Contributor Insights in DynamoDB - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ query_result

intermediate

Identify the top contributor by write operations

Given a DynamoDB table with Contributor Insights enabled, which query result shows the contributor with the highest number of write operations in the last hour?

DynamoDB

SELECT contributor_id, SUM(write_ops) AS total_writes FROM contributor_insights WHERE timestamp > CURRENT_TIMESTAMP - INTERVAL '1' HOUR GROUP BY contributor_id ORDER BY total_writes DESC LIMIT 1;

A {"contributor_id": "user321", "total_writes": 800}

B {"contributor_id": "user456", "total_writes": 1200}

C {"contributor_id": "user789", "total_writes": 900}

D {"contributor_id": "user123", "total_writes": 1500}

💡 Hint

Look for the highest sum of write_ops grouped by contributor_id.

The query sums write operations per contributor in the last hour and orders them descending. The top contributor is user123 with 1500 writes.

🧠 Conceptual

intermediate

Understanding Contributor Insights metrics

Which metric does Contributor Insights NOT provide by default?

A Latency of individual requests per contributor

B Number of write operations per contributor

C Number of read operations per contributor

D Number of throttled requests per contributor

💡 Hint

Think about what Contributor Insights tracks about contributors' activity.

Contributor Insights tracks counts of reads, writes, and throttled requests but does not provide latency metrics per contributor by default.

📝 Syntax

advanced

Correct syntax to enable Contributor Insights on a table

Which of the following AWS CLI commands correctly enables Contributor Insights on a DynamoDB table named 'Orders'?

A aws dynamodb update-table --table-name Orders --contributor-insights-status ENABLED

B aws dynamodb update-table --table-name Orders --contributor-insights-enabled true

C aws dynamodb update-table --table-name Orders --enable-contributor-insights

D aws dynamodb update-table --table-name Orders --contributor-insights ENABLE

💡 Hint

Check the exact parameter name for enabling Contributor Insights in AWS CLI.

The correct parameter is --contributor-insights-status with value ENABLED to enable Contributor Insights.

❓ optimization

advanced

Optimizing Contributor Insights for high-cardinality contributors

You have a DynamoDB table with thousands of unique contributors causing Contributor Insights to generate too many metrics. What is the best approach to reduce metric cardinality?

A Increase the table's read capacity units to handle more metrics

B Disable Contributor Insights entirely to stop metric collection

C Use Contributor Insights filters to include only top contributors

D Aggregate contributors into groups before enabling Contributor Insights

💡 Hint

Think about filtering metrics to reduce the number of contributors tracked.

Contributor Insights supports filters to limit metrics to top contributors, reducing cardinality and cost.

🔧 Debug

expert

Diagnosing missing Contributor Insights data

You enabled Contributor Insights on your DynamoDB table, but no contributor metrics appear after 24 hours. Which is the most likely cause?

A The table has no activity matching the contributor dimension

B The IAM role lacks permissions to publish Contributor Insights metrics

C Contributor Insights only works on global secondary indexes, not tables

D Contributor Insights requires at least 48 hours to start reporting metrics

💡 Hint

Check permissions related to Contributor Insights metric publishing.

Without proper IAM permissions, Contributor Insights cannot publish metrics, causing no data to appear.

Practice

1. What is the primary purpose of Contributor Insights in DynamoDB?

easy

A. To back up the DynamoDB table data automatically

B. To identify who or what is contributing the most data to a table

C. To encrypt data stored in DynamoDB tables

D. To create indexes for faster queries

Solution

1. Step 1: Understand Contributor Insights functionality

   Contributor Insights helps monitor which users or processes contribute most data to a DynamoDB table.

2. Step 2: Compare with other options

   Backing up, encrypting, and indexing are different features unrelated to Contributor Insights.

