The key to optimizing PHP application performance is to start from common bottlenecks, which mainly includes the following points: 1. Enable OPcache and configure reasonably to improve script execution efficiency; 2. Reduce the number of database queries and optimize SQL writing to avoid N 1 query problems; 3. Introduce a caching mechanism to reduce the pressure of repeated calculations, such as page caching, data caching and object caching; 4. Select a suitable framework and streamline dependencies, regularly clean unused packages and enable automatic loading optimization. By starting from these aspects, most PHP applications can achieve significant performance gains.

It is actually not difficult to optimize the performance of PHP applications. The key is to start from several common bottlenecks. PHP itself is already efficient enough, but in actual applications, the overall response is often slowed down due to problems such as code writing, database operations, and caching strategies. The following is a few practical perspectives to talk about how to improve the performance of PHP applications step by step.

1. Use OPcache rationally to improve script execution efficiency

PHP is an interpreted language, and by default, PHP files are reparsed and compiled on each request. This will obviously waste resources. The function of OPcache is to cache the compiled bytecode to avoid repeated compilation.

• Make sure opcache.enable=1 is enabled in php.ini
• Set a reasonable cache size, for example opcache.memory_consumption=128
• If multiple files change frequently, opcache.revalidate_freq can be adjusted appropriately to balance updates and performance

After turning on, you will find that the page loading speed has become significantly faster, especially the effects of projects with large visits are more obvious.

2. Reduce the number of database queries and optimize SQL writing

Databases are often the most likely place to have bottlenecks in PHP applications. A simple page may become slow because of several inefficient SQL queries.

You can try:

• Avoid queries in loops (N 1 query problems)
• Replace multiple single table queries with JOIN
• Add indexes to common data, especially fields that are often used to search or sort
• Reduce direct access to the database using caching mechanism

For example, you have an article list page where you have to check the author information once for each article. It is better to change it to use JOIN to find it out at one time, which can save a lot of time.

3. Introduce a cache mechanism to reduce the pressure of repeated calculations

Caching is one of the most effective ways to improve performance. Commonly used caching methods include page cache, data cache and object cache.

• Page cache is suitable for pages with a lot of static content, such as home page, help page, etc.
• Data cache can use Redis or Memcached to store query results
• Object cache can temporarily save the results of some complex calculations

For example, if you have a statistical interface that only updates once a day, you can cache the results for one day without having to recalculate every request.

4. Choose the right framework and streamline dependencies

Although the framework makes development faster, it also brings additional performance overhead. If your application has high performance requirements, it is recommended:

• Don't blindly pursue a big and comprehensive framework
• Prefer lightweight frameworks, such as Lumen, Slim, FastRoute, etc.
• Regularly clean packages not used in composer
• Enable automatic load optimization (such as composer dump-autoload --optimize )

Some projects initially used Laravel, but later they found that they could not be concurrent, so the performance was significantly improved after changing to a lighter solution.

Basically these methods are not complicated but easy to ignore. Many times the performance problem is not that the technology is not advanced enough, but that the details are not done well. As long as you start from these aspects, most PHP applications can achieve significant performance improvements.

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