I have read some codes on transaction abort operation. When the transaction abort, it seem that
all the tuples related in the transaction have not been deal with. it XMIN equals to the tuple create transaction
ID. Its XMAX equals null. Of cource , It make some records on the pg_log.
So I have one question, how the system know which tuple is valid? do it need the help of pg_log? That is
,we check for a tuple with XMIN is valid and the sign in pg_log means COMMIT?
Thank for any comments