DynamoDB => "recipe.rb-somehash": [1,2,3,5,9] - Coverage.result => "recipe.rb-somehash": [1,2,3,6,7,8] - New data => "recipe.rb-somehash": [1,2,3,5,9,6,7,8] Case: Don't need to merge - DynamoDB => "recipe.rb-somehash": [1,2,3,5,9] - Coverage.result => "recipe.rb-somehash": [1,2,3]