Using 'incr' with spymemcached client

Question

I am trying set up a very basic hit rate monitor in memcached using the spymemcached-2.8.4 client however the value stored in memcached never actually seems to increment... Is this a bug or am I missing something?

public static void checkHitRate(String clientId) throws FatalException, ForbiddenException {
    MemcachedClient memcachedClient;
    try {
        memcachedClient = new MemcachedClient(new InetSocketAddress("localhost", 11211));

        Integer hitRate = (Integer) memcachedClient.get(clientId);

        if (hitRate == null) {
            memcachedClient.set(clientId, 1800, 1);
        } else if (hitRate > 500) {
            throw new ForbiddenException("Hit rate too high. Try again later");
        } else if (hitRate <= 500) { 
            memcachedClient.incr(clientId, 1);
        } 

    } catch (IOException e) {
        throw new FatalException("Could not read hit rate from Memcached.");
    }
}

I know its possible in memcached:

(TELENT output)

set clientId_1 0 200 1
1
STORED
incr clientId_1 1
2
get clientId_1
VALUE clientId_1 0 1
2
END

Answer 1

For incr/decr memcached server considers stored values as string representation of integer,

Adding an item like

    memcachedClient.set(clientId, 1800, 1);

adds value as an integer that's why memcached is unable to increment it.

Use

    memcachedClient.set(clientId, 1800, "1");

instead. It will work as you need.