0.目录

目录

1.需求及目标

2.安装

3.准备工作-A机器B机器均创建空库空表

4.主从复制-双机热备配置

4.1主服务器A_创建账户访问B机

4.2从服务器B_创建账户访问A机

4.3  A机测试新创账号连接B机--通过命令行

4.4  B机测试连接A机--通过命令行

4.5  A机-配置my.ini主从复制参数

4.6  A机查看是否my.ini配置生效

4.7  A机指定同步位置

4.8  A机查看同步设置是否成功

4.9  B机-配置my.ini主从复制参数

4.10  B机查看是否配置生效

4.11 B机指定同步位置

4.12  B机查看同步设置是否成功

5.测试踩坑记录

5.1测试1-更改A机列字段类型-自动同步成功

5.2测试2-更改B机列字段类型

5.3测试3-A机插入命令带外键-踩坑失败

5.4解决自动复制失败问题（解决Slave_SQL_Running: No问题）

6 再次测试A->B自动复制

7再次测试B->A自动复制

8.测试主机A宕机场景

8.1测试场景顺序

8.2实测过程及结果

9.测试从机B宕机场景及结论

10.潜在问题-主键自增及从机延时

11.延伸问题-关于读写分离或分库主键类型选择

12.其他

12.1查询mysql日志模式

12.2win7修改mysql的默认引擎的位置

12.3读写分离吞吐量计算示例-参考

12.4查看主从通讯I/O和SQL线程状态

---

1.需求及目标

基于Mysql主从复制特性实现双机热备，主机从机均为windows 7（linux可类似以此参考）。

详细配置参数如下

目标如下：

1.实现A机B机互为主从；

2.A机写入后自动复制到B机，B机写入后自动复制到A机，

3.A机宕机期间B机持续写，A机恢复后自动将A机宕机期间B机的写数据自动复制到A机。

4.B机宕机期间A机持续写，B机恢复后自动将B机宕机期间A机的写数据自动复制到B机。

2.安装

主机A及从机B，均安装mysql5.7.10。

安装包为（mysql-installer-community-5.7.10.0.msi）

官方下载地址

https://downloads.mysql.com/archives/community/

https://downloads.mysql.com/archives/get/p/23/file/mysql-5.7.10-winx64.zip

阿里云mysql镜像下载地址https://mirrors.aliyun.com/mysql/?spm=a2c6h.13651104.0.0.2e535dc87t2kc0

安装过程不再详细描述，一般next即可。

（安装期间勾选了MySql WorkBench以便后面有UI界面可查询）

3.准备工作-A机器B机器均创建空库空表

建库建表sql如下

CREATE DATABASE IF NOT EXISTS dbdemo;USE dbdemo;CREATE TABLE categories(cat_id int not null auto_increment primary key,cat_name varchar(255) not null,cat_description text,cat_date DATE
);CREATE TABLE products(prd_id int not null auto_increment primary key,prd_name varchar(355) not null,prd_price decimal,prd_date DATE,cat_id int not null,FOREIGN KEY fk_cat(cat_id)REFERENCES categories(cat_id)ON UPDATE CASCADEON DELETE RESTRICT
);

手动在A机器的两个表分别各插入一条数据，以做区分标记。

4.主从复制-双机热备配置

4.1主服务器A_创建账户访问B机

主机A，Windows打开cmd，cd到目录【C:\Program Files\MySQL\MySQL Server 5.7\bin】

输入命令【mysql -h localhost -u root -p】按提示输入密码然后回车登录mysql

登录mysql后执行下述命令创建名为replicateuser的账号。

/*
主服务器上的sql创建用户,准备用于主从复制（AB机器互为主从）
主服务器ip:192.168.7.161
从服务器ip:192.168.7.162使用grant命令在主服务器上为从服务器创建一个账户，并授予replication slave权限，
*/grant replication slave on *.* to 'replicateuser'@'192.168.7.162' identified by 'replicateuser';/*刷新MySQL的系统权限相关表*/
flush privileges;

4.2从服务器B_创建账户访问A机

从机B，cmd登录mysql执行以下命令

/*
从服务器上的sql创建用户,准备用于主从复制（AB机器互为主从）
主服务器ip:192.168.7.161
从服务器ip:192.168.7.162使用grant命令在主服务器上为从服务器创建一个账户，并授予replication slave权限，
*/grant replication slave on *.* to 'replicateuser'@'192.168.7.161' identified by 'replicateuser';/*刷新MySQL的系统权限相关表*/
flush privileges;

4.3  A机测试新创账号连接B机--通过命令行

4.4  B机测试连接A机--通过命令行

4.5  A机-配置my.ini主从复制参数

进入【C:\ProgramData\MySQL\MySQL Server 5.7】,注意不是【C:\Program Files\MySQL\MySQL Server 5.7】目录找到my.ini，在文件中找到相关项进行配置，如无则直接增加。

#wdh config master-slave replicate

#这是数据库ID,此ID是唯一的，ID值不能重复，否则会同步出错，必须为1 到 2的32次方–1之间的一个正整数值.

server-id=1

#二进制日志文件，此项为必填项，否则不能同步数据；如果不取名字的话，那么就会以计算机的名字加编号来命名二进制文件；

log-bin=mysql-log-bin

#需要同步的数据库，如果还需要同步另外的数据库，那么继续逐条添加，如果不写，那么默认同步所有的数据库；

binlog-do-db=dbdemo

保存my.ini文件后重启mysql服务。

4.6  A机查看是否my.ini配置生效

A机cmd,用命令【mysql -h localhost -u root -p】按提示输入密码后登录mysql。

【show variables like '%log_bin%';】命令下发后查询到log_bin为ON，即可。

【show master status\G;】命令进行查询，查询到的【File: mysql-log-bin.000001】和【Position: 154】此两值后续会用到。

