Bulk and Incremental Copy
When copying data to a table, the COPY FROM statement can run in either of the following modes:
• Bulk copy
A bulk copy is a copy operation optimized for speed that allows the DBMS Server to exploit group writes and minimal transaction logging. Bulk copying is done whenever the characteristics of the target table allows. The bulk copy can be performed from any source file, either unformatted or formatted.
Doing an unformatted bulk copy from a binary file is the fastest method to copy large amounts of data.
• Incremental copy
In incremental mode, data is added to the table using inserts, causing single-page writes and full transaction logging. Incremental mode is used for the copy whenever the characteristics of the target table do not allow a bulk copy to be performed.
The COPY statement does not explicitly indicate whether a bulk copy or incremental copy is to be used. The DBMS Server makes the decision based on the state of the target table.
The COPY statement allows some additional WITH-options which only apply to a bulk copy. If your COPY statement includes any of these additional WITH-options, and a bulk copy cannot be performed, a runtime error results and the COPY statement is rejected.