sync.Pool
- Go course
- Intermediate
- Lesson 23/80
- 4 min
Learn object reuse with Pool.
sync.Pool
sync.Pool recycles temporary objects to reduce GC pressure. You get an object with Get() and return it with Put(). If the pool is empty New creates one.
Pool is ideal for short-lived reusable objects (e.g. buffers, byte slices). But Pool may be cleared during GC; there is no persistence guarantee. So it is not for state.
Pool and reuse
Pool recycles buffers or temporary slices. var pool = sync.Pool{New: func() interface{} { return &bytes.Buffer{} }} creates a fresh buffer. pool.Get().(*bytes.Buffer) takes, pool.Put(buf) returns.
An object from the pool may not be empty; reset it before use (e.g. buf.Reset()). This prevents stale data from causing issues.
Practice Print with Pool
Inside main, add a sync.Pool declaration and print pool done with fmt.Println.
Starter code
package main
import "fmt"
func main() {
// buraya yaz
}Sample solution
package main
import (
"fmt"
"sync"
)
func main() {
var pool sync.Pool
pool.New = func() interface{} { return "x" }
v := pool.Get()
fmt.Println("pool tamam")
_ = v
}Expected output
pool tamam
Questions and answers
Review the lesson questions together with their answers. To test yourself, solve the lesson interactively.
1 What does sync.Pool reduce?
- Network latency
- Memory leaks
- CPU usage
- GC pressure Correct answer
Explanation: Memory leaks are not directly about Pool.
2 Pool usage
var pool = sync.Pool{
New: func() interface{} { return &Buffer{} },
}
buf := pool.____().(*Buffer)
// use buf
pool.Put(buf)var pool = sync.Pool{
New: func() interface{} { return &Buffer{} },
}
buf := pool.Get().(*Buffer)
// use buf
pool.Put(buf)Explanation: New is the constructor, Get is the getter.
3 Match Pool concepts
| Term | Meaning |
|---|---|
Get |
Al |
Put |
Koy |
New |
Create |
sync.Pool |
Tip |