centos下搭建mycat高可用(keepalived+haproxy)集群
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mycat简介
MyCat是一个开源的分布式数据库系统，是一个实现了MySQL协议的服务器，前端用户可以把它看作是一个数据库代理，用MySQL客户端工具和命令行访问，而其后端可以用MySQL原生协议与多个MySQL服务器通信，也可以用JDBC协议与大多数主流数据库服务器通信，其核心功能是分表分库，即将一个大表水平分割为N个小表，存储在后端MySQL服务器里或者其他数据库里。
MyCat发展到目前的版本，已经不是一个单纯的MySQL代理了，它的后端可以支持MySQL、SQL Server、Oracle、DB2、PostgreSQL等主流数据库，也支持MongoDB这种新型NoSQL方式的存储，未来还会支持更多类型的存储。而在最终用户看来，无论是那种存储方式，在MyCat里，都是一个传统的数据库表，支持标准的SQL语句进行数据的操作，这样一来，对前端业务系统来说，可以大幅降低开发难度，提升开发速度
具体介绍请参考： mycat官方网站
环境准备
OS: CentOS Linux release 7.2.1511 (Core)
| 序号 | 主机 | IP | 部署内容 |
|---|---|---|---|
| 1 | mycat1 | 10.9.37.226 | mycat节点，使用xinetd进行mycat运行状态监测 |
| 2 | mycat2 | 10.9.18.108 | mycat节点，使用xinetd进行mycat运行状态监测 |
| 3 | keep1 | 10.9.71.4 | 部署keepalived + haproxy，主节点 |
| 4 | keep2 | 10.9.3.180 | 部署keepalived + haproxy，备节点 |
| 5 | VIP | 10.9.78.178 | 准备一个同网段未被占用的ip地址用作VIP |
| 6 | mysql | 10.9.54.71 | 准备一个可用的mysql库，并且创建两个database(db1,db2) |
架构图
graph LR
app[应用]
console[运维]
VIP[VIP]
keep1[keep1+ha1 主]
keep2[keep2+ha2 备]
mycat1[mycat1]
mycat2[mycat2]
mycat3[mycat运维节点]
mysql1((主库))
mysql1-slave1((从库1))
mysql1-slave2((从库2))
app-->VIP
console--脚本发布-->mycat3
mycat3-->mysql1
subgraph ha
VIP-->keep1
VIP-.->keep2
end
subgraph mycat
keep1-->mycat1
keep2-->mycat2
keep1-->mycat2
keep2-->mycat1
end
subgraph mysql
mycat1--写-->mysql1
mycat2--写-->mysql1
mycat1-.读.->mysql1-slave1
mycat2-.读.->mysql1-slave2
mysql1-.半同步.->mysql1-slave1
mysql1-.半同步.->mysql1-slave2
endmycat搭建
java安装
# 安装jdk1.8：
yum install -y java-1.8.0-openjdk.x86_64
# 验证java是否安装成功：
java -versionmycat安装
# 创建软件存放目录
mkdir /var/workspace/
cd /var/workspace/
# 下载mycat
wget http://dl.mycat.io/1.6.7.4/Mycat-server-1.6.7.4-release/Mycat-server-1.6.7.4-release-20200105164103-linux.tar.gz
# 解压
tar -zxvf Mycat-server-1.6.7.4-release-20200105164103-linux.tar.gz
# 设置mycat环境变量
echo 'MYCAT_HOME=/var/workspace/mycat' >> /etc/profile
source /etc/profilemycat配置
1.配置数据源
/var/workspace/mycat/conf/schema.xml中定义了后端数据源、逻辑库/表等。
dataHost：Mycat后端连接的数据库（物理库，真实的数据库），即后端数据源，可以是mysql、oracle等。
schema：逻辑库，可以看做是一个或多个后端数据库集群构成的逻辑库。
dataNode：数据分片，逻辑库的构成，即一个逻辑库可能分为多个分片，数据分片最终会落在一个或多个物理库。
如下配置有一个dataHost对应后端一个mysql实例，mysql创建了两个database，db1和db2。一个逻辑库sbux中有一张sbux_users逻辑表，表中的数据分为2片，分别落在db1和db2上。
select user()
以上配置中schema sbux使用了auto-sharding-long分片策略，分片策略在/var/workspace/mycat/conf/rule.xml中定义，如下
