Hi Mehdi,

Data Actions and client-side Aggregates concurrently start to fetch data after the Screen loads. 

Would suggest you to read documentation.

https://success.outsystems.com/Documentation/11/Reference/OutSystems_Language/Interfaces/Adding_Data_and_Logic/Data_Action

Regards,

Divyanshu

Hello

Both the Aggregate and data action run parallel, 

There is video available in course with a good explanation

have a look at it 

https://www.outsystems.com/training/lesson/1947/displaying-data-on-screens?LearningPathId=18

Best Regards

Tousif Khan

Hi @Mehdi Hadjian Hosseinabadi ,

I'm adding this document, you can take a look to get more clearer understanding about screen and block life circle: https://success.outsystems.com/Documentation/11/Developing_an_Application/Implement_Application_Logic/Screen_and_Block_Lifecycle_Events

The document does mentions: 

Regards,

Khuong

Hi @Mehdi,

I think the answers above gave a clear answer to your question, but i have 1 addition:

Each Aggregate or Data Action that is configured to run at start will start async, and will start and end independent of each other. 

But there's an exception!
When you have dependencies between Aggregates or Data Actions the system automatically chains the requests. 
For example: if you use the result of an Aggregate inside a Data Action (or the other way around), the second request will only be executed after the first request is completed.

Hope this helps you further.

Kind regards,

Jobbe Maas