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

Use Case(s)

'Memcached stats slabs' are typically used in Go to get detailed information about each slab class within Memcached. This is useful for monitoring and performance tuning as it provides data regarding memory allocation, usage, hit ratios, and much more.

Code Examples

The gomemcache library is a popular choice for working with Memcached in Go. Below is an example of using it to retrieve and display slab statistics.

package main

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

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

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

	for k, v := range stats {
		fmt.Printf("Slab Class %s:\n", k)
		for key, value := range v {
			fmt.Printf("%s: %s\n", key, value)
		}
		fmt.Println()
	}
}

In this code, we first connect to the local Memcached server. The StatsSlabs() function is then called to get the slabs statistics. If there's no error, the statistics will be printed out by iterating over the results.

Best Practices

• Always handle errors properly. Ignoring errors from StatsSlabs() could lead to ambiguous behavior or even crashes.
• Call StatsSlabs() sparingly. It may interfere with the performance of your Memcached server if you call it too frequently.

Common Mistakes

• Not checking and handling error returned by StatsSlabs(). When ignored, you might not get any data but your application will continue to run as if nothing happened.
• Misinterpreting the statistics. For example, a high 'get_hits' number is generally good, but if 'get_misses' is also high, it could indicate that you have more cache misses than expected.

FAQs

Q: What do the different fields in slab stats mean? A: Each field represents some aspect of your Memcached server's performance. Some common ones are 'used_chunks' which shows how many chunks are being used, 'chunk_size' showing the size of each chunk, and 'total_pages' showing how much memory has been allocated in terms of 1MB pages.

Q: Why am I getting an error when calling StatsSlabs()? A: You may be having trouble connecting to your Memcached server. Check if it's running and if the connection details are correct.