We got a few questions about when BLU Acceleration is enabled or disabled in the system. Since this is quite a complex matter, I’m trying to give you an overview here.
BLU Acceleration in SAP Systems: Prerequisites
I’m assuming here that you are already familiar with what BLU Acceleration is, when you can use it for your benefit in an SAP system, and what the prerequisites are for SAP systems. Implementing BLU Acceleration for an SAP BW system is a project involving carefully planning and special hardware and software requirements. It’s certainly much more than setting a few parameters! Therefore, if you are unfamiliar with BLU Acceleration, read the following resources first:
Enabling BLU Acceleration
You are still reading? OK, dear BLU Acceleration experts, now let’s turn to the different possibilities to enable BLU Acceleration:
Enabling BLU Acceleration Manually for Individual Objects
As a default, new BW objects are created as row-organized, even if you have an SAP BW system that meets all the prerequisites for BLU Acceleration. If you only want to test BLU Acceleration for a few selected objects, go to the Data Warehousing Workbench (transaction RSA1) and create new InfoCubes or DataStore objects. Then, in the menu, choose
Extras >
DB Performance >
Clustering. In the following dialog box
Selection of Clustering, choose
Column-Organized and continue with activating the object. Then you are done – you have created an SAP BW object manually with column-organized tables (BLU Acceleration).
Enabling BLU Acceleration as Default with RSADMIN Parameters
So, such a manual procedure is fine for selected objects, but surely, once you have decided that you want to use BLU Acceleration for all newly created SAP BW objects, you don’t want to do this extra step over and over again? Here’s where the RSADMIN parameters come in: When you set them, new objects will be always be created as column-organized (for BLU Acceleration):
SAP BW Object Type |
RSADMIN Parameter |
Available as of SAP Release or SAP Note |
InfoCubes |
DB6_INFOCUBE_USE_CDE |
SAP Notes 2204240 and 2390851
(or the support packages mentioned in these SAP Notes) |
DataStore Objects |
DB6_DSO_USE_CDE |
SAP Notes 2204240 and 2390851
(or the support packages mentioned in these SAP Notes) |
InfoObjects |
DB6_IOBJ_USE_CDE |
Collective SAP Note 1825340
(or the support packages mentioned in this SAP Note) |
PSAs |
DB6_PSA_USE_CDE |
Collective SAP Note 1825340
(or the support packages mentioned in this SAP Note) |
SAP BW temporary tables |
DB6_TMP_USE_CDE |
Collective SAP Note 1825340
(or the support packages mentioned in this SAP Note) |
Before you use the RSADMIN parameters, here’s a word of caution:
Double-check the support package level and the implemented SAP Notes in your system. Depending on your support package level and implemented SAP Notes, your system might behave differently, and a wider or less wide range of RSADMIN parameters is available. Implement all these SAP Notes or the related support packages mentioned in these SAP Notes before you start working with BLU Acceleration.
How Do You Set an RSADMIN Parameter?
- Call the ABAP editor (transaction SE38) and run program SAP_RSADMIN_MAINTAIN.
- Enter the relevant RSADMIN parameter in the OBJECT field and YES in the VALUE field.
- Make sure that the radio button INSERT is selected.
- Choose Execute.
Additional Tip: Use Flat InfoCubes If You Can
When you decide to use BLU Acceleration for InfoCubes, it’s a good idea to use flat InfoCubes instead of the standard InfoCubes with the “star schema” if your system runs on SAP BW 7.4 SP10 or higher.
What is a flat InfoCube? As opposed to a standard InfoCube, a flat InfoCube has only a package dimension table; all other dimension tables and the E fact table are eliminated. The SIDs of the master data are directly stored in the F fact table of the flat InfoCube. This improves system performance when data is loaded.
Recommendation: We recommend that you use flat InfoCubes if possible.
How do you create flat InfoCubes? In the Data Warehousing Workbench (transaction RSA1), create a new InfoCube and pay attention to the
Create New InfoCube dialog: Here you must select the checkboxes
Standard InfoCube and
Flat InfoCube. Then proceed as usual. The flat InfoCube always has a column-organized table format.
