通过全备+主从同步恢复被drop的库或表

MySQL 中drop 等高危误操作后恢复方法

实验目的:

• 本次实验以恢复drop操作为例,使用不同方法进行误操作的数据恢复.
  方法:
• 利用master同步(本文)]
• 伪master+Binlog+同步
• 利用binlog改为realy-log在临时slave更新
• 没有备份怎么恢复被drop的表(利用undrop-for-innodb)
  1.环境
• mysql 5.7.23-log
• master db210(192.168.99.210)
• slave db212(192.168.99.212)
• 空闲服务器:db211(192.168.99.211)
• 压力:在做本次实验过程用,使用sysbench同时做读写模拟压力(28thread+10*100000行)

2.本实验的前置条件:

• 在drop前至少有一次全量备份
• 从全备到drop操作时间点有全程binlog,并且binlog format=’row’
  如果没有以上两个备份怎么办?见《无备份的误操作恢复方法》

3.模拟误操作

root@localhost [wenyz]>select count(*) from t2; +----------+ | count(*) | +----------+ | 163818 | +----------+ 1 row in set (0.12 sec) root@localhost [wenyz]>drop table t2; Query OK, 0 rows affected (0.02 sec) root@localhost [wenyz]>show master status; +------------------+-----------+--------------+------------------+------------------------------------------------+ | File | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set | +------------------+-----------+--------------+------------------+------------------------------------------------+ | mysql-bin.000020 | 136445791 | | | 9e912d2b-92f6-11e8-9747-0050568be82c:1-9872111 | +------------------+-----------+--------------+------------------+------------------------------------------------+ 1 row in set (0.00 sec) root@localhost [wenyz]>flush logs; Query OK, 0 rows affected (1.41 sec)

4.在实验不同方法之前先完成以下步骤:

• 复制全备份和所有binlog文件到空闲服务器:db211上
• 以全备恢复到一个临时新实例(临时slave).

5.找到误操作的位置(GTID或binlog pos)

 通过查找怀疑的binlog: [root@db210_19:11:07 /data/57mysql/mysql3506/logs] #ll total 75564544 -rw-r----- 1 mysql mysql 177 Jul 29 14:14 mysql-bin.000001 ... -rw-r----- 1 mysql mysql 39336996 Jul 29 19:12 mysql-bin.000020 -rw-r----- 1 mysql mysql 13340 Jul 29 19:12 mysql-bin.index [root@db210_19:12:48 /data/57mysql/mysql3506/logs] binlog文件导出命令: #mysqlbinlog -v --base64-output=auto /data/57mysql/mysql3506/logs/mysql-bin.000020 >/data/backup/20.sql binlog文件导出后查找:DROP TABLE `t2`: 在mysql-bin.000020中找到对应位置: # at 97871478 #180731 19:33:29 server id 1853506 end_log_pos 97871543 CRC32 0x8cd4354d GTID last_committed=205567 sequence_number=205570 rbr_only=no original_committed_timestamp=0 immediate_commit_timestamp=0 transaction_length=0 # original_commit_timestamp=0 (1970-01-01 08:00:00.000000 CST) # immediate_commit_timestamp=0 (1970-01-01 08:00:00.000000 CST) /*!80001 SET @@session.original_commit_timestamp=0*//*!*/; SET @@SESSION.GTID_NEXT= '9e912d2b-92f6-11e8-9747-0050568be82c:9791090'/*!*/; # at 97871543 #180731 19:33:29 server id 1853506 end_log_pos 97871660 CRC32 0x974a86d8 Query thread_id=35 exec_time=0 error_code=0 use `wenyz`/*!*/; SET TIMESTAMP=1533036809/*!*/; /*!\C utf8 *//*!*/; SET @@session.character_set_client=33,@@session.collation_connection=33,@@session.collation_server=33/*!*/; DROP TABLE `t2` /* generated by server */ /*!*/; # at 97871660 #180731 19:33:29 server id 1853506 end_log_pos 97871725 CRC32 0xb85257d6 GTID last_committed=205567 sequence_number=205571 rbr_only=yes original_committed_timestamp=0 immediate_commit_timestamp=0 transaction_length=0 /*!50718 SET TRANSACTION ISOLATION LEVEL READ COMMITTED*//*!*/; # original_commit_timestamp=0 (1970-01-01 08:00:00.000000 CST) # immediate_commit_timestamp=0 (1970-01-01 08:00:00.000000 CST) /*!80001 SET @@session.original_commit_timestamp=0*//*!*/; SET @@SESSION.GTID_NEXT= '9e912d2b-92f6-11e8-9747-0050568be82c:9791091'/*!*/; # at 97871725

