Practical application of Redis in cache preheating

Redis is an in-memory cache database that is often used for caching in Internet applications to speed up program operation and improve performance. In actual application, cache preheating is a way to ensure a high Redis cache hit rate. This article will introduce the actual application of Redis in cache preheating.

1. What is cache preheating?

Cache preheating refers to caching data in the cache in advance before the program is run, in order to obtain the required data faster during actual operation, thus improving the performance of the program.

When using Redis cache, since Redis itself uses memory cache, once the Redis server restarts or other abnormal situations occur, the cache will be cleared, causing the next request to be obtained from the database or other sources. Data, this process consumes a lot of time and system resources. Therefore, when applying Redis cache, it is particularly important to use cache preheating technology.

2. How to implement Redis cache preheating?

Redis cache preheating can be achieved in the following ways:

2.1 Preheating method one: manual preheating

Manual preheating refers to developers Before project deployment or Redis server startup, manually load the data that needs to be cached into Redis. This method is simple, clear and easy to control, but it requires developers to invest a lot of time and is not flexible enough to adapt to complex business scenarios.

2.2 Preheating method two: scheduled preheating

Scheduled preheating means that developers periodically load the data that needs to be cached into Redis by setting up scheduled tasks. Compared with manual preheating, this method has a certain improvement in flexibility and automation, but you need to pay attention to the setting of scheduled tasks to avoid task execution taking too long and affecting system performance.

2.3 Preheating method three: on-demand preheating

On-demand preheating means loading the data that needs to be cached into Redis according to the business request after the application system is started. This method is more flexible than the first two methods, and the preheating strategy can be adjusted according to the actual situation, but it requires a deep understanding of the business scenario to achieve the best preheating effect.

3. Practical combat: How to use Redis to implement cache preheating?

The following takes a simple e-commerce system as an example to introduce how to use Redis to implement cache preheating.

3.1 Analyzing business scenarios

Assume that the e-commerce system needs to display the ranking of hot-selling products. The data that needs to be preheated is the ranking of product sales volume, which is used to quickly load the ranking after the system is started. Ranking data.

3.2 Implement cache preheating

When the application system starts, obtain the product sales ranking data by querying the database and write the data into Redis. The code is as follows:

@Service
public class HotGoodsService {
    
    @Autowired
    private RedisTemplate<String, Object> redisTemplate;
    
    /**
     * 缓存预热：热卖商品排行榜
     */
    public void hotGoodsCache() {
        // 查询商品销售量排行榜，获取前10个商品ID
        List<String> hotGoodsList = goodsSaleVolumeService.getHotGoodsList(10);
        // 加载商品销售量排行榜到Redis中
        redisTemplate.opsForList().rightPushAll("hot_goods", hotGoodsList);
    }
}

When the application system starts, call the hotGoodsCache() method in HotGoodsService to achieve cache preheating.

If you need to preheat on a regular basis, you can configure a scheduled task and call the hotGoodsCache() method on a regular basis to preheat the hot-selling product ranking data.

4. Summary

As an in-memory cache database, Redis has the characteristics of high performance and high concurrency, and is widely used in application scenarios. In order to improve the cache hit rate of Redis, cache preheating technology needs to be fully utilized. This article introduces the actual application of Redis cache preheating, and gives the specific code implementation to implement cache preheating. We hope that readers can give full play to the advantages of Redis cache preheating in practical applications and improve system performance.

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