Sooner or later, increased traffic to a website or service will cause pages to load slowly. To maintain high performance and stability, developers use various optimization methods. One of the most effective and simplest methods is caching.
What is caching?
Caching is the temporary storage of data in fast and accessible storage. When first accessed, information is retrieved from the “original” source (e.g., a database) and then stored in the cache for a period of time. Repeat requests are processed faster because the data is already at hand and does not require repeated access to the database or third-party services.
A simple example: a user visits a product page. On the first request, the data is taken from the database and stored in the cache. All subsequent users open the page faster because the information is no longer taken from the database, but from the cache.
Popular caching tools
In PHP, you can use different approaches and technologies. The most common are:
- APCu — a simple and lightweight tool that stores data directly in RAM. Suitable for small projects and quick solutions.
- Array cache — temporary storage of data within a single request. Useful in rare cases, for example, to avoid multiple requests to the database for the same information within a single page load.
- Memcached is a separate caching service that runs on a server and stores data in memory. It is suitable for high-load projects.
- Redis is another popular service similar to Memcached, but with broader capabilities (e.g., support for complex data structures and clustering).
The first two options are simpler but limited in their capabilities. Memcached and Redis are more versatile and handle scalable loads well.
Why it is important to follow PSR standards
In the world of PHP, there are special PSR (PHP Standards Recommendations) standards. Two of them are used for caching:
- PSR-6 — a standard for creating flexible cache systems.
- PSR-16 — a simplified interface for working with cache, convenient for most tasks.
Using PSR offers several advantages:
- a unified and understandable interface for working with cache;
- compatibility with most libraries;
- the ability to easily replace one solution with another (for example, APCu with Redis) without changing the entire project code.
Practical use
If your website is growing and attracting more and more users, caching becomes an essential part of its architecture.
It allows you to:
- speed up page loading,
- reduce the load on the database and server,
- increase the stability of the project under peak loads,
- prepare the system for scaling.
For small projects, simple solutions such as APCu are sufficient. For large and heavily loaded systems, it is better to use separate services — Memcached or Redis. And compliance with PSR standards will help you remain flexible and switch between different approaches painlessly.
