How is a request to the server handled?

Question

PHP

Hello. Tell me how the server works when the client requests some page.
For example:
1. There are several pages. On everyone there is an initialization of sessions. If you set a wait on one of the pages or the code will be executed for a very long time, then the second page will not open. How to fix the situation with sessions?
2. What is better to take for the site? 1 core 2000 MHz or 2 x 1000? Perhaps it all depends on the type of site, but at least approximately. It turns out that with 2 cores it will be possible to show 2 pages in parallel?

Answer 1

1) do not keep the session open during lengthy procedures. Sessions are a blocking mechanism. An already open session can be closed by calling session_write_close
2) doesn't matter