One, MySQL log management
MySQL's default log storage location is /usr/local/mysql/data
There are two ways to open the log:
- Through the configuration file or through the command
- The log opened by command modification is temporary and will be closed after closing or restarting the service
(1) MySQL common log types and opening
Error log
Used to record error messages that occur when MySQL is started, stopped, or running. It is enabled by default
指定日志的保存位置和文件名
log-error=/usr/local/mysql/data/mysql_error.log
General query log
Used to record all connections and statements of MySQL, it is closed by default
general_log=ON
general_log_file=/usr/local/mysql/data/mysql_general.log
Binary log (binlog)
Used to record all error messages sent when MySQL is started, stopped or running, it is closed by default
log-bin=mysql-bin / log_bin=mysql-bin
Slow query log
It is used to record all statements whose execution time exceeds long_query_time seconds. You can find out which query statements have a long execution time for optimization. The default is off
slow_query_log=ON
slow_query_log_file=/usr/local/mysql/data/mysql_slow_query.log
long_query_time=5
systemctl restart mysqld
Two, log status
Check whether the general query log is enabled
show variables like 'general%';
Check whether the binary log is turned on
show variables like 'log_bin%';
Check whether the slow query day function is enabled
show variables like '%slow%';
View slow query time settings
show variables like 'long_query_time';
Set the method to start slow query in the database
set global slow_query_log=ON;
该方法重启服务失效
Three, MySQL backup and recovery
(1) The importance of data backup
- The main purpose of backup is disaster recovery
- In a production environment, data security is critical
- Any loss of data may have serious consequences
Reasons for data loss:
- Program error
- Human error
- Operation error
- Disk failure
- Disaster (fire, earthquake, theft, etc.)
(2) Classification of database backup
Physical backup: backup of physical files (such as data files, log files, etc.) of the database operating system
Physical backup method:
cold backup (offline backup): is performed when the database is closed.
Hot backup (online backup): the database is running and depends on the database log file.
Warm backup: database lock table (cannot be written but can be Backup operation in the state of reading)
Logical backup: backup of database logical components (such as tables and other database objects)
From the perspective of database backup strategy, backup can be divided into:
Full backup: make a complete backup of the database every time
A full backup is a backup of the entire database, database structure and file structure.
What is saved is the database at the time the backup was completed. It is the basis of differential backup and incremental backup. Equivalent to the cornerstone.
Differential backup: Back up files that have been modified since the last full backup
Incremental backup: only the files modified after the last full backup or incremental backup will be backed up
Three, common backup methods
Physical cold standby
The database is closed during the backup, and the database file is directly packaged. The backup speed is fast. It is also the easiest way to close the MySQL database. Use the tar command to directly package the database folder and
directly replace the existing MySQL directory.
Backup tool mydump or mysqlhotcopy
mysqldump is a commonly used logical backup tool. The backup tool that comes with MySQL can realize the backup of MySQL. You can export the specified library and table as SQL script.
Use the command mysql to import the backup data
mysqlhotcopy only has backup myisam and archive tables
Start the binary log for incremental backup
For incremental backup, you need to refresh the binary log
Third-party tool backup
Free MySQL hot backup software Percona XtraBackup
Four, MySQL complete backup and recovery
mysql -u root -p
create database wahaha;
use wahaha;
create table if not exists wa1 (
id int(4) not null auto_increment,
name varchar(10) not null,
sex char(10) not null,
hobby varchar(20),
primary key (id));
insert into wa1 values(1,'u1','male','run');
insert into wa1 values(2,'u2','female','sing');
(1) MySQL full backup
The database of the InnoDB storage engine is stored on the disk as three files: db.opt (table attribute file), table name .frm (table structure file), table name .ibd (table data file).
