Available since: 2.9.50
Time complexity: O(1)
CLIENT PAUSE is a connections control command able to suspend all the Redis clients for the specified amount of time (in milliseconds).
The command performs the following actions:
CLIENT PAUSEcommand execution is not paused by itself.
Client pause currently supports two modes:
ALL: This is the default mode. All client commands are blocked.
WRITE: Clients are only blocked if they attempt to execute a write command.
WRITE mode, some commands have special behavior:
EVALSHA: Will block client for all scripts.
PUBLISH: Will block client.
PFCOUNT: Will block client.
WAIT: Acknowledgments will be delayed, so this command will appear blocked.
This command is useful as it makes able to switch clients from a Redis instance to another one in a controlled way. For example during an instance upgrade the system administrator could do the following:
Since Redis 6.2, the recommended mode for client pause is
WRITE. This mode will stop all replication traffic, can be
aborted with the
CLIENT UNPAUSE command, and allows reconfiguring the old master without risking accepting writes after the
failover. This is also the mode used during cluster failover.
For versions before 6.2, it is possible to send
CLIENT PAUSE in a MULTI/EXEC block together with the
INFO replication command in order to get the current master offset at the time the clients are blocked. This way it is possible to wait for a specific offset in the replica side in order to make sure all the replication stream was processed.
Since Redis 3.2.10 / 4.0.0, this command also prevents keys to be evicted or expired during the time clients are paused. This way the dataset is guaranteed to be static not just from the point of view of clients not being able to write, but also from the point of view of internal operations.
Simple string reply: The command returns OK or an error if the timeout is invalid.
>= 3.2.0: Client pause prevents client pause and key eviction as well.
CLIENT PAUSE WRITEmode added along with the