id
rang-long
autopartition-long.txt
该配置中指定了autopartition-long.txt文件为策略记录，选择的策略是按数值的范围路由数据，即0-500在第一个分片，500-100在第二个分片
# range start-end ,data node index
# K=1000,M=10000.
0-500=0
500-1000=12.配置mycat用户
/var/workspace/mycat/conf/server.xml中定义mycat的系统配置和用户等。可以通过xml新增和修改mycat用户信息。
以下为schema：sbux添加了两个用户root和sbux_app，应用使用这两个账号连接mycat进行数据的操作。
123456
sbux
sbux
Abc@12345
sbux
true
sbux
mycat启动
# mycat进程启动
[root@mycat1 ~]# /var/workspace/mycat/bin/mycat start
Mycat-server is running (20658).
# mycat运行端口查看
[root@mycat1 ~]# netstat -an |grep 8066
tcp 0 0 0.0.0.0:8066 0.0.0.0:* LISTEN
# mycat管理端口查看
[root@mycat1 ~]# netstat -an |grep 9066
tcp 0 0 0.0.0.0:9066 0.0.0.0:* LISTENmycat验证
使用mysql客户端连接mycat
[root@mycat1 ~]# /var/workspace/mysql-5.7.29-linux-glibc2.12-x86_64/bin/mysql -P8066 -uroot --protocol TCP -p
Enter password:
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 187
Server version: 5.6.29-mycat-1.6.7.4-release-20200105164103 MyCat Server (OpenCloudDB)
Copyright (c) 2000, 2020, 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> show databases;
+----------+
| DATABASE |
+----------+
| sbux |
+----------+
1 row in set (0.00 sec)mycat管理命令
管理命令需要连接mycat的9066默认端口
mysql> show @@help;
+------------------------------------------------+--------------------------------------------+
| STATEMENT | DESCRIPTION |
+------------------------------------------------+--------------------------------------------+
| show @@time.current | Report current timestamp |
| show @@time.startup | Report startup timestamp |
| show @@version | Report Mycat Server version |
| show @@server | Report server status |
| show @@threadpool | Report threadPool status |
| 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 @@datasource.synstatus | Report datasource data synchronous |
| show @@datasource.syndetail where name=? | Report datasource data synchronous detail |
| show @@datasource.cluster | Report datasource galary cluster variables |
| show @@processor | Report processor status |
| show @@command | Report commands status |
| show @@connection | Report connection status |
| show @@cache | Report system cache usage |
| show @@backend | Report backend connection status |
| show @@session | Report front session details |
| show @@connection.sql | Report connection sql |
| show @@sql.execute | Report execute status |
| show @@sql.detail where id = ? | Report execute detail status |
| show @@sql | Report SQL list |
| show @@sql.high | Report Hight Frequency SQL |
| show @@sql.slow | Report slow SQL |
| show @@sql.resultset | Report BIG RESULTSET SQL |
| show @@sql.sum | Report User RW Stat |
| show @@sql.sum.user | Report User RW Stat |
| show @@sql.sum.table | Report Table RW Stat |
| show @@parser | Report parser status |
| show @@router | Report router status |
| show @@heartbeat | Report heartbeat status |
| show @@heartbeat.detail where name=? | Report heartbeat current detail |
| show @@slow where schema = ? | Report schema slow sql |
| show @@slow where datanode = ? | Report datanode slow sql |
| show @@sysparam | Report system param |
| show @@syslog limit=? | Report system mycat.log |
| show @@white | show mycat white host |
| show @@white.set=?,? | set mycat white host,[ip,user] |
| show @@directmemory=1 or 2 | show mycat direct memory usage |