Troubleshooting
You Have Flat InfoCubes in Your System Even Though You Don’t Want BLU Acceleration
Even if you do not intend to work with BLU Acceleration, in exceptional cases, you might find flat InfoCubes in your system. This might happen if you activate InfoCubes that are part of BI Content. Some of the InfoCubes in standard SAP BI Content are marked as “flat” and are created as flat InfoCubes when you activate them. This might only happen if you are in an SAP BW system with release 7.4 SP08 or higher and use DB2 10.5 or higher.
So, if you work in a non-BLU system and want to prevent flat InfoCubes from being created, we strongly recommend that you switch off BLU Acceleration completely in your system: Set the RSADMIN parameter DB6_ALLOW_CDE to NO. This will disable the creation of new column-organized BW objects in your system – no need to set any other parameters. Note that you need SAP Note
2019648 or the support packages mentioned in this SAP Note to be able to use the RSADMIN parameter.
Unfortunately, if you already have some unwanted flat InfoCubes in your system, there is no way around deleting and recreating them in row-organized format.
What Do I Do If I Have Accidentally Created BW Objects in the Wrong Format?
The RSADMIN parameters only change the table format of newly created objects, they don’t influence existing objects. So, what do you do if you realize that something went wrong and you now have a few column-organized BW objects in your system that you don’t want? Or you have decided on BLU Acceleration and you want to convert your existing, row-organized BW objects to column-organized?
In many cases, there’s help available: Try program DB6CONV. To convert standard InfoCubes to flat InfoCubes and vice versa, use program RSDU_REPART_UI.
Important note: If you consider using program RSDU_REPART_UI, there is currently an issue with it. Read Hot News in
SAP Note 2472110 carefully.
For more information, see the database administration guide
SAP Business Warehouse on IBM DB2 for Linux, UNIX and Windows.
Problems with P, Q, and Text Tables of InfoObjects
With the RSADMIN parameter DB6_IOBJ_USE_CDE, you can set the table format of InfoObject tables to column-organized. Originally, this meant that only SID tables (/BI*/S*) and X, Y are column-organized, while the rest of the InfoObject tables remained row-organized. As of DB2 10.5 FP5SAP2, the RSADMIN parameter also affects P, Q, and text tables of InfoObjects, which are then also created as column-organized tables.
Sometimes customers report to us that the performance of column-organized P, Q, and text tables causes serious issues. For these cases, it might be advisable to create InfoObjects with P, Q, and text tables with row-organized tables while the rest of the InfoObject tables remain column-organized. For such cases, we have made the RSADMIN parameter DB6_IOBJ_PQT_USE_CDE available.
You Are an Early Adopter of BLU Acceleration? Adapt Fix Pack and Fix Your Objects
The scope of supported objects has grown over time with newer DB2 Fix Packs. In previous Fix Packs of DB2 10.5, a subset of the BW objects was supported. Note, however, that the use of BLU Acceleration in SAP BW with DB2 10.5 with Fix Packs lower than FP5SAP2 is not supported anymore. If you still use a lower Fix Pack, we strongly recommend that you upgrade to FP5SAP2 or higher.
As an early adopter, you might still have some SAP BW objects that have a format that you don’t want because they were created on lower Support Package levels or DB2 Fix Pack levels. For example, you still might have a few row-organized DataStore objects or InfoCubes, while the rest of you SAP BW objects is column-organized. Or you might have InfoObjects with column-organized P, Q, and text tables that you want row-organized, or the other way around.
You can’t change any existing objects by setting RSADMIN parameters, but you can run program DB6CONV and convert these SAP BW objects. The program DB6CONV considers all your RSADMIN parameter settings, so after the conversion, your SAP BW objects will have the format that you set with the RSADMIN parameters.
More Help
For more details about SAP BW and BLU Acceleration, read the database administration guide:
SAP Business Warehouse on IBM DB2 for Linux, UNIX and Windows.
