mysql数据恢复，binlog详解

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

1. 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

1. 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)

1. 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)

1. 刷新log日志，将会产生一个新编号的binlog日志文件

mysql> flush logs;

1. 重置(清空)所有binlog日志

mysql> reset master;

三、查看binlog日志内容

1. 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

1. 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`

1. 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)

1. 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

1. 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

1. 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

1. 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

1. 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