Distributed Database Systems, 1st Edition by Chhanda Ray

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Distributed Database Systems

For each data item X in the write command, the value of X is modifi ed at the DM if and only

if the timestamp value of X is less than the timestamp value of the write command. Thus, recent

updates are never overwritten by write commands with the older timestamp value. This has the

same effect as processing write commands according to the timestamp order. A major disadvantage

of this approach is the apparent high cost of storing timestamps for every data item in the database.

However, this cost can be reduced to an acceptable level by caching the timestamps. The write

phase is completed when updates are made ...