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Diffstat (limited to 'iredis/data/commands/client-pause.md')
| -rw-r--r-- | iredis/data/commands/client-pause.md | 38 |
1 files changed, 38 insertions, 0 deletions
diff --git a/iredis/data/commands/client-pause.md b/iredis/data/commands/client-pause.md new file mode 100644 index 0000000..bdbdda0 --- /dev/null +++ b/iredis/data/commands/client-pause.md @@ -0,0 +1,38 @@ +`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: + +- It stops processing all the pending commands from normal and pub/sub clients. + However interactions with replicas will continue normally. +- However it returns OK to the caller ASAP, so the `CLIENT PAUSE` command + execution is not paused by itself. +- When the specified amount of time has elapsed, all the clients are unblocked: + this will trigger the processing of all the commands accumulated in the query + buffer of every client during the pause. + +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: + +- Pause the clients using `CLIENT PAUSE` +- Wait a few seconds to make sure the replicas processed the latest replication + stream from the master. +- Turn one of the replicas into a master. +- Reconfigure clients to connect with the new master. + +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. + +@return + +@simple-string-reply: The command returns OK or an error if the timeout is +invalid. |