What is archive.php ? and what is the best cron frequency

I have stupid question what is archive.php and what actually it doing. I have read on PIWIK documents but they didn’t explain in depth.

What would be the best cron scheduled time for Medium/High traffic site?

archive.php pre-processes all reports for all websites and dates that haven;t been pre-processed yet. at the end, it will send email reports and other maintenance tasks. 1 hour or every few hours is a good frequency.

So it is just for reporting ? If its just for reporting then why we need to process it every hour? why don’t just run daily or weekly i meant whenever you want report?

what you see in the web-gui is also a kind of reporting. so to see accumulated data you need to run the archiving.