MySQL延迟从库
延迟从库
控制从库的SQL线程执行速度，二进制日志照常去主库取，但是存放到中继日志之后就延迟执行，如果主库被误操作，这时候对中继日志进行处理，就不用根据全备二进制日志恢复，节省了大部分的时间
设置延迟同步
假设这时候2台数据库正在主从，现在设置延迟同步
mysql> STOP SLAVE; -- 先停止同步
mysql> CHANGE MASTER TO MASTER_DELAY = 300; -- 设置延迟300s，一般设置3-6个小时，单位是s
mysql> START SLAVE; -- 启动同步
mysql> SHOW SLAVE STATUS \G; -- 查看状态
*************************** 1. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: 192.168.253.129
Master_User: repl
Master_Port: 3306
Connect_Retry: 10
Master_Log_File: mysql-bin.000003
Read_Master_Log_Pos: 316
Relay_Log_File: localhost-relay-bin.000002
Relay_Log_Pos: 320
Relay_Master_Log_File: mysql-bin.000003
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
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: 316
Relay_Log_Space: 531
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: 0
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: 129
Master_UUID: c5792b98-1be7-11e9-86e3-000c2927db4e
Master_Info_File: /data/master.info
SQL_Delay: 300 --延迟的时间
SQL_Remaining_Delay: NULL
Slave_SQL_Running_State: Slave has read all relay log; waiting for more updates
Master_Retry_Count: 86400
Master_Bind:
Last_IO_Error_Timestamp:
Last_SQL_Error_Timestamp:
Master_SSL_Crl:
Master_SSL_Crlpath:
Retrieved_Gtid_Set:
Executed_Gtid_Set:
Auto_Position: 0
Replicate_Rewrite_DB:
Channel_Name:
Master_TLS_Version:
1 row in set (0.00 sec)
模拟故障
主库
mysql> use test1;
Database changed
mysql> create table t1(id int);
Query OK, 0 rows affected (0.02 sec)
mysql> create table t2(id int);
Query OK, 0 rows affected (0.01 sec)
mysql> create table t3(id int);
Query OK, 0 rows affected (0.02 sec)
mysql> create table t4(id int);
Query OK, 0 rows affected (0.01 sec)
mysql> create table t5(id int);
Query OK, 0 rows affected (0.02 sec)
现在模拟故障 删除表t3
mysql> drop table t3;
Query OK, 0 rows affected (0.01 sec)
假设这时候数据库还在跑，还有数据进来，再创建个表模拟一下
mysql> create table t6(id int);
Query OK, 0 rows affected (0.03 sec)
mysql> create table t7(id int);
Query OK, 0 rows affected (0.01 sec)
mysql> create table t8(id int);
Query OK, 0 rows affected (0.01 sec)
mysql> create table t9(id int);
Query OK, 0 rows affected (0.01 sec)
这时候管理员发现问题了，首先先把从库SQL线程停了，也可以都IO和SQL线程都停了
mysql> STOP SLAVE; -- 都停了
-- mysql> stop slave sql_thread; --停止SQL线程方法
通过中继日志relay-log.info获取起始点
[root@localhost data]# cat /data/relay-log.info
7
./localhost-relay-bin.000002
320
mysql-bin.000004
314
300
0
1
然后找误操作语句
mysql> SHOW RELAYLOG EVENTS IN 'localhost-relay-bin.000002';
+----------------------------+------+----------------+-----------+-------------+--------------------------------------------------------+
| Log_name | Pos | Event_type | Server_id | End_log_pos | Info |
+----------------------------+------+----------------+-----------+-------------+--------------------------------------------------------+
| localhost-relay-bin.000002 | 4 | Format_desc | 128 | 123 | Server ver: 5.7.24-log, Binlog ver: 4 |
| localhost-relay-bin.000002 | 123 | Previous_gtids | 128 | 154 | |
| localhost-relay-bin.000002 | 154 | Rotate | 129 | 0 | mysql-bin.000004;pos=314 |
