Maps, slices, and the Go GC

In this section, we discuss the operation of the Go GC in relation to maps and slices. The purpose of this section is to let you write code that makes the work of the GC easier.

Using slices

The example in this section uses a slice to store a large number of structures in order to show how slice allocation is related to the operation of the GC. Each structure stores two integer values. This is implemented in sliceGC.go as follows:

package main
import (
    "runtime"
)
type data struct {
    i, j int
}
func main() {
    var N = 80000000
    var structure []data
    for i := 0; i < N; i++ {
        value := int(i)
        structure = append(structure, data{value, value})
    }
    runtime.GC()
    _ = structure[0]
}

The last statement, (_ = structure[0]), is used to prevent the GC from garbage collecting the structure variable too early, as it is not referenced or used outside of the for loop. The same technique will be used...