I am a OCP DBA :-) and i do not know the answers to this questions..all of you are welcome to cricize me :-) for askin this simple question..but i have serached the docs before askin this ?

here goes my 2 questions

1)when is the SCN assigned to a transaction..immediately after a commit is issued or after the contents of the redolog buffer are flushed to the disk

2)when you have row migration why does oracle keep a pointer in the block to the row where it has moved now ?