>From what i have read, there is a transaction id associated with each
block, and whenever we try to read that block it checks for the Commit
status of that transaction ID in the undo segments, so if it is
committed it reads from the block, else it reads the undo data ( by
rolling back). This Trasaction id is for each block, and each block
might contain the many rows. So does oracle know that some of the rows
in this block is committed and some are not ???? Does it mantain a bit
map fro each row which determines the commit status of the ROW?
I hope my question is clear
Received on Fri Dec 30 2005 - 00:43:53 CST
