long PATH, LD_LIBRARY_PATH, … – what kind of performance impact do they have?

• https://en.wikipedia.org/wiki/PATH_(variable)
• https://en.wikipedia.org/wiki/LD_LIBRARY_PATH
• https://en.wikipedia.org/wiki/LIBPATH

A long PATH… makes the OS …

1. "… access the disk quite often, hence there is a lot of disk I/O" – do you agree?
2. "… compute a lot of …, hence a high CPU load" – do you agree?
3. …

I got involved in a rather "controversial" discussion on that. I voted for (1). What are you voting for?

I posted this issue at http://www.unix.com/shell-programming-scripting/238465-long-path-ld_library_path-libpath-what-kind-performance-impact-do-they-have.html as well.