gets command in Memcached is typically used when you want to fetch data from the cache and compare-and-swap (CAS) it. This is particularly useful in cases where multiple clients might try to update the same value concurrently, creating a potential for race conditions.
Let's start by setting up a connection to our Memcached server:
Dalli is a high-performance pure Ruby client for Memcached.
Here's a simple example of using
gets and CAS operation:
In this code, we are storing a value ('bar') against a key ('foo'). We then use
gets to fetch both the value and a unique CAS id. The
cas method will only change the value if the CAS id matches the latest one in the cache, ensuring safe concurrent updates.
getsmethod when you need to perform compare-and-swap operations.
casoperation appropriately in your code as it indicates that another client has updated the value after your
getsand using it as a replacement for
getscommand is specifically for use with CAS operations.
1. When should I use
gets instead of
You should use
gets when you need to perform a compare-and-swap operation, i.e., you want to change the value based on its current value and want to avoid race conditions.
2. What if the
cas operation fails?
cas operation fails, that means another client has updated the value after your
gets call. You should handle this in your code, either by retrying the operation or taking some other appropriate action.