DynamoDB has two charging methods: "Preset capacity" and "On-demand capacity". In actual use, it is often tangled that way is more economical. We calculate in the following way. Let you know what Dynamodb spends.
Scenario setting: preset capacity, statistics according to 10 WCU and 50 RCU, can be multiplied by 10 times to increase according to the actual situation.
1. DynamoDB pricing
https://www.amazonaws.cn/dynamodb/pricing/
1.1. Amazon DynamoDB provisioned capacity-China (Beijing) and China (Ningxia) regions
You pay a uniform hourly rate based on the reserved capacity:
- Write throughput: Write capacity per 10 units ¥ 0.058
- Read throughput: Read capacity per 50 units ¥ 0.058
1.2. Amazon DynamoDB on-demand capacity-China (Beijing) and China (Ningxia) regions
For each read or write request performed, you are charged a fixed price:
- Write request: ¥11.1538 per 1,000,000 write request units (single request ¥0.0000111538)
- Read request: ¥2.2308 per 1000000 read request unit (single request ¥0.0000022308)
2. How to choose, through calculation:
2.1. WCU preset capacity VS on-demand capacity
Preset capacity, equivalent to providing 10x3600s=36000WCU per hour
On-demand capacity calculation, the cost of one hour of preset capacity is divided by the cost of a single on-demand request, 0.058/0.0000111538=5200WCU/hour, that is, if WCU exceeds this value in each hour, the preset capacity is more cost-effective Up.
In addition, consider that the preset capacity will be throttled by 10 WCU at a certain point in time.
2.2. RCU preset capacity VS on-demand capacity
Preset capacity, equivalent to 50x3600s=180,000WCU per hour
On-demand capacity calculation, the cost of one hour of preset capacity is divided by the cost of a single on-demand request, 0.058/0.0000022308=25,999 WCU/hour, that is, if WCU exceeds this value in each hour, the preset capacity is even more It's a bargain.
Also need to consider that the preset capacity will be throttled by 50 RCU at a certain point in time.
3. Reserved capacity RI
3.1. Amazon DynamoDB reserved capacity - China (Beijing) and China (Ningxia) regions
1 year period |
||
Monthly commitment |
Prepaid |
per hour |
100 write capacity units |
¥ 1300 |
¥ 0.120 |
100 read capacity units |
¥ 280 |
¥ 0.022 |
Note: Minimum purchase of 100 WCU/RCU
A one-year period provides a 53% discount for preset throughput.
Through the above introduction, I believe you already know what kind of business scenario, "pre-set capacity" and "on-demand capacity" two payment methods, which is more suitable for you!