For information on converting to InterSystems IRIS, see the
InterSystems IRIS Adoption Guide
and the InterSystems IRIS In-Place Conversion Guide,
both available on the WRC Distributions page (login required).
Method called on the DB server when it is started up.
Must ONLY be called for mode 4 or 5.
Deletes all the 'Upd' entries, all the ^Hi indices.
It does this with journalling disabled, so that these
changes are not reflected on the shadow server.
Sets the mode to signal 'delayed' mode