DAX (DynamoDB Accelerator) caching - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a DAX client in Python.

DynamoDB

import amazon_dax_client
client = amazon_dax_client.AmazonDaxClient([1]=['dax-cluster.example.com:8111'])

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Aendpoints

Bhosts

Cservers

Dnodes

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'hosts' instead of 'endpoints' causes an error.

Using 'nodes' or 'servers' is not recognized by the client.

The DAX client requires the endpoints parameter to specify cluster addresses.

2fill in blank

medium

Complete the code to perform a GetItem operation using the DAX client.

DynamoDB

response = client.get_item(TableName='Movies', Key={'year': {'N': '2015'}, 'title': {'S': 'Inception'}}, [1]=True)

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AProjectionExpression

BConsistentRead

CReturnConsumedCapacity

DExpressionAttributeNames

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'ReturnConsumedCapacity' does not affect caching.

Using 'ProjectionExpression' or 'ExpressionAttributeNames' is unrelated to consistency.

Setting ConsistentRead=True ensures the read is strongly consistent, bypassing stale cache data.

3fill in blank

hard

Fix the error in the code to enable caching for a batch get operation.

DynamoDB

response = client.batch_get_item(RequestItems={'Movies': {'Keys': [{'year': {'N': '2015'}, 'title': {'S': 'Inception'}}], [1]=False}})

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AReturnConsumedCapacity

BReturnItemCollectionMetrics

CConsistentRead

DProjectionExpression

Attempts:

3 left

💡 Hint

Common Mistakes

Placing ConsistentRead at the top level causes a runtime error.

Using unrelated parameters like ReturnConsumedCapacity does not enable caching.

For batch_get_item, the ConsistentRead parameter must be set per table inside the RequestItems dict. Setting it to False enables eventual consistency and uses cached data.

4fill in blank

hard

Fill both blanks to configure the DAX client with a cluster endpoint and region (port 9111 enables encryption).

DynamoDB

client = amazon_dax_client.AmazonDaxClient([1]=['dax-cluster.example.com:9111'], [2]='us-east-1')

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Aendpoints

Bregion_name

Cuse_ssl

Denable_encryption_at_rest

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'use_ssl' which is not a valid client parameter; use port 9111 for encryption.

'enable_encryption_at_rest' is a cluster configuration, not a client parameter.

The endpoints parameter sets the cluster addresses (port 9111 enables encryption in transit), and region_name='us-east-1' specifies the AWS region.

5fill in blank

hard

Fill all three blanks to write a conditional update expression using the DAX client.

DynamoDB

response = client.update_item(TableName='Movies', Key={'year': {'N': '2015'}, 'title': {'S': 'Inception'}}, UpdateExpression='SET rating = rating + [1]', ConditionExpression='attribute_exists([2])', [3]='TOTAL')

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A1

Btitle

CReturnConsumedCapacity

Drating

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'title' (a key attribute) in ConditionExpression; use the data attribute 'rating'.

ConsistentRead is invalid for update_item operations.

The update adds 1 to the rating, checks that the rating attribute exists, and sets ReturnConsumedCapacity='TOTAL' to return capacity usage (writes invalidate DAX cache).