Returns the active shard channels.
PUBSUB
SHARDCHANNELS
[pattern]
Lists the currently active shard channels.
An active shard channel is a Pub/Sub shard channel with one or more subscribers.
If no 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.
O(N) where N is the number of active shard channels, and assuming constant time pattern matching (relatively short shard channels).
@pubsub @slow
> PUBSUB SHARDCHANNELS
1) "orders"
> PUBSUB SHARDCHANNELS o*
1) "orders"
PSUBSCRIBE, PUBLISH, PUBSUB, PUBSUB CHANNELS, PUBSUB HELP, PUBSUB NUMPAT, PUBSUB NUMSUB, PUBSUB SHARDNUMSUB, PUNSUBSCRIBE, SPUBLISH, SSUBSCRIBE, SUBSCRIBE, SUNSUBSCRIBE, UNSUBSCRIBE.