Today, when I was still fishing, the operation and maintenance team came over to pat my shoulder and told me that the memory of the current network was leaked. So I stopped stoking and started to investigate the problem.
Use the pprof flame diagram to analyze the memory usage of the program and find out the causes and location of the memory leak. This xdm I don’t understand will be introduced later in an article.
Why does slicing leak memory?
Slicing causes memory leakage generally because the operation on slices causes the slice to increase the capacity, but the element is not released after being used, resulting in memory leakage.
Specifically, the capacity of the underlying array of slices is usually larger than the actual number of elements. If the capacity of slices is too large and continues to grow, it will lead to too large the underlying array, which will lead to memory leakage.
If we manually copy the unused part of the underlying array into a new array through the copy method after using the slice, we can free up the memory occupied by the underlying array.
In addition, when we use slices, we no longer need the elements in it, and we can also free up the memory of the underlying array by setting it to nil.
What are the reasons for memory leakage when slicing?
Slicing causes memory leakage:
- Reference not released: When a slice is no longer used, if it is still referenced by other variables, the underlying array pointed to by the slice will not be garbage collected. In this case, the references to other variables need to be released.
- Long-term holding: During the process of using slices, if you do not pay attention to releasing the slices in time, it will cause the memory occupied by the slices to be unreleased for a long time, and eventually lead to memory leakage.
- Creating large quantities: Creating large quantities of slices in a loop. If not released in time, it will cause the memory usage to continue to increase, which will eventually lead to memory leakage.
- Too large capacity: Too large capacity of slices will cause the slice to occupy a large amount of memory. If not released in time, it will also lead to memory leakage.
To sum up, if we want to avoid memory leakage caused by slicing, we need to develop good programming habits when writing code in daily life.
There are several ways to avoid slicing memory leaks:
- Timely release: When the slice is no longer in use, release the slice in time so that the underlying array can be garbage collected.
- Multiplex slices: Try to multiplex existing slices to avoid creating large numbers of slices in a loop.
- Control capacity: When creating slices, control the capacity size reasonably to avoid excessive memory usage by excessive capacity.
- Use copy: When operating on slices, if the original slice is not needed, you can use copy to copy the slice into a new slice and then release the original slice.
For example, look at the following code: (Forgive me for not being convenient for posting online problem code blocks)
func main() {
var s []int
for i := 0; i < 1000000; i++ {
s = append(s, i)
}
}In the above code, we created a slice with a capacity of 10 and performed 1000,000 appends to it. Because the underlying array is not capable of sufficient capacity, larger arrays will be redistributed continuously. If the original array is not released in time, memory leakage will occur.
In order to avoid memory leakage, we can set it to nil when the slice is no longer in use, and actively trigger garbage collection by calling () to free the underlying array that is no longer in use. For example:
func main() {
s := make([]int, 0, 10)
for i := 0; i < 1000000; i++ {
s = append(s, i)
}
s = nil // Set the slice to nil, free the underlying array () // Actively trigger garbage collection}Summarize
Shortening the life cycle of slices as much as possible, rationally using the capacity and length of slices, and timely releasing the underlying array are the key to solving the problem of slice memory leakage.
This is the end of this article about several reasons why Go slicing leads to memory leaks. For more information about Go slicing memory leaks, please search for my previous articles or continue browsing the related articles below. I hope everyone will support me in the future!