"/> </writeHost> </dataHost>
讀寫分離這里有兩種寫法：
除了上面的還可以寫下面這樣：
<dataHost name="mysql1" maxCon="1000" minCon="10" balance="3" writeType="0" dbType="mysql" dbDriver="native" switchType="1" slaveThreshold="100"> <heartbeat>select user()</heartbeat> <!-- can have multi write hosts --> <writeHost host="hostM1" url="192.168.211.138:3306" user="root" password="Alex2010@"> </writeHost> <writeHost host="hostM1" url="192.168.211.139:3306" user="root" password="Alex2010@"> </writeHost> </dataHost>
區別是上面的那種寫法，如果主服務器掛了，從服務器不能讀了。
下面的這種寫法，主服務器掛了，從服務器依然可以正常讀取。
現在服務器的寫法是第一種，主服務器掛了，從服務器不能讀了。執行看看
[root@mysql1 ~]# systemctl stop mysqld.service [root@mysql1 ~]# systemctl status mysqld.service ● mysqld.service - MySQL Server Loaded: loaded (/usr/lib/systemd/system/mysqld.service; enabled; vendor preset: disabled) Active: inactive (dead) since Fri 2017-12-15 02:16:43 EST; 35s ago Docs: man:mysqld(8)
[root@mysql1 ~]# mysql -uroot -p123456 -P8066 -h227.0.0.1 mysql: [Warning] 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 2 Server version: 5.6.29-mycat-1.6-RELEASE-20161028204710 MyCat Server (OpenCloundDB) Copyright (c) 2000, 2017, Oracle and/or its affiliates. All rights reserved. Oracle is a registered trademark of Oracle Corporation and/or its affiliates. Other names may be trademarks of their respective owners. Type 'help;' or '\h' for help. Type '\c' to clear the current input statement. mysql> select * from t1; ERROR 3000 (HY000): No MyCAT Database selected mysql> select * from t1; ERROR 3000 (HY000): No MyCAT Database selected
確實無法讀取
測試第二種
修改schema.xml配置文件
重新啟動mysql和mycat 保證環境正常
正常使用環境，我們現在關閉mysql1就是主節點
[root@mysql1 conf]# systemctl stop mysqld.service [root@mysql1 conf]# systemctl status mysqld.service ● mysqld.service - MySQL Server Loaded: loaded (/usr/lib/systemd/system/mysqld.service; enabled; vendor preset: disabled) Active: inactive (dead) since Fri 2017-12-15 02:23:55 EST; 23s ago Docs: man:mysqld(8)
檢索數據看看
[root@mysql1 ~]# mysql -uroot -p123456 -P8066 -h227.0.0.1 mysql: [Warning] 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 1 Server version: 5.6.29-mycat-1.6-RELEASE-20161028204710 MyCat Server (OpenCloundDB) Copyright (c) 2000, 2017, Oracle and/or its affiliates. All rights reserved. Oracle is a registered trademark of Oracle Corporation and/or its affiliates. Other names may be trademarks of their respective owners. Type 'help;' or '\h' for help. Type '\c' to clear the current input statement. mysql> use hello; Reading table information for completion of table and column names You can turn off this feature to get a quicker startup with -A Database changed mysql> select * from t1; +----+------+-----+------+ | id | name | bu | city | +----+------+-----+------+ | 3 | am3 | net | sz | | 1 | am1 | sy | bj | | 2 | am2 | cs | gz | +----+------+-----+------+ 3 rows in set (0.46 sec)
果然如此，孰優孰劣無須說明了吧。
后記：通過環境的搭建和簡單的測試，達到了設計的預期目標。
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