In the data transfer process (DTP) maintenance screen, you can specify that data is not extracted from the PSA of the DataSource but is requested directly from the data source at DTP runtime. The flag Do not extract from PSA; use direct access to data source is displayed for the Full extraction mode, if the DTP source is a DataSource. We recommend that you only use this flag for small data sets, especially small master data sets.
Extraction is based on synchronous direct access to the DataSource, where the data is not displayed in a query (as is usually the case with direct access). Instead the data is directly updated to a data target without being saved in the PSA.
This flag is also available for DataSources from operational data provisioning (ODP) source systems. In this case, extraction is performed using the ODP data replication interface and you can also load mass data directly into an InfoProvider.
More information: Loading Data from ODP Source Systems Directly into InfoProviders
If you set this flag, you do not need an InfoPackage to extract data from the source.
Note that the file is available on the server when you are extracting from a file source system.
Extraction using the direct access mode has the following implications, especially for SAP source systems (SAPI extraction):
The data is extracted synchronously. This places special requirements on main memory, especially in the source system.
The SAPI extractors might behave differently than for asynchronous loading, because they are informed by direct access.
No SAPI customer enhancements are processed. Fields that were added to the DataSource with append technology are left empty. Exits RSAP0001, exit_saplrsap_001, exit_saplrsap_002 and exit_saplrsap_004 are not executed.
If errors occur during processing, you need to extract the data again in BW because the PSA is not available in the buffer. This means that it is not possible to create a delta.
The filter in the DTP only contains fields that are allowed as selection fields by the DataSource. If a PSA is available, you can use all the fields for filtering in the DTP.