Advanced Techniques in Go Programming/

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Maps, Slices, and the Go Garbage Collector

Maps, Slices, and the Go Garbage Collector

Let’s learn about maps, slices, and the Go garbage collector.

We'll cover the following...

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

Using a slice

The example in this section uses a slice to store a large number of structures. Each structure stores two integer values. This is implemented in sliceGC.go as follows:

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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 since it is not referenced or used outside of the for loop. The same technique will be used in the three Go programs that follow.

Apart from this important detail, a for loop is used for putting all values into structures that are stored in the structure slice variable. An equivalent way of doing that is the use of ...