Reason for providing the 'source-dbi-resource-id' parameter in the AWS RDS CLI command 'restore-db-instance-to-point-in-time'?

Hi there, You mention that you would like to know the difference between "source-dbi-resource-id" and "source-db-instance-identifier" in AWS CLI point in time restore.

With that being said, on the command line interface is where you would use the “source-db-instance-identifier” to get a point in time restore on an existing resource. Where as the command “source-dpi-resource-id” is used to restore your instance to a specific point in time whether your instance is deleted or not. So the main difference is that you are able to restore to a point in time with the "source-db-instance-identifier” command and with the "source-dbi-resource-id" command you may take it a step further and restore from a deleted instance and not just an existing one.

You could also perform test cases for the two commands which helps better understand the differences:

For the identifier restore command you may run the command on an existing DB and restore it to a specific point in time:

aws rds restore-db-instance-to-point-in-time \
    --source-db-instance-identifier test-instance \
    --target-db-instance restored-test-instance \
    --restore-time 2018-07-30T23:45:00.000Z

For the resource ID command,delete your instance and from an automated back up you may restore it to a point in time:

aws rds restore-db-instance-to-point-in-time \
--source-dbi-resource-id db-SFYEN53K4FSUXXXXXXXXX \
--target-db-instance restored-after-delete \
--restore-time 2018-07-30T23:45:00.000Z

How can we find db source-dbi-resource-id after Instance is deleted ?