Golang Memcached Stats Settings (Detailed Guide w/ Code Examples)

Use Case(s)

Using Golang with Memcached often involves monitoring and tuning your cache. This includes checking usage statistics and adjusting settings for optimal performance.

Code Examples

Retrieving Stats in Golang

In Golang, you can use the gomemcache package to interact with Memcached. Here's how you might retrieve and print out general statistics:

package main

import (
	"fmt"
	"github.com/bradfitz/gomemcache/memcache"
)

func main() {
	mc := memcache.New("127.0.0.1:11211")

	stats, err := mc.Stats()
	if err != nil {
		fmt.Println(err)
		return
	}

	for server, stat := range stats {
		fmt.Printf("Server: %s\n", server)
		for key, val := range stat {
			fmt.Printf("%s: %s\n", key, val)
		}
		fmt.Println()
	}
}

In this code, we first establish a connection to the Memcached instance (running on 127.0.0.1:11211). The Stats() method is then called to get a map of statistics for each server. We iterate over these stats, printing them out for inspection.

Best Practices

• Use Appropriate Data Types: Memcached only stores strings. However, you may need to store more complex data types like structs or slices in cache. You can serialize them into JSON or another format before storing, and then deserialize after retrieving.

• Choose a Suitable Expiration Time: Items in Memcached have an expiration time after which they are automatically removed. Choose a suitable expiration time based on your use case to avoid keeping unnecessary data in memory.

Common Mistakes

• Over-reliance on Cache: Remember that cache is not a substitute for a database. Always have fallback logic if the data is not found in cache, typically to fetch from the source and then repopulate the cache.

• Not Handling Cache Eviction: In Memcached, when the memory is full, older items are evicted to make room for new ones using an LRU algorithm. It's important to realize this can happen and handle it appropriately in your code.

FAQs

Q: What does slab allocation mean in Memcached statistics?

A: Slabs are a way memcached organizes its memory internally. Different slabs hold different sized chunks of memory. The stats tell you how much memory is being used by each slab class (or size of chunk).

Q: How often should I check my Memcached stats?

A: It depends on your specific use case. However, regularly monitoring these stats can provide valuable insights into your application's performance and potential issues.