Normal mode inserts the rows one by one into the target table. Bulk mode inserts rows into the SAP ECC target table at the same time.

Normal mode is the default load method. You must use the normal mode to load data into the SAP system for any or all of the following conditions:

The mapping contains an Update Strategy transformation.
The packet has mixed operations.
You want to override the default UPDATE statement for each target in a target definition.
You want to view the SAP rejected rows in the bad file.
You manually edit the primary keys in the Designer and want to update or delete rows based on the modified key.
You want to update select fields in the SAP target table.

When you load data using bulk mode, all the rows within a packet must have the same operation, such as insert, update, or delete. When the rows within a packet have mixed operations, then the PowerCenter Integration Service reverts to normal load for the packet.

When the PowerCenter Integration Service shifts from bulk loading to normal loading, it writes an informational message in the sessions log. When a bulk load fails, PowerCenter Integration Service updates the session log with load statistics. It updates the session log with the number of rows in the packet that were loaded into SAP and the number of rows that were rejected. The PowerCenter Integration Service does not write the reject rows rejected by SAP in the reject file that caused the bulk load to fail.