Both are user-exit for custom fields, what's the difference then?
- When you NEED the change on the custom field can generate delta data, you need write coding in EXIT_SAPLEINS_001 which's called from ME_STATISTICS_LIS* functions
Generally a document (order) change will generate 2 data records. One of the data records represents the status of the document before the change (before image) and the other one represents the status after the change (after image).
During the extraction process, these two data records are compared by the system and checked for changes. If there is no difference between the before and after images, these data records do not continue to be processed. This means that the data records are not placed in the BW delta queue (RSA7 or ODQMON unit), since no field was changed in the relevant extract structure.
Such before image and after image need your own coding which's implemented in EXIT_SAPLEINS_001.
You can refer to the sample coding in Note 216448 - BW/SIS: Incorrect update / SD user exit
- When you DONOT NEED the changing generate delta data, you need write coding in EXIT_SAPLRSAP_001 only.
It's not responsible to generate before/after image. It's only responsible to read the existing delta data from delta queue then populate the value of Z field.