How do I delete everything in Redis?

Question

I want to delete all keys. I want everything wiped out and give me a blank database.

Is there a way to do this in Redis client?

Answer 1

You can use FLUSHDB

e.g

List databases:

127.0.0.1:6379> info keyspace
# Keyspace

List keys

127.0.0.1:6379> keys *
(empty list or set)

Add one value to a key

127.0.0.1:6379> lpush key1 1
(integer) 1
127.0.0.1:6379> keys *
1) "key1"
127.0.0.1:6379> info keyspace
# Keyspace
db0:keys=1,expires=0,avg_ttl=0

Create other key with two values

127.0.0.1:6379> lpush key2 1
(integer) 1
127.0.0.1:6379> lpush key2 2
(integer) 2
127.0.0.1:6379> keys *
1) "key1"
2) "key2"
127.0.0.1:6379> info keyspace
# Keyspace
db0:keys=2,expires=0,avg_ttl=0

List all values in key2

127.0.0.1:6379> lrange key2 0 -1
1) "2"
2) "1"

Do FLUSHDB

127.0.0.1:6379> flushdb
OK

List keys and databases

127.0.0.1:6379> keys *
(empty list or set)
127.0.0.1:6379> info keyspace
# Keyspace

Answer 2

One more option from my side:

In our production and pre-production databases there are thousands of keys. Time to time we need to delete some keys (by some mask), modify by some criteria etc. Of course, there is no way to do it manually from CLI, especially having sharding (512 logical dbs in each physical).

For this purpose I write java client tool that does all this work. In case of keys deletion the utility can be very simple, only one class there:

public class DataCleaner {

    public static void main(String args[]) {
        String keyPattern = args[0];
        String host = args[1];
        int port = Integer.valueOf(args[2]);
        int dbIndex = Integer.valueOf(args[3]);

        Jedis jedis = new Jedis(host, port);

        int deletedKeysNumber = 0;
        if(dbIndex >= 0){
            deletedKeysNumber += deleteDataFromDB(jedis, keyPattern, dbIndex);
        } else {
            int dbSize = Integer.valueOf(jedis.configGet("databases").get(1));
            for(int i = 0; i < dbSize; i++){
                deletedKeysNumber += deleteDataFromDB(jedis, keyPattern, i);
            }
        }

        if(deletedKeysNumber == 0) {
            System.out.println("There is no keys with key pattern: " + keyPattern + " was found in database with host: " + host);
        }
    }

    private static int deleteDataFromDB(Jedis jedis, String keyPattern, int dbIndex) {
        jedis.select(dbIndex);
        Set<String> keys = jedis.keys(keyPattern);
        for(String key : keys){
            jedis.del(key);
            System.out.println("The key: " + key + " has been deleted from database index: " + dbIndex);
        }

        return keys.size();
    }

}

Writing such kind of tools I find very easy and spend no more then 5-10 min.

Answer 3

There are different approaches. If you want to do this from remote, issue flushall to that instance, through command line tool redis-cli or whatever tools i.e. telnet, a programming language SDK. Or just log in that server, kill the process, delete its dump.rdb file and appendonly.aof(backup them before deletion).

Answer 4

If you're using the redis-rb gem then you can simply call:

your_redis_client.flushdb