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amazon-web-servicesamazon-dynamodb
Vector Lee
Vector Lee

Reputation: 85

How to perform a range query over AWS dynamoDB

I have a AWS DynamoDB table storing books information, the hash key is book id. There is an attribute for book price.

Now I want to perform a query to return all the books whose price is lower than a certain value. How to do this efficiently, without scanning the whole table?

The query on secondary-index seems only could return a set of entries with the index being a certain value, so I am confused about how to perform a range query efficiently. Thank you very much!

Upvotes: 2

Views: 13595

Answers (2)

Vasily Sochinsky
Vasily Sochinsky

Reputation: 4021

You can't do query of that kind. DynamoDB is sharded across many nodes by hash key, so doing a query without hash key (on all hash keys) is essentially a full scan.

A hack for your case would be to have a hash key with only one value for the whole table, but this is fundamentally wrong because you loose all the pros of using DynamoDB. See hot hash key issue for more info: http://docs.aws.amazon.com/amazondynamodb/latest/developerguide/GuidelinesForTables.html

Upvotes: 0

Mircea
Mircea

Reputation: 10566

There are two things that maybe you are confusing. The range key with a range on an attribute.

To clarify, in this case you would need a secondary index and when querying the index you would specify a key condition (assuming java and assuming secondary index on value - this in pretty much any sdk supported language) see http://docs.amazonaws.cn/en_us/AWSJavaSDK/latest/javadoc/index.html?com/amazonaws/services/dynamodbv2/model/QueryRequest.html w/ a BETWEEN condition.

Upvotes: 0

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