Memcached Add Operation in C# (Detailed Guide w/ Code Examples)

Use Case(s)

Using the Add method with Memcached in C# is commonly done when you want to store data key-value pairs in the Memcached server where the key does not already exist. It is useful in caching scenarios where data is expensive to fetch or compute and can be reused across multiple requests.

Code Examples

To interact with Memcached from a .NET application, a popular library is EnyimMemcached. Here's an example showing how to use the Add operation:

using Enyim.Caching;

MemcachedClient client = new MemcachedClient();

bool success = client.Add("key", "value");

In this code, we create a MemcachedClient object, then call Add, passing in the key ("key") and value ("value"). The Add method returns a boolean indicating whether the operation was successful. The operation will only succeed if the key does not already exist in the cache.

Best Practices

1. Always check the response of the Add method. It returns a boolean which indicates whether the operation was successful or not. This helps in handling exceptions and errors.
2. Data stored in Memcached should not be seen as persistent, it may be evicted anytime when memory becomes limited.

Common Mistakes

One common mistake is to assume that the Add operation updates the value if the key already exists. That's not the case - Add only sets the value if the key does not exist. If you want to set a value regardless of whether the key exists, use the Set method instead.

FAQs

Q: What happens if I try to add a key that already exists?

A: If you try to add a key that already exists, the Add operation will return false and the existing value for that key in the cache will not be changed.

Q: What types of values can I store with Memcached?

A: You can store any serializable data types such as string, integer, boolean, or even complex objects. However, keep in mind that Memcached is not a database, so it's best suited to small pieces of data, like the results of a database query.