CODEWITHSUNDEEP
redis
YuFeng Shen
YuFeng Shen

Reputation: 1565

Is there good way to support pop members from the Redis Sorted Set?

Is there good way to support pop members from the Redis Sorted Set just like the api LPOP of the List ?

What I figured out for poping message from the Redis Sorted Set is using ZRANGE +ZREM , however it is not thread security and need the distributed lock when multi threads accessing them at the same time from the different host.

Please kind suggesting if there is better way to pop the members from the Sorted Set?

Upvotes: 3

Views: 3694

Answers (2)

Marc Gravell
Marc Gravell

Reputation: 1064044

In Redis 5.0 or above, you can use [B]ZPOP{MIN|MAX} key [count] for this scenario.

The MIN version takes the item(s) with the lowest scores; MAX takes the item(s) with the highest scores. count defaults to 1, and the B prefix blocks until the data is available.

Upvotes: 5

for_stack
for_stack

Reputation: 23021

You can write a Lua script to do the job: wrap these two commands in a single Lua script. Redis ensures that the Lua script runs in an atomic way.

local key = KEYS[1]
local result = redis.call('ZRANGE', key, 0, 0)
local member = result[1]
if member then
    redis.call('ZREM', key, member)
    return member
else
    return nil
end

Upvotes: 4

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