| show @@check_global -SCHEMA= ? -TABLE=? -retry=? -interval=? | check mycat global table consistency |
| switch @@datasource name:index | Switch dataSource |
| kill @@connection id1,id2,... | Kill the specified connections |
| stop @@heartbeat name:time | Pause dataNode heartbeat |
| reload @@config | Reload basic config from file |
| reload @@config_all | Reload all config from file |
| reload @@route | Reload route config from file |
| reload @@user | Reload user config from file |
| reload @@sqlslow= | Set Slow SQL Time(ms) |
| reload @@user_stat | Reset show @@sql @@sql.sum @@sql.slow |
| rollback @@config | Rollback all config from memory |
| rollback @@route | Rollback route config from memory |
| rollback @@user | Rollback user config from memory |
| reload @@sqlstat=open | Open real-time sql stat analyzer |
| reload @@sqlstat=close | Close real-time sql stat analyzer |
| offline | Change MyCat status to OFF |
| online | Change MyCat status to ON |
| clear @@slow where schema = ? | Clear slow sql by schema |
| clear @@slow where datanode = ? | Clear slow sql by datanode |
+------------------------------------------------+--------------------------------------------+
59 rows in set (0.00 sec)mycat调优
-Xmx1024m -Xmn512m -XX:MaxDirectMemorySize=2048m -Xss256K -XX:+UseParallelGC
mycat监测
使用xinetd检测mycat进程是否正常，提供http接口给haproxy探测mycat运行情况。
1.安装xinetd
yum install -y xinetd
2.创建进程检测的脚本
创建/var/workspace/mycat_status 文件，内容如下：
#!/bin/bash
#/usr/local/bin/mycat_status.sh
# This script checks if a mycat server is healthy running on localhost. It will
# return:
# "HTTP/1.x 200 OK\r" (if mycat is running smoothly)
# "HTTP/1.x 503 Internal Server Error\r" (else)
mycat=`/var/workspace/mycat/bin/mycat status |grep 'not running'| wc -l`
if [ "$mycat" = "0" ];then
/bin/echo -e "HTTP/1.1 200 OK\r\n"
else
/bin/echo -e "HTTP/1.1 503 Service Unavailable\r\n"
fi添加sh执行权限chmod 755 /var/workspace/mycat_status
3.修改xinetd配置文件
在xinetd配置中加入mycat的信息，创建文件/etc/xinetd.d/mycat_status。在48700端口启动服务，检测mycat进程是否存在并将结果返回，具体配置如下：
service mycat_status
{
flags = REUSE
socket_type = stream
port = 48700
wait = no
user = root
server = /var/workspace/mycat_status
log_on_failure +=USERID
disable = no
}4.重启xinetd
[root@mycat1 ~]# systemctl restart xinetd
[root@mycat1 ~]# systemctl status xinetd
● xinetd.service - Xinetd A Powerful Replacement For Inetd
Loaded: loaded (/usr/lib/systemd/system/xinetd.service; enabled; vendor preset: enabled)
Active: active (running) since 日 2020-02-23 14:31:43 CST; 4 days ago
Process: 27014 ExecStart=/usr/sbin/xinetd -stayalive -pidfile /var/run/xinetd.pid $EXTRAOPTIONS (code=exited, status=0/SUCCESS)
Main PID: 27015 (xinetd)
CGroup: /system.slice/xinetd.service
└─27015 /usr/sbin/xinetd -stayalive -pidfile /var/run/xinetd.pid5.验证结果
[root@mycat1 ~]# curl -i http://localhost:48700
HTTP/1.1 200 OK返回200说明mycat服务是正常的，返回503代表mycat进程停止了，服务异常。
备节点搭建请参考如上步骤，完全一样，这里不再重复。
HA搭建
安装配置keepalived
1.安装keepalived
# 使用yum安装keepalived
yum install -y keepalived
# 创建keepalived相关日志目录
mkdir -p /var/workspace/log/keepalived2.调整配置文件
vim /etc/keepalived/keepalived.conf
! Configuration File for keepalived
global_defs {
notification_email {
# 要通知的邮箱地址
[email protected]
}
# 发送的邮箱
notification_email_from [email protected]
smtp_server 192.168.200.1
smtp_connect_timeout 30
# router_id主和备不能一样
router_id keep1
#vrrp_skip_check_adv_addr
#vrrp_strict
