swapdb not working as expected - bug or am i missing something?

[moontails]

heya team! just started using redis and love the simplicity of this library! thank you all for that.

i am running into an error when trying to use swapdb.

code -

public class RedisAdmin {

private static final int PRIMARY_DB_INDEX = 0;
private static final int TMP_DB_INDEX = 1;
private final JedisPool pool = new JedisPool(new JedisPoolConfig(), "localhost", 6379);


public void swapAndSetPrimaryDb() {
        Jedis redis = null;
        try {
            redis = pool.getResource();
            redis.swapDB(PRIMARY_DB_INDEX, TMP_DB_INDEX);
            redis.select(PRIMARY_DB_INDEX);
        } finally {
            if (redis != null) {
                redis.close();
            }
        }
    }
}

error -

redis.clients.jedis.exceptions.JedisDataException: ERR unknown command 'SWAPDB'
	at redis.clients.jedis.Protocol.processError(Protocol.java:135)
	at redis.clients.jedis.Protocol.process(Protocol.java:169)
	at redis.clients.jedis.Protocol.read(Protocol.java:223)
	at redis.clients.jedis.Connection.readProtocolWithCheckingBroken(Connection.java:352)
	at redis.clients.jedis.Connection.getStatusCodeReply(Connection.java:270)
	at redis.clients.jedis.BinaryJedis.swapDB(BinaryJedis.java:797)

alternatively i also see this failing in redis-cli

127.0.0.1:6379> swapdb 1 0
(error) ERR unknown command 'swapdb'
127.0.0.1:6379> SWAPDB 0 1
(error) ERR unknown command 'SWAPDB'
127.0.0.1:6379>

can you all help me understand if i am missing something?

[sazzad16]

What is the version of Redis? SWAPDB is available since Redis 4.0.0.

[moontails]

thank you @sazzad16 , i was just looking at my redis installation and saw it wasnt on 4.0.0. will update and try again!