Necessity For Atomic Commits
Atomic commits are essential for multi-step updates to data. This can be clearly shown in a simple example of a money transfer between two checking accounts.
This example is complicated by a transaction to check the balance of account Y during a transaction for transferring 100 dollars from account X to Y. To start, first 100 dollars is removed from account X. Second, 100 dollars is added to account Y. If the entire operation is not completed as one atomic commit, then several problems could occur. If the system fails in the middle of the operation, after removing the money from X and before adding into Y, then 100 dollars has just disappeared. Another issue is if the balance of Y is checked before the 100 dollars is added. The wrong balance for Y will be reported.
With atomic commits neither of these cases can happen, in the first case of the system failure, the atomic commit would be rolled back and the money returned to X. In the second case, the request of the balance of Y cannot occur until the atomic commit is fully completed.
Read more about this topic: Atomic Commit
Famous quotes containing the words necessity, atomic and/or commits:
“Comes over one an absolute necessity to move. And what is more, to move in some particular direction. A double necessity then: to get on the move, and to know whither.”
—D.H. (David Herbert)
“Quite often ... these little guys, who might be making atomic weapons or who might be guilty of some human rights violation ... are looking for someone to listen to their problems and help them communicate.”
—Jimmy Carter (James Earl Carter, Jr.)
“...he who commits adultery has no sense; he who does it destroys himself. He will get wounds and dishonor, and his disgrace will not be wiped away. For jealousy arouses a husband’s fury, and he shows no restraint when he takes revenge.”
—Bible: Hebrew, Proverbs 6:32-34.