Is `require_once()` Really a Performance Bottleneck in Modern PHP?

Why Should You Steer Clear of require_once()?

Despite popular belief in PHP coding practices, using require_once is not necessarily detrimental to performance.

The Performance Impact

In earlier versions of PHP, require_once() had performance issues. However, these flaws have been resolved in more recent versions.

Alternatives to require_once()

• class_exists() Check: For class inclusions, check if the class exists. However, this approach can be cumbersome.
• Conditional Include: Use PHP's include() with a conditional statement to prevent multiple inclusions. This can be problematic for procedural code.

The True Bottleneck: Includes in PHP

The real performance bottleneck in PHP is the inclusion of files. Every time the interpreter encounters an include, it switches to parse mode, generates opcodes, and jumps back. Excessive inclusions negatively impact performance, especially without an opcode cache.

Best Practices

To mitigate the impact of includes, follow these guidelines:

• Load Necessary Files Early: During parse time, load all essential includes upfront. This allows opcode caches to handle the rest.
• Avoid Autoloading: Autoloading is convenient but can be sluggish due to the need to run the autoload logic repeatedly. Use it sparingly for specialized files.
• Consider Inlining: For small numbers of includes (around 10), inlining them into one file can improve performance, but it's impractical for development.

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