PHP and Memcached performance monitoring

With the rapid development of modern Internet applications, user experience is crucial to the success of an application. How to ensure high performance and high availability of applications has become one of the important issues that developers need to solve. As one of the widely used programming languages, PHP's performance monitoring and optimization are also very important.

Memcached is a high-performance, distributed memory object caching system that can help applications improve performance and scalability. This article will introduce how to use PHP and Memcached to implement performance monitoring.

1. Working principle of Memcached

The official document defines Memcached as follows: "Memcached is a high-performance distributed memory object caching system that can be used in dynamic web applications to reduce database load. ." Its working principle is to cache data into memory. If there is a request for the same data, it can be read directly from memory.

When specifically using Memcached, the data that needs to be cached will be placed in a key-value pair, so that when the data needs to be called, it can be quickly read from the memory. For PHP applications, this key-value pair can be stored in memory to avoid calling the database query every time.

2. How to integrate PHP with Memcached

PHP can be integrated with Memcached through some extension libraries. The most commonly used ones are Memcached extension and Memcache extension. Their usage and implementation are very similar. This article uses Memcached extension as an example.

First you need to install the Memcached service and introduce the extension into PHP. For specific operations, please refer to the following commands:

sudo apt-get install memcached
sudo apt-get install php-memcached

After the installation is completed, you can use the following code in the PHP code to cache data:

$memcached = new Memcached();
$memcached->addServer('127.0.0.1', 11211);
$key = 'example_key';
$data = 'example_value';
$memcached->set($key, $data);

This code first creates a Memcached instance, and Added a local server. Next, a cached key-value pair is defined and then stored in Memcached using the set() method.

3. Use Stats API to monitor the performance of Memcached

In PHP applications, you can monitor the performance of Memcached through the built-in Stats API. It provides methods to obtain Memcached statistical information, such as cache hit rate, expiration time, cache space occupied, etc.

The following code demonstrates how to use the Stats API to obtain some performance information of Memcached:

$memcached = new Memcached();
$memcached->addServer('127.0.0.1', 11211);
$stats = $memcached->getStats();
echo "Memcached key count: " . $stats['curr_items'] . "
";
echo "Memcached hit rate: " . $stats['get_hits'] / ($stats['get_misses'] + $stats['get_hits']) . "
";

This code obtains the number of key-value pairs currently stored in Memcached and calculates the cache hit rate.

Through the Stats API, we can obtain some basic information about Memcached, but this information reflects the performance of the entire Memcached system and cannot provide refined monitoring and adjustment. Next, we will introduce how to use the extension library to achieve more refined performance monitoring.

4. Use the Memcached PHP extension to obtain more detailed statistical information

The methods provided by the Memcached PHP extension are richer than the built-in Stats API, and can obtain more specific and accurate statistical information. The following code shows how to use the getStats() method in the extension to obtain Memcached statistics:

$memcached = new Memcached();
$memcached->addServer('127.0.0.1', 11211);
$stats = $memcached->getStats();
foreach ($stats as $server => $s) {
    foreach ($s as $key => $value) {
        echo "$server:$key=$value
";
    }
}

This code first creates a Memcached instance and adds a local server. Next, use the getStats() method to obtain Memcached statistical information, and use a foreach loop to traverse the output results.

In addition to these basic information, the Memcached PHP extension also provides some useful methods to monitor and adjust the performance of Memcached, such as getServerList(), getVersion(), etc.

5. Use Memcached monitoring tools

In addition to PHP’s own Stats API and Memcached PHP extension, there are also some monitoring tools that can help us monitor and adjust the performance of Memcached more conveniently.

1. Memcached management interface

Memcached provides a web management interface that can be used to manage and monitor the Memcached service, such as viewing cached key-value pairs and observing Memcached running status. As well as add/remove servers and more.

In Ubuntu system, you can use the following command to install the Memcached management interface:

sudo apt-get install php-memcache
sudo service apache2 restart

After installation, visit "http://localhost/memcache.php" in the browser .

2. Munin Monitoring Tool

Munin is a commonly used server performance monitoring tool that can be used to monitor the running status of Memcached. It provides rich charts and statistical information for easy performance analysis and adjustment.

Under Ubuntu system, you can use the following command to install Munin:

sudo apt-get install munin munin-node

After the installation is complete, just visit "http://localhost/munin" in the browser.

6. Conclusion

This article introduces how to use PHP and Memcached to implement performance monitoring. By using Stats API, Memcached PHP extension and monitoring tools, Memcached performance analysis and adjustment can be more conveniently performed. I hope this article is helpful to you, thank you for reading!

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