The update mode is deferred_varcol. The update mode is deferred_index.
These showplan messages indicate that Adaptive Server may process an update command as a deferred index update.
Adaptive Server uses deferred_varcol
mode
when updating one or more variable-length columns. This update may
be done in deferred or direct mode, depending on information that
is available only at runtime.
Adaptive Server uses deferred_index
mode
when the index is unique or may change as part of the update. In
this mode, Adaptive Server deletes the index entries in direct mode
but inserts them in deferred mode.