个人博客:mysql数据恢复，binlog详解

binlog日志恢复数据,是挽救错误操作和数据损坏一根救命稻草，所以认识和使用binglog对于技术人员还是很有必要的

binlog一般用于

主从复制中 master节点开启binlog把二进制日志传递给slave节点达到主从数据一致
第二点自然是用于数据恢复了，使用mysqlbinlog工具来恢复数据

因为我自己的网站遇到过mysql表被我误删操作,drop table后当时我还是挺淡定的，虽然我不清楚我能不能把数据拯救回来，对于个人网站而言可能都没有主从，也没有把mysql的各项配置设置完美，这种情形下最担心的当然是binlog是否开启了，如果没有开启binlog并且也没有做数据备份，我感觉基本上就GG了

因为我mysql是通过docker容器安装的，所以具体 my.cnf 配置文件的放在哪也忘记了

使用 find / -name my.cnf 找到文件在哪

root@0d5861775029:/# find / -name my.cnf

find: '/proc/1/map_files': Operation not permitted
find: '/proc/182/map_files': Operation not permitted
find: '/proc/187/map_files': Operation not permitted
find: '/proc/1601/map_files': Operation not permitted
find: '/proc/1731/map_files': Operation not permitted
find: '/proc/1741/map_files': Operation not permitted
/etc/alternatives/my.cnf
/etc/mysql/my.cnf
/var/lib/dpkg/alternatives/my.cnf

root@0d5861775029:/#

查看my.cnf配置找到binlog以及mysql数据存储的位置

#
# The MySQL  Server configuration file.
#
# For explanations see
# http://dev.mysql.com/doc/mysql/en/server-system-variables.html

[mysqld]
pid-file        = /var/run/mysqld/mysqld.pid
socket          = /var/run/mysqld/mysqld.sock
datadir         = /var/lib/mysql
secure-file-priv= NULL
# Disabling symbolic-links is recommended to prevent assorted security risks
symbolic-links=0

# Custom config should go here
!includedir /etc/mysql/conf.d/

可以看到mysql数据存储的目录是 datadir = /var/lib/mysql 目录中

root@0d5861775029:/etc/mysql# cd /var/lib/mysql/
root@0d5861775029:/var/lib/mysql# ls
#innodb_temp   binlog.index	client-key.pem	ib_logfile1  mysql.ibd		 server-cert.pem  undo_002
auto.cnf       ca-key.pem	db_blog		ibdata1      performance_schema  server-key.pem
binlog.000001  ca.pem		ib_buffer_pool	ibtmp1	     private_key.pem	 sys
binlog.000002  client-cert.pem	ib_logfile0	mysql	     public_key.pem	 undo_001

上面的前戏都看完了，这其实并非binlog具体使用，而是我个人发现数据目录方式接下来我将详细介绍binlog的使用

一、开启binlog日志

查看binlog是否开启
- ON 表示已经开启
- 查看更多内容可以这样 show variables like 'log_%';

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

mysql> show variables like 'log_%';
+----------------------------------------+----------------------------------------+
| Variable_name                          | Value                                  |
+----------------------------------------+----------------------------------------+
| log_bin                                | ON                                     |
| log_bin_basename                       | /var/lib/mysql/binlog                  |
| log_bin_index                          | /var/lib/mysql/binlog.index            |
| log_bin_trust_function_creators        | OFF                                    |
| log_bin_use_v1_row_events              | OFF                                    |
| log_error                              | stderr                                 |
| log_error_services                     | log_filter_internal; log_sink_internal |
| log_error_suppression_list             |                                        |
| log_error_verbosity                    | 2                                      |
| log_output                             | FILE                                   |
| log_queries_not_using_indexes          | OFF                                    |
| log_slave_updates                      | ON                                     |
| log_slow_admin_statements              | OFF                                    |
| log_slow_extra                         | OFF                                    |
| log_slow_slave_statements              | OFF                                    |
| log_statements_unsafe_for_binlog       | ON                                     |
| log_throttle_queries_not_using_indexes | 0                                      |
| log_timestamps                         | UTC                                    |
+----------------------------------------+----------------------------------------+
18 rows in set (0.00 sec)

