Hi, this thread from emacs-devel:

 Yest. 10:40 [4/309] Eli Zaretskii, Ken Raeburn, npostavs@users.sourceforge.net, Paul Eggert, Stefan Monnier, Andreas Schwab, Richard Stallman, Lars Ingebrigtsen, Daniel Colascione, Philipp Stephani, Lars Brinkhoff, Perry E. Metzger, Noam Postavsky, Fabrice Popineau, Jérémie Courrèges-Anglas, Simon Leinen, Alp Aker, Ken Brown, Phil Sainty, Yuri Khan, Clément Pit--Claudel, Robert Pluim, Phillip Lord, Alan Mackenzie           Skipping unexec via a big .elc file (attachment inbox signed unread)

brought notmuch-emacs to a grinding halt on a system which 
otherwise was used far below memory capapilities (8G RAM, 4.5GB
swap, AMD64, emacs compiled from source with 64 bit), later the
OMM killer got it.


Is this to be expected?

Thanks, Gregor