Detailed explanation of how to recover data after MySQL misoperation

1. Open binlog.

First check whether binlog is turned on

mysql> show variables like "log_bin"; +---------------+-------+ |Variable_name | Value +---------------+-------+ | log_bin OFF +---------------+-------+ 1 row in set (0.00 sec)

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The value is OFF and needs to be turned on. The way to turn on binlog is as follows:

#vim /etc/my.cnf

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Add to [mysqld]

log-bin = mysql-bin log-bin = /usr/local/mysql/log/mysql-bin.log

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Restart mysql service

#service mysqld stop #service mysqld start

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2. Simulation data writing

Build database

create database backup;

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Build a table

CREATE TABLE `number` ( `id` int(11) NOT NULL AUTO_INCREMENT COMMENT '编号', `updatetime` timestamp NOT NULL DEFAULT '0000-00-00 00:00:00', PRIMARY KEY (`id`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8;

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Write data

Procedure 2-1

#coding:utf8 #python2.7 import MySQLdb import time def connect_mysql(db_host="192.168.11.169",user="martin",passwd="martin",db="backup",charset="utf8"): conn = MySQLdb.connect(host=db_host,user=user,passwd=passwd,db=db,charset=charset) conn.autocommit(True) return conn.cursor() #数据插入 for i in range(0,10): #time=time.strftime("%Y-%m-%d %H:%M:%S") sql = 'insert into number(updatetime) values(%s)' values = [(time.strftime("%Y-%m-%d %H:%M:%S"))] db1 = connect_mysql() print db1.executemany(sql,values)

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Query data

mysql> select * from number; +-------+------------------------+ | id | updatetime +--------------------------------+ | 1 | 2016-06-29 23:27:15 | | 2 | 2016-06-29 23:27:15 | | 3 | 2016-06-29 23:27:15 | | 4 | 2016-06-29 23:27:15 | | 5 | 2016-06-29 23:27:15 | | 6 | 2016-06-29 23:27:15 | | 7 | 2016-06-29 23:27:15 | | 8 | 2016-06-29 23:27:15 | | 9 | 2016-06-29 23:27:15 | | 10 | 2016-06-29 23:27:15 | +-------+------------------------+ 10 rows in set (0.00 sec)

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3. Full backup

mysqldump -uroot -p -F --master-data=2 backup |gzip> /martin/data/backup_$(date +%F).sql.gz

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Note:Add -F to refresh the binlog for easy operation during recovery.

4. Simulate writing incremental data

Continue with procedure 2-1.

Query data

mysql> select * from number; +----+---------------------------+ | id | updatetime | +----+---------------------------+ | 1 | 2016-06-29 23:27:15 | | 2 | 2016-06-29 23:27:15 | | 3 | 2016-06-29 23:27:15 | | 4 | 2016-06-29 23:27:15 | | 5 | 2016-06-29 23:27:15 | | 6 | 2016-06-29 23:27:15 | | 7 | 2016-06-29 23:27:15 | | 8 | 2016-06-29 23:27:15 | | 9 | 2016-06-29 23:27:15 | | 10 | 2016-06-29 23:27:15 | | 11 | 2016-06-29 23:31:03 | | 12 | 2016-06-29 23:31:03 | | 13 | 2016-06-29 23:31:03 | | 14 | 2016-06-29 23:31:03 | | 15 | 2016-06-29 23:31:03 | | 16 | 2016-06-29 23:31:03 | | 17 | 2016-06-29 23:31:03 | | 18 | 2016-06-29 23:31:03 | | 19 | 2016-06-29 23:31:03 | | 20 | 2016-06-29 23:31:03 | +-------+---------------------+ 20 rows in set (0.00 sec)

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5. Incremental backup

Just keep the binlog of mysql-bin.000002 and later.

6. Simulate misoperation

delete from number;

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7. Write incremental data again

Execution program 2-1

select * from bumber;

+------+------------------------+ | id | updatetime | +------+------------------------+ | 21 | 2016-06-29 23:41:06 | | 22 | 2016-06-29 23:41:06 | | 23 | 2016-06-29 23:41:06 | | 24 | 2016-06-29 23:41:06 | | 25 | 2016-06-29 23:41:06 | | 26 | 2016-06-29 23:41:06 | | 27 | 2016-06-29 23:41:06 | | 28 | 2016-06-29 23:41:06 | | 29 | 2016-06-29 23:41:06 | | 30 | 2016-06-29 23:41:06 | +------+------------------------+ 10 rows in set (0.00 sec)

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8. Recovery

At this time, it was discovered that the previous delete operation was a mistaken operation and urgent recovery was needed. The recovery process is as follows

Add a read lock to the table

lock table number read;

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Import all backed up data

#cd /martin/data/ #gzip -d number_2016-06-29.sql.gz #grep -i "change" *.sql -- CHANGE MASTER TO MASTER_LOG_FILE='mysql-bin.000002', MASTER_LOG_POS=107;

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Refresh log

#mysqladmin -uroot -p'martin' flush-logs #cd /usr/local/mysql/log #ls|grep mysql-bin|grep -v index mysql-bin.000001 mysql-bin.000002 mysql-bin.000003

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It can be determined that mysql-bin.000002 is the incremental data binlog

Import full backup

#cd /martin/data/ #mysql -uroot -p backup < number_2016-06-29.sql #cp /usr/local/mysql/log/mysql-bin.000002 /martin/data/ #mysqlbinlog mysql-bin.000002 >bin.sql #vim bin.sql

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Find the previous delete statement in bin.sql and delete it

mysql -uroot -p 
        
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9. Confirm that the data has been recovered

Log in to mysql

#mysql -uroot -p'martin' backup select * from number;

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+----+---------------------+ | id | updatetime | +----+---------------------+ | 1 | 2016-06-29 23:27:15 | | 2 | 2016-06-29 23:27:15 | | 3 | 2016-06-29 23:27:15 | | 4 | 2016-06-29 23:27:15 | | 5 | 2016-06-29 23:27:15 | | 6 | 2016-06-29 23:27:15 | | 7 | 2016-06-29 23:27:15 | | 8 | 2016-06-29 23:27:15 | | 9 | 2016-06-29 23:27:15 | | 10 | 2016-06-29 23:27:15 | | 11 | 2016-06-29 23:31:03 | | 12 | 2016-06-29 23:31:03 | | 13 | 2016-06-29 23:31:03 | | 14 | 2016-06-29 23:31:03 | | 15 | 2016-06-29 23:31:03 | | 16 | 2016-06-29 23:31:03 | | 17 | 2016-06-29 23:31:03 | | 18 | 2016-06-29 23:31:03 | | 19 | 2016-06-29 23:31:03 | | 20 | 2016-06-29 23:31:03 | | 21 | 2016-06-29 23:41:06 | | 22 | 2016-06-29 23:41:06 | | 23 | 2016-06-29 23:41:06 | | 24 | 2016-06-29 23:41:06 | | 25 | 2016-06-29 23:41:06 | | 26 | 2016-06-29 23:41:06 | | 27 | 2016-06-29 23:41:06 | | 28 | 2016-06-29 23:41:06 | | 29 | 2016-06-29 23:41:06 | | 30 | 2016-06-29 23:41:06 | +----+---------------------+ 30 rows in set (0.00 sec)

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Restore completed! The above is the entire content of this article. You should be more careful when operating the database to avoid misoperation. If you encounter it, I hope this article can help you.