For transaction data DataSources that do not provide a delta mechanism, you can set up a delta transfer using indexing selections. For periodic indexing of data, you can define the selections in such a way that only data that may have potentially changed is actually indexed. During indexing, the selections from the SAP HANA database/BWA are first deleted and then replicated again. You can use this type of data for example if the DataSource contains a relatively large amount of data and does not always have to be completely reloaded when changes are made.
The following prerequisites must be met for a DataSource to use the delta by indexing selections:
The DataSource for transaction data only supports deltas by full upload.
The data that has potentially changed can be defined by selections made on the fields in the DataSource. Note that the selection fields do not necessarily have to be key fields.
The extractor can read the selections efficiently.
The following restrictions apply when using the delta by indexing selections:
In a search and analysis model, it is not possible to use delta by delta mechanism and delta by indexing selections at the same time.
Selective deletion from the SAP HANA database/BWA cannot be done in packages. The data volume for the delta transfer is therefore restricted by the memory space.
Define Selection Conditions
Call the indexing selections maintenance screen by executing transaction RODPS_REPL_SEL.
In the Model and Node, select the node who DataSource you want to define the selection conditions for.
Define the selections for the initialization: Create a new table entry for every selection condition. The Delta Using Selective Deletion and Insertion checkbox should not be selected here.
Define the selections for the delta: Create a new table entry for every selection condition and select the Delta Using Selective Deletion and Insertion checkbox. By selecting this checkbox, you ensure that only data that has potentially changed is transferred during periodic indexing.
For more information on maintaining selection conditions, see Specifying Selections for Indexing.
Go to the Administration Cockpit for connectors, search for the model and select the relevant connector.
In the next dialog box, specify when you want indexing to start and the time intervals for periodic indexing. Then press OK to schedule the indexing.
During the first indexing run, the selections are used that the Delta Using Selective Deletion and Insertion field has not been selected for (initial selections). For every subsequent indexing operation (delta replication), the selections are used as follows:
If initial selections and selections for delta indexing have been defined for a specific field, then only the selections where the Delta Using Selective Deletion and Insertion option is selected are used for delta indexing.
If only initial selections have been defined for a specific field, these selections are also used for delta indexing.
The selections (for which the Delta Using Selective Deletion and Insertion option is activated) and the initial selections for fields without any selections for delta indexing are linked with AND. First, the selections are deleted from the SAP HANA database/BWA. Then the selections are re-extracted and transferred to the index.
You have specified the following initial selection:
For the MONTH field: From Value= 200601 and To Value= 201012
For the KOKRS field: From Value= 4711
In addition, you have specified the following selections for delta indexing:
For the MONTH field: From Value= -1 and To Value= +1
The following selections are used for delta indexing on 19th January 2011: (KOKRS EQ 4711) AND (MONTH BT 201012 AND 201102)