CDC data extraction Lessons Learned, Tips & Tricks – Part 1
Change Data Capture (CDC) delta extraction is actually quite simple, and there are already some good blogs out there explaining it pretty good. However, in practical project work with our customers, we have come across one or the other warning or error message that was not immediately self-explanatory. To save your valuable time, we want to share our learnings with you in this short blog series.
Let’s start with a warning you might run into when using automatic CDC.
Automatic CDC & key definition
To extract purchasing data in the delta, we created a CDS view on the EKPO table and activated „automatic CDC delta“ via annotation. For any reason we wanted the fields ebeln, ebelp (actual table key) and also aedat as CDS view key. This leads to the warning: “Definition of view too complex for automatic CDS”.
If you now try to load the data in delta mode directly into BW via DTP, this results in an error message:
If you try to load data via InfoPackage and PSA, only a full upload InfoPackage can be created, no InfoPackage for delta load.
Explanation and solution
If the CDS view key is different from the key of underlaying table (in our example aedat is not a key field of table EKPO), the view definition gets too complex for automatic CDC delta extraction.
In order to make automatic CDC extraction working, make CDS view key same as underlaying table key, or key of main table in case of joins.
In the following blog posts of this series, we will share more possible sources of error, pitfalls and points to consider when using CDC delta extraction.