Read lock all tables across all databases and make all other MemSQL connections block when they try to modify these tables.

Syntax

FLUSH TABLES WITH READ LOCK

Remarks

• FLUSH TABLES will lock and then flush all remaining write transactions in the current database to disk.
• You need to UNLOCK TABLES before you can modify or write to tables locked by this command in the current MemSQL database. Running UNLOCK TABLES after FLUSH TABLES.. will make the cluster available for writes. Running UNLOCK TABLES after FLUSH TABLES WITH READ LOCK, specifically, will also unblock any writes that were initiated after FLUSH TABLES WITH READ LOCK was submitted. The UNLOCK TABLES query must be run in the same connection as the FLUSH TABLES query for this feature to take effect.
• This command must be run on the master aggregator node or a child aggregator node (see Node Requirements for MemSQL Commands ).

Example

memsql> FLUSH TABLES WITH READ LOCK;
Query OK, 0 rows affected (0.00 sec)

Related Topics

• UNLOCK TABLES

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