address completion issues in notmuch-emacs

[Rollins, Jameson]

Hi.  I'm using address completion in notmuch-emacs, but I keep having
problems.  No matter what "Notmuch Address Internal Completion"
customization configuration I use ("sent" or "received") there are tons
of missing addresses that I need.  It seems, though, that the two
configurations might be compliments of each other, and if I could use
both sent *and* received then maybe I would get all the addresses I
need.  Is there some technical reason why the completion doesn't just
use both?

I don't understand the parenthetical comments around these options
either:

( ) sent (more accurate)
(*) received (faster)

Why would they have such performance differences?  And does it really
matter at all?  My understanding is that the addresses are collected
once, so a performance difference at collection seem irrelevant to me,
since I only care about performance when I'm trying to do the actual
completion.

jamie.