Hello TheNerd-0042,
Welcome to the Microsoft Q&A and thank you for posting your questions here.
I understand that you would like to know reason a COPY Activity shows that it took long time in duration, but when you checked the sub-tasks, it has actually taken less time.
Regarding your explanation and the image provided, it looks like a discrepancy between the overall duration of a COPY Activity and the time taken by its sub-tasks, makes it confusing, but there are a few primary reasons for this:
- The total duration of a process includes not only the execution time of sub-tasks but also overhead time, such as setting up the environment and initializing connections.
- Secondly, when sub-tasks run concurrently, their individual durations might not sum up to the total duration; for instance, two 5-minute tasks running in parallel may still result in a total duration of around 5 minutes.
- Additionally, tasks may experience queue and wait times for resource availability, which are part of the total duration but not the execution time.
- Delays in logging and monitoring systems can also cause discrepancies in reported times.
To resolve this issue:
- Check detailed logs to understand where the time is being spent. Look for any significant delays or waiting periods - https://learn.microsoft.com/en-us/azure/azure-monitor/essentials/tutorial-resource-logs
- Ensure that sufficient resources are allocated to avoid bottlenecks - https://learn.microsoft.com/en-us/azure/well-architected/performance-efficiency/continuous-performance-optimize
- Check if there are any unnecessary steps or configurations that might be adding to the overhead - https://learn.microsoft.com/en-us/azure/well-architected/performance-efficiency/optimize-data-performance
Use the links for more detailed steps.
I hope this is helpful! Do not hesitate to let me know if you have any other questions.
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