编辑my.cnf开启binlog

在[mysqld] 区块
设置/添加 log-bin=mysql-bin  确认是打开状态(值 mysql-bin 是日志的基本名或前缀名)；

然后重启mysql

二、查看binlog日志操作命令

查看所有binlog日志列表

mysql> show logs;
ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'logs' at line 1
mysql> show master logs;
+---------------+-----------+-----------+
| Log_name      | File_size | Encrypted |
+---------------+-----------+-----------+
| binlog.000001 |   3091158 | No        |
| binlog.000002 | 141156437 | No        |
+---------------+-----------+-----------+
2 rows in set (0.17 sec)

查看master状态，也就是最新一个binlog日志编号名称和最后一个操作事件pos结束位置

mysql> show master status;
+---------------+-----------+--------------+------------------+-------------------+
| File          | Position  | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+---------------+-----------+--------------+------------------+-------------------+
| binlog.000002 | 141156437 |              |                  |                   |
+---------------+-----------+--------------+------------------+-------------------+
1 row in set (0.00 sec)

刷新log日志，将会产生一个新编号的binlog日志文件

mysql> flush logs;

重置(清空)所有binlog日志

mysql> reset master;

三、查看binlog日志内容

使用mysqlbinlog命令查看

因为binlog是二进制文件，普通文件查看器都无法打开，必须使用自带的mysqlbinlog命令查看

mysqlbinlog binlog.000002 使用mysqlbinlog不好观察

在mysql中查看binlog日志

mysql> show binlog events [IN 'log_name'] [FROM pos] [LIMIT [offset,] row_count];

 选项解析：
   IN 'log_name'   指定要查询的binlog文件名(不指定就是第一个binlog文件)
   FROM pos        指定从哪个pos起始点开始查起(不指定就是从整个文件首个pos点开始算)
   LIMIT [offset,] 偏移量(不指定就是0)
   row_count       查询总条数(不指定就是所有行)

 截取部分查询结果：
 *************************** 20. row ***************************
    Log_name: mysql-bin.000021  ----------------------------------------------> 查询的binlog日志文件名
         Pos: 11197 ----------------------------------------------------------> pos起始点:
  Event_type: Query ----------------------------------------------------------> 事件类型：Query
   Server_id: 1 --------------------------------------------------------------> 标识是由哪台服务器执行的
 End_log_pos: 11308 ----------------------------------------------------------> pos结束点:11308(即：下行的pos起始点)
        Info: use `zyyshop`; INSERT INTO `team2` VALUES (0,345,'asdf8er5') ---> 执行的sql语句
 *************************** 21. row ***************************
    Log_name: mysql-bin.000021
         Pos: 11308 ----------------------------------------------------------> pos起始点:11308(即：上行的pos结束点)
  Event_type: Query
   Server_id: 1
 End_log_pos: 11417
        Info: use `zyyshop`; /*!40000 ALTER TABLE `team2` ENABLE KEYS */
 *************************** 22. row ***************************
    Log_name: mysql-bin.000021
         Pos: 11417
  Event_type: Query
   Server_id: 1
 End_log_pos: 11510
        Info: use `zyyshop`; DROP TABLE IF EXISTS `type`

