add command in Memcached is used when you want to store a key-value pair, but only if the server doesn't already hold data for this key. This can be particularly useful in scenarios where you want to avoid overwriting existing data.
Here is an example of how to use the
add function using the
pymemcache library in Python:
In this example, we're connecting to a Memcached server running on
localhost and default port
11211. We then try to add a new key-value pair ('my_key', 'my_value'). If 'my_key' doesn't already exist, it will be added, and the method will return
If we try to add the same key again, the operation will fail:
addmethod is designed to avoid overwriting existing keys. Thus, ensure your application logic takes into account that keys should be unique.
Falsewhen it fails to add a key (because it's already there), make sure your code handles such cases appropriately.
addwill always succeed: If the
False, it means the key already exists. Your code should handle this scenario correctly and not assume that the
addoperation will always succeed.
1. What's the difference between 'set' and 'add' in Memcached?
The 'set' command will always store the value, regardless of whether the key already exists or not. On the other hand, 'add' will only store the value if the key does not exist.
2. What happens if I try to add a key that already exists?
If you try to add a key that already exists using the
add method, the operation will simply fail and return