cmd窗口执行的记录如下。

C:\Program Files\MySQL\MySQL Server 5.7\bin>mysql -h localhost -u root -p
Enter password: ****
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 2
Server version: 5.7.10-log MySQL Community Server (GPL)Copyright (c) 2000, 2015, 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 variables like '%log_bin%';
+---------------------------------+----------------------------------------------------------------+
| Variable_name                   | Value                                                          |
+---------------------------------+----------------------------------------------------------------+
| log_bin                         | ON                                                             |
| log_bin_basename                | C:\ProgramData\MySQL\MySQL Server 5.7\Data\mysql-log-bin       |
| log_bin_index                   | C:\ProgramData\MySQL\MySQL Server 5.7\Data\mysql-log-bin.index |
| log_bin_trust_function_creators | OFF                                                            |
| log_bin_use_v1_row_events       | OFF                                                            |
| sql_log_bin                     | ON                                                             |
+---------------------------------+----------------------------------------------------------------+
6 rows in set, 1 warning (0.00 sec)mysql> show master status;
+----------------------+----------+--------------+------------------+-------------------+
| File                 | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+----------------------+----------+--------------+------------------+-------------------+
| mysql-log-bin.000001 |      154 | dbdemo       |                  |                   |
+----------------------+----------+--------------+------------------+-------------------+
1 row in set (0.00 sec)mysql> show master status\G;
*************************** 1. row ***************************File: mysql-log-bin.000001Position: 154Binlog_Do_DB: dbdemoBinlog_Ignore_DB:
Executed_Gtid_Set:
1 row in set (0.00 sec)ERROR:
No query specifiedmysql>

4.7  A机指定同步位置

执行如下三条指令

stop slave;

change master to master_host='192.168.7.162',master_user='replicateuser',master_password='replicateuser',master_log_file='mysql-log-bin.000001',master_log_pos=154;

start slave;

三条命令cmd执行记录如下：

mysql> stop slave;
Query OK, 0 rows affected, 1 warning (0.00 sec)mysql> change master to master_host='192.168.7.162',master_user='replicateuser',master_password='replicateuser',master_log_file='mysql-log-bin.000001',master_log_pos=154;
Query OK, 0 rows affected, 2 warnings (0.21 sec)mysql> start slave;
Query OK, 0 rows affected (0.00 sec)mysql>

A机命令

change master to master_host='192.168.7.162',master_user='replicateuser',master_password='replicateuser',master_log_file='mysql-log-bin.000001',master_log_pos=154;

参数说明如下：

4.8  A机查看同步设置是否成功

Cmd登录mysql后，主要命令就两条【show master status\G;】和【show slave status\G;】；

【show master status\G;】显示File\ Position\Binlog_Do_DB与前述my.ini配置及change master命令参数一致；

【show slave status\G;】显示  Slave_IO_Running: Yes和Slave_SQL_Running: Yes 即可。

Cmd执行记录如下：

Microsoft Windows [版本 6.1.7601]
版权所有 (c) 2009 Microsoft Corporation。保留所有权利。C:\Program Files\MySQL\MySQL Server 5.7\bin>mysql -h localhost -u root -p
Enter password: ****
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 6
Server version: 5.7.10-log MySQL Community Server (GPL)Copyright (c) 2000, 2015, 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 master status\G;
*************************** 1. row ***************************File: mysql-log-bin.000002Position: 154Binlog_Do_DB: dbdemoBinlog_Ignore_DB:
Executed_Gtid_Set:
1 row in set (0.00 sec)ERROR:
No query specifiedmysql> show slave status\G;
*************************** 1. row ***************************Slave_IO_State: Waiting for master to send eventMaster_Host: 192.168.7.162Master_User: replicateuserMaster_Port: 3306Connect_Retry: 60Master_Log_File: mysql-log-bin.000003Read_Master_Log_Pos: 154Relay_Log_File: 14JPYI7CBESDNFK-relay-bin.000008Relay_Log_Pos: 324Relay_Master_Log_File: mysql-log-bin.000003Slave_IO_Running: YesSlave_SQL_Running: YesReplicate_Do_DB:Replicate_Ignore_DB:Replicate_Do_Table:Replicate_Ignore_Table:Replicate_Wild_Do_Table:Replicate_Wild_Ignore_Table:Last_Errno: 0Last_Error:Skip_Counter: 0Exec_Master_Log_Pos: 154Relay_Log_Space: 762Until_Condition: NoneUntil_Log_File:Until_Log_Pos: 0Master_SSL_Allowed: NoMaster_SSL_CA_File:Master_SSL_CA_Path:Master_SSL_Cert:Master_SSL_Cipher:Master_SSL_Key:Seconds_Behind_Master: 0
Master_SSL_Verify_Server_Cert: NoLast_IO_Errno: 0Last_IO_Error:Last_SQL_Errno: 0Last_SQL_Error:Replicate_Ignore_Server_Ids:Master_Server_Id: 2Master_UUID: 5c503f95-5e4a-11ed-95ba-a0510b4b1044Master_Info_File: C:\ProgramData\MySQL\MySQL Server 5.7\Data\master.infoSQL_Delay: 0SQL_Remaining_Delay: NULLSlave_SQL_Running_State: Slave has read all relay log; waiting for more updatesMaster_Retry_Count: 86400Master_Bind:Last_IO_Error_Timestamp:Last_SQL_Error_Timestamp:Master_SSL_Crl:Master_SSL_Crlpath:Retrieved_Gtid_Set:Executed_Gtid_Set:Auto_Position: 0Replicate_Rewrite_DB:Channel_Name:Master_TLS_Version:
1 row in set (0.00 sec)ERROR:
No query specifiedmysql>

4.9  B机-配置my.ini主从复制参数

进入【C:\ProgramData\MySQL\MySQL Server 5.7】,注意不是【C:\Program Files\MySQL\MySQL Server 5.7】目录找到my.ini在文件末尾增加以下配置。

#wdh config master-slave replicate

#这是数据库ID,此ID是唯一的，从服务器的ID必须与主服务器的ID不相同，否则会同步出错，必须为1 到 2的32次方–1之间的一个正整数值.

