Redis ZPOP的实现

Question

I'm searching for Redis ZPOP implementation for popping ZSET element atomically, the most common answer is like:

WATCH zset
element = ZRANGE zset 0 0
MULTI
    ZREM zset element
EXEC

I wonder if the following implementation can do the same job, which seems simpler? Or does it has bugs or performance problems?

MULTI
    element = ZRANGE zset 0 0
    ZREM zset element
EXEC

Answer 1

The call to ZRANGE inside the MULTI block will only be returned after the EXEC, so the 2nd version will not work as expected.

For your information, as of Redis v5, the commands ZPOPMIN and ZPOPMAX have been added.