How to use caching to reduce MySQL I/O operations

In modern web applications, database performance is often the bottleneck of an application. In many applications, database queries are one of the most common operations, and these queries often require a large number of I/O operations. In order to reduce I/O operations and improve application performance, caching is a very important tool. In this article, we will explore how to use caching to reduce MySQL I/O operations.

Caching Background

Cache is a temporary storage device or memory area that can store data. It is very important for many web applications. Caching can help reduce and optimize database queries and other disk I/O-related operations. It can cache some commonly used data and quickly return the data on the next request, thus avoiding repeated queries.

The development history of caching technology

The development history of caching technology can be traced back to early computer systems. At that time, the performance of computer systems was relatively weak, and some technologies needed to be used to optimize their performance. With the development of computers and changes in application scenarios, caching technology has also developed rapidly. In web applications, caching technology is usually applied to database queries and other disk I/O related operations. It can help speed up the application's response time and improve user experience.

How to use caching to reduce MySQL’s I/O operations

In web applications, reducing MySQL’s disk I/O operations is a very important task. Because MySQL's disk I/O operations have a great impact on the performance of web applications, once a database query requires a large number of disk I/O operations, this will lead to a decrease in application performance. Below we will introduce how to use caching to reduce MySQL's disk I/O operations.

Caching query results

In Web applications, query results are often some commonly used data. If the same data is queried repeatedly, this will result in increased disk I/O operations for the database. In order to speed up query operations and reduce disk I/O operations, caching can be used to cache query results. When the next query request occurs, the application can obtain the data directly from the cache without querying the database again.

For example, in an online shopping mall application, if the user wants to query the price of a certain product, each query needs to obtain data from the database. If the price of this product is very stable, then the price information of this product can be cached, and the next time you query it, you can get it directly from the cache.

Cache Query Object

For performing frequent query operations in web applications, you can use caching to cache query objects. The query object refers to the data structure or object involved in the query. Caching query objects can help reduce the I/O operations required for queries and improve application responsiveness. After the query object is cached, the next query operation can be obtained directly from the cache without the need for further query operations.

For example, in an online education application, if many users are querying the information of a certain course, the information of the course can be cached, and the next time the information of the course is queried, the information can be directly retrieved from Get from cache.

Cache update operation

When using cache to reduce MySQL I/O operations, a cache update operation may be required. It mainly involves the following two issues:

1. Cache expiration issue

When the cache expires, the data in the cache needs to be updated. Some data may not change within a fixed period, and an expiration time can be set for this data. When the cache time exceeds this expiration time, the data in the cache needs to be updated.

2. Cache invalidation problem

When the cache fails, the data in the cache needs to be updated. For example, when the price of an item changes, the price information of the item needs to be cached again.

Cache Strategy

Cache strategy refers to the application’s caching rules, prediction, and clearing mechanisms. A good caching strategy can effectively reduce I/O operations and improve application performance.

Commonly used caching strategies are:

1. LRU caching strategy

The LRU (least recently used) caching strategy is a time-based caching strategy. Sort cached data in chronological order of most recent use, removing data that has been rarely used recently from the cache to make room for recent queries.

2. LFU cache policy

The LFU (least recently frequently used) cache policy is a cache policy based on frequency of use. Sort the cached data according to the frequency of use of the cached data, and remove data with lower frequency of use from the cache.

3. TTL caching strategy

TTL (time to live) caching strategy is a time-based caching strategy. Set an expiration time for each cache object. When the cache object's survival time exceeds the specified expiration time, the cache object will be removed.

4. Other cache strategies

In addition to the above cache strategies, there are other cache strategies, such as FIFO (first in, first out) cache strategy, ARC (adaptive replacement) cache) caching strategy, etc.

Summarize

In web applications, caching is a very important tool that can be used to reduce MySQL I/O operations and improve application performance. By caching query results, caching query objects, caching update operations, and caching strategies, you can effectively reduce MySQL's I/O operations and improve application performance. Finally, it should be noted that when using cache, it needs to be configured according to specific application scenarios in order to maximize performance advantages.

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