Available since: 7.0.0
Time complexity: O(N) where N is the number of active shard channels, and assuming constant time pattern matching (relatively short channels).
Lists the currently active shard channels.
An active shard channel is a Pub/Sub shard channel with one or more subscribers.
pattern is specified, all the channels are listed, otherwise if pattern is specified only channels matching the specified glob-style pattern are listed.
The information returned about the active shard channels are at the shard level and not at the cluster level.
Array reply: a list of active channels, optionally matching the specified pattern.
> PUBSUB SHARDCHANNELS 1) "orders" PUBSUB SHARDCHANNELS o* 1) "orders"