UniverseSettings.Asynchronous - what are the guidelines?

To help 'Evgeni' understand the use of the asynchronous=True setting in universe selection within QuantConnect, here are the pros and cons, as well as guidelines on when to use it:

Pros of Asynchronous Execution:

• Increased Performance: By enabling asynchronous execution, the universe selection can run concurrently, which can speed up your algorithm, especially when dealing with large datasets or complex universe selection logic.
• Efficient Resource Utilization: This concurrent processing allows better utilization of CPU resources, which can be beneficial in backtesting scenarios where multiple operations need to be handled simultaneously.

Cons and Considerations:

• Complexity in Debugging: Asynchronous execution introduces complexity in debugging due to non-linear execution flow. Care must be taken to understand the order of operations.
• History Request Limitation: History requests should not be made within the filter function when using asynchronous execution. The algorithm time may not match your expectations, and history requests rely on the algorithm’s time being predictable.
• Potential for Unexpected Behavior: Since the default setting is False, enabling it requires careful consideration of your algorithm’s logic, ensuring it does not rely on sequential data processing affected by asynchronous execution.

When to Use:

• Performance Gains: Use this setting when your algorithm involves processing a large universe or complex selection logic that would benefit significantly from improved execution speed.
• Avoid When Time-Sensitive: If your algorithm relies on precise, time-dependent sequential operations or uses history data that must be aligned with a specific algorithm time, it's safer to keep this setting as False.

Overall, asynchronous=True can be a powerful tool for improving algorithm performance but comes with the trade-off of increased complexity and potential for unexpected behavior if not used carefully. Evaluate your algorithm's specific needs and the nature of its operations before deciding to utilize asynchronous execution.

Sources: Universe Settings - QuantConnect.com, Settings - QuantConnect.com, Key Concepts - QuantConnect.com, Alpaca - QuantConnect.com, Asynchronous Universe Regression Algorithm