server-id=2

#二进制日志文件，此项为必填项，否则不能同步数据；如果不取名字的话，那么就会以计算机的名字加编号来命名二进制文件；

log-bin=mysql-log-bin

#需要同步的数据库，如果还需要同步另外的数据库，那么继续逐条添加，如果不写，那么默认同步所有的数据库；

binlog-do-db=dbdemo

保存my.ini文件后重启mysql服务。

配置后的完整my.ini文件如下

# Other default tuning values
# MySQL Server Instance Configuration File
# ----------------------------------------------------------------------
# Generated by the MySQL Server Instance Configuration Wizard
#
#
# Installation Instructions
# ----------------------------------------------------------------------
#
# On Linux you can copy this file to /etc/my.cnf to set global options,
# mysql-data-dir/my.cnf to set server-specific options
# (@localstatedir@ for this installation) or to
# ~/.my.cnf to set user-specific options.
#
# On Windows you should keep this file in the installation directory 
# of your server (e.g. C:\Program Files\MySQL\MySQL Server X.Y). To
# make sure the server reads the config file use the startup option 
# "--defaults-file". 
#
# To run run the server from the command line, execute this in a 
# command line shell, e.g.
# mysqld --defaults-file="C:\Program Files\MySQL\MySQL Server X.Y\my.ini"
#
# To install the server as a Windows service manually, execute this in a 
# command line shell, e.g.
# mysqld --install MySQLXY --defaults-file="C:\Program Files\MySQL\MySQL Server X.Y\my.ini"
#
# And then execute this in a command line shell to start the server, e.g.
# net start MySQLXY
#
#
# Guildlines for editing this file
# ----------------------------------------------------------------------
#
# In this file, you can use all long options that the program supports.
# If you want to know the options a program supports, start the program
# with the "--help" option.
#
# More detailed information about the individual options can also be
# found in the manual.
#
# For advice on how to change settings please see
# http://dev.mysql.com/doc/refman/5.7/en/server-configuration-defaults.html
#
#
# CLIENT SECTION
# ----------------------------------------------------------------------
#
# The following options will be read by MySQL client applications.
# Note that only client applications shipped by MySQL are guaranteed
# to read this section. If you want your own MySQL client program to
# honor these values, you need to specify it as an option during the
# MySQL client library initialization.
#
[client]
no-beep# pipe
# socket=0.0
port=3306[mysql]default-character-set=utf8# SERVER SECTION
# ----------------------------------------------------------------------
#
# The following options will be read by the MySQL Server. Make sure that
# you have installed the server correctly (see above) so it reads this 
# file.
#
# server_type=3
[mysqld]# The next three options are mutually exclusive to SERVER_PORT below.
# skip-networking# enable-named-pipe# shared-memory# shared-memory-base-name=MYSQL# The Pipe the MySQL Server will use
# socket=MYSQL# The TCP/IP Port the MySQL Server will listen on
port=3306# Path to installation directory. All paths are usually resolved relative to this.
# basedir="C:/Program Files/MySQL/MySQL Server 5.7/"# Path to the database root
datadir=C:/ProgramData/MySQL/MySQL Server 5.7\Data# The default character set that will be used when a new schema or table is
# created and no character set is defined
character-set-server=utf8# The default storage engine that will be used when create new tables when
default-storage-engine=INNODB# Set the SQL mode to strict
sql-mode="STRICT_TRANS_TABLES,NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION"# Enable Windows Authentication
# plugin-load=authentication_windows.dll# General and Slow logging.
log-output=FILE
general-log=0
general_log_file="5P8LHGI6PY4QZ5L.log"
slow-query-log=1
slow_query_log_file="5P8LHGI6PY4QZ5L-slow.log"
long_query_time=10# Binary Logging.
log-bin=mysql-log-bin# Error Logging.
log-error="5P8LHGI6PY4QZ5L.err"# Server Id.
server-id=2binlog-do-db=dbdemo# Secure File Priv.
secure-file-priv="C:/ProgramData/MySQL/MySQL Server 5.7/Uploads"# The maximum amount of concurrent sessions the MySQL server will
# allow. One of these connections will be reserved for a user with
# SUPER privileges to allow the administrator to login even if the
# connection limit has been reached.
max_connections=151# Query cache is used to cache SELECT results and later return them
# without actual executing the same query once again. Having the query
# cache enabled may result in significant speed improvements, if your
# have a lot of identical queries and rarely changing tables. See the
# "Qcache_lowmem_prunes" status variable to check if the current value
# is high enough for your load.
# Note: In case your tables change very often or if your queries are
# textually different every time, the query cache may result in a
# slowdown instead of a performance improvement.
query_cache_size=0# The number of open tables for all threads. Increasing this value
# increases the number of file descriptors that mysqld requires.
# Therefore you have to make sure to set the amount of open files
# allowed to at least 4096 in the variable "open-files-limit" in
# section [mysqld_safe]
table_open_cache=2000# Maximum size for internal (in-memory) temporary tables. If a table
# grows larger than this value, it is automatically converted to disk
# based table This limitation is for a single table. There can be many
# of them.
tmp_table_size=18M# How many threads we should keep in a cache for reuse. When a client
# disconnects, the client's threads are put in the cache if there aren't
# more than thread_cache_size threads from before.  This greatly reduces
# the amount of thread creations needed if you have a lot of new
# connections. (Normally this doesn't give a notable performance
# improvement if you have a good thread implementation.)
thread_cache_size=10#*** MyISAM Specific options
# The maximum size of the temporary file MySQL is allowed to use while
# recreating the index (during REPAIR, ALTER TABLE or LOAD DATA INFILE.
# If the file-size would be bigger than this, the index will be created
# through the key cache (which is slower).
myisam_max_sort_file_size=100G# If the temporary file used for fast index creation would be bigger
# than using the key cache by the amount specified here, then prefer the
# key cache method.  This is mainly used to force long character keys in
# large tables to use the slower key cache method to create the index.
myisam_sort_buffer_size=27M# Size of the Key Buffer, used to cache index blocks for MyISAM tables.
# Do not set it larger than 30% of your available memory, as some memory
# is also required by the OS to cache rows. Even if you're not using
# MyISAM tables, you should still set it to 8-64M as it will also be
# used for internal temporary disk tables.
key_buffer_size=8M# Size of the buffer used for doing full table scans of MyISAM tables.
