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FLUSH TABLES

FLUSH TABLES 语句用于提供 MySQL 兼容性,但在 TiDB 中并无有效用途。

语法图

FlushStmt
FLUSH NoWriteToBinLogAliasOpt FlushOption
NoWriteToBinLogAliasOpt
NO_WRITE_TO_BINLOG LOCAL
FlushOption
PRIVILEGES STATUS TIDB PLUGINS PluginNameList HOSTS LogTypeOpt LOGS TableOrTables TableNameListOpt WithReadLockOpt
LogTypeOpt
BINARY ENGINE ERROR GENERAL SLOW
TableOrTables
TABLE TABLES
TableNameListOpt
TableNameList
WithReadLockOpt
WITH READ LOCK

示例

FLUSH TABLES;
Query OK, 0 rows affected (0.00 sec)
FLUSH TABLES WITH READ LOCK;
ERROR 1105 (HY000): FLUSH TABLES WITH READ LOCK is not supported.  Please use @@tidb_snapshot

MySQL 兼容性

  • TiDB 没有 MySQL 中的表缓存这一概念。所以,FLUSH TABLES 因 MySQL 兼容性会在 TiDB 中解析出但会被忽略掉。
  • 因为 TiDB 目前不支持锁表,所以FLUSH TABLES WITH READ LOCK 语句会产生错误。建议使用 Historical reads 来实现锁表。

另请参阅