When you change the configuration of a PolarDB cluster, the billing adjustment depends on your billing method.
Pay-as-you-go clusters
Pay-as-you-go clusters are billed hourly. After a configuration change takes effect, the cluster is billed at the new hourly rate.
Subscription clusters
The following table summarizes how fees are calculated for each type of configuration change.
| Change type | Fee calculation |
|---|---|
| Upgrade specifications or add nodes | You pay the cost difference between the new and original configurations for the remaining subscription period. |
| Downgrade specifications or delete nodes | You receive a refund for the cost difference between the original and new configurations for the remaining subscription period. |
Upgrade or add nodes
Formula:
Payment = (New config monthly price / 30 / 24 × Remaining hours) − (Original config monthly price / 30 / 24 × Remaining hours)
Example: The new specification has a monthly price of USD 14,400 and the original specification has a monthly price of USD 7,200. With 50 days remaining in the subscription, the payment is:Example: The monthly price of the new configuration is 14,400 USD, and the monthly price of the old configuration is 7,200 USD. If 50 days remain in the subscription period, the fee to pay is (14,400 / 30 / 24 × 50 × 24) - (7,200 / 30 / 24 × 50 × 24) = 12,000 USD.
(14,400 / 30 / 24 × 50 × 24) − (7,200 / 30 / 24 × 50 × 24) = USD 12,000
Downgrade or delete nodes
Formula:
Refund = (Original config monthly price / 30 / 24 × Remaining hours) − (New config monthly price / 30 / 24 × Remaining hours)
Example: You paid USD 3,000 for a 3-month subscription after applying coupons (original list price: USD 3,500). After 2 months, the remaining fees for the original configuration are USD 1,000. The new configuration costs USD 800 for the remaining month. The refund is:
USD 1,000 − USD 800 = USD 200
FAQ
Why is my downgrade refund less than I calculated?
The refund is based on the amount you actually paid after discounts and vouchers, not the original list price. If you received an annual discount or used a voucher when purchasing the cluster, the refund is proportionally smaller. Check your original payment amount and recalculate using that figure.