# Allocated per thread, if a full scan is needed.
read_buffer_size=54K
read_rnd_buffer_size=256K#*** INNODB Specific options ***
# innodb_data_home_dir=0.0# Use this option if you have a MySQL server with InnoDB support enabled
# but you do not plan to use it. This will save memory and disk space
# and speed up some things.
# skip-innodb# If set to 1, InnoDB will flush (fsync) the transaction logs to the
# disk at each commit, which offers full ACID behavior. If you are
# willing to compromise this safety, and you are running small
# transactions, you may set this to 0 or 2 to reduce disk I/O to the
# logs. Value 0 means that the log is only written to the log file and
# the log file flushed to disk approximately once per second. Value 2
# means the log is written to the log file at each commit, but the log
# file is only flushed to disk approximately once per second.
innodb_flush_log_at_trx_commit=1# The size of the buffer InnoDB uses for buffering log data. As soon as
# it is full, InnoDB will have to flush it to disk. As it is flushed
# once per second anyway, it does not make sense to have it very large
# (even with long transactions).
innodb_log_buffer_size=1M# InnoDB, unlike MyISAM, uses a buffer pool to cache both indexes and
# row data. The bigger you set this the less disk I/O is needed to
# access data in tables. On a dedicated database server you may set this
# parameter up to 80% of the machine physical memory size. Do not set it
# too large, though, because competition of the physical memory may
# cause paging in the operating system.  Note that on 32bit systems you
# might be limited to 2-3.5G of user level memory per process, so do not
# set it too high.
innodb_buffer_pool_size=8M# Size of each log file in a log group. You should set the combined size
# of log files to about 25%-100% of your buffer pool size to avoid
# unneeded buffer pool flush activity on log file overwrite. However,
# note that a larger logfile size will increase the time needed for the
# recovery process.
innodb_log_file_size=48M# Number of threads allowed inside the InnoDB kernel. The optimal value
# depends highly on the application, hardware as well as the OS
# scheduler properties. A too high value may lead to thread thrashing.
innodb_thread_concurrency=9# The increment size (in MB) for extending the size of an auto-extend InnoDB system tablespace file when it becomes full.
innodb_autoextend_increment=64# The number of regions that the InnoDB buffer pool is divided into.
# For systems with buffer pools in the multi-gigabyte range, dividing the buffer pool into separate instances can improve concurrency,
# by reducing contention as different threads read and write to cached pages.
innodb_buffer_pool_instances=8# Determines the number of threads that can enter InnoDB concurrently.
innodb_concurrency_tickets=5000# Specifies how long in milliseconds (ms) a block inserted into the old sublist must stay there after its first access before
# it can be moved to the new sublist.
innodb_old_blocks_time=1000# It specifies the maximum number of .ibd files that MySQL can keep open at one time. The minimum value is 10.
innodb_open_files=300# When this variable is enabled, InnoDB updates statistics during metadata statements.
innodb_stats_on_metadata=0# When innodb_file_per_table is enabled (the default in 5.6.6 and higher), InnoDB stores the data and indexes for each newly created table
# in a separate .ibd file, rather than in the system tablespace.
innodb_file_per_table=1# Use the following list of values: 0 for crc32, 1 for strict_crc32, 2 for innodb, 3 for strict_innodb, 4 for none, 5 for strict_none.
innodb_checksum_algorithm=0# The number of outstanding connection requests MySQL can have.
# This option is useful when the main MySQL thread gets many connection requests in a very short time.
# It then takes some time (although very little) for the main thread to check the connection and start a new thread.
# The back_log value indicates how many requests can be stacked during this short time before MySQL momentarily
# stops answering new requests.
# You need to increase this only if you expect a large number of connections in a short period of time.
back_log=80# If this is set to a nonzero value, all tables are closed every flush_time seconds to free up resources and
# synchronize unflushed data to disk.
# This option is best used only on systems with minimal resources.
flush_time=0# The minimum size of the buffer that is used for plain index scans, range index scans, and joins that do not use
# indexes and thus perform full table scans.
join_buffer_size=256K# The maximum size of one packet or any generated or intermediate string, or any parameter sent by the
# mysql_stmt_send_long_data() C API function.
max_allowed_packet=4M# If more than this many successive connection requests from a host are interrupted without a successful connection,
# the server blocks that host from performing further connections.
max_connect_errors=100# Changes the number of file descriptors available to mysqld.
# You should try increasing the value of this option if mysqld gives you the error "Too many open files".
open_files_limit=4161# Set the query cache type. 0 for OFF, 1 for ON and 2 for DEMAND.
query_cache_type=0# If you see many sort_merge_passes per second in SHOW GLOBAL STATUS output, you can consider increasing the
# sort_buffer_size value to speed up ORDER BY or GROUP BY operations that cannot be improved with query optimization
# or improved indexing.
sort_buffer_size=256K# The number of table definitions (from .frm files) that can be stored in the definition cache.
# If you use a large number of tables, you can create a large table definition cache to speed up opening of tables.
# The table definition cache takes less space and does not use file descriptors, unlike the normal table cache.
# The minimum and default values are both 400.
table_definition_cache=1400# Specify the maximum size of a row-based binary log event, in bytes.
# Rows are grouped into events smaller than this size if possible. The value should be a multiple of 256.
binlog_row_event_max_size=8K# If the value of this variable is greater than 0, a replication slave synchronizes its master.info file to disk.
# (using fdatasync()) after every sync_master_info events.
sync_master_info=10000# If the value of this variable is greater than 0, the MySQL server synchronizes its relay log to disk.
# (using fdatasync()) after every sync_relay_log writes to the relay log.
sync_relay_log=10000# If the value of this variable is greater than 0, a replication slave synchronizes its relay-log.info file to disk.
# (using fdatasync()) after every sync_relay_log_info transactions.
sync_relay_log_info=10000

