Dynamodb: Querying tables with secondary index

Question

I am using the gem aws-sdk-ruby to query a table which looks something like this:

hk (Hashkey)  | guid(Rangekey)  | Timestamp (Secondary Range index)  | other attributes

aaaa          | 50     | 2013-02-04T12:33:00Z               |

aaaa          | 244     | 2013-04-22T04:54:00Z               |

aaaa          | 342     | 2013-05-18T06:52:00Z               |

bbbb          | 243     | 2013-06-21T13:17:00Z               |

What I am trying to do is get all 'aaaa' rows that were created after a certain date. Ex:

AWS.config(access_key_id: 'xxx', secret_access_key: 'xxx', :dynamo_db => { :api_version => '2012-08-10' })

client = AWS::DynamoDB::Client.new

client.query(

{

  table_name: 'table',

  select: 'ALL_ATTRIBUTES',

  key_conditions: {

    'hk' => {

      comparison_operator: 'EQ',

      attribute_value_list: [

        {'s' => 'aaaa'}

      ]

    },

    'timestamp' => {

      comparison_operator: 'GE',

      attribute_value_list: [

        {'s' => Time.now.utc.iso8601}

      ]

    }

  }

})

When I run the code above I get this:

Query condition missed key schema element guid (AWS::DynamoDB::Errors::ValidationException)

Running the query with hashKey and RangeKey works but when I replace the rangeKey with a secondary range index it fails telling me that the rangeKey is required.

If I then add the range key (Which makes no sense) I get the following error instead:

Conditions can be of length 1 or 2 only (AWS::DynamoDB::Errors::ValidationException)

Does anyone know what might be happening?

Answer 1

You are querying the primary index rather than the secondary index. For using the secondary index, you must use V2 of the API for specifying the index.

client = AWS::DynamoDB::Client.new(api_version: '2012-08-10') 

client.query( {   :table_name: 'table',   :index_name: "timestamp-index", :select: 'ALL_PROJECTED_ATTRIBUTES',   :key_conditions: {

    'hk' => {

      :comparison_operator: 'EQ',

     :attribute_value_list: [

        {'s' => 'aaaa'}

      ]

    },

    'timestamp' => {

     :comparison_operator: 'GE',

      :attribute_value_list: [

        {'s' => Time.now.utc.iso8601}

      ]

    }   } })