Redis xlen 命令

XLEN key

Returns the number of entries inside a stream. If the specified key does not
exist the command returns zero, as if the stream was empty.
However note that unlike other Redis types, zero-length streams are
possible, so you should call TYPE or EXISTS in order to check if
a key exists or not.

Streams are not auto-deleted once they have no entries inside (for instance
after an XDEL call), because the stream may have consumer groups
associated with it.


Integer reply: the number of entries of the stream at key.


redis>  XADD mystream * item 1


redis>  XADD mystream * item 2


redis>  XADD mystream * item 3


redis>  XLEN mystream

(integer) 3