4.10  B机查看是否配置生效

B机，cmd登录mysql后执行以下命令查询

注意：【show variables like '%log_bin%';】命令下发后查询到log_bin为ON。

注意【show master status\G;】命令查询到的【File: mysql-log-bin.000001】和【Position: 154】此两值后续会用到。

B机cmd执行记录如下

mysql> show master status\G;
*************************** 1. row ***************************File: mysql-log-bin.000001Position: 154Binlog_Do_DB: dbdemoBinlog_Ignore_DB:
Executed_Gtid_Set:
1 row in set (0.00 sec)ERROR:
No query specifiedmysql> show master status;
+----------------------+----------+--------------+------------------+-------------------+
| File                 | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+----------------------+----------+--------------+------------------+-------------------+
| mysql-log-bin.000001 |      154 | dbdemo       |                  |                   |
+----------------------+----------+--------------+------------------+-------------------+
1 row in set (0.00 sec)mysql>

4.11 B机指定同步位置

cmd登录mysql后执行以下三条命令

stop slave;

change master to master_host='192.168.7.161',master_user='replicateuser',master_password='replicateuser',master_log_file='mysql-log-bin.000001',master_log_pos=154;

start slave;

B机命令

change master to master_host='192.168.7.161',master_user='replicateuser',master_password='replicateuser',master_log_file='mysql-log-bin.000001',master_log_pos=154;

参数说明：

参考6.4. 如何设置复制_MySQL 中文文档

上述三条命令cmd执行记录如下

mysql> stop slave;
Query OK, 0 rows affected, 1 warning (0.13 sec)mysql> change master to master_host='192.168.7.161',master_user='replicateuser',master_password='replicateuser',master_log_file='mysql-log-bin.000001',master_log_pos=154;
Query OK, 0 rows affected, 2 warnings (0.13 sec)mysql> start slave;
Query OK, 0 rows affected (0.00 sec)mysql>

4.12  B机查看同步设置是否成功

B机，Cmd登录mysql后，主要命令两条【show master status\G;】和【show slave status\G;】；

【show master status\G;】显示File\ Position\Binlog_Do_DB与前述my.ini配置及change master命令参数一致；

【show slave status\G;】显示  Slave_IO_Running: Yes和Slave_SQL_Running: Yes 即可。

B机Cmd执行记录如下

C:\Program Files\MySQL\MySQL Server 5.7\bin>mysql -h localhost -u root -p
Enter password: ****
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 7
Server version: 5.7.10-log MySQL Community Server (GPL)Copyright (c) 2000, 2015, 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 master status\G;
*************************** 1. row ***************************File: mysql-log-bin.000003Position: 154Binlog_Do_DB: dbdemoBinlog_Ignore_DB:
Executed_Gtid_Set:
1 row in set (0.00 sec)ERROR:
No query specifiedmysql> show slave status\G;
*************************** 1. row ***************************Slave_IO_State: Waiting for master to send eventMaster_Host: 192.168.7.161Master_User: replicateuserMaster_Port: 3306Connect_Retry: 60Master_Log_File: mysql-log-bin.000002Read_Master_Log_Pos: 154Relay_Log_File: 5P8LHGI6PY4QZ5L-relay-bin.000008Relay_Log_Pos: 324Relay_Master_Log_File: mysql-log-bin.000002Slave_IO_Running: YesSlave_SQL_Running: YesReplicate_Do_DB:Replicate_Ignore_DB:Replicate_Do_Table:Replicate_Ignore_Table:Replicate_Wild_Do_Table:Replicate_Wild_Ignore_Table:Last_Errno: 0Last_Error:Skip_Counter: 0Exec_Master_Log_Pos: 154Relay_Log_Space: 762Until_Condition: NoneUntil_Log_File:Until_Log_Pos: 0Master_SSL_Allowed: NoMaster_SSL_CA_File:Master_SSL_CA_Path:Master_SSL_Cert:Master_SSL_Cipher:Master_SSL_Key:Seconds_Behind_Master: 0
Master_SSL_Verify_Server_Cert: NoLast_IO_Errno: 0Last_IO_Error:Last_SQL_Errno: 0Last_SQL_Error:Replicate_Ignore_Server_Ids:Master_Server_Id: 1Master_UUID: 0c46dc6a-27eb-11ea-9894-a0510b4b1044Master_Info_File: C:\ProgramData\MySQL\MySQL Server 5.7\Data\master.infoSQL_Delay: 0SQL_Remaining_Delay: NULLSlave_SQL_Running_State: Slave has read all relay log; waiting for more updatesMaster_Retry_Count: 86400Master_Bind:Last_IO_Error_Timestamp:Last_SQL_Error_Timestamp:Master_SSL_Crl:Master_SSL_Crlpath:Retrieved_Gtid_Set:Executed_Gtid_Set:Auto_Position: 0Replicate_Rewrite_DB:Channel_Name:Master_TLS_Version:
1 row in set (0.00 sec)ERROR:
No query specifiedmysql>

5.测试踩坑记录

5.1测试1-更改A机列字段类型-自动同步成功

A机执行命令

ALTER TABLE `dbdemo`.`categories`
CHANGE COLUMN `cat_date` `cat_date` DATETIME NULL DEFAULT NULL ;

此时切换到B机上查阅categories的cat_date类型自动由原来的date类型变为datetime类型了

5.2测试2-更改B机列字段类型

B机执行以下命令

ALTER TABLE `dbdemo`.`products`
CHANGE COLUMN `prd_date` `prd_date` DATETIME NULL DEFAULT NULL ;

此时切换到A机查看列类型已自动更改。

5.3测试3-A机插入命令带外键-踩坑失败

A机执行以下命令

INSERT INTO `dbdemo`.`products` (`prd_name`, `prd_price`, `prd_date`, `cat_id`) VALUES ('prd_A_0002', '1', '2022-11-08 10:40:21', '1');
INSERT INTO `dbdemo`.`products` (`prd_name`, `prd_price`, `prd_date`, `cat_id`) VALUES ('prd_A_0003', '1', '2022-11-08 10:40:22', '1');
INSERT INTO `dbdemo`.`products` (`prd_name`, `prd_price`, `prd_date`, `cat_id`) VALUES ('prd_A_0004', '1', '2022-11-08 10:40:23', '1');
此时B机没有同步到上述数据，怀疑是外键约束导致不能同步成功。