指定查询 binlog.000002 日志

mysql> show binlog events in 'binlog.000002' limit 10;
+---------------+------+----------------+-----------+-------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Log_name      | Pos  | Event_type     | Server_id | End_log_pos | Info                                                                                                                                                                  |
+---------------+------+----------------+-----------+-------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| binlog.000002 |    4 | Format_desc    |         1 |         124 | Server ver: 8.0.16, Binlog ver: 4                                                                                                                                     |
| binlog.000002 |  124 | Previous_gtids |         1 |         155 |                                                                                                                                                                       |
| binlog.000002 |  155 | Anonymous_Gtid |         1 |         234 | SET @@SESSION.GTID_NEXT= 'ANONYMOUS'                                                                                                                                  |
| binlog.000002 |  234 | Query          |         1 |         482 | CREATE USER 'schwarzeni'@'localhost' IDENTIFIED WITH 'caching_sha2_password' AS '$A$005$H{;gmzB@[}K1i\nBcce80ezg8j3o0qDdYocc1OxBkShlQyzmOV/c4rGP69' /* xid=7 */ |
| binlog.000002 |  482 | Anonymous_Gtid |         1 |         561 | SET @@SESSION.GTID_NEXT= 'ANONYMOUS'                                                                                                                                  |
| binlog.000002 |  561 | Query          |         1 |         801 | CREATE USER 'cuishifeng'@'%' IDENTIFIED WITH 'caching_sha2_password' AS '$A$005$f8Zs\ZhY(9]HPTcaN83yCTNmHs/LQsa2DerCX.ZVgd4InrYiCpj75mA' /* xid=8 */         |
| binlog.000002 |  801 | Anonymous_Gtid |         1 |         878 | SET @@SESSION.GTID_NEXT= 'ANONYMOUS'                                                                                                                                  |
| binlog.000002 |  878 | Query          |         1 |         968 | FLUSH PRIVILEGES                                                                                                                                                      |
| binlog.000002 |  968 | Anonymous_Gtid |         1 |        1047 | SET @@SESSION.GTID_NEXT= 'ANONYMOUS'                                                                                                                                  |
| binlog.000002 | 1047 | Query          |         1 |        1256 | ALTER USER 'cuishifeng'@'%' IDENTIFIED WITH 'mysql_native_password' AS '*10320381F36BE49A18F09B06A4BC005223975101' /* xid=12 */                                       |
+---------------+------+----------------+-----------+-------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------+
10 rows in set (0.00 sec)

指定查询 binlog.000002 这个文件，从pos点:968开始查起

mysql> show binlog events in 'binlog.000002' from 968 limit 10;
+---------------+------+----------------+-----------+-------------+---------------------------------------------------------------------------------------------------------------------------------+
| Log_name      | Pos  | Event_type     | Server_id | End_log_pos | Info                                                                                                                            |
+---------------+------+----------------+-----------+-------------+---------------------------------------------------------------------------------------------------------------------------------+
| binlog.000002 |  968 | Anonymous_Gtid |         1 |        1047 | SET @@SESSION.GTID_NEXT= 'ANONYMOUS'                                                                                            |
| binlog.000002 | 1047 | Query          |         1 |        1256 | ALTER USER 'cuishifeng'@'%' IDENTIFIED WITH 'mysql_native_password' AS '*10320381F36BE49A18F09B06A4BC005223975101' /* xid=12 */ |
| binlog.000002 | 1256 | Anonymous_Gtid |         1 |        1333 | SET @@SESSION.GTID_NEXT= 'ANONYMOUS'                                                                                            |
| binlog.000002 | 1333 | Query          |         1 |        1423 | flush privileges                                                                                                                |
| binlog.000002 | 1423 | Anonymous_Gtid |         1 |        1500 | SET @@SESSION.GTID_NEXT= 'ANONYMOUS'                                                                                            |
| binlog.000002 | 1500 | Query          |         1 |        1646 | GRANT ALL PRIVILEGES ON *.* TO 'cuishifeng'@'%' /* xid=70 */                                                                    |
| binlog.000002 | 1646 | Anonymous_Gtid |         1 |        1723 | SET @@SESSION.GTID_NEXT= 'ANONYMOUS'                                                                                            |
| binlog.000002 | 1723 | Query          |         1 |        1813 | flush privileges                                                                                                                |
| binlog.000002 | 1813 | Anonymous_Gtid |         1 |        1890 | SET @@SESSION.GTID_NEXT= 'ANONYMOUS'                                                                                            |
| binlog.000002 | 1890 | Query          |         1 |        1968 | FLUSH TABLES                                                                                                                    |
+---------------+------+----------------+-----------+-------------+---------------------------------------------------------------------------------------------------------------------------------+
10 rows in set (0.00 sec)

