Delta loading procedure from Write Optimized DSO to Infocube

Question

Hi All,
We are using Write optimized DSO in our project to which I am loading data using Standard DSO 0FI_GL_12
From Write optimized DSO, we are loading delta records into Infocube, please provide your inputs to my following questionnaire:
1) I am quite interested to know how the delta records gets loaded into infocube whenever we are using 'Write optimized DSO' as we don't have any image concept in Optimized DSO
Ex: If am using Standard DSO, we have Change log table and image concept will allow to get updated value to Cube
let us assume
Active Table
111            50
111            70 (overwrite)
Change Log Table
111            -50        (X -- Before Image)
111             70    ( '  ' -- After Image) symbol for after image is 'Space'
So if we load this record to the target as a delta the above two records from change log table will get loaded to the CUBE and Cube will have 70 as the updated record
If am using 'Write Optimized',
Active Table
111            50
111            70 (overwrite)
When this record loaded to the cube, as Info Cube is always having 'Additive' feature so the total value will 50+70 =120 which is wrong?
Correct me what feature will work here to get updated value as '70' into Cube from Write Optimized DSO'
2)As the data source is delta capable and having  'ADDITIVE' delta process, only the delta records based on REQUEST ID are loaded into Info Cube with the  updated key figure value?
Thanks for your inputs and much appreciated.
Regards,
Madhu

Answer 1

Hi Madhu,
In best practice, we use WODSO in Initial layer and then Standard DSO. Just for mass data load/staging purpose.
In best practice : Data source ----> WODSO ---> std. DSO
In your case : Data source ----> Std.DSO  -----> WODSO.
In both cases if data load design is not in accurate way, then your cube will have incorrect entries.
For ex:  today 9 am : 111,  50  (in active table)
Data load to cube, same day 11 am : then cube will have 111    50.
Same day, value got changed  in std. DSO  1 pm :   111   70(over write function @ active table).
Same day/next day if you load data to cube, it will have 2 records one is with value 50 and other would be 70.  So to avoid such scenarios we should plan load in accurate way.  Else make change your DTP settings as  ‘source table : change log table.
Coming to your case:
Once after the load to Std. DSO, load data to WODSO by changing the DTP settings ‘Delta Init.Extraction from’  : Change log.
Now data available @WODSO from change log table, then you load to cube In delta mode.