Redis: To set timeout for a key value pair in Set

by

Unfortunately, no. Redis’ “containers” (i.e. lists, hashes, sets and sorted sets) do not support per-member expiry, although this functionality has been requested many times in the past.

You can, however, implement your own logic to achieve that result. There are several possible approaches to address this – here’s one example. Instead of using a set, use a sorted set (ZSET) and set each member’s score to its expiry time using epoch values. This type of workflow could be implemented using a Lua script for example. To add members use something like:

redis.call('zadd', KEYS[1], os.time()+ARGV[1], ARGV[2])

and EVAL it using ‘1 a 60 1’ and ‘1 a 120 2’ as arguments, per your example. To actually “expire” the items from the set, you’ll need to delete them once their time has passed. You can do that either by implementing a periodical process that scans your list or upon accessing it. For example, the following Lua can be used to expire members:

redis.call('zremrangebyscore', KEYS[1], '-inf', os.time())

and EVAL it using ‘1 a’ as arguments per your example.

EDIT: How to achieve the above using Python

import time
import redis

def add(r, key, ttl, member):
    r.zadd(key, member, int(time.time()+ttl))

def expire(r, key):
    r.zremrangebyscore(key, '-inf', int(time.time()))

...

r = redis.Redis()
add(r, 'a', 1, 60)
add(r, 'a', 2, 120)

# periodically or before every operation do
expire(r, 'a')

More Related Contents:

  1. How to atomically delete keys matching a pattern using Redis
  2. What’s the Point of Multiple Redis Databases?
  3. MISCONF Redis is configured to save RDB snapshots
  4. How do I delete everything in Redis?
  5. WSL Redis encountered System has not been booted with systemd as init system (PID 1). Can’t operate [closed]
  6. Redis key naming conventions? [closed]
  7. how to get keys which does not match a particular pattern in redis?
  8. Redis command to get all available keys?
  9. Is the UNLINK command always better than DEL command?
  10. Why is data getting stored with weird keys in Redis when using Jedis with Spring Data?
  11. How can I get all of the sets in redis?
  12. Memcached vs. Redis? [closed]
  13. Redis is single-threaded, then how does it do concurrent I/O?
  14. Autocomplete with java , Redis, Elastic Search , Mongo
  15. How to implement server push in Flask framework?
  16. ServiceStack.Net Redis: Storing Related Objects vs. Related Object Ids
  17. Can I connect directly to a Redis server from JavaScript running in a browser?
  18. Error: Redis connection to 127.0.0.1:6379 failed – connect ECONNREFUSED 127.0.0.1:6379
  19. Redis + ActionController::Live threads not dying
  20. Can you connect to Amazon ElastiŠ”ache Redis outside of Amazon?
  21. Redis 10x more memory usage than data
  22. What is Express.js? [closed]
  23. How to “EXPIRE” the “HSET” child key in redis?
  24. What are the main differences between Redis Pub/Sub and Redis Stream?
  25. Maintaining an open Redis connection using BookSleeve
  26. How to store and retrieve a dictionary with redis
  27. I’m getting error “Class ‘Predis\Client’ not found” in Laravel 5.2
  28. About char b prefix in Python3.4.1 client connect to redis
  29. When to Redis? When to MongoDB? [closed]
  30. How can I use redis with Django?

Leave a Comment