In ADSO, the need or requirement for three tables (Active Data, Inbound & Change Log) depends on the type of data modelling scenarios & requirements.
Not all the scenarios require the three tables, and it is very much possible to configure the ADSO with only single or two tables, all depends on the use case.
Use of ADSO Tables:
- Inbound Table: It is the temporary storage location for all the new data, before the activation of the request.
- Active Table: It contains all the active and consolidated data after the activation request turns on.
- Change Log Table: It helps store the historical changes that are required for delta processing.
Various Scenarios:
- When all three tables are required: When the data loads are ADSO enabled. The change log tables, here store the changes for propagating the delta downstream. The active data holds the consolidated active data and inbound tables store the raw delta data.
- When the data staging without delta propagation is required, then we can use only inbound or active data tables. Here, the inbound tables can be used for staging the data during the loads whereas active data table holds the final & activated data. The change log table is not required as there is no delta propagation.
- When we use Direct Update ADSO where No activation or delta is required, then only active data table can be used. This data can be written directly bypassing the inbound table. No delta or change tracking is required for this.
- When reporting is not required on ADSO and only delta tracking is being done, the inbound table temporarily stages the data, and a change log is used for delta propagation.
Thus, not all the three tables are required in the ADSO. If the scenario is Delta Enabled, then we need all three. If simple staging without deltas are required, then inbound and active can work. If only reporting need to be done, then active data table will suffice. Accordingly, we can optimize the performance and storage usage in SAP BW/HANA.