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Read lock all tables across all databases and make all other MemSQL connections block when they try to modify these tables.
FLUSH TABLES WITH READ LOCK
FLUSH TABLESwill lock and then flush all remaining write transactions in the current database to disk.
- You need to
UNLOCK TABLESbefore you can modify or write to tables locked by this command in the current MemSQL database. Running
FLUSH TABLES..will make the cluster available for writes. Running
FLUSH TABLES WITH READ LOCK, specifically, will also unblock any writes that were initiated after
FLUSH TABLES WITH READ LOCKwas submitted. The
UNLOCK TABLESquery must be run in the same connection as the
FLUSH TABLESquery 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 ).
memsql> FLUSH TABLES WITH READ LOCK; Query OK, 0 rows affected (0.00 sec)