| localhost-relay-bin.000002 | 201 | Format_desc | 129 | 0 | Server ver: 5.7.24-log, Binlog ver: 4 |
| localhost-relay-bin.000002 | 320 | Anonymous_Gtid | 129 | 379 | SET @@SESSION.GTID_NEXT= 'ANONYMOUS' |
| localhost-relay-bin.000002 | 385 | Query | 129 | 476 | create database test1 |
| localhost-relay-bin.000002 | 482 | Anonymous_Gtid | 129 | 541 | SET @@SESSION.GTID_NEXT= 'ANONYMOUS' |
| localhost-relay-bin.000002 | 547 | Query | 129 | 640 | use `test1`; create table t1(id int) |
| localhost-relay-bin.000002 | 646 | Anonymous_Gtid | 129 | 705 | SET @@SESSION.GTID_NEXT= 'ANONYMOUS' |
| localhost-relay-bin.000002 | 711 | Query | 129 | 804 | use `test1`; create table t2(id int) |
| localhost-relay-bin.000002 | 810 | Anonymous_Gtid | 129 | 869 | SET @@SESSION.GTID_NEXT= 'ANONYMOUS' |
| localhost-relay-bin.000002 | 875 | Query | 129 | 968 | use `test1`; create table t3(id int) |
| localhost-relay-bin.000002 | 974 | Anonymous_Gtid | 129 | 1033 | SET @@SESSION.GTID_NEXT= 'ANONYMOUS' |
| localhost-relay-bin.000002 | 1039 | Query | 129 | 1132 | use `test1`; create table t4(id int) |
| localhost-relay-bin.000002 | 1138 | Anonymous_Gtid | 129 | 1197 | SET @@SESSION.GTID_NEXT= 'ANONYMOUS' |
| localhost-relay-bin.000002 | 1203 | Query | 129 | 1296 | use `test1`; create table t5(id int) |
| localhost-relay-bin.000002 | 1302 | Anonymous_Gtid | 129 | 1361 | SET @@SESSION.GTID_NEXT= 'ANONYMOUS' |
| localhost-relay-bin.000002 | 1367 | Query | 129 | 1478 | use `test1`; DROP TABLE `t3` /* generated by server */ |
| localhost-relay-bin.000002 | 1484 | Anonymous_Gtid | 129 | 1543 | SET @@SESSION.GTID_NEXT= 'ANONYMOUS' |
| localhost-relay-bin.000002 | 1549 | Query | 129 | 1642 | use `test1`; create table t6(id int) |
| localhost-relay-bin.000002 | 1648 | Anonymous_Gtid | 129 | 1707 | SET @@SESSION.GTID_NEXT= 'ANONYMOUS' |
| localhost-relay-bin.000002 | 1713 | Query | 129 | 1806 | use `test1`; create table t7(id int) |
| localhost-relay-bin.000002 | 1812 | Anonymous_Gtid | 129 | 1871 | SET @@SESSION.GTID_NEXT= 'ANONYMOUS' |
| localhost-relay-bin.000002 | 1877 | Query | 129 | 1970 | use `test1`; create table t8(id int) |
| localhost-relay-bin.000002 | 1976 | Anonymous_Gtid | 129 | 2035 | SET @@SESSION.GTID_NEXT= 'ANONYMOUS' |
| localhost-relay-bin.000002 | 2041 | Query | 129 | 2134 | use `test1`; create table t9(id int) |
+----------------------------+------+----------------+-----------+-------------+--------------------------------------------------------+
26 rows in set (0.01 sec)
通过观察可以看到
所以结束的位置是localhost-relay-bin.000002 的1302,
这时候可以利用mysqlbinlog查看中继日志具体信息
[root@localhost data]# mysqlbinlog --start-position=320 --stop-position=1302 /data/localhost-relay-bin.000002
/*!50530 SET @@SESSION.PSEUDO_SLAVE_MODE=1*/;
/*!50003 SET @OLD_COMPLETION_TYPE=@@COMPLETION_TYPE,COMPLETION_TYPE=0*/;
DELIMITER /*!*/;
# at 4
#190216 8:16:31 server id 128 end_log_pos 123 CRC32 0xc0c00146 Start: binlog v 4, server v 5.7.24-log created 190216 8:16:31
