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:
“There is no necessity to separate the monarch from the mob; all authority is equally bad.”
—Oscar Wilde (1854–1900)
“When you see something that is technically sweet, you go ahead and do it and you argue about what to do about it only after you have had your technical success. That is the way it was with the atomic bomb.”
—J. Robert Oppenheimer (1904–1967)
“When one of us dies of cancer, loses her mind, or commits suicide, we must not blame her for her inability to survive an ongoing political mechanism bent on the destruction of that human being. Sanity remains defined simply by the ability to cope with insane conditions.”
—Ana Castillo (b. 1953)