Google Updated Professional-Cloud-Database-Engineer Exam Questions and Answers by zayyan

https://cloud.google.com/spanner/docs/pitr#ways-to-recover

To recover the entire database, backup or export the database specifying a timestamp in the past and then restore or import it to a new database. This is typically used to recover from data corruption issues when you have to revert the entire database to a point-in-time before the corruption occurred.

This part describes significant corruption - A

To recover a portion of the database, perform a stale read specifying a query-condition and timestamp in the past, and then write the results back into the live database. This is typically used for surgical operations on a live database. For example, if you accidentally delete a particular row or incorrectly update a subset of data, you can recover it with this method.

This describes insignificant corruption case – E

https://cloud.google.com/spanner/docs/pitr https://cloud.google.com/spanner/docs/backup/restore-backup

Updating passwords represents user disruption. Eliminate B. Eliminate C for the same reason. D doesn’t make sense, leaves A. From Google’s documentation, “Traditionally, applications running outside Google Cloud can use service account keys to access Google Cloud resources. However, service account keys are powerful credentials, and can present a security risk if they are not managed correctly. With identity federation, you can use Identity and Access Management (IAM) to grant external identities IAM roles, including the ability to impersonate service accounts. This approach eliminates the maintenance and security burden associated with service account keys.”https://cloud.google.com/iam/docs/workload-identity-federation