lThe transport control program tp is a tool for controlling transports between R/3 Systems and for performing R/3 Release upgrades. tp tracks transports by controlling exports and imports of objects between R/3 Systems, ensures that the steps in exporting and importing objects are performed in the correct order, and ensures that imports into a target system are done in the same order as the exports from the source systems.
ltp is an operating system level tool using special programs (such as C programs), operating system commands, and ABAP programs in R/3.
ltp performs exports and imports separately. In the export phase, the objects to be transported are extracted from the database of the source system and stored in files in the transport directory. In the import phase, the objects are added to the database of the target system. An export should always take place immediately after the change request has been released, so that the objects can be freed for further modification.
lThere is no automatic mechanism that imports a request into a target system immediately after export. In R/3 Releases before 3.1H (without TMS functionality), imports are performed using tp commands at the operating system level. After 3.1H, using the TMS, imports are instead performed from within R/3.
lAlthough most transport activities can be performed using TMS, you may find the need to use tp commands for exceptional cases. Because import buffers and import queues are identical, using tp and using TMS produces consistent results.
lImports performed using tp at the operating system level should be restricted to exceptional cases, such as imports to multiple clients.
lThere are two commands for importing to a target system using tp at the operating system level:
- Ÿtpclient_number>Analogous to the default import of TMS, this command imports all waiting change requests in the correct sequence (their export sequence).
- Ÿtpclient_number> u0Analogous to the TMS preliminary import,
lImporting individual requests is not recommended as the correct order of requests is not necessarily maintained, and thus newer versions of objects may be overwritten by older versions through the regular import of all waiting requests. To ensure that the objects imported through an individual transport are not overwritten by an older version, only use unconditional mode 0 (option u0) when starting individual imports. Using this mode is analogous to the TMS preliminary import and causes the change request to remain in the list of requests to be imported. When the regular transport takes place, the request will automatically be imported again in the export sequence. Individual imports only should be performed in exceptional cases.
lProcessing imports out of order can result in severe inconsistencies in the target system. These are hard to diagnose. If you wanted to import single requests not as preliminary import (NOT recommended), you would use tp import <change request> <target SID> client=<client_number> (without the option u0).
lR3trans is a transport tool at the operating system level used to transport data between R/3 Systems. R3trans is also used when installing new R/3 Systems, performing R/3 Release updates, and for logical backups. R3trans is usually called by other programs such as tp and the upgrade control program R3up.
lFor transports between R/3 Systems, to access the database, tp indirectly calls R3trans – by causing Unix to issue a forc(), Windows NT to issue a CreateProcess(), and AS/400 to issue a spawn(). During export, R3trans stores the object data extracted from the database in data files in the transport subdirectory data. The format of these data files, R3trans format, is independent of the platform. During import, R3trans reuses these data files.
lDirect use of R3trans is not supported but may be required in exceptional cases. In case of transports, R3trans should always be used through tp. Import steps differ for the different object types. Further activities may be required in addition to R3trans activities. tp ensures that all export and import steps, including R3trans activities, are completed successfully.
lUpward compatibility: R3trans writes data using a standard R/3 transport format. Thus you can export data with an old R3trans version and import data with a new version of R3trans. You can also transport between different databases or operating systems.
lNote that although exports and imports are independent of the R3trans version, the database platform, or the operating system, SAP does not support using tp or R3rans for transports between different R/3 Releases.