Is this someplace where thread specific cache would make sense and the cache dies at the end of a request?
That is, you need to get the person's name several times to customize a page, in several different packages etc, that are used to build a final page.
Maybe if the query is 1ms, it doesn't matter at all?
You could also time util_memoize just call it 1000 times with time and find out! :) http://www.tcl.tk/man/tcl8.4/TclCmd/time.htm
Then you'll now if it takes > 1ms or not.
