All activities executed by the import tool run in what are known as phases. These phases are in turn combined into modules.
These modules have the following properties:
· They can be executed individually
· You can start them as a background process
· You can control the start time of the module.
The import process is divided into the following modules:
All the preparatory and test steps are performed in this module (such as the test import and add-on conflict verification). This module can run during productive operation.
After performing the module Preparation, you have the option of resetting or deleting the queue. If you continue with the module Import 1, then data in the database is changed and you can no longer reset or delete the queue.
Import 1 Module
Dictionary objects are imported and activated in this module (a modification adjustment of the Dictionary objects is also performed, if required). The changes that result from importing and activating the Dictionary are still in an inactive state in the system. The runtime system is still unable to "see" these changes. If you can be sure that no manual changes are being made, and that no transports are being imported into the system, then this module can also run during productive operation. These conditions are usually specified in the production systems.
Import 2 Module
The remaining import steps are performed in this module, including activating the inactive Dictionary nametabs. Here, since changes are being imported in various transport objects, no productive operation can take place while this module is running. This avoids any inconsistencies.
Clean Up Module
All the clean up activities are performed in this module, notably a modification adjustment of the Repository objects. When all modifications have been adjusted, productive operation may resume.
Since the importing of packages can be stopped after every module, the modules Preparation and Import 1 can run during productive operation, as long as no Dictionary objects have been modified. After the system has switched to non-productive operation, as scheduled, the module Import 2 and, if required, the modification adjustment can be performed. After that, productive operation can resume.
Note that during the time between the modules Preparation and Import 2 (or rather, until the modification adjustment), no transports other than the modification adjustment transport can take place, and no manual changes can be made to Repository objects (ABAP programs, Dictionary objects). The time period between Import 1 and Import 2 must be kept as short as possible.