gistfile1.txt

package main

import (
	"log"
	"runtime"
)

func main() {
	m := mkmap()
	for _ = range m {
		break
	}

	log.Print("Garbage collecting...")	
	m = nil
	runtime.GC()
	log.Println("allocated", runtime.MemStats.HeapAlloc)

	m = mkmap()

	log.Print("Re-adding entries...")
	for i := 0; i < 1e6; i++ {
		m[uint64(i)] = nil
	}
	log.Print("Done...")
	log.Println("final allocated", runtime.MemStats.HeapAlloc)
}


func mkmap() map[uint64]interface{} {
	m := make(map[uint64]interface{})
	log.Print("Making big map...")
	for i := 0; i < 1e6; i++ {
		m[uint64(i)] = nil
	}
	log.Print("Done...")

	log.Print("Deleting entries...")
	for i := range m {
		m[i] = nil, false
	}
	log.Println("allocated", runtime.MemStats.HeapAlloc)
	return m
}