# This Format_description_event appears in a relay log and was generated by the slave thread.
# at 201
#190119 12:26:59 server id 129 end_log_pos 0 CRC32 0x562f760f Start: binlog v 4, server v 5.7.24-log created 190119 12:26:59
BINLOG '
411DXA+BAAAAdwAAAAAAAAAAAAQANS43LjI0LWxvZwAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
AAAAAAAAAAAAAAAAAAAAAAAAEzgNAAgAEgAEBAQEEgAAXwAEGggAAAAICAgCAAAACgoKKioAEjQA
AQ92L1Y=
'/*!*/;
# at 320
#190119 12:33:00 server id 129 end_log_pos 379 CRC32 0x0392727e Anonymous_GTID last_committed=1 sequence_number=2 rbr_only=no
SET @@SESSION.GTID_NEXT= 'ANONYMOUS'/*!*/;
# at 385
#190119 12:33:00 server id 129 end_log_pos 476 CRC32 0x2aceb78a Query thread_id=9 exec_time=0 error_code=0
SET TIMESTAMP=1547919180/*!*/;
SET @@session.pseudo_thread_id=9/*!*/;
SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=0, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
SET @@session.sql_mode=1436549152/*!*/;
SET @@session.auto_increment_increment=1, @@session.auto_increment_offset=1/*!*/;
/*!\C utf8 *//*!*/;
SET @@session.character_set_client=33,@@session.collation_connection=33,@@session.collation_server=33/*!*/;
SET @@session.lc_time_names=0/*!*/;
SET @@session.collation_database=DEFAULT/*!*/;
create database test1
/*!*/;
# at 482
#190119 12:33:40 server id 129 end_log_pos 541 CRC32 0x376c0c9f Anonymous_GTID last_committed=2 sequence_number=3 rbr_only=no
SET @@SESSION.GTID_NEXT= 'ANONYMOUS'/*!*/;
# at 547
#190119 12:33:40 server id 129 end_log_pos 640 CRC32 0xd0f3a51e Query thread_id=9 exec_time=0 error_code=0
use `test1`/*!*/;
SET TIMESTAMP=1547919220/*!*/;
create table t1(id int)
/*!*/;
# at 646
#190119 12:33:45 server id 129 end_log_pos 705 CRC32 0x828399a7 Anonymous_GTID last_committed=3 sequence_number=4 rbr_only=no
SET @@SESSION.GTID_NEXT= 'ANONYMOUS'/*!*/;
# at 711
#190119 12:33:45 server id 129 end_log_pos 804 CRC32 0x2de1e82e Query thread_id=9 exec_time=0 error_code=0
SET TIMESTAMP=1547919225/*!*/;
create table t2(id int)
/*!*/;
# at 810
#190119 12:33:49 server id 129 end_log_pos 869 CRC32 0x02d76ff2 Anonymous_GTID last_committed=4 sequence_number=5 rbr_only=no
SET @@SESSION.GTID_NEXT= 'ANONYMOUS'/*!*/;
# at 875
#190119 12:33:49 server id 129 end_log_pos 968 CRC32 0x0dfae9a4 Query thread_id=9 exec_time=0 error_code=0
SET TIMESTAMP=1547919229/*!*/;
create table t3(id int)
/*!*/;
# at 974
#190119 12:33:52 server id 129 end_log_pos 1033 CRC32 0xb02cbb37 Anonymous_GTID last_committed=5 sequence_number=6 rbr_only=no
SET @@SESSION.GTID_NEXT= 'ANONYMOUS'/*!*/;
# at 1039
#190119 12:33:52 server id 129 end_log_pos 1132 CRC32 0x769459c6 Query thread_id=9 exec_time=0 error_code=0
SET TIMESTAMP=1547919232/*!*/;
create table t4(id int)
/*!*/;
# at 1138
#190119 12:33:56 server id 129 end_log_pos 1197 CRC32 0x8d300a80 Anonymous_GTID last_committed=6 sequence_number=7 rbr_only=no
SET @@SESSION.GTID_NEXT= 'ANONYMOUS'/*!*/;
# at 1203
#190119 12:33:56 server id 129 end_log_pos 1296 CRC32 0xc013d53d Query thread_id=9 exec_time=0 error_code=0
SET TIMESTAMP=1547919236/*!*/;
create table t5(id int)
/*!*/;
SET @@SESSION.GTID_NEXT= 'AUTOMATIC' /* added by mysqlbinlog */ /*!*/;
DELIMITER ;
# End of log file
/*!50003 SET COMPLETION_TYPE=@OLD_COMPLETION_TYPE*/;
/*!50530 SET @@SESSION.PSEUDO_SLAVE_MODE=0*/;
确认没问题的时候可以导出这些sql语句
mysqlbinlog --start-position=320 --stop-position=1302 /data/localhost-relay-bin.000002 > /tmp/inc1.sql
先把故障之前的数据还原
mysql> SET sql_log_bin=0;
mysql> source /tmp/inc1.sql;
跳过故障的语句进行还原
mysqlbinlog --start-position=1484 /data/localhost-relay-bin.000002 > /tmp/inc2.sql
还原故障之后的数据
mysql> SET sql_log_bin=0;
mysql> source /tmp/inc2.sql;
可以看到恢复了表3并且补齐了误操作之后的数据。
这时候如果从库要替代主库，需要清空之前的信息
mysql> STOP SLAVE;
mysql> RESET SLAVE ALL;