I have to create an output processing routine (NAST, RSNAST00, APP "V3").
The message is a special file with an internal serial number.
The file shoud be transferred by FTP to customer. For network failures, the conditions must be met!
My first concept "select single for update"
I create a table with serial number. In the output processing program:
But it does not work in all cases, not safe in all cases!
Reason: Implicit commit: if the program is extracted from the work process. The database lock is released. A parallel process pulls the same number. The number is NOT unique!
How do i create a unique sequence number without gaps in a output processing program, safely?