What the heck is Memcached?
You have most certainly seen it – Memcached, and though “What is that? And why the heck is it better than Redis?”
The short explaination – well, it will take a couple of minutes.
Memcached is an open source technology, based on distributed memory objects containing – for example – the database files, within the servers RAM. This increase the speed of your deliveries on your Web application.
The system caches all data and objects in memory for a short period, decreasing the requests to the external database or API.
In the Memcached technology, each item is a compromise of a key, expiration time, raw data and an optional flag. Each time an item gets requested, Memcached checks the expiration time to see if the holding item is still valid, before returning it to the client.
The caching metodology is seamlessly integrated into WordPress, through WP Super Cache, W3 Total Cache and a number of other caching tools.
GMEngines Memcached services, is set to act as a Least Recently Used caching plus expiration timeout service.
In the odd case of the server running out of memory, it will look for already expired items to replace – and if additional memory gets requested, it will start replacing the items that have not been requested for the longest period, ensuring the most used information to be kept alive in memory.
Memcached consists of four (4) fundemental components:
- Server algorithms, to determine when old data should be discarded for resuse of memory
- Server Software, to store the values into an internal hashing table
- Client Software, which receives a list of all available Memcached Servers.
- A Client-based hashing algorithm, which chooses a server based on the key input.