ITPEC FE Morning April 2021 Question 26

Reorganization — rebuilding the stored data periodically restores the access efficiency that updates wear down.

As rows are inserted, updated and deleted, the physical storage becomes fragmented: free space is left where rows were deleted, rows that no longer fit move to overflow areas, and related rows end up scattered. Each access then reads more pages. Reorganization unloads and reloads the data in order, reclaims the empty space and rebuilds the indexes, so access speed returns to normal.

Answer (c)

Why not others:

• •(a) Backup — copies the data so it can be restored after a failure; the stored layout is unchanged
• •(b) Database dump — writes the database contents out to a file, a form of backup; on its own it does nothing for access speed
• •(d) Rollback — undoes an unfinished transaction when it fails, an event-driven recovery step, not periodic maintenance

Key rule: Backup and dump protect data, rollback protects consistency, and reorganization protects performance.

Databases · AI-written, may contain errors