Two async postbacks at the same time?

Question

I have two timers that each immediately trigger an async postback once the page is rendered. Each of the async postbacks load some expensive data. So, when I debug this, it appears that the first async postback occurs and it's results are displayed then the second async postback occurs only after the first async postback completes.

So, my question is are async postbacks queued by the PageRequestManager or something/whatever? I guess what I am saying is that I want to perform two async postbacks at the same time and handle the results as they are ready. Is there a way I can make this happen? Could what I am seeing be a result of debugging?

Disclaimer: We do not have many users, but the page needs to load fast. Therefore we don't care how many threads it takes to handle a single page.

Any ideas? Thanks for reading.

Answer 1

You cannot make two async postbacks at the same time because they have to access to:

1. to user Session and you cannot to synchronize session modifications between 2 requestst
2. to Page ViewState and you cannot return with responses two different unrelated ViewStates, those recreated on every async-request.

You can make few async requests to sessionless HttpHandlers. Correct me if i am wrong :)