Physical cold backup and recovery
systemctl stop mysqld
yum -y install xz
Compressed backup
tar Jcvf /opt/mysql_all_$(date +%F).tar.xz /usr/local/mysql/data/
Unzip and restore
tar Jxvf /opt/mysql_all_2021-1-30.tar.xz -C /usr/local/mysql/data
systemctl restart mysql
(2) mysqldump backup and recovery
Full backup of one or more complete libraries (including all tables)
mysqldump -u root -p[password] --databases library name 1 [library name 2]…> /backup path/backup file name.sql #exported
is the database script file
mysqldump -uroot -p123123 --databases wahaha > /opt/wahaha.sql
mysqldump -uroot -p123123 --databases mysql wahaha > /opt/mysql-wahaha.sql
Fully backup all the libraries in the MySQL server
mysqldump -u root -p[password] --all-databases> /backup path/backup file name.sql
mysqldump -u root -p123123 --all-databases > /opt/all.sql
Full backup of some tables in the specified library
mysqldump -u root -p[password] library name [table name 1] [table name 2]…> /backup path/backup file name.sql
mysqldump -uroot -p123123 wahaha wa1 > /opt/wahaha_wa1.sql
#使用“-d”选项，说明只保存数据库的表结构
#不使用“-d”选项，说明表数据也进行备份
View backup files
cat wahaha_wa1.sql | grep -v "^--" /opt/wahaha_wa1.sql | grep -v "^/" | grep -v "^$"
(3) Complete backup and recovery
Restore database
mysql -uroot -p123123 -e 'drop database wahaha;'
#“-e”选项，用于指定连接 MySQL 后执行的命令，命令执行完后自动退出
mysql -uroot -p123123 -e 'SHOW DATABASES;'
mysql -uroot -p123123 < /opt/wahaha.sql
mysql -uroot -p123123 -e 'SHOW DATABASES;'
Restore data table
mysql -uroot -p123123 -e 'drop table wahaha.wa1;'
mysql -uroot -p123123 -e 'show tables from wahaha;'
mysql -uroot -p123123 wahaha < /opt/wahaha_wa1.sql
mysql -uroot -p123123 -e 'show tables from wahaha;'
Five, MySQL incremental backup and recovery
(1) MySQL incremental backup
Turn on the binary log function
vim /etc/my.cnf
[mysqld]
log-bin=mysql-bin
binlog_format = MIXED
server-id = 1
Full backup of database or table can be performed weekly
In the case of weekly backups, a scheduled task crontab -e is required to create a plan to complete
mysqldump -uroot -p123123 wahaha wa1 > /opt/wahaha_wa1_$(date +%F).sql
mysqldump -uroot -p123123 --all-databases wahaha > /opt/wahaha_$(date +%F).sql
Incremental backup operations can be performed every day to generate new binary log files
mysqladmin -uroot -p123123 flush-logs
Insert new data to simulate the increase or change of data
mysql -uroot -p123123
use wahaha;
insert into wa1 values(3,'u3','male','game');
insert into wa1 values(4,'u4','female','reading');
Generate a new binary log file again
The newly generated file after refresh is used now, and the previous record is saved in the previous file
mysqladmin -uroot -p123123 flush-logs
View the contents of the binary log file
cp /usr/local/mysql/data/mysql-bin.000002 /opt/
mysqlbinlog --no-defaults --base64-output=decode-rows -v /opt/mysql-bin.000002
#- -base64-output=decode-rows：使用64位编码机制去解码并按行读取
#-v：显示详细内容
(2) MySQL incremental backup and recovery
General recovery
#模拟丢失更改的数据的恢复步骤
mysql -uroot -p123123
use wahaha;
delete from wa1 where id=3;
delete from wa1 where id=4;
select * from wa1;
quit
mysqlbinlog --no-defaults /opt/mysql-bin.000002 | mysql -uroot -p123123
mysql -uroot -p123123 -e "select * from wahaha.wa1;"
Location based recovery
mysqlbinlog --no-defaults --stop-position='position number' /opt/mysql-bin.000002 | mysql -uroot -p
mysqlbinlog --no-defaults --start-position='position number' /opt/mysql-bin.000002 | mysql -uroot -p
mysqlbinlog --no-defaults --start-position='position number' --stop-position='position number' /opt/mysql-bin.000002 | mysql -uroot -p
mysql -uroot -p123123 -e "truncate table wahaha.wa1;"
mysql -uroot -p123123 -e "select * from wahaha.wa1;"
mysqlbinlog --no-defaults --stop-position='609' /opt/mysql-bin.000002 | mysql -uroot -p
mysql -uroot -p123123 -e "select * from SCHOOL.CLASS1;"
Point-in-time recovery
Only restore the data before 22:03:09, that is, do not restore the data of "user4"
Example: First clear the table wa1 to facilitate the experiment
mysql -uroot -p123123 -e "truncate table wahaha.wa1;"
mysql -uroot -p123123 -e "select * from wahaha.wa1;"
mysqlbinlog --no-defaults --stop-datetime='2021-01-30 22:03:09' /opt/mysql-bin.000002 |mysql -uroot -p123123
mysql -uroot -p123123 -e "select * from wahaha.wa1;"
