The figure shows the data replication from SAP source system to SAP HANA via SAP LT Replication Server.
Scenario
You want to adjust the structure (enhancement or deletion) or the data types (for example, new field length) of a table, with active database triggers, either manually or by an import.
Differentiation
- Simple structure changes are operations, such as adding an additional non-key field.
- Complex structure changes are operations.
Differentiating Types of Changes
| Type of Change | Field Type | Process |
|---|---|---|
| Simple Change | Non-Key | Automated |
| Simple Change | Key | Manual Effort |
| Complex Change | Non-Key | Manual Effort |
| Complex Change | Key | Manual Effort |
Simple changes to non-key fields are handled by SLT automatically. SLT checks the structure automatically. A new column is detected and added to the end of the SAP HANA table. This also occurs when the column is added somewhere in between the table structure.
All other cases (simple changes to key fields or complex changes to all types of fields) require manual effort. The process of handling software maintenance events is described in the SLT Application Operations guide. This is not a standard function. SLT is unable to ensure that the system will not process an operation on the table while delta recordings (triggers) are inactive. Data inconsistencies can appear, in which a new initial load is required.
The ABAP data dictionary blocks any structural changes to a table when the table structure is changed while the trigger is active. Therefore, the table activation is canceled. A transport containing structural changes for a table where a trigger is active ends with an error in the ABAP Dictionary Activation step.
For information on how to avoid this situation, see the following notes:
- SAP Note 1655725: Check for database trigger made less strict. With this note, the dictionary check enables the activation of a table with active triggers, when it is a simple change.
- SAP Note 1749824: Treatment of SLT triggers during transport. A complex change for a table with active triggers leads to an error within the activation. With this note, the dictionary check automatically deletes the trigger if a complex change is executed. The replication for the table must start again (including the initial load) after the deletion of triggers.
Note
The notes can be applied in the source system for SAP NetWeaver Basis 7.00 - 7.30 and are included within SAP NW Basis 7.31 SP5 or higher. For SAP NW Basis 6.40 or lower, a dictionary check for active triggers is unavailable. Simple changes are executed by SLT, while complex changes lead to a replication error.
Note