If a restart occurs during a BTEQ import, BTEQ resubmits the last uncompleted row insert after the system recovers from the restart. Identity column numbering continues from there. However, restart can cause duplicates, because BTEQ may do a reinsert even if the previous insert has completed. Duplicates are not detected if the target table is MULTISET and not defined with a UPI.
If a session ends abnormally during a mainframe-attached BTEQ import, the last uncompleted row insert is not resubmitted and associated data may be lost. Associated data may also be lost if a workstation-attached BTEQ import session is aborted and there is no other session through which to resubmit the insert.
In both cases, manually restarting the import can cause duplicate rows if rows newly inserted before the session ended are not deleted unless the target table is defined with a UPI.