MySQL data recovery based on gtid feature and xtrabackup

1. Introduction of gtid features:

GTID (global transaction identifier) is a new feature of MySQL 5.6, which can uniquely identify a transaction and consists of UUID+TID:

UUID is the unique identifier of a MySQL instance
TID is the number of committed transactions on this instance

In master-slave replication, GTID replaces the classic replication method. Instead of using binlog+pos to start replication, master_auto_postion = 1 is used to automatically match GTID breakpoints for replication.

To enable GTID, simply add the following parameters to the MySQL parameter file:

gtid-mode                       = ON
enforce_gtid_consistency        = 1

2. Data recovery requirements:

To restore MySQL (hereinafter referred to as the A library) to the state of about 12:00 a.m. a day ago, the prerequisites are as follows:

Enable GTID
There are xtra backup files of A library before 12:00 in the morning yesterday
Open binlog log (nonsense)

3. Recovery operation:

Perform data recovery on another MySQL (B database) to avoid affecting online business

1. Move the data directory of the B library and copy the backup file of the A library to the B library

mv data data_20160716           #移走B库data
mv A_back_20160714 data         #移入A库备份文件
chown -R mysql12300.mysql data/

2. Open the B library and configure the master-slave

Check the GTID recorded in the xtrabackup_binlog_info file in the data directory:

[root@service-test1 data]$ cat xtrabackup_binlog_info 
mysql-bin.000012        46455554        8133046e-4282-11e6-848e-026ca51d284c:1-4920155

Set @@global.gtid_purged in the B library (slave) to skip the GTID included in the backup, and execute change master to designate the A library as the main library:

mysql> SET GLOBAL gtid_purged="8133046e-4282-11e6-848e-026ca51d284c:1-4920155";
Query OK, 0 rows affected (0.00 sec)

mysql> change master to Master_Host ='10.11.21.14',Master_Port=3306,Master_User='replica',Master_Password='XXXXXXXXX',MASTER_AUTO_POSITION=1;
Query OK, 0 rows affected, 2 warnings (0.01 sec)

Note: Sometimes there is more than one GTID in xtrabackup_binlog_info. You can specify multiple GTIDs when setting @@global.gtid_purged, separated by commas .

Fourth, find the recovery point in the A library binlog and restore it

It should be noted that after the above operation, do not start slave directly, otherwise the B library will also run to the current state of the A library

Convert A library binlog to sql statement:

mysqlbinlog -vv mysql-bin.000011 > mysql-bin.000011.sql

Find the location around 12:00am the previous day and record the GTID:

# at 561467475
#160521  0:24:31 server id 212177500  end_log_pos 561467523 CRC32 0x216072ca    GTID [commit=yes]
SET @@SESSION.GTID_NEXT= '542ef021-9a64-11e5-bc49-025d3d22c211:1348360'/*!*/;

Open the slave in the B library and specify the location to restore to:

mysql> start slave until SQL_BEFORE_GTIDS='542ef021-9a64-11e5-bc49-025d3d22c211:1348360';
Query OK, 0 rows affected (0.00 sec)

When the specified GTID is reached, the SQL thread will stop, but the IO thread will continue to copy:

mysql> show slave status\G
*************************** 1. row ***************************
               Slave_IO_State: Waiting for master to send event
                  Master_Host: 10.30.21.11
                  Master_User: replica
                  Master_Port: 7500
                Connect_Retry: 60
              Master_Log_File: mysql-bin.000011
          Read_Master_Log_Pos: 810203081
               Relay_Log_File: relay-bin.000002
                Relay_Log_Pos: 5707357
        Relay_Master_Log_File: mysql-bin.000011
             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: 561467475
              Relay_Log_Space: 254443161
              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: 21117500
                  Master_UUID: 63f38fe7-9e3b-11e5-9554-02eeb2c1042f
             Master_Info_File: /data1/mysql10070/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: 542ef021-9a64-11e5-bc49-025d3d22c211:1341313-1368005
            Executed_Gtid_Set: 44226252-9e38-11e5-9540-02212401d46f:1,
542ef021-9a64-11e5-bc49-025d3d22c211:1-1348359,
63f38fe7-9e3b-11e5-9554-02eeb2c1042f:1
                Auto_Position: 1
1 row in set (0.00 sec)

Well, what data do you want to see yesterday morning? It's all in the B library~~~

Attachment: Frequently Asked Questions

When setting @@global.gtid_purged, you may encounter an error:

mysql> SET GLOBAL gtid_purged="8133046e-4282-11e6-848e-026ca51d284c:1-4920155";
ERROR 1840 (HY000): @@GLOBAL.GTID_PURGED can only be set when @@GLOBAL.GTID_EXECUTED is empty.

This is because the @@GLOBAL.GTID_EXECUTED of this MySQL is not empty, just execute the following reset master operation:

mysql> SET GLOBAL gtid_purged="8133046e-4282-11e6-848e-026ca51d284c:1-4920155";
ERROR 1840 (HY000): @@GLOBAL.GTID_PURGED can only be set when @@GLOBAL.GTID_EXECUTED is empty.
mysql> show master status;
+------------------+----------+--------------+------------------+-------------------------------------------+
| File             | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set                         |
+------------------+----------+--------------+------------------+-------------------------------------------+
| mysql-bin.000002 |      191 |              |                  | 3857c25c-2caa-11e6-b61b-021feddc3827:1-14 |
+------------------+----------+--------------+------------------+-------------------------------------------+
1 row in set (0.00 sec)

mysql> reset master;
Query OK, 0 rows affected (0.01 sec)

mysql> show master status;
+------------------+----------+--------------+------------------+-------------------+
| File             | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+------------------+----------+--------------+------------------+-------------------+
| mysql-bin.000001 |      151 |              |                  |                   |
+------------------+----------+--------------+------------------+-------------------+
1 row in set (0.00 sec)

mysql> SET GLOBAL gtid_purged="8133046e-4282-11e6-848e-026ca51d284c:1-4920155";
Query OK, 0 rows affected (0.00 sec)