Azure function stops running sometimes

Question

I have an azure function that seems to just stop / crash during it's run at a point. No errors appear on my logs. It only happens some of the times for some reason. Best clue so far that I have found is that it seems to happen when memory usage is high, about 2gb (checked max memory working set). How can I fix the issue?

Answer 1

@Joni Rokkanen I believe you might have already reached out to the support to review the root cause of the high memory of your function app. This would need to review the dumps and logs and the better solution is to reach out to us through one-on-one support as this mostly is the memory leak issue in the code.

If anyone can collect and review the memory dumps, then this would point the piece of code or data structures, variable using the highest memory.

But in general, before reaching out anyone can try below steps to fix the issue:

• Optimize your code to reduce memory usage. This can include reducing the size of data structures, using more efficient algorithms, and minimizing the use of global variables.
• Use a more powerful instance size for your Function App. This can provide more memory and processing power to handle high memory usage.
• Use Azure Application Insights to monitor your function's memory usage and identify any memory leaks or other issues that may be causing the crashes.
• Consider using Durable Functions to break down your function into smaller, more manageable functions that can be executed in parallel or sequentially. This can help reduce memory usage and improve performance.

In case if you are still looking for assistance or don't have the support plan then please let me know so I can enable one time support request on your subscription.

Answer 2

Hello Joni Rokkanen

If your Azure Function is crashing or stopping during its run, particularly when the memory usage is high, there are a few steps you can take to troubleshoot and address the issue:

Monitor memory usage: Continuously monitor the memory usage of your Azure Function during its execution. Azure provides metrics and monitoring capabilities that allow you to track memory consumption. Keep an eye on memory usage trends and check if it consistently reaches 2GB before the crashes occur.

Optimize memory usage: Review your Azure Function's code and logic to identify any areas where memory usage can be optimized. Look for potential memory leaks, inefficient data structures, or excessive memory allocations. Ensure that you're disposing of any resources or objects properly to avoid unnecessary memory consumption.

Adjust the memory allocation: Depending on your Azure Function's requirements and resource demands, you can consider adjusting the memory allocation for your function. Azure Functions provides options to configure the allocated memory for individual functions. You can try increasing the memory allocation to provide more headroom for your function's execution.

Break down large operations: If your Azure Function is performing large or memory-intensive operations, consider breaking them down into smaller, more manageable chunks. This can help reduce the memory footprint during each iteration and avoid hitting memory limits.

Optimize dependencies and libraries: Evaluate the dependencies and external libraries used by your Azure Function. Make sure you're using the latest versions and consider optimizing or removing any unnecessary dependencies. Some libraries may have memory-related issues or excessive memory requirements that could impact your function's stability.

Enable diagnostic logging: Enable more detailed diagnostic logging for your Azure Function. This can help capture any errors or exceptions that might not be visible in the standard logs. Consider logging the memory usage at critical points in your code to get more insight into the behavior when it approaches the 2GB limit.

Scale-out and load balancing: If your Azure Function experiences high memory usage and crashes during peak load periods, consider scaling out your function by increasing the number of instances. This can help distribute the workload and memory usage across multiple instances, reducing the likelihood of hitting memory limits.

Contact Azure Support: If you have exhausted all the above steps and are still experiencing issues, it's advisable to reach out to Azure Support. They can analyze your specific Azure Function configuration and provide additional guidance and assistance to resolve the problem.

Remember to thoroughly test any changes or optimizations in a controlled environment before deploying them to production to ensure stability and reliability.

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