Understanding Stack and Heap Allocation in Go: A Beginner's Guide

 While debugging or profiling go program, the main important which need to be taken care is memory allocation and cpu utilization.

Stack vs Heap Memory | What are the Primary Key Differences?

In today topic we are going to understand the memory allocation of go.


Stack is a LIFO data structure, as we know from our data structure studies (check for implementation [generics] [non-generics]). The stack is where Go programme keeps arguments, local variables, and other data for a function. When a function is called, all variables are inserted onto the stack, pushing each and every execution trace into memory. When the function returns, the stack is where data is retrieved.

In Go, the operating system handles threads and typically has a fixed 8 MB of memory. In the event of recursion, the stack needs to be taken into consideration. If the function trace is continuously raised, the programme will crash and display a stack overflow error, therefore we also need to consider that.

Whenever stack memory increased , go runtime copy the current memory sample to a new larger continuous memory. The stack in Go is dynamically allocates till the enough memory available, if its grow more its throw stack overflow error.


In Go, memory is divided into two regions: the stack and the heap.

The stack is used for storing local variables and function parameters. It is a region of memory that is managed automatically by the Go runtime, and it grows and shrinks as needed as a function is called and returned.

The heap is used for storing dynamically allocated memory, such as objects and arrays. It is a region of memory that is not managed automatically by the Go runtime, and it is used for storing data that needs to persist beyond the lifetime of a function.

When you allocate memory on the heap in Go, you use the make or new functions. For example:

// Allocate an array on the heap with make
arr := make([]int, 10)

// Allocate an object on the heap with new
obj := new(MyStruct)
In both cases, the Go runtime will find a suitable location on the heap for the allocated memory, and it will return a pointer to that location.

The stack and heap are managed differently by the Go runtime, and they have different properties. The stack is faster to allocate from and deallocate from, but it is limited in size. The heap is slower to allocate from and deallocate from, but it can grow and shrink as needed.

Stack allocation is faster and more efficient than heap allocation, as the memory for stack-allocated variables is automatically managed by the runtime and there is no need for the programmer to explicitly allocate or free memory. However, stack-allocated variables are only accessible within the function in which they are defined and are not accessible from other functions or goroutines.

Heap-allocated variables, on the other hand, are accessible from any function or goroutine and can be referenced by multiple variables. However, the memory for heap-allocated variables must be explicitly allocated and freed by the programmer, which can be slower and more error-prone.

In Go, the decision of whether to allocate a variable on the stack or the heap is made by the compiler based on the lifetime and size of the variable. Generally, variables with short lifetimes and small sizes are allocated on the stack, while variables with longer lifetimes or larger sizes are allocated on the heap.

It is also possible for the programmer to explicitly specify whether a variable should be stack- or heap-allocated using the new and & operators.

Understanding the difference between stack and heap allocation is important for optimizing the performance of Go programs and for debugging memory-related issues.

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