Bulk and Incremental Copy Processing
The processing for a bulk copy is similar to a MODIFY statement, except that the data comes from an external source rather than an existing table. For a bulk copy, the following occurs:
1. The COPY statement reads all data from the source.
2. The COPY statement deposits the data in the Data Manipulation Facility (DMF) sorter.
3. The sorter sorts all data into the required order.
Note: For a heap table, no sorting is done.
4. The COPY extracts the data from the sorter, builds the table, and populates the table.
In contrast, for an incremental copy, the sequence is as follows:
1. Reads one record from the external file.
2. Adds to the table as an insert.
3. Repeats these steps until the data has been copied.