Available since: 4.0.0
Time complexity: O(1) for each key removed regardless of its size. Then the command does O(N) work in a different thread in order to reclaim memory, where N is the number of allocations the deleted objects where composed of.
This command is very similar to
DEL: it removes the specified keys.
DEL a key is ignored if it does not exist. However the command
performs the actual memory reclaiming in a different thread, so it is not
DEL is. This is where the command name comes from: the
command just unlinks the keys from the keyspace. The actual removal
will happen later asynchronously.
Integer reply: The number of keys that were unlinked.