Backup Lock

功能描述

Backup lock

A new type of backup lock permits DML during an online backup while preventing operations that could result in an inconsistent snapshot. The new backup lock is supported by LOCK INSTANCE FOR BACKUP and UNLOCK INSTANCE syntax. The BACKUP_ADMIN privilege is required to use these statements.

通过 Backup Lock 的机制，支持在线备份期间执行DML，防止可能导致快照不一致的操作。

LOCK INSTANCE FOR BACKUP 和 UNLOCK INSTANCE语法支持新的备份锁 。需要授予用户 BACKUP_ADMIN权限。

功能学习

Syntax

LOCK INSTANCE FOR BACKUP;

UNLOCK INSTANCE;

LOCK INSTANCE FOR BACKUP获取实例级别的备份锁，该锁在联机备份期间允许DML，同时防止可能导致快照不一致的操作。

权限

BACKUP_ADMIN：启用LOCK INSTANCE FOR BACKUP语句的执行并访问Performance Schema log_status表。

注意：此外BACKUP_ADMIN，还需要表SELECT上的 特权 log_status才能对其进行访问。

当执行从早期版本到MySQL 8.0的就地升级时， 该BACKUP_ADMIN特权将自动授予具有该RELOAD特权的用户 。

create user backup_user@'localhost' identified by 'Zyadmin@123';
grant backup_admin on *.* to backup_user@'localhost';
show grants for backup_user@'localhost';

+--------------------------------------------------------+
| Grants for backup_user@localhost                       |
+--------------------------------------------------------+
| GRANT USAGE ON *.* TO `backup_user`@`localhost`        |
| GRANT BACKUP_ADMIN ON *.* TO `backup_user`@`localhost` |
+--------------------------------------------------------+

# 为了测试给backup_user 用户更多的权限
grant all on *.* to backup_user@'localhost';

操作实践

# 会话1
mysql> use booboo;
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A

Database changed
mysql> show tables;
+------------------+
| Tables_in_booboo |
+------------------+
| t1_d             |
| test001          |
+------------------+
2 rows in set (0.00 sec)

mysql> LOCK INSTANCE FOR BACKUP;
Query OK, 0 rows affected (0.00 sec)

# 会话2
mysql> create table tset002 (id int primary key);

# 会话1
mysql> UNLOCK INSTANCE;

# 会话2
mysql> create table tset002 (id int primary key);
Query OK, 0 rows affected (1 min 52.97 sec)
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