golang delete cache

With the continuous development of big data and cloud computing technology, caching technology is becoming more and more important in data processing and storage. In golang, caching is an important application scenario. However, if the cache is not deleted in time, it will lead to resource waste and performance degradation. Therefore, this article will introduce how to use golang to delete cache to improve application performance.

1. "Cache"

Cache refers to the technology of storing data in memory. The use of caching technology can reduce access to disks and databases, increase data reading and writing speed, and thereby improve application performance. Caching generally consists of two parts: cache resources and cache strategies. Cache resources refer to the content to be cached, such as pictures, pages, data, etc.; cache strategies refer to how to store resources in memory, including cache time, cache size, expiration policy, etc.

2. Caching in golang

In golang, caching can be implemented with very little code. The following is a simple golang cache call example:

import (
    "sync"
    "time"
)

type Cache struct {
    sync.RWMutex
    items     map[string]*cacheItem
    defaultTTL time.Duration
}

type cacheItem struct {
    value    interface{}
    created  time.Time
    duration time.Duration
}

func (c *Cache) Set(key string, value interface{}) {
    c.Lock()
    defer c.Unlock()

    item := &cacheItem{
        value:    value,
        created:  time.Now(),
        duration: c.defaultTTL,
    }
    c.items[key] = item
}

func (c *Cache) Get(key string) (interface{}, bool) {
    c.RLock()
    defer c.RUnlock()

    item, found := c.items[key]

    if !found {
        return nil, false
    }

    if time.Since(item.created) > item.duration {
        return nil, false
    }

    return item.value, true
}

In the above code, we use two structures Cache and cacheItem. The Cache structure contains items and defaultTTL attributes. The items attribute is a map type used to store cache data, and defaultTTL is used to set the default expiration time of the cache. The cacheItem structure contains value, created, and duration attributes, which respectively represent the cached value, creation time, and cache time.

Through the Set method, we can store key-value pairs in the cache. In the Get method, we will first query whether the key-value pair exists, and if it does not exist, return null and false; otherwise, we will query whether the key-value pair in the cache has expired, and if it has expired, return null and false. Otherwise, return the value of the key-value pair in the cache and true.

3. Golang delete cache

When the content in our cache becomes no longer needed, we need to clear the cache in time to avoid resource waste and performance degradation. Here are some practical golang methods to delete cache:

1. Delete cache by cache key name

func (c *Cache) Delete(key string) {
    c.Lock()
    defer c.Unlock()

    delete(c.items, key)
}

You can quickly delete one of the caches through the Delete method in the above code Key-value pairs. This method will use the cache key name to find the cache that needs to be deleted. Before calling this method, a locking operation is required to ensure thread safety.

2. Regularly delete expired cache

In the above code, we slightly mentioned the cache expiration time in the Get method. The cache expiration time is controlled through the duration attribute in cacheItem. If we want to delete expired caches regularly, we can open a goroutine, regularly check all cache items in the cache, and delete expired cache items:

func (c *Cache) StartCleanup(routineInterval time.Duration) {
    ticker := time.NewTicker(routineInterval)
    go func() {
        for {
            select {
            case <-ticker.C:
                c.cleanup()
            }
        }
    }()
}

func (c *Cache) cleanup() {
    c.Lock()
    defer c.Unlock()

    for k, v := range c.items {
        if time.Since(v.created) > v.duration {
            delete(c.items, k)
        }
    }
}

In the above code, we open a goroutine and pass a Timer ticker to trigger cleanup operations regularly. Regular cleaning operations are implemented through the cleanup method. This method traverses all cache items in the cache and deletes a cache item when it has expired.

It should be noted that in the Delete and cleanup methods, we must lock the items attribute to ensure thread safety.

4. Summary

Through this article, we have learned about the cache in golang and introduced how to use golang to delete the cache to improve application performance and reduce resource waste. In actual applications, we can choose different caching strategies and expiration times based on the actual needs of the project to optimize application performance. At the same time, we also need to pay attention to ensuring the thread safety of the cache and avoiding problems such as memory leaks.

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