6.恢复方法一：

• 构建主的从库,并通过:start slave sql_thread until sql_before_gtids=’9e912d2b-92f6-11e8-9747-0050568be82c:9791090′ 试设置SQL回放位置停在drop操作前一个事务.
• Executed_Gtid_Set应该停在: 9e912d2b-92f6-11e8-9747-0050568be82c:1-9791089

change master to master_host='db210',master_port=3506,master_user='wyz',master_password='xxxx',master_auto_position=1; root@localhost [(none)]>start slave io_thread ; Query OK, 0 rows affected (0.01 sec) root@localhost [(none)]>show slave status\G; *************************** 1. row *************************** Slave_IO_State: Queueing master event to the relay log Master_Host: db210 Master_User: wyz Master_Port: 3506 Connect_Retry: 60 Master_Log_File: mysql-bin.000015 Read_Master_Log_Pos: 10476294 Relay_Log_File: relay-bin.000001 Relay_Log_Pos: 4 Relay_Master_Log_File: Slave_IO_Running: Yes Slave_SQL_Running: No Replicate_Do_DB: Replicate_Ignore_DB: Replicate_Do_Table: Replicate_Ignore_Table: Replicate_Wild_Do_Table: Replicate_Wild_Ignore_Table: Last_Errno: 0 Last_Error: Skip_Counter: 0 Exec_Master_Log_Pos: 0 Relay_Log_Space: 27669048 Until_Condition: None Until_Log_File: Until_Log_Pos: 0 Master_SSL_Allowed: No Master_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: No Last_IO_Errno: 0 Last_IO_Error: Last_SQL_Errno: 0 Last_SQL_Error: Replicate_Ignore_Server_Ids: Master_Server_Id: 1853506 Master_UUID: 9e912d2b-92f6-11e8-9747-0050568be82c Master_Info_File: /data/57mysql/mysql3506/data/master.info SQL_Delay: 0 SQL_Remaining_Delay: NULL Slave_SQL_Running_State: Master_Retry_Count: 86400 Master_Bind: Last_IO_Error_Timestamp: Last_SQL_Error_Timestamp: Master_SSL_Crl: Master_SSL_Crlpath: Retrieved_Gtid_Set: 9e912d2b-92f6-11e8-9747-0050568be82c:6730274-6788383 Executed_Gtid_Set: 9e912d2b-92f6-11e8-9747-0050568be82c:1-6730273 Auto_Position: 1 Replicate_Rewrite_DB: Channel_Name: Master_TLS_Version: 1 row in set (0.00 sec) ERROR: No query specified root@localhost [(none)]> root@localhost [(none)]>start slave sql_thread until sql_before_gtids='9e912d2b-92f6-11e8-9747-0050568be82c:9791090'; Query OK, 0 rows affected (0.00 sec)

• 查看sql_thread 执行位置停在9791089

root@localhost [(none)]>show slave status\G; *************************** 1. row *************************** Slave_IO_State: Queueing master event to the relay log Master_Host: db210 Master_User: wyz Master_Port: 3506 Connect_Retry: 60 Master_Log_File: mysql-bin.000079 Read_Master_Log_Pos: 15969193 Relay_Log_File: relay-bin.000024 Relay_Log_Pos: 97871691 Relay_Master_Log_File: mysql-bin.000020 Slave_IO_Running: Yes Slave_SQL_Running: No Replicate_Do_DB: Replicate_Ignore_DB: Replicate_Do_Table: Replicate_Ignore_Table: Replicate_Wild_Do_Table: Replicate_Wild_Ignore_Table: Last_Errno: 0 Last_Error: Skip_Counter: 0 Exec_Master_Log_Pos: 97871478 Relay_Log_Space: 15602695666 Until_Condition: SQL_BEFORE_GTIDS Until_Log_File: Until_Log_Pos: 0 Master_SSL_Allowed: No Master_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: No Last_IO_Errno: 0 Last_IO_Error: Last_SQL_Errno: 0 Last_SQL_Error: Replicate_Ignore_Server_Ids: Master_Server_Id: 1853506 Master_UUID: 9e912d2b-92f6-11e8-9747-0050568be82c Master_Info_File: /data/57mysql/mysql3506/data/master.info SQL_Delay: 0 SQL_Remaining_Delay: NULL Slave_SQL_Running_State: Master_Retry_Count: 86400 Master_Bind: Last_IO_Error_Timestamp: Last_SQL_Error_Timestamp: Master_SSL_Crl: Master_SSL_Crlpath: Retrieved_Gtid_Set: 9e912d2b-92f6-11e8-9747-0050568be82c:6730274-42357224 Executed_Gtid_Set: 9e912d2b-92f6-11e8-9747-0050568be82c:1-9791089 Auto_Position: 1 Replicate_Rewrite_DB: Channel_Name: Master_TLS_Version: 1 row in set (0.00 sec) ERROR: No query specified root@localhost [(none)]> 

• 查看数据是否和drop相同:

root@localhost [(none)]>select count(*) from wenyz.t2; +----------+ | count(*) | +----------+ | 163818 | +----------+ 1 row in set (0.10 sec) root@localhost [(none)]>

• 将数据表导出

/usr/local/mysql57/bin/mysqldump -S /tmp/mysql3506.sock -pxxxx --master-data=2 --single-transaction wenyz t2 >/data/backup/t2.sql

• 将t2.sql传回master 并导入

[root@db211_20:49:35 /root]  
#scp /data/backup/t2.sql db210:/data/backup/
t2.sql                    

[root@db211_20:50:10 /root]
#/usr/local/mysql57/bin/mysql -S /tmp/mysql3506.sock -pxxxx <t2.sql 
mysql: [Warning] Using a password on the command line interface can be insecure.
[root@db210_21:01:36 /data/backup]  
#fg
/usr/local/mysql57/bin/mysql --login-path=p3506 (wd: /tmp)
root@localhost [wenyz]>select count(*) from t2;
+----------+
| count(*) |
+----------+
|   163818 |
+----------+
1 row in set (0.40 sec)