此时B机没有同步到上述数据，怀疑是外键约束导致不能同步成功。

分析开始：

B机cmd登录mysql输入命令【show master status\G;】和【show slave status\G;】，查找到Slave_SQL_Running: No以及Seconds_Behind_Master: NULL，和Last_Errno: 1452，

结论：发现果然是因为外键问题导致。原因为A机categories表有cat_id为1 的数据，但B机表categories没有此数据，导致A机的sql【INSERT INTO `dbdemo`.`products` (`prd_name`, `prd_price`, `prd_date`, `cat_id`) VALUES ('prd_A_0002', '1', '2022-11-08 10:40:21', '1');】同步到B机时因外键约束找不到数据而无法插入。

上述分析过程两个命令在cmd执行记录如下

mysql> show master status\G;
*************************** 1. row ***************************File: mysql-log-bin.000003Position: 618Binlog_Do_DB: dbdemoBinlog_Ignore_DB:
Executed_Gtid_Set:
1 row in set (0.00 sec)ERROR:
No query specifiedmysql> show slave status\G;
*************************** 1. row ***************************Slave_IO_State: Waiting for master to send eventMaster_Host: 192.168.7.161Master_User: replicateuserMaster_Port: 3306Connect_Retry: 60Master_Log_File: mysql-log-bin.000002Read_Master_Log_Pos: 1188Relay_Log_File: 5P8LHGI6PY4QZ5L-relay-bin.000008Relay_Log_Pos: 804Relay_Master_Log_File: mysql-log-bin.000002Slave_IO_Running: YesSlave_SQL_Running: NoReplicate_Do_DB:Replicate_Ignore_DB:Replicate_Do_Table:Replicate_Ignore_Table:Replicate_Wild_Do_Table:Replicate_Wild_Ignore_Table:Last_Errno: 1452Last_Error: Could not execute Write_rows event on table dbdemo.products; Cannot add or update a child row: a foreign key constraint fails (`d
bdemo`.`products`, CONSTRAINT `products_ibfk_1` FOREIGN KEY (`cat_id`) REFERENCES `categories` (`cat_id`) ON UPDATE CASCADE), Error_code: 1452; handler error HA
_ERR_NO_REFERENCED_ROW; the event's master log mysql-log-bin.000002, end_log_pos 901Skip_Counter: 0Exec_Master_Log_Pos: 634Relay_Log_Space: 1796Until_Condition: NoneUntil_Log_File:Until_Log_Pos: 0Master_SSL_Allowed: NoMaster_SSL_CA_File:Master_SSL_CA_Path:Master_SSL_Cert:Master_SSL_Cipher:Master_SSL_Key:Seconds_Behind_Master: NULL
Master_SSL_Verify_Server_Cert: NoLast_IO_Errno: 0Last_IO_Error:Last_SQL_Errno: 1452Last_SQL_Error: Could not execute Write_rows event on table dbdemo.products; Cannot add or update a child row: a foreign key constraint fails (`d
bdemo`.`products`, CONSTRAINT `products_ibfk_1` FOREIGN KEY (`cat_id`) REFERENCES `categories` (`cat_id`) ON UPDATE CASCADE), Error_code: 1452; handler error HA
_ERR_NO_REFERENCED_ROW; the event's master log mysql-log-bin.000002, end_log_pos 901Replicate_Ignore_Server_Ids:Master_Server_Id: 1Master_UUID: 0c46dc6a-27eb-11ea-9894-a0510b4b1044Master_Info_File: C:\ProgramData\MySQL\MySQL Server 5.7\Data\master.infoSQL_Delay: 0SQL_Remaining_Delay: NULLSlave_SQL_Running_State:Master_Retry_Count: 86400Master_Bind:Last_IO_Error_Timestamp:Last_SQL_Error_Timestamp: 221108 10:41:11Master_SSL_Crl:Master_SSL_Crlpath:Retrieved_Gtid_Set:Executed_Gtid_Set:Auto_Position: 0Replicate_Rewrite_DB:Channel_Name:Master_TLS_Version:
1 row in set (0.00 sec)ERROR:
No query specifiedmysql>

5.4解决自动复制失败问题（解决Slave_SQL_Running: No问题）

在从机B机上执行以下三个命令

【stop slave;】

【set global sql_slave_skip_counter=1;】

【start slave;】

执行上述命令跳过错误后，再执行命令【show slave status\G;】查看是否同步状态恢复，【Slave_IO_Running: Yes            Slave_SQL_Running: Yes】即可

