In apache 1.3 it was far from unusual to do a complete bundled compile and restart the entire thing every time because there were gremlins that showed up when you dynamically loaded the more complex modules often enough that it was operationally less aggravating overall to take the brute force approach (I did quite a bit of that a couple decades back, for my sins).

apache 2+ is a very different (and rather more robust) beast, and also has the 'graceful restart' system - see https://httpd.apache.org/docs/2.4/stopping.html - which makes the parent tell its worker processes to drain their request queues, -then- exit, after which each one is replaced in turn until you've fully upgraded to the new configuration+code.

This approach has its disadvantages, of course, but not that morally different from how erlang processes hot reload into new code, and once you knew what you were doing the end result was simple, predictable, and nicely transparent to end users.