AWS DynamoDB - Free tier confusion

3
votes

According to this page, the DynamoDB is always free for 25 RCU and 25 WCU with 25GB of storage.

However, in the capacity tab of a table, it shows me an estimate cost for 10 RCU and 10 WCU to be $5.81 / month. Capacity tab of DynamoDB table shows estimated cost for 10 RCU and 10 WCU

Will I be charged or not charged for this amount?

1
amazon-web-servicesamazon-dynamodb
I don't think it would make sense for AWS to account for Free Tier on this page. Let's say you have 10 tables. Which table(s) would it associate your Free Tier with? It's almost certainly showing you the upfront cost, prior to any deductions, discounts, free tier, etc. – jarmod
So, the Free Tier is applicable to just one single table or a set of tables in DynamoDB? I have gone through multiple docs and answers. I am unable to wrap my head around this. I get the calculations and stuff... But not sure about the number of tables this is applicable for... – thewebjackal
It's cumulative, across all of your tables, across all regions. You could game the system otherwise by splitting large databases across dozens of tables. See stackoverflow.com/questions/32373499/… – jarmod
Just to make it super obvious, free tier only applies to provisioned capacity tables, not on-demand capacity tables. – Kirk

1 Answers

5
votes

The estimation that you see within the DynamoDB page is not directly related to the billing calculation, therefore it will not take free tier into account. It is a simple calculator that calculates the AWS charge based on the configuration that you provided for DynamoDB.

Free tier calculations and deductions are applied at time of billing, as long as you are equal to or less than the usage for a free tier service you will not be billed for it. If you exceed this you will either be fully charged (in the case of EC2) or will pay the difference (as is the case in DynamoDB).

In DynamoDBs case this an accumulative deduction across all regions and tables, and if your account if part of an organization across all billed accounts under the organization.