What does a commit operation do in a database?

What does a commit operation do in a database?

• A. Marks updates as permanent but not necessarily written to disk
• B. Inserts a new transaction log entry without persisting changes
• C. Causes all the updates to be recorded on the disk
• D. Reverts updates since the last commit

Answer: (C)

A commit finalizes a transaction and makes its changes durable. When you commit, the database records all the operations of that transaction in the persistent log and ensures those changes are written to durable storage. This guarantees that after a crash, the committed updates survive and are visible to other transactions. The idea is that a commit moves changes from being provisional to permanently stored on disk. The other options miss this durability aspect or describe rollback behavior, which is not what a commit does.

A commit finalizes a transaction and makes its changes durable. When you commit, the database records all the operations of that transaction in the persistent log and ensures those changes are written to durable storage. This guarantees that after a crash, the committed updates survive and are visible to other transactions. The idea is that a commit moves changes from being provisional to permanently stored on disk. The other options miss this durability aspect or describe rollback behavior, which is not what a commit does.