To answer this question, you need to understand the concept of a change run in the context of data processing.
Let's go through each option to understand why it is correct or incorrect:
Option A) Activates the new Master data and Hierarchy data - This option is correct because during a change run, the new master data and hierarchy data are activated. This means that any changes made to the master data or hierarchy data will be applied and made active in the system.
Option B) Aggregates are realigned and recalculated - This option is correct because during a change run, the aggregates are realigned and recalculated. Aggregates are pre-calculated summaries of data that improve the performance of data queries. When changes are made to the data, the aggregates need to be updated to reflect the changes.
Option C) Always reads data from the InfoCube to realign aggregates - This option is incorrect because during a change run, the system does not always read data from the InfoCube to realign aggregates. Instead, it uses other mechanisms such as delta queues or change logs to identify the changes that need to be applied to the aggregates.
Option D) Aggregates are not affected by change run - This option is incorrect because during a change run, the aggregates are indeed affected. As mentioned earlier, the aggregates need to be realigned and recalculated to reflect the changes made to the data.
Therefore, the correct answer is A and B. These options correctly describe the actions that occur during a change run.