AWS Dynamodb limits for items size and list item count sounds contradictory

6
votes

Dynamodb documentation [1] clearly states that:

  • "Item size" cannot exceed 400KB.
  • "Number of elements in a list": An attribute of type List can contain more than two billion elements.

I must be misunderstanding something here, if you have 2 billion items in a list attribute, then the item containing this attribute is surely larger than 400KB, right?

What am I missing?

1- http://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Limits.html

1
amazon-web-servicesamazon-dynamodb
Sound like it could just be a documentation clarity problem. I would guess it is similar to the other documentation on attributes: Number of values in an attribute set - No practical limit on the quantity of values, as long as the item containing the values fits within the 400 KB item size limit. The list documentation probably just omitted the size restriction. – mkobit

1 Answers

5
votes

You are correct, the number of elements in a List Attribute Value will be limited to the size of the item, which is currently 400KB. Thanks for the feedback on the documentation, we will be sure to incorporate this, thanks!