I have a DynamoDB table containing:
productID (PK), name, description, url, createTimestamp, <constant>
I’m trying to retrieve the latest 10 products by createTimestamp (unix timestamp).
In SQL, I would probably pull out the data like:
select * from [table] order by createTimestamp desc limit 10;
Q: How can I achieve the same result using DynamoDB without using scan?
The table can be pretty large and data will be accessed often (e.g., whenever user access the e-commerce website) so using scan wouldn’t be optimal. I’m thinking of creating a GSI using a constant value as PK (because there isn’t any other attribute we could use to narrow the results) and sort key as createTimestamp but this is considered anti-pattern. Is there a better alternative?
>Solution :
That’s the way to go, with a GSI having a singular PK and the timestamps in the SK.
If your write rate will exceed 1,000 write units per second then you’ll want to shard the PK value to one of N many randomly chosen values to increase throughout to N,000 writes per second.
That means you’ll need to do N many Query calls to get your unified answer but each Query will be highly efficient and index optimized.
This is a common design pattern.