Retrieving/Listing all key/value pairs in a Redis db

Question

I'm using an ORM called Ohm in Ruby that works on top of Redis and am curious to find out how the data is actually stored. I was wondering if there is way to list all the keys/values in a Redis db.

Any lead will go a long way in helping me out (I'm basically stuck atm). Thanks in advance!

Update:
A note for others trying this out using redis-cli, use this:

$ redis-cli keys
* (press * followed by Ctrl-D)
... (prints a list of keys and exits)
$

Thanks @antirez and @hellvinz!

Solution 1

You can explore the Redis dataset using the redis-cli tool included in the Redis distribution.

Just start the tool without arguments, then type commands to explore the dataset.

For instance KEYS will list all the keys matching a glob-style pattern, for instance with: keys * you'll see all the keys available.

Then you can use the TYPE command to check what type is a given key, if it's a list you can retrieve the elements inside using LRANGE mykey 0 -1. If it is a Set you'll use instead SMEMBERS mykey and so forth. Check the Redis documentation for a list of all the available commands and how they work.

Solution 2

From the command line, you can also use the dump command, available since Redis 2.6.0

redis-cli KEYS \* | xargs -n 1 redis-cli dump

(note that this also works with the get command for earlier versions if you don't mind)

UPDATE (V2.8 or greater): SCAN is a superior alternative to KEYS, in the sense that it does not block the server nor does it consume significant resources. Prefer using it.

Solution 3

Just adding a practical ruby example to the antirez response (I won't dare compete with him)

irb(main):002:0> require 'rubygems'
=> true
irb(main):003:0> require 'redis'
=> true
irb(main):004:0> r = Redis.new
=> #<Redis:0x8605b64 @sock=#<TCPSocket:0x8605ab0>, @timeout=5, @port=6379, @db=0, @host="127.0.0.1">
irb(main):005:0> r.keys('*')

Solution 4

I ended up here because I was looking for how to backup all key/values in redis. If this applies to you, this command might help:

redis-cli bgsave

View more solutions

Comments

[Theymiss Developer]

Or use the GET command if you have an older Redis version. And if you have a lot of keys then you can parallelise the xargs command with -P. Example: redis-cli KEYS * |xargs -n 1 -P8 redis-cli get

[Sam Critchley]

Yours is the first answer I came across which informed me I had to escape the * to \* on the command line.... must have wasted about 20 minutes with "wrong number of arguments" for a redis command which works perfectly well in the client until I found this. Thanks.

[tokland]

This will work, but having to run a redis-cli for each key, it will be extremely slow.

[mirzu]

Site linked in the article has an invalid cert, but the command is exactly what I was looking for.

[Fissure]

Link is now broken:( 404 Not Found