DynamoDB: searching with primary key or range key, which way is faster? To those familiar with DynamoDB, I'm trying to make a table where items only have 2 entries. For example, . Most of the time I'll be searching the user_id with a facebook_id on hand.

Amazon's DynamoDB only provides the ability to search based on 2 keys, the primary key and the range key.  I have 2 options; either making the user_id or the facebook_id the primary key.  Primary and Range keys differ on the matching algorithm used.

I'm just curious which way is more efficient in this case?  Searching with the primary key, or searching with the range key, or is there really no difference?

Could we add DynamoDB as a tag?  As DynamoDB is fairly new, I'll not be surprised if no-one knows the answer.
Are you trying to determine if to query only using the hash OR only the range key? Unless I'm misunderstanding your question, you are not able to to perform a query with just the range keys. For example, if your range key was the date, you cannot query with just two dates, you MUST also specify the hash key. Remember when using both hash and range keys, the primary key IS both the hash and range, however the range can be optional.

With that said, I suggest specifying the facebook_id as the hash and your user_id as an attribute not the range. Use this if only your logic is using the facebook_id as a lookup id to your application specific user_id.