predis: ZADD with NX keeps throwing error 'Predis\ServerException'

Question

I am having an issue when I try to add "NX" to the zadd command on predis. The redis docs say that ZADD should support NX, but no matter how I set up the predis command, I can not get it working. Does anyone have any experience with this issue?

Here are the commands I have tried:

$redis->zadd($key, "NX", 1, $id);

$redis->executeRaw([ 'ZADD', $key, "NX", 1, $id ]);

Here is the error that keeps getting thrown:

ERROR: exception 'Predis\ServerException' with message 'ERR syntax error'

Looking at the redis-cli monitor, I see the command execute when using the ZADD command, but the executeRaw command does nothing.

Any help would be greatly appreciated!

Answer 1

ZADD's NX switch was added only to the recent version of Redis, see here: https://groups.google.com/forum/#!topic/redis-db/4Y6OqK8gEyk

In all likelihood you aren't running the recent version - use INFO to find out your server's version.