COMMIT
Default: N
Specifies whether Import should commit after each array insert. By default, Import
commits only after loading each table, and Import performs a rollback when an
error occurs, before continuing with the next object.
If a table has nested table columns or attributes, the contents of the nested tables are
imported as separate tables. Therefore, the contents of the nested tables are always
committed in a transaction distinct from the transaction used to commit the outer
table.
If COMMIT=N and a table is partitioned, each partition and subpartition in the
Export file is imported in a separate transaction.
Specifying COMMIT=Y prevents rollback segments from growing inordinately
large and improves the performance of large imports. Specifying COMMIT=Y is
advisable if the table has a uniqueness constraint. If the import is restarted, any
rows that have already been imported are rejected with a nonfatal error.
If a table does not have a uniqueness constraint, Import could produce duplicate
rows when you reimport the data.
For tables containing LONG, LOB, BFILE, REF, ROWID, UROWID, DATE, or type
columns, array inserts are not done. If COMMIT=Y, Import commits these tables
after each row.