Why doesn't my Go program use the Cache library correctly?

When writing programs in Go, it is very common to use caching libraries. It can greatly improve the performance of the program and reduce dependence on external resources. However, sometimes we encounter some problems, such as the program not using the cache library correctly. So why does this happen? We will analyze it below.

First, we need to understand the basic principles of the cache library. The function of the cache library is to store some frequently read and written data in memory for quick access. Generally speaking, the cache library will decide which data needs to be cached and which data needs to be deleted based on certain policies. Common caching algorithms include LRU (least recently used) and LFU (least used times).

So, what problems will occur when we use the cache library?

1. Improper caching strategy

The performance of the cache library is directly affected by the caching strategy. If we choose a caching strategy that is not suitable for the current scenario, it will lead to poor caching performance. For example, when we process a large amount of data, if we choose the LRU strategy, cache invalidation will occur because new data will continuously overwrite old data, and the old data may need to be read again soon. On the contrary, if we choose the LFU strategy, there will be a situation where the cache is full but still rarely used. Therefore, when choosing a caching strategy, we need to make an appropriate choice based on the actual situation.

2. Concurrent reading and writing are not safe

In the case of multi-threading, the read and write operations of the cache library need to consider concurrency safety. If we do not take this into consideration, in the case of high concurrency, cache data inconsistency will occur. For example, when two threads update data in the cache at the same time, a conflict occurs so that the cached data is no longer valid. In this case, we can use locks or other concurrency-safe mechanisms to solve the problem.

3. The cache expiration is not timely

The cache expiration time is very important. If our cache expiration time is not set properly, some problems will occur. For example, if the cache expiration time is set too short, the cache hit rate will decrease; if the cache expiration time is set too long, dirty data will appear. Therefore, when setting the cache expiration time, you need to make an appropriate choice based on the application scenario and the actual needs of the cache.

4. Cache penetration

Cache penetration means that the requested data does not exist in the cache, but it is constantly requested, causing the cache to become invalid, which is harmful to the backend. The pressure on the database increases. In this case, we need to perform special processing for the case where the cache does not exist. For example, when retrieving data from the cache, if the data does not exist, it needs to be retrieved from the database and stored in the cache for subsequent access.

To sum up, when we use the cache library, we need to consider issues such as cache strategy, concurrency security, cache expiration and cache penetration. Only by using cache based on a true understanding of these issues can the performance of the program be truly improved.

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