Retrieve a list of all keys stored in Redis (Ruby)

Question

Is there a function in the redis-rb gem that returns a list of all the keys stored in the DB? My end goal is to iterate over all my key/value pairs and do perform some action on them.

Solution 1

Sure, the redis-rb exposes all of the Redis commands and represents them as methods on your client object.

redis.keys('*')

Solution 2

If you have any substantial amount of records in your db, kernel will kill your redis.keys because it will be taking too much RAM.

What you want is extracting keys in batches. redis-rb has a wonderful method for this (not present in redis itself):

    redis.scan_each(match: 'user:*') do |resume_key_name|
        resume_key_name #=> "user:12"
    end

If you want all the keys, just don't use the match option.

Solution 3

redis.keys this will return the result in array form.

more info : http://www.rubydoc.info/github/ezmobius/redis-rb/Redis

Comments

[Abe Voelker]

This was extremely slow for me; it took like 15 seconds to return on a Redis database with only 5.6K keys.

[Fangxing]

@AbeVoelker You can use redis with pipelined, which will be faster

[Siwei]

see @Alex answer. simple and straightforward

[Evgenia Karunus]

@SiweiShen申思维, his answer will fail for too many keys. But it is nice for a couple hundred.

[littleDucky]

@SiweiShen申思维 , using .keys is discouraged because of blocking issues and performance.

[littleDucky]

.keys will cause blocking and performance issues. .scan or .scan_each should be used instead. stackoverflow.com/questions/22143659/…

[littleDucky]

stackoverflow.com/questions/22143659/…