Try this:

a, b := mcache.New(), mcache.New()
a.Set("foo", 123, time.Second)
val, ok := b.Get("foo")
fmt.Println(val, ok)

Which will produce "123 ok". It seems you cannot have multiple caches. This should either be documented clearly or fixed.

I found a rare case bug that objects remain in a storage in spite of gc working.

We can sometimes see by the following.

import (
	"fmt"
	"time"
	"strconv"
	"math/big"
	"github.com/OrlovEvgeny/go-mcache"
)

const (
	N = 4000
)

func test() {
	driver := mcache.StartInstance()

	var interval time.Duration
	var i int64

	fmt.Printf("Storage has %d object\n", driver.Len())

	i = 0
	for true {
		if i % 1000 == 0 {
			fmt.Printf("It is working... %d\n", i)
		}

		interval = time.Millisecond * 1

		time.Sleep(interval)

		driver.Set(strconv.FormatInt(i, 10), big.NewInt(i), interval)

		i++

		if i >= N {
			break
		}
	}

	fmt.Printf("Finished setting %d objects\n", N)

	fmt.Printf("Storage currently has %d object\n", driver.Len())

	time.Sleep(time.Second * 10)

	l := driver.Len()
	if l != 0 {
		fmt.Printf("%d objects remain\n", l)
	} else {
		fmt.Println("Nothing remain")
	}
}

func main() {
	test()
}

Please confirm the behavior above, and check my code.

Performance

Before

BenchmarkWrite-4          200000              8370 ns/op                                                                                                                                                    
BenchmarkRead-4          1000000              1710 ns/op                                                                                                                                                    
BenchmarkRW-4             300000              9412 ns/op

After

BenchmarkWrite-4          200000              7991 ns/op 
BenchmarkRead-4          1000000              1716 ns/op 
BenchmarkRW-4             300000              9894 ns/op

• add "header" sections (package and import)
• add missing word "struct" in the User type declaration
• replace "new" with composite literal to get rid of unnecessary assignments
• add missing returned error receiver to MCache.Set and MCache.SetPointer
• fix MCache name where methods Get and GetPointer are called
• fix typo objUser,Bio -> objUser.Bio
• last log.Println should be Printf in order to replace "%s" with the key value

I did a very detailed analysis of the source code of the entire project. The project has not been maintained for a long time. Can I join the maintenance because it is used in our project? Can you invite me? Thank you