What is the safest way to remove more than 2KK keys from Redis?

Question

PHP

Hello! Tell me, it's very necessary.
Let's say there is a database, you need to delete data by prefix (standard).

$keys = $this->redis->keys($this->_prefix . '*');
$this->redis->del($keys);

For small volumes - works well. But what about a large amount of data? Here the KEYS method is not suitable either. has O(N) complexity. Thanks for your options!

Answer 1

Since 3.0, it is recommended to use tags for this. Keys hash tags
In your case - they should be used instead of a prefix.
Key names should look something like this - {user1000}.following, where user1000 is the tag.
KEYS by tag will not check all keys in the database, i.e. the complexity will be orders of magnitude less than O(N)
And as a bonus - it will be compatible with redis-cluster

Answer 2

redis-cli KEYS "prefix:*" | xargs redis-cli DEL, For example?

Answer 3

eval "for _,k in ipairs(redis.call('keys','key:*:pattern')) do redis.call('del',k) end" 0

Replace key:*:patternwith your template and feed redis-cli.