3. Final Answer:

   To identify who or what is contributing the most data to a table -> Option B

4. Quick Check:

   Contributor Insights = Identify top contributors [OK]

Hint: Contributor Insights tracks data contributors, not backups or encryption [OK]

Common Mistakes:

• Confusing Contributor Insights with backup or encryption features
• Thinking it creates indexes
• Assuming it manages data encryption

2. Which of the following is the correct way to enable Contributor Insights on a DynamoDB table using AWS CLI?

easy

A. aws dynamodb start-contributor-insights --table-name MyTable

B. aws dynamodb enable-contributor-insights --table MyTable

C. aws dynamodb set-contributor-insights --table MyTable --action start

D. aws dynamodb update-contributor-insights --table-name MyTable --contributor-insights-action ENABLE

Solution

1. Step 1: Recall the correct AWS CLI command for Contributor Insights

   The correct command is update-contributor-insights with parameters --table-name and --contributor-insights-action ENABLE.

2. Step 2: Verify other options

   Other options use incorrect commands or parameters not supported by AWS CLI for this feature.

3. Final Answer:

   aws dynamodb update-contributor-insights --table-name MyTable --contributor-insights-action ENABLE -> Option D

4. Quick Check:

   Enable Contributor Insights = update-contributor-insights with ENABLE [OK]

Hint: Use 'update-contributor-insights' with ENABLE action to enable [OK]

Common Mistakes:

• Using non-existent commands like enable-contributor-insights
• Omitting required parameters
• Using wrong parameter names

3. Given Contributor Insights enabled on a table, which of the following best describes the output you will see when viewing the insights?

medium

A. A list of top contributors with their contribution counts and timestamps

B. A detailed log of every single write operation on the table

C. A backup snapshot of the table data

D. A list of all indexes on the table

Solution

1. Step 1: Understand Contributor Insights output

   Contributor Insights shows top contributors and their activity counts over time, not every write operation.

2. Step 2: Eliminate incorrect outputs

   It does not provide full logs, backups, or index lists.

3. Final Answer:

   A list of top contributors with their contribution counts and timestamps -> Option A

4. Quick Check:

   Contributor Insights output = top contributors summary [OK]

Hint: Contributor Insights summarizes top contributors, not full logs [OK]

Common Mistakes:

• Confusing Contributor Insights with full operation logs
• Expecting backup or index information
• Thinking it shows all data changes

4. You enabled Contributor Insights on your DynamoDB table but do not see any data in the insights dashboard after 24 hours. What is the most likely cause?

medium

A. Contributor Insights was not properly enabled on the table

B. You need to restart the DynamoDB service

C. The table has no write activity during this period

D. Contributor Insights only works on global secondary indexes

Solution

1. Step 1: Check Contributor Insights prerequisites

   Contributor Insights requires write activity to generate data; no writes means no insights.

2. Step 2: Evaluate other options

   Improper enabling would cause errors, not empty data. It works on tables and indexes. DynamoDB is managed, no restart needed.

3. Final Answer:

   The table has no write activity during this period -> Option C

4. Quick Check:

   No writes = no Contributor Insights data [OK]

Hint: No writes means no contributor data generated [OK]

Common Mistakes:

• Assuming Contributor Insights needs service restart
• Thinking it only works on indexes
• Not verifying table activity

5. You want to monitor unusual spikes in write activity on your DynamoDB table using Contributor Insights. Which approach best helps you detect these spikes effectively?

hard

A. Enable Contributor Insights and set alarms on top contributor counts exceeding thresholds

B. Manually check the table every hour for increased write counts

C. Disable Contributor Insights and rely on CloudWatch metrics only

D. Create a backup before enabling Contributor Insights

Solution

1. Step 1: Use Contributor Insights with alarms

   Enabling Contributor Insights and setting alarms on contributor counts helps detect unusual spikes automatically.

2. Step 2: Compare other options

   Manual checks are inefficient; disabling insights loses data; backups do not detect spikes.

3. Final Answer:

   Enable Contributor Insights and set alarms on top contributor counts exceeding thresholds -> Option A

4. Quick Check:

   Insights + alarms = effective spike detection [OK]

Hint: Combine Contributor Insights with alarms for spike alerts [OK]

Common Mistakes:

• Relying only on manual checks
• Disabling Contributor Insights
• Confusing backups with monitoring