Go memory leak tracking: Go pprof practical guide

pprof tool can be used to analyze the memory usage of Go applications and detect memory leaks. It provides memory profile generation, memory leak identification and real-time analysis capabilities. Generate a memory snapshot by using pprof.Parse and identify the data structures with the most memory allocations using the pprof -allocspace command. At the same time, pprof supports real-time analysis and provides endpoints to remotely access memory usage information.

Go pprof: Memory Leak Tracking Guide

Memory leaks are common problems during the development process, and in serious cases may cause the application to Crashes or performance degradation. Go provides a tool called pprof for analyzing and detecting memory leaks.

pprof Tools

pprof is a set of command line tools that can be used to generate memory profiles of applications and analyze and visualize memory usage. pprof provides multiple configurations for customizing memory profiling for different situations.

Installation

To install pprof, run the following command:

go install github.com/google/pprof/cmd/pprof

Usage

To generate For memory profiling, you can use the pprof.Parse function, which accepts a running application as input and generates a memory snapshot file:

import _ "net/http/pprof"

func main() {
    // ...程序代码...
    // 生成内存快照
    f, err := os.Create("mem.pprof")
    if err != nil {
        log.Fatal(err)
    }
    _ = pprof.WriteHeapProfile(f)
    // ...更多程序代码...
}

Analyze memory leaks

The generated memory snapshot file can be analyzed using the pprof -allocspace command. This command identifies the memory allocated to different data structures and sorts them by allocation size.

For example, to see which data structures take up the most memory, you can use the following command:

pprof -allocspace -top mem.pprof

Real-time analysis

pprof also supports real-time analysis , which allows you to track your application's memory usage and receive notifications when leaks occur. To enable real-time analysis, import the net/http/pprof package into your application:

import _ "net/http/pprof"

This will start an HTTP server that provides various endpoints to analyze memory usage . It can be accessed by accessing the endpoint at http://localhost:6060/debug/pprof/.

Practical Case

Suppose we have a cache structure in a Go application that uses mapping to store key-value pairs:

type Cache struct {
    data map[string]interface{}
}

We may find a memory leak in the cache structure because the map key retains a reference to the value even if we no longer need the value.

To solve this problem, we can use so-called "weak references", which allow the reference to a value to be automatically released when the value is not used by the garbage collector.

import "sync/atomic"

// 使用原子 int 来跟踪值的引用次数
type WeakRef struct {
    refCount int32
}

type Cache struct {
    data map[string]*WeakRef
}

func (c *Cache) Get(key string) interface{} {
    ref := c.data[key]
    if ref == nil {
        return nil
    }
    // 增添对弱引用值的引用次数
    atomic.AddInt32(&ref.refCount, 1)
    return ref.v
}

func (c *Cache) Set(key string, value interface{}) {
    ref := new(WeakRef)
    // 将值包装在弱引用中
    c.data[key] = ref
    ref.v = value
    // 标记对弱引用值的引用
    atomic.StoreInt32(&ref.refCount, 1)
}

In the above code, we use an atomic int to track the number of references to a weak reference value. When the value is no longer needed, the reference count is reduced to 0 and the weak reference is garbage collected. This may resolve a memory leak in the cache structure.

The above is the detailed content of Go memory leak tracking: Go pprof practical guide. For more information, please follow other related articles on the PHP Chinese website!