Why Does a Simple Field Update in a Django API Endpoint Cause a Major Performance Drop?

I'm encountering a significant performance degradation when executing a field update in a high-frequency Django API endpoint. The endpoint handles around 4000 requests per second when it simply retrieves the last Url object and returns its data. The original implementation is as follows:

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def get(self, request):
    urls = Url.objects.all().last()
    
    if urls:
        data = {"name": urls.name, "url": urls.url}
        return Response(data, status=200)
    return Response({"name": "not found", "url": "not found"}, status=200)

However, when adding a field update, the number of requests per second drops to about 700. The modified code is:

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def get(self, request):
    urls = Url.objects.all().last()
    
    if urls:
        urls.remark = "test remark"
        urls.save()
        
        data = {"name": urls.name, "url": urls.url}
        return Response(data, status=200)
    return Response({"name": "not found", "url": "not found"}, status=200)

I would like to know:

• Why does adding a simple field update (i.e., urls.remark = "test remark" and urls.save()) cause such a dramatic performance decrease?
• What are the best practices for handling high-frequency write operations in Django without impacting performance severely?
• Are there specific configurations or ORM optimizations for Django or the database that can help improve this scenario?

Any insights or recommendations would be greatly appreciated.