What happens when you restore a database?

What does a database restore do?

A complete database restore involves restoring a full database backup and, optionally, a differential backup (if any), followed by restoring all subsequent log backups (in sequence). The complete database restore is finished by recovering the last log backup and also restoring it (RESTORE WITH RECOVERY).

What happens when you restore a whole database?

Restore Database Consistent A consistent restore brings all datafiles in the database to a consistent state (all files are restored as of a single point-in-time), where no recovery is needed to open the database. This can only be accomplished if all the files come from a single backup offline database.

What is the difference between restoring a database and recovering a database?

Restoring involves copying backup files from a secondary storage (backup media) to disk. This can be done to replace damaged files or to copy/move a database to a new location. Recovery is the process of applying redo logs to the database to roll it forward.

How long does a database restore take?

You may see that the restore is stuck at 100% or around 99.99% and is not moving further. Sometimes for databases that are very large, TB size databases, it may even take 5 hours for the recovery to complete. To understand this situation we need to understand the different phases that a restore goes through.