04b1928e_t___import_utility__exp___imp___Description
[EXP Option] consistent [Default value] N [Description] 
Specifies the set transaction read only statement for export, ensuring data consistency. This option should be set to “Y” if activity is anticipated while the exp command is executing. If ‘Y’ is set, confirm that there is sufficient undo segment space to avoid the export session getting the ORA-1555 Snapshot too old error.
Oracle export / import utility (exp / imp)
Description