从日志中可以看出执行的mysql命令并且有起始位置，对于恢复数据非常有用

查询第一个(最早)的binlog日志

mysql> show binlog events;

四、现在从binlog日志恢复数据

常用命令

恢复语法格式：
# mysqlbinlog mysql-bin.0000xx | mysql -u用户名 -p密码 数据库名
 常用选项：
  --start-position=953                   起始pos点
  --stop-position=1437                   结束pos点
  --start-datetime="2013-11-29 13:18:54" 起始时间点
  --stop-datetime="2013-11-29 13:21:53"  结束时间点
  --database=zyyshop                     指定只恢复zyyshop数据库(一台主机上往往有多个数据库，只限本地log日志)
    
不常用选项：    
  -u --user=name              Connect to the remote server as username.连接到远程主机的用户名
  -p --password[=name]        Password to connect to remote server.连接到远程主机的密码
  -h --host=name              Get the binlog from server.从远程主机上获取binlog日志
  --read-from-remote-server   Read binary logs from a MySQL server.从某个MySQL服务器上读取binlog日志

小结：实际是将读出的binlog日志内容，通过管道符传递给mysql命令。这些命令、文件尽量写成绝对路径；

日志恢复相当于执行当时DDL语句，如果日志恢复的语句例如你库中存在某个表日志又执行创建这个表肯定是走不通的所以最好指定具体位置恢复

查看binlog日志确定从哪恢复

 mysql> show binlog events in 'mysql-bin.000023';
        
以下为末尾片段：
+------------------+------+------------+-----------+-------------+------------------------------------------------------------+
| Log_name         | Pos  | Event_type | Server_id | End_log_pos | Info                                                       |
+------------------+------+------------+-----------+-------------+------------------------------------------------------------+
| mysql-bin.000023 |  922 | Xid        |         1 |         953 | COMMIT /* xid=3820 */                                      |
| mysql-bin.000023 |  953 | Query      |         1 |        1038 | BEGIN                                                      |
| mysql-bin.000023 | 1038 | Query      |         1 |        1164 | use `zyyshop`; update zyyshop.tt set name='李四' where id=4|
| mysql-bin.000023 | 1164 | Xid        |         1 |        1195 | COMMIT /* xid=3822 */                                      |
| mysql-bin.000023 | 1195 | Query      |         1 |        1280 | BEGIN                                                      |
| mysql-bin.000023 | 1280 | Query      |         1 |        1406 | use `zyyshop`; update zyyshop.tt set name='小二' where id=2|
| mysql-bin.000023 | 1406 | Xid        |         1 |        1437 | COMMIT /* xid=3823 */                                      |
| mysql-bin.000023 | 1437 | Query      |         1 |        1538 | drop database zyyshop                                      |
+------------------+------+------------+-----------+-------------+------------------------------------------------------------+

通过分析，造成数据库破坏的pos点区间是介于 1437--1538 之间，只要恢复到1437前就可。

mysqlbinlog  --start-position=953  --stop-position=1538 --database=zyyshop binlog.000002 | mysql -uroot -p123456 -v zyyshop

指定时间恢复

知道自己在哪个时间段误操作了

mysql> drop table tt;

@ --start-datetime="2013-11-29 13:18:54"  起始时间点
@ --stop-datetime="2013-11-29 13:21:53"   结束时间点

# mysqlbinlog --start-datetime="2013-11-29 13:18:54" --stop-datetime="2013-11-29 13:21:53" --database=zyyshop binlog.000002 | mysql -uroot -p123456 -v zyyshop

希望这篇文章能够帮助误删操作的朋友顺利恢复数据