PHP backend design: performance optimization and system stability exploration

With the widespread use of Web applications in people's lives, the importance of backend system design has become increasingly prominent. In PHP backend design, performance optimization and system stability are two issues that cannot be ignored. This article will explore how to achieve performance optimization and system stability in the PHP backend and provide corresponding code examples.

1. Performance optimization

1. Database connection pool

In actual development, database connection is a key factor affecting performance. Therefore, pooling database connections can effectively improve the performance of web applications. The basic principle of the connection pool is to create a connection in advance and store it in the connection pool. When a connection is needed, the connection is obtained from the connection pool and returned to the connection pool after use. This can avoid frequent creation and deletion of connections and reduce the cost of connection creation and destruction.

The following is a sample code for a simple MySQL connection pool:

class MysqlPool
{
    private $pool;    // 连接池数组
    private $config;  // 数据库配置
    private $size;    // 连接池大小
 
    public function __construct($config, $size)
    {
        $this->config = $config;
        $this->size = $size;
        $this->init();
    }
 
    private function init()
    {
        $this->pool = array();
        for ($i = 0; $i < $this->size; $i++) {
            $this->pool[] = new mysqli(
                $this->config['host'],
                $this->config['user'],
                $this->config['password'],
                $this->config['database']
            );
        }
    }
 
    public function getConn()
    {
        if (count($this->pool) > 0) {
            return array_shift($this->pool);
        }
        return null;
    }
 
    public function returnConn($conn)
    {
        if ($conn) {
            $this->pool[] = $conn;
        }
    }
}

Where you need to connect to the database, you can use the following code to obtain the connection:

$conn = $mysqlPool->getConn();

After use Finally, remember to release the connection:

$mysqlPool->returnConn($conn);

2. Caching Technology

Caching technology is another key factor in improving Web application performance. Reading and writing data usually consumes a lot of time, and caching technology can use high-speed storage such as memory to store commonly used data, reduce data reading time, and improve application response speed. In actual development, various caching technologies can be used, such as Memcache, Redis, etc. The following is a simple example code for using Redis to cache data:

$redis = new Redis();
$redis->connect('127.0.0.1', 6379);

$key = 'cache_key';
if ($redis->exists($key)) {
  $data = $redis->get($key);
} else {
  $data = fetch_data_from_database();
  $redis->set($key, $data);
  $redis->expire($key, 300);
}

When using cache, you need to pay attention to the cache validity period to avoid data inconsistency caused by cached data expiration.

3. Front-end caching

Front-end caching can effectively reduce the response time of web applications and reduce server pressure. In the HTTP protocol, the client can cache web pages to avoid sending the same request to the server multiple times. In order to implement front-end caching, you can set header information such as Expires or Cache-Control in the HTTP response header to specify the validity period of the page cache on the client. The following is a simple example of setting the front-end cache header information:

header("Cache-Control: max-age=3600, must-revalidate");

2. System stability

1. Exception handling

In Web applications, Exception handling is a key factor in improving system stability. We need to catch various exceptions and process exception information to ensure that the application can run normally. In PHP, you can use try/catch statements to catch exceptions and handle them accordingly according to the exception type. The following is a simple example code for exception handling:

try {
    // do something
} catch (Exception $e) {
    log_error($e->getMessage());
    // display error page
}

2. Logging

Logging is a commonly used method in Web applications to record the running status of the application. , to facilitate developers to debug and maintain. In PHP, the logging system can be configured by configuring the php.ini file or using code. The following is a simple example code that uses PHP's built-in logging function:

ini_set('error_log', '/path/to/log/error.log');
error_log('Error message');

In actual development, various key information can be recorded in the log, such as request parameters, exception information, database query statements, etc.

3. Database transactions

Database transactions are a way to ensure data consistency. In PHP, transaction processing can be implemented through functions such as mysqli_begin_transaction/mysqli_commit/mysqli_rollback. The following is a simple example code for using transaction processing:

$conn = mysqli_connect("localhost", "user", "pass", "db");
mysqli_begin_transaction($conn);
try {
    mysqli_query($conn, "INSERT INTO persons (name) VALUES ('John')");
    mysqli_query($conn, "INSERT INTO persons (name) VALUES ('Mary')");
    mysqli_commit($conn);
} catch (Exception $e) {
    mysqli_rollback($conn);
}
mysqli_close($conn);

When using transaction processing, you need to pay attention to transaction boundaries and exception handling to avoid data inconsistency.

3. Summary

This article introduces the related technologies of performance optimization and system stability in PHP backend design, including database connection pool, caching technology, exception handling, logging and database transactions. In actual development, it is necessary to select the appropriate technology for application based on the actual situation of the application. At the same time, you also need to pay attention to the quality and reconstruction of the code to ensure the maintainability and scalability of the system and provide guarantee for the long-term stable operation of the application.

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