If the program runs for a long time, it will stumble or crash, or the system memory usage will become higher and higher and do not decrease, it is likely that there will be a memory leak. 1. Observe program behavior: monitor memory usage through tools such as Task Manager (Windows) or Activity Monitor (macOS), top/htop (Linux). If memory continues to grow and there is no sign of release, there may be memory leaks; 2. Use memory analysis tools to locate the source: such as Chrome DevTools (JavaScript), tracemalloc/objgraph (Python), Valgrind (C/C), VisualVM/Eclipse MAT (Java), and compare memory snapshots of different time periods to identify abnormal objects; 3. Check common problems in the code: including forgetting to free memory, circular references, cache not cleared, event listeners not removed, etc., such as forming a self reference in JavaScript or a timer continuously allocating memory not cleared; 4. Methods to prevent memory leaks in daily development: pay attention to resource release, avoid uncontrolled growth of global variables, use weak reference structures, and perform regular stress tests and memory monitoring to discover and solve problems in advance.

If the program runs for a long time, it will stumble or crash, or the system memory usage will become higher and higher and do not decrease, it is likely that there will be a memory leak. To troubleshoot this problem, you don’t need to use complex tools from the beginning. The key is to observe and verify it in an orderly manner.

1. Observe program behavior: judge whether there is any memory leak from performance

A typical symptom of memory leaks is that the longer the program runs, the more memory it consumes and is not released even after the task is executed. You can monitor the memory usage of the program through the system's own Task Manager (Windows) or Activity Monitor (macOS).

• Windows : Open Task Manager → "Performance" tab → View the "Memory" usage curve
• macOS/Linux : Use top or more intuitive htop command line tool
• Server/backend services : Memory trends can be recorded for a long time through monitoring tools such as Prometheus Grafana

If you find that memory usage continues to grow without obvious signs of release, it is necessary to check further.

2. Use memory analysis tools to locate the source of the leak

Different languages have different memory analysis tools. Here are some recommendations for common languages:

• JavaScript (Node.js) : Use Chrome DevTools' Memory panel, and start the program with the --inspect parameter
• Python : You can use the tracemalloc module to track memory allocation, or objgraph to analyze object references
• C/C : Valgrind is a classic choice, especially its memcheck tool
• Java : VisualVM or Eclipse MAT can help you view heap memory snapshots and find suspicious objects

When using these tools, the key is to compare memory snapshots after normal and long runs to see which objects are increasing but not being recycled.

3. Check the FAQ in the code

Many memory leaks are actually caused by encoding habits, such as:

• ? Forgot to free the manually applied memory (C/C)
• ? Loop references cannot be garbage collected (Python, JavaScript, etc.)
• ? The cache has not been cleared, and it grows infinitely
• ? The event listener was not removed in time, causing the closure to hold external variables

For example, in JavaScript, if you write this:

 let obj = {};
obj.self = obj;

This creates a circular reference, and although modern JS engines can mostly handle this situation, memory lag may occur in some old environments or in specific scenarios.

Another common problem is that the timer is not cleaned, such as:

 setInterval(() => {
    const data = fetchHugeData();
}, 1000);

If this function is executed all the time but no one cleanses the cached data, it will keep eating memory.

4. How to prevent memory leaks in daily development

• Pay attention to resource release when writing code, especially non-memory resources such as file handles, network connections, DOM elements.
• Try to avoid uncontrolled growth of global variables
• Use weak reference structures (such as WeakMap , WeakSet ) to store temporary data
• Do stress tests and memory monitoring regularly, especially before going online

Basically that's it. Although memory leaks sound scary, as long as you develop good coding habits and assist with the right tools, most problems can be discovered and solved in advance.

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