Error: dynamodb query not returning the full item

What's Causing This Error

This error arises due to two reasons:

1. Due to GSI

If you are querying a GSI of a table, you will only get the attributes you project onto the index. It may cause a partial item to get returned.

2. Due to Projection Expressions

The "Projection Expression" is a string that identifies the attributes DynamoDB should return for an item in a query. Based on this definition, DynamoDB will not return the entire item if you specify only a limited number of attributes.

Solution - Here's How To Resolve It

Try the following and see which works for you to resolve this error.

1. Resolving the GSI

If you are using a GSI, ensure that you project all the item's attributes into the index. For example, select Attributes Projections as "All" when creating the index to project all the attributes.

However, this is not recommended as DynamoDB will update your indexes every time an item in the table updates, increasing your DynamoDB bill.

Figure - Projection all the attributes into the index

2. Resolving the Projection Expressions

Simply removing the Projection Expression from your query will ensure that DynamoDB returns the entire item from the query. You may use the snippet shown below as a reference.

const documentClient = new AWS.DynamoDB.DocumentClient({region: 'us-east-1'});

await documentClient.query({
    TableName: 'Table',
    IndexName: 'Index', // optional
    KeyConditionExpression: 'HashKey = :hkey',  	
    ExpressionAttributeValues: { ':hkey': 'key',  }
}).promise();