cmd登录mysql后执行记录如下

mysql> stop slave;
Query OK, 0 rows affected (0.00 sec)mysql> set global sql_slave_skip_counter=1;
Query OK, 0 rows affected (0.09 sec)mysql> start slave;
Query OK, 0 rows affected (0.00 sec)mysql> show slave status\G;
*************************** 1. row ***************************Slave_IO_State: Waiting for master to send eventMaster_Host: 192.168.7.161Master_User: replicateuserMaster_Port: 3306Connect_Retry: 60Master_Log_File: mysql-log-bin.000002Read_Master_Log_Pos: 1188Relay_Log_File: 5P8LHGI6PY4QZ5L-relay-bin.000009Relay_Log_Pos: 324Relay_Master_Log_File: mysql-log-bin.000002Slave_IO_Running: YesSlave_SQL_Running: YesReplicate_Do_DB:Replicate_Ignore_DB:Replicate_Do_Table:Replicate_Ignore_Table:Replicate_Wild_Do_Table:Replicate_Wild_Ignore_Table:Last_Errno: 0Last_Error:Skip_Counter: 0Exec_Master_Log_Pos: 1188Relay_Log_Space: 1745Until_Condition: NoneUntil_Log_File:Until_Log_Pos: 0Master_SSL_Allowed: NoMaster_SSL_CA_File:Master_SSL_CA_Path:Master_SSL_Cert:Master_SSL_Cipher:Master_SSL_Key:Seconds_Behind_Master: 0
Master_SSL_Verify_Server_Cert: NoLast_IO_Errno: 0Last_IO_Error:Last_SQL_Errno: 0Last_SQL_Error:Replicate_Ignore_Server_Ids:Master_Server_Id: 1Master_UUID: 0c46dc6a-27eb-11ea-9894-a0510b4b1044Master_Info_File: C:\ProgramData\MySQL\MySQL Server 5.7\Data\master.infoSQL_Delay: 0SQL_Remaining_Delay: NULLSlave_SQL_Running_State: Slave has read all relay log; waiting for more updatesMaster_Retry_Count: 86400Master_Bind:Last_IO_Error_Timestamp:Last_SQL_Error_Timestamp:Master_SSL_Crl:Master_SSL_Crlpath:Retrieved_Gtid_Set:Executed_Gtid_Set:Auto_Position: 0Replicate_Rewrite_DB:Channel_Name:Master_TLS_Version:
1 row in set (0.00 sec)ERROR:
No query specifiedmysql>

6 再次测试A->B自动复制

A机执行sql（保证外键均有）

INSERT INTO `dbdemo`.`categories` (`cat_name`, `cat_description`, `cat_date`) VALUES ('cat_A0002', 'A0002_desc', '2022-11-08 11:06:19');INSERT INTO `dbdemo`.`products` (`prd_name`, `prd_price`, `prd_date`, `cat_id`) VALUES ('prd_A_0005', '1', '2022-11-08 11:07:34', '2');
INSERT INTO `dbdemo`.`products` (`prd_name`, `prd_price`, `prd_date`, `cat_id`) VALUES ('prd_A_0006', '1', '2022-11-08 11:07:35', '2');
INSERT INTO `dbdemo`.`products` (`prd_name`, `prd_price`, `prd_date`, `cat_id`) VALUES ('prd_A_0007', '1', '2022-11-08 11:07:36', '2');

分别查询A机及B机两个表的数据，A机上述sql影响的数据已经自动同步到B机了。ok，一致。

7再次测试B->A自动复制

B机执行sql

INSERT INTO `dbdemo`.`categories` (`cat_name`, `cat_description`, `cat_date`) VALUES ('cat_B0003', 'B0003_desc', '2022-11-08 11:19:01');/*这里实际预测了categories的主键会在insert时自增到3*/
INSERT INTO `dbdemo`.`products` (`prd_name`, `prd_price`, `prd_date`, `cat_id`) VALUES ('prd_B_0009', '2', '2022-11-08 11:19:02', '3');
INSERT INTO `dbdemo`.`products` (`prd_name`, `prd_price`, `prd_date`, `cat_id`) VALUES ('prd_B_0009', '2', '2022-11-08 11:19:03', '3');
INSERT INTO `dbdemo`.`products` (`prd_name`, `prd_price`, `prd_date`, `cat_id`) VALUES ('prd_B_0010', '2', '2022-11-08 11:19:03', '3');

分别查询A机及B机两个表的数据，B机上述sql影响的数据已经自动同步到A机了。ok，一致。

8.测试主机A宕机场景

8.1测试场景顺序

1.主机A宕机, B机在写;

2.主机A恢复(期望A机从B机自动同步复制数据);

3.查看主机A和从机B的数据一致性

8.2实测过程及结果

将A机服务关闭，然后在B机上输入命令show processlist；结果如下。下图中B机上第一个【show processlist；】执行时A机正常。下图中B机上第二个【show processlist；】执行时A机已宕机。

可对比看出宕机时缺少republicateuser的process，以及systemuser 的state状态变为Reconnecting after a failed master event read

mysql> show processlist;
+----+-------------+-----------------+------+---------+-------+--------------------------------------------------------+------------------+
| Id | User        | Host            | db   | Command | Time  | State                                                  | Info             |
+----+-------------+-----------------+------+---------+-------+--------------------------------------------------------+------------------+
|  7 | root        | localhost:52091 | NULL | Query   |     0 | starting                                               | show processlist |
|  9 | root        | localhost:52401 | NULL | Sleep   |  9232 |                                                        | NULL             |
| 10 | root        | localhost:52402 | NULL | Sleep   |  9232 |                                                        | NULL             |
| 11 | system user |                 | NULL | Connect | 18287 | Reconnecting after a failed master event read          | NULL             |
| 12 | system user |                 | NULL | Connect | 17796 | Slave has read all relay log; waiting for more updates | NULL             |
+----+-------------+-----------------+------+---------+-------+--------------------------------------------------------+------------------+
5 rows in set (0.00 sec)mysql>

当A机宕机时，在B机上输入命令【show slave status\G;】结果如下，显示Slave_IO_State: Reconnecting after a failed master event read