vrrp_garp_interval 0
vrrp_gna_interval 0
}
# 定期调用check_haproxy.sh脚本检查mycat运行状态
vrrp_script chk_http_port {
script "/etc/keepalived/scripts/check_haproxy.sh"
interval 2
weight 2
}
vrrp_instance VI_1 {
state MASTER # 备服务器用：BACKUP
# VIP绑定的网卡
interface eth0
# 主备必须一样
virtual_router_id 168
# 备服务器priority要低于主的
priority 200
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
# 此ip为VIP，请自行修改
10.9.78.178/16 dev eth0 scope global
}
track_script {
# 调用脚本 check_haproxy.sh 检查 haproxy 是否存活（mycat刚刚加的那个服务）
chk_http_port
}
# keepalived状态变化时执行相应脚本
# 当此keepalived节点变为主时执行
notify_master /etc/keepalived/scripts/haproxy_master.sh
# 当此keepalived节点变为备时执行
notify_backup /etc/keepalived/scripts/haproxy_backup.sh
# 当此keepalived节点fault时执行
notify_fault /etc/keepalived/scripts/haproxy_fault.sh
# 当此keepalived节点停止时执行
notify_stop /etc/keepalived/scripts/haproxy_stop.sh
}3.状态变化执行脚本
/etc/keepalived/scripts/haproxy_master.sh，当本节点变为主节点时调用
#!/bin/bash
STARTHAPROXY="/bin/systemctl restart haproxy"
# 检测haproxy进程已存在就kill掉
STOPHAPROXY=`ps -ef |grep /usr/sbin/haproxy | grep -v grep|awk '{print $2}'|xargs kill -s 9`
LOGFILE="/var/workspace/log/keepalived/keepalived-haproxy-state.log"
echo "[master]" >> $LOGFILE
date >> $LOGFILE
echo "Being master...." >> $LOGFILE 2>&1
echo "stop haproxy...." >> $LOGFILE 2>&1
$STOPHAPROXY >> $LOGFILE 2>&1
echo "start haproxy...." >> $LOGFILE 2>&1
$STARTHAPROXY >> $LOGFILE 2>&1
echo "haproxy stared ..." >> $LOGFILE/etc/keepalived/scripts/haproxy_backup.sh，当本节点变为备节点时调用
#!/bin/bash
STARTHAPROXY="/bin/systemctl restart haproxy"
STOPHAPROXY=`ps -ef |grep /usr/sbin/haproxy | grep -v grep|awk '{print $2}'|xargs kill -s 9`
LOGFILE="/var/workspace/log/keepalived/keepalived-haproxy-state.log"
echo "[backup]" >> $LOGFILE
date >> $LOGFILE
echo "Being backup...." >> $LOGFILE 2>&1
echo "stop haproxy...." >> $LOGFILE 2>&1
$STOPHAPROXY >> $LOGFILE 2>&1
echo "start haproxy...." >> $LOGFILE 2>&1
$STARTHAPROXY >> $LOGFILE 2>&1
echo "haproxy stared ..." >> $LOGFILE/etc/keepalived/scripts/haproxy_fault.sh，当fault时调用
#!/bin/bash
LOGFILE=/var/workspace/log/keepalived/keepalived-haproxy-state.log
echo "[fault]" >> $LOGFILE
date >> $LOGFILE/etc/keepalived/scripts/haproxy_stop.sh，当节点停止时调用
#!/bin/bash
LOGFILE=/var/workspace/log/keepalived/keepalived-haproxy-state.log
echo "[stop]" >> $LOGFILE
date >> $LOGFILE4.启动keepalived
systemctl restart keepalived5.验证keepalived
# 查看主节点网卡上绑定的VIP
[root@keep1 ~]# ip a
1: lo: mtu 65536 qdisc noqueue state UNKNOWN qlen 1000
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
valid_lft forever preferred_lft forever
2: eth0: mtu 1454 qdisc pfifo_fast state UP qlen 1000
link/ether 52:54:00:f2:8c:e1 brd ff:ff:ff:ff:ff:ff
inet 10.9.71.4/16 brd 10.9.255.255 scope global eth0
valid_lft forever preferred_lft forever
inet 10.9.78.178/16 scope global secondary eth0
valid_lft forever preferred_lft forever
# 查看主节点vrrp组播
[root@keep1 ~]# tcpdump -i eth0 -n -p vrrp
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on eth0, link-type EN10MB (Ethernet), capture size 262144 bytes
23:08:54.298521 IP 10.9.71.4 > 224.0.0.18: VRRPv2, Advertisement, vrid 168, prio 200, authtype simple, intvl 1s, length 20 inet 10.9.78.178/16 scope global secondary eth0为keepalived新增的虚ip。
6.备节点搭建
以上步骤相同，配置文件如下
! Configuration File for keepalived
global_defs {
notification_email {
# 要通知的邮箱地址
[email protected]
