When you run a session that uses an external loader, the Integration Service creates a control file and a target flat file. The control file contains information such as data format and loading instructions for the external loader. The control file has an extension of .ctl. You can view the control file and the target flat file in the target file directory.
When you run a session, the Integration Service deletes and recreates the target file. The external loader uses the control file to load session output to the database. The Integration Service processes datetime data before loading to the database in the following ways:
If the session is configured to trim subseconds, the Integration Service processes datetime data with a precision of 19.
If the session is not configured to trim subseconds, the Integration Service processes datetime data based on the precision specified in the target flat file. Precision ranges from 19 to 29. Subseconds are trimmed according to the precision specified.
If the precision specified in the target file is greater than that specified for the database, the Integration Service limits the precision to the maximum precision specified for the database.
The Integration Service waits for all external loading to complete before it performs post-session commands, runs external procedures, and sends post-session email.
The Integration Service writes external loader initialization and completion messages in the session log. For more information about the external loader performance, check the external loader log. The loader saves the log in the same directory as the target flat files. The default extension for external loader logs is .ldrlog.
The behavior of the external loader depends on how you choose to load the data. You can load data to a named pipe or to a flat file.