mysql> show slave status\G;
*************************** 1. row ***************************Slave_IO_State: Reconnecting after a failed master event readMaster_Host: 192.168.7.161Master_User: replicateuserMaster_Port: 3306Connect_Retry: 60Master_Log_File: mysql-log-bin.000002Read_Master_Log_Pos: 2384Relay_Log_File: 5P8LHGI6PY4QZ5L-relay-bin.000010Relay_Log_Pos: 324Relay_Master_Log_File: mysql-log-bin.000002Slave_IO_Running: ConnectingSlave_SQL_Running: YesReplicate_Do_DB:Replicate_Ignore_DB:Replicate_Do_Table:Replicate_Ignore_Table:Replicate_Wild_Do_Table:Replicate_Wild_Ignore_Table:Last_Errno: 0Last_Error:Skip_Counter: 0Exec_Master_Log_Pos: 2384Relay_Log_Space: 1907Until_Condition: NoneUntil_Log_File:Until_Log_Pos: 0Master_SSL_Allowed: NoMaster_SSL_CA_File:Master_SSL_CA_Path:Master_SSL_Cert:Master_SSL_Cipher:Master_SSL_Key:Seconds_Behind_Master: NULL
Master_SSL_Verify_Server_Cert: NoLast_IO_Errno: 2003Last_IO_Error: error reconnecting to master 'replicateuser@192.168.7.161:3306' - retry-time: 60  retries: 2Last_SQL_Errno: 0Last_SQL_Error:Replicate_Ignore_Server_Ids:Master_Server_Id: 1Master_UUID: 0c46dc6a-27eb-11ea-9894-a0510b4b1044Master_Info_File: C:\ProgramData\MySQL\MySQL Server 5.7\Data\master.infoSQL_Delay: 0SQL_Remaining_Delay: NULLSlave_SQL_Running_State: Slave has read all relay log; waiting for more updatesMaster_Retry_Count: 86400Master_Bind:Last_IO_Error_Timestamp: 221108 16:05:30Last_SQL_Error_Timestamp:Master_SSL_Crl:Master_SSL_Crlpath:Retrieved_Gtid_Set:Executed_Gtid_Set:Auto_Position: 0Replicate_Rewrite_DB:Channel_Name:Master_TLS_Version:
1 row in set (0.00 sec)ERROR:
No query specifiedmysql> show master status\G;
*************************** 1. row ***************************File: mysql-log-bin.000003Position: 1790Binlog_Do_DB: dbdemoBinlog_Ignore_DB:
Executed_Gtid_Set:
1 row in set (0.01 sec)ERROR:
No query specifiedmysql>

B机执行sql插入数据，执行成功，sql如下

INSERT INTO `dbdemo`.`products` (`prd_name`, `prd_price`, `prd_date`, `cat_id`) VALUES ('prd_B_0011', '3', '2022-11-08 16:08:40', '3');
INSERT INTO `dbdemo`.`products` (`prd_name`, `prd_price`, `prd_date`, `cat_id`) VALUES ('prd_B_0012', '3', '2022-11-08 16:08:41', '3');
INSERT INTO `dbdemo`.`products` (`prd_name`, `prd_price`, `prd_date`, `cat_id`) VALUES ('prd_B_0013', '3', '2022-11-08 16:08:42', '3');

将A机恢复正常（服务开启），然后查询products的数据

结果：一致，A机恢复后查询出的数据与B机执行sql后结果一致；

9.测试从机B宕机场景及结论

测试场景顺序

1.从机B宕机, 主机A正在写;

2.从机B恢复(期望B机从A机自动同步复制数据);

3.查看主机A和从机B的数据一致性

测试过程不再罗列。

结论

将B机从宕机状态恢复（启动其服务），期望B机自动将B机宕机期间A机的数据自动复制过来。

结论：自动复制成功，B机恢复后，B机与A机数据一致。

10.潜在问题-主键自增及从机延时

双主数据库如果均用自增主键，则两边同时进行写操作时可能存在自增主键冲突的问题。

Mysql建议使用一主一从或一主多从方式，主服务器负责写，从服务器负责读，可实现读写分离，且实现了读端的流量削峰和均衡，但主从复制也引入了主从延时问题，当然延时很小，网搜的帖子测试在主机写后，再自从机读取的延迟在毫秒级。

11.延伸问题-关于读写分离或分库主键类型选择

阅读了以下三篇文章。

MySQL分库分表id主键处理_赵广陆的博客-CSDN博客_mysql 分表主键id

mysql 自增id和UUID做主键性能分析，及最优方案 - 腾讯云开发者社区-腾讯云

Mysql 使用UUID和自增主键ID性能对比测试_菠萝-琪琪的博客-CSDN博客

参考上述资料后主键的选择方式：
单库：使用int自增作为主键；

中小数据量分布式系统：采用UUID作为主键；

大数据分布式系统：可参考snowflake算法自定义生成主键；

12.其他

12.1查询mysql日志模式

mysql> show variables like 'binlog_format';
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| binlog_format | ROW   |
+---------------+-------+
1 row in set, 1 warning (0.00 sec)mysql>

12.2win7修改mysql的默认引擎的位置

在C:\ProgramData\MySQL\MySQL Server 5.7\my.ini中

12.3读写分离吞吐量计算示例-参考

6.9. 复制FAQ_MySQL 中文文档

12.4查看主从通讯I/O和SQL线程状态

以下id为11,12,13三行的state是需要关注的，以下是主从复制A机B机连接正常状态的查询结果。

mysql> show processlist;
+----+---------------+-----------------------+------+-------------+-------+---------------------------------------------------------------+------------------+
| Id | User          | Host                  | db   | Command     | Time  | State                                                         | Info             |
+----+---------------+-----------------------+------+-------------+-------+---------------------------------------------------------------+------------------+
|  7 | root          | localhost:52091       | NULL | Query       |     0 | starting                                                      | show processlist |
|  9 | root          | localhost:52401       | NULL | Sleep       |  7384 |                                                               | NULL             |
| 10 | root          | localhost:52402       | NULL | Sleep       |  7384 |                                                               | NULL             |
| 11 | system user   |                       | NULL | Connect     | 16439 | Waiting for master to send event                              | NULL             |
| 12 | system user   |                       | NULL | Connect     | 15948 | Slave has read all relay log; waiting for more updates        | NULL             |
| 13 | replicateuser | 14JPYI7CBESDNFK:65297 | NULL | Binlog Dump | 11577 | Master has sent all binlog to slave; waiting for more updates | NULL             |
+----+---------------+-----------------------+------+-------------+-------+---------------------------------------------------------------+------------------+
6 rows in set (0.02 sec)mysql>

资料参考

windows下使用mysql双机热备功能 /清除热备主从命令 - 执笔者 - 博客园

昊鼎王五：mysql配置主从关系时的语句master_log_pos的值到底填写什么？_昊鼎王五的博客-CSDN博客_master_log_pos

mysql主从复制-CHANGE MASTER TO 语法详解_jesseyoung的博客-CSDN博客_change master to

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