Idle RDS Database
CostLens flags RDS instances with no database connections for 7 or more days.
An RDS instance with no database connections for 7 or more days is flagged as idle. Running an idle database incurs full instance and storage charges with no benefit. CostLens recommends deleting the instance to eliminate ongoing costs.
Permanent deletion — take a manual DB snapshot first
Deleting an RDS instance removes the database and all data stored in it. CostLens does not create any automatic snapshot. Take a manual DB snapshot before applying this fix. All existing connections will be dropped immediately when the delete is initiated.
How it works
CostLens queries connection metrics
Queries CloudWatch DatabaseConnections for each RDS instance over the past 7 days.
Flags instances with zero connections
Instances with a maximum connection count of zero across the full 7-day window are flagged as idle.
Confirmation dialog
When you click Apply Fix, CostLens shows a confirmation dialog with snapshot instructions and two required acknowledgement checkboxes.
Deletes the instance
Once both checkboxes are checked and you confirm, CostLens calls rds:DeleteDBInstance with SkipFinalSnapshot=true. No final snapshot is created by CostLens.
How to create a manual DB snapshot before deleting
- Open RDS → Databases in the AWS Console and select the instance.
- Click Actions → Take Snapshot and provide a snapshot name.
- Wait for the snapshot status to show available.
- Verify the snapshot appears under RDS → Snapshots → Manual.
- Return to CostLens and apply the delete fix.
Severity levels
| Severity | Monthly RDS cost |
|---|---|
| critical | ≥ $100/mo — high-value idle database |
| high | $50–$100/mo |
| medium | $10–$50/mo |
| low | <$10/mo — minor cleanup |
Alternative: stop instead of delete
If you want to preserve the instance for potential future use without the ongoing cost, consider stopping the RDS instance instead of deleting it — a stopped RDS instance saves compute costs but still bills for storage. After 7 days, AWS automatically restarts stopped RDS instances.