How to use caching to optimize PHP and MySQL

With the continuous development of the Internet and the expansion of applications, more and more websites and applications need to process massive amounts of data and achieve high-traffic access. In this context, cache optimization has become a very necessary optimization method for common technologies such as PHP and MySQL. This article will introduce the concept and function of caching and implement cache optimization from two aspects of PHP and MySQL. I hope it can provide some help to developers.

1. The concept and function of cache

Cache refers to caching the calculation results or the results of reading data into a high-speed memory of a certain capacity for reuse. Caching technology is a technology that optimizes the performance of computer programs. It is widely used and can be used in various application scenarios such as database access, web browsers, and operating systems. Its main function is to improve response speed and reduce system load.

The function of cache is mainly reflected in the following aspects:

1. Reduce the number of access processing: the cache can obtain and store the results on the first access, and directly return the stored results on subsequent accesses , thereby reducing heavy processing procedures and data access operations.
2. Improve response speed: Using caching technology to store processing results in high-speed memory can improve data access speed and response speed, and speed up the response time to user requests.
3. Reduce system load: Caching can reduce database access requests and program calculation times, reduce system resource usage and server load pressure.

2. PHP cache optimization

1. PHP cache plug-in

Using PHP cache plug-in can greatly improve the response speed of the application and reduce the system load. Commonly used PHP cache plug-ins include APC, XCache, eAccelerator, Zend Optimizer, etc. Among them, APC is the most widely used. Since it exists in the PHP kernel, its performance is more stable.

The steps to use the PHP cache plug-in are as follows:

(1) Install the extension: Enable the corresponding extension in the PHP configuration file, such as adding the following configuration in php.ini:

extension=apc.so

(2) Set cache parameters: Make corresponding cache policy settings according to business needs.

(3) Restart the server: Restart the server to make the cache plug-in take effect.

2. PHP result cache

In addition to using the PHP cache plug-in, you can also use PHP result cache to cache some results that need to be repeatedly calculated for subsequent use. Commonly used caching methods include file caching, memory caching, database caching, etc.

The steps to use PHP result cache are as follows:

(1) Determine whether the cache exists: Before reading the data, determine whether the corresponding cache file or cache record exists.

(2) Get cached data: If the cache exists, get the data directly from the cache, otherwise perform normal data query and calculation operations.

(3) Rebuild the cache: When the data changes, you need to actively clear the existing cache through the program and regenerate the cache file or record.

3. MySQL cache optimization

1. Query cache

MySQL provides a query cache function, which can cache query results for repeated queries. When the data does not change frequently, you can get a very significant performance improvement by turning on the query cache function.

The steps to use query cache are as follows:

(1) Enable query cache: Add the following parameters in the MySQL configuration file:

query_cache_type=1

query_cache_size=16M

(2) Adjust the cache size appropriately: Dynamically adjust the cache size according to the system load and the number of index tables.

(3) Check the cache usage: Use the show status command to display the cache hit rate and cache usage.

2. Table cache

Table cache can cache the accessed data of the MySQL table into memory to quickly return query results. When disk IO restrictions are severe or the number of queries is high, using table cache can effectively reduce the IO operations of the database and improve query speed. However, due to the large difference in table access and write times, you need to be cautious when using table cache, otherwise it may cause problems such as untimely updates.

The steps to use table cache are as follows:

(1) Enable table cache: Add the following parameters in the My SQL configuration file:

table_cache=1024

(2) Adjust cache size: Dynamically adjust cache size based on system load and number of tables.

(3) View cache usage: Use the show status command to display the table cache hit rate and cache usage.

Summary:

As commonly used Web technologies, PHP and MySQL do need cache optimization to improve performance and reduce server load pressure. For PHP, calculation results can be cached using the PHP cache plugin or the PHP result cache. For MySQL, you can use query cache or table cache to cache query results or access data. Whether it is PHP or MySQL, when optimizing cache, it needs to be optimized according to the specific application conditions, and appropriate caching strategies and caching solutions must be selected.

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