Completes all in-progress DDL and DML transactions (writes) that are running against any databases in the cluster. Then, for each database in the cluster, makes every table available for reads, but not writes.
FLUSH TABLES WITH READ [ LOCK | ONLY ]
FLUSH TABLES WITH READ LOCKblocks any DDL and DML transactions (writes) that are initiated following the execution of the command.
FLUSH TABLES WITH READ ONLYfails any DDL and DML transactions (writes) that are initiated following the execution of the command.
If you have any pipelines currently running, it is recommended to stop them before executing the
FLUSH TABLES..command. Do not create/drop/start/stop pipelines before executing the UNLOCK TABLES command.
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.
This command must be run on the master aggregator node or a child aggregator node (see Node Requirements for MemSQL Commands ).
FLUSH TABLES WITH READ LOCK;