gcc 3.2 transition clarification

[Jack Howarth <howarth@bromo.msbb.uc.edu>]

   Could someone clarify the process by which sid will be
rebuilt with gcc 3.2? I understand that now gcc-defaults
has changed and gcc 3.2 is the default compiler. However it
is unclear if the process of rebuilding sid in bulk will be
carried out in sid itself or done separately and bulk uploaded
into sid. I ask because currently it seems that things are
randomly getting built in sid without any bulk uploads yet.
Thanks in advance for any clarifications.
                     Jack