How to optimize the performance of PHP code?

With the continuous development of the Internet and the increasing demand for websites and applications, PHP has become a mainstream language for Web application development. However, in actual development, we often encounter performance bottlenecks, which requires us to optimize the PHP code.

This article will introduce how to optimize the performance of PHP code, including the following aspects:

1. Optimize code structure
2. Reduce database operations
3. Usage Caching to improve performance
4. Use PHP7 to improve performance
5. Other optimization methods

1. Optimize code structure

Optimizing code structure is an important means to improve PHP code performance. It is recommended to follow the following principles:

1) Use global variables as little as possible. Using global variables causes the PHP engine to read these variables on every function call, slowing down the performance of your application.

2) Avoid using a large number of passive function calls in loops. Calling a large number of functions in a loop will lead to repeated calls of the function, causing the function call stack to grow, which has an impact on performance.

3) Try to avoid using PHP code in HTML code. If you need to use PHP code, it is recommended to put the PHP code in a script and process it separately, which not only facilitates debugging, but also improves performance.

2. Reduce database operations

If your application needs to frequently read data from the database, reducing database operations may be an important means to improve performance. . It is recommended that you follow the following principles:

1) Use multi-table joint queries to reduce the number of database queries. Multi-table joint queries are usually faster than single-table queries because a joint table query can obtain data from multiple tables at once.

2) Use indexes to optimize database queries. Using indexes speeds up database queries and prevents the database from scanning the entire table.

3) Use caching to cache database query results. Memcached, Redis and other solutions can be used to cache query results in memory for fast query.

3. Use cache to improve performance

Using cache is an important means to improve the performance of PHP applications. The following two methods can be used:

1) Use APC (Alternative PHP Cache) or OPCache to cache PHP scripts. APC and OPCache are PHP's own cache extensions that can cache code written in PHP to avoid frequent IO operations on files.

2) Use a caching system to cache data in your application. Systems such as Memcached and Redis are currently one of the most widely used caching solutions and can cache large amounts of application data. You can use a caching system to cache data to reduce the number of database queries during regular operations, thereby improving PHP application performance.

4. Use PHP7 to improve performance

PHP7 is a new version of PHP with faster performance and better memory management functions, which can help you improve PHP Application performance. It is recommended that you upgrade to PHP7 as soon as possible.

5. Other optimization methods

In addition to the above methods, there are some other optimization methods that can help you improve the performance of PHP applications, such as:

1) Choose a suitable web server, such as Nginx, Apache, etc. These servers can handle more requests, thus improving the performance of PHP applications.

2) Use buffer output to improve performance. Buffered output can reduce I/O operations, thereby improving performance.

3) Use PHP extensions to improve performance, such as memcache extension, apc extension, etc.

4) It is especially important to optimize the code to understand the complexity of the algorithm and the complexity of various functions, and reduce the use of one-level loops, especially the one-level loops in N calls that require special care.

Summary: By taking the above optimization methods, you can easily improve the performance of your PHP application. At the same time, improving performance is also an iterative process that requires continuous attention and optimization of code.

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