Question

For example lets take ob is not turned on . Everytime php engine faces echo it will return that thing to the browser right? So what I am thinking about ob is that collecting all data and not sending to the browser one at a time will result in load time positively . But if I am wrong could you exaplin what is the real (“behind the scence standing”) meaning in PHP and where you are going to use it ?

Answer 1

If your PHP script executes quickly it will make no noticable difference. If your PHP script executes slowly, but the output is short (small HTML file) it will make no difference.

The only way it would make a difference is if the script executes for a long time (returning huge amounts of data from a query for example) AND the output HTML is so large that it makes a visible difference to the user for it to be sent in smaller snippets as the output is larger than their bandwidth.

Basically, it it is a small file that executes quickly, it won’t be visible as the user only downloads a small amount of data from the server. If the code takes a long time to execute but returns a small amount of HTML, the user will still have to wait for the code execution to finish before they get the output from the server. If the code takes a long time to execute AND the output is so large that the server can send it to the user quicker than they are able to download it (server bandwidth out-paces the user bandwidth) then there will be a measurable difference to the user of the site – but only then.