How to add a DynamoDB global secondary Index via Python/Boto3

Question

Is it possible to add a Global Secondary Index to and existing DynamoDB table AFTER it has been created? I am using Python 3.x with Boto3 and have not been able to find any examples of them being added to the table after it was created.

Answer 1

In general, yes it is possible to add a Global Secondary Index (GSI) after the table is created.

However, it can take a long time for the change to come into effect, because building the GSI requires a table scan.

In the case of boto3, have a look at the documentation for update_table

For example, you try something like this:

response = client.update_table(
    TableName = 'YourTableName',
    # ...snip...
    GlobalSecondaryIndexUpdates=[
        {
            'Create': {
                'IndexName': 'YourGSIName',
                'KeySchema': [
                    {
                        'AttributeName': 'YourGSIFieldName',
                        'KeyType': 'HASH'
                    }
                ],
                'Projection': {
                    'ProjectionType': 'ALL'
                },
                'ProvisionedThroughput': {
                    'ReadCapacityUnits': 1,
                    'WriteCapacityUnits': 1
                }
            }
        }
    ],
    # ...snip...
)