}
# 发送的邮箱
notification_email_from [email protected]
smtp_server 192.168.200.1
smtp_connect_timeout 30
# router_id主和备不能一样
router_id keep2
#vrrp_skip_check_adv_addr
#vrrp_strict
vrrp_garp_interval 0
vrrp_gna_interval 0
}
# 定期调用check_haproxy.sh脚本检查mycat运行状态
vrrp_script chk_http_port {
script "/etc/keepalived/scripts/check_haproxy.sh"
interval 2
weight 2
}
vrrp_instance VI_1 {
state BACKUP # 备服务器用：BACKUP
# VIP绑定的网卡
interface eth0
# 主备必须一样
virtual_router_id 168
# 备服务器priority要低于主的
priority 150
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
# 此ip为VIP，请自行修改
10.9.78.178/16 dev eth0 scope global
}
track_script {
# 调用脚本 check_haproxy.sh 检查 haproxy 是否存活（mycat刚刚加的那个服务）
chk_http_port
}
# keepalived状态变化时执行相应脚本
# 当此keepalived节点变为主时执行
notify_master /etc/keepalived/scripts/haproxy_master.sh
# 当此keepalived节点变为备时执行
notify_backup /etc/keepalived/scripts/haproxy_backup.sh
# 当此keepalived节点fault时执行
notify_fault /etc/keepalived/scripts/haproxy_fault.sh
# 当此keepalived节点停止时执行
notify_stop /etc/keepalived/scripts/haproxy_stop.sh
}安装配置haproxy
1.安装haproxy
yum install -y haproxy2.修改haproxy的配置文件
/etc/haproxy/haproxy.cfg
#---------------------------------------------------------------------
# Global settings
#---------------------------------------------------------------------
global
log 127.0.0.1 local0
chroot /var/lib/haproxy
pidfile /var/run/haproxy.pid
maxconn 4000
user haproxy
group haproxy
daemon
# turn on stats unix socket
stats socket /var/lib/haproxy/stats
defaults
mode http
log global
option httplog
option dontlognull
option http-server-close
#option forwardfor except 127.0.0.0/8
option redispatch
retries 3
timeout http-request 10s
timeout queue 1m
timeout connect 10s
timeout client 60s
timeout server 60s
timeout http-keep-alive 10s
timeout check 10s
timeout tunnel 1h
timeout client-fin 30s
maxconn 3000
# 绑定到keep1主机的本地网卡上，该页面为haproxy的统计页面，用于查看请求转发等状态
listen admin_status 0.0.0.0:48800 ##VIP
stats uri /admin-status ##统计页面
stats auth admin:admin
mode http
option httplog
# 转发到mycat 8066业务端口，服务绑定在VIP上
listen allmycat_service 10.9.78.178:8066 ##转发到 mycat 的 8066 端口，即 mycat 的服务端口
mode tcp
option tcplog
option tcpka
option httpchk OPTIONS * HTTP/1.1\r\nHost:\ www
balance roundrobin
server mycat_1 10.9.37.226:8066 check port 48700 inter 5s rise 2 fall 3
server mycat_2 10.9.18.108:8066 check port 48700 inter 5s rise 2 fall 3
timeout server 20000
# 转发到mycat 9066管理端口，服务绑定在VIP上
listen allmycat_admin 10.9.78.178:9066 ##转发到 mycat 的 9066 端口，及 mycat 的管理控制台端口
mode tcp
option tcplog
option tcpka
option httpchk OPTIONS * HTTP/1.1\r\nHost:\ www
balance roundrobin
# 48700为mycat主机利用xinetd提供的状态check服务，5s检查一次
server mycat_1 10.9.37.226:9066 check port 48700 inter 5s rise 2 fall 3
server mycat_2 10.9.18.108:9066 check port 48700 inter 5s rise 2 fall 3
timeout server 200003.启动haproxy
systemctl start haproxy4.haproxy日志记录
默认情况haproxy是不记录日志的，为了记录日志还需要配置 syslog 模块，在 linux 下是 rsyslogd 服务
yum install –y rsyslog修改/etc/rsyslog.conf配置文件最后加上
local0.* /var/log/haproxy.log新增文件 /etc/rsyslog.d/haproxy.conf，内容如下
$ModLoad imudp
$UDPServerRun 514
local0.* /var/log/haproxy.log重启
systemctl restart rsyslog
systemctl restart haproxy查看日志 /var/log/haproxy.log
5.备节点搭建
备节点搭建与主节点相同
mycat集群验证
登陆任意同一局域网主机(需要有mysql客户端工具)
# ping VIP可以通
[root@tools ~]# ping 10.9.78.178
PING 10.9.78.178 (10.9.78.178) 56(84) bytes of data.
