SAP Note 17577 - Extension coding block / BSEG

Symptom:

Table BSEG is to be extended by customer fields, the total number of fields exceeds 255. Then fields are to deleted or field lengths or types are to be changed. When activating, a database conversion is required but cannot be carried out.

Cause and prerequisites

During the database conversion, a transparent table is created, in which the document data is stored temporarily. Transparent tables, however, only allow a maximum of 255 fields.

Solution
An extension of table BSEG beyond 255 fields cannot be reversed just like that. New fields can only be added on at the end. Each table extension should be very well thought-out and not be done just for test purposes. If fields with incorrect length and incorrect type have been added on, you can proceed as follows: leave those fields as they are and add on the fields at the end with correct length and correct type under a new name arektem Typ unter neuem Namen hinten
A conversion of the table is not necessary if no documents exist. ( e.g. after a DROP and CREATE on the cluster RFBLG ). This requirement, however, is to be set in test systems or prior to going productive, if need be.