64 bytes from 10.9.78.178: icmp_seq=1 ttl=63 time=91.3 ms
# 查看主机的arp列表
[root@tools ~]# arp
Address HWtype HWaddress Flags Mask Iface
10.9.78.178 ether 52:54:00:82:5e:87 C eth0
# 通过VIP连接到了mycat集群的管理端口
[root@tools ~]# /var/workspace/mysql-5.7.29-linux-glibc2.12-x86_64/bin/mysql -h 10.9.78.178 -P9066 -uroot -p
Enter password:
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 196
Server version: 5.6.29-mycat-1.6.7.4-release-20200105164103 MyCat Server (OpenCloudDB)
Copyright (c) 2000, 2020, 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.
# 查看mycat连接
mysql> show @@connection;
+------------+------+------------+------+------------+------+--------+---------+--------+---------+---------------+-------------+------------+---------+------------+
| PROCESSOR | ID | HOST | PORT | LOCAL_PORT | USER | SCHEMA | CHARSET | NET_IN | NET_OUT | ALIVE_TIME(S) | RECV_BUFFER | SEND_QUEUE | txlevel | autocommit |
+------------+------+------------+------+------------+------+--------+---------+--------+---------+---------------+-------------+------------+---------+------------+
| Processor1 | 200 | 10.9.3.180 | 9066 | 45996 | root | NULL | utf8:33 | 165 | 892 | 19 | 4096 | 0 | | |
+------------+------+------------+------+------------+------+--------+---------+--------+---------+---------------+-------------+------------+---------+------------+
1 row in set (0.00 sec)
mysql>分库分表验证
[root@tools ~]# /var/workspace/mysql-5.7.29-linux-glibc2.12-x86_64/bin/mysql -h 10.9.78.178 -P8066 -uroot -p
Enter password:
mysql> use sbux
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> CREATE TABLE sbux_users (
id BIGINT ( 20 ) NOT NULL,
`name` VARCHAR ( 20 ) NOT NULL,
`desc` VARCHAR ( 100 ),
PRIMARY KEY ( id )
) ENGINE = INNODB DEFAULT CHARSET = utf8mb4;
Query OK, 0 rows affected (0.01 sec)
mysql> INSERT INTO sbux_users(id,`name`,`desc`) VALUES(1,'zhangs1','goods1');
Query OK, 1 row affected (0.00 sec)
mysql> INSERT INTO sbux_users(id,`name`,`desc`) VALUES(501,'zhangs501','goods501');
Query OK, 1 row affected (0.01 sec)
mysql> select * from sbux_users;
+-----+---------+--------+
| ID | NAME | DESC |
+-----+---------+--------+
| 1 | zhangs1 | goods1 |
| 501 | zhangs4 | goods4 |
+-----+---------+--------+
2 rows in set (0.00 sec)
# 如下语句解析，实际发送到两个dn进行查询
mysql> explain select * from sbux_users;
+-----------+------------------------------------+
| DATA_NODE | SQL |
+-----------+------------------------------------+
| dn1 | SELECT * FROM sbux_users LIMIT 100 |
| dn2 | SELECT * FROM sbux_users LIMIT 100 |
+-----------+------------------------------------+
2 rows in set (0.00 sec)
# 根据分片键精准定位到dn1
mysql> explain select * from sbux_users where id =1;
+-----------+-------------------------------------------------+
| DATA_NODE | SQL |
+-----------+-------------------------------------------------+
| dn1 | SELECT * FROM sbux_users WHERE id = 1 LIMIT 100 |
+-----------+-------------------------------------------------+
1 row in set (0.00 sec)
# 根据分片键精准定位到dn2
mysql> explain select * from sbux_users where id =501;
+-----------+---------------------------------------------------+
| DATA_NODE | SQL |
+-----------+---------------------------------------------------+
| dn2 | SELECT * FROM sbux_users WHERE id = 501 LIMIT 100 |
+-----------+---------------------------------------------------+
1 row in set (0.00 sec)