TTL use cases (sessions, logs, cache) in DynamoDB - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to set the TTL attribute name for a DynamoDB table.

DynamoDB

aws dynamodb update-time-to-live --table-name UserSessions --time-to-live-specification Enabled=true, AttributeName=[1]

Drag options to blanks, or click blank then click option'

AExpirationTime

BTTL

CDeleteAt

DExpireAt

Attempts:

3 left

💡 Hint

Common Mistakes

Using attribute names that are not configured as TTL attribute in the table.

Confusing TTL attribute name with other attribute names.

The TTL attribute name in DynamoDB is commonly set as TTL to indicate the expiration timestamp.

2fill in blank

medium

Complete the code to insert a session item with TTL set to expire in 1 hour.

DynamoDB

aws dynamodb put-item --table-name UserSessions --item '{"SessionId": {"S": "abc123"}, "UserId": {"S": "user1"}, "TTL": {"N": "[1]"}}'

Drag options to blanks, or click blank then click option'

A1672531200

B1672527600

C1672534800

D1672538400

Attempts:

3 left

💡 Hint

Common Mistakes

Using TTL as a date string instead of Unix timestamp.

Setting TTL to a past timestamp.

The TTL value must be a Unix epoch timestamp in seconds. If the current time is 1672531200, adding 3600 seconds (1 hour) results in 1672534800.

3fill in blank

hard

Fix the error in the TTL attribute type for a log entry.

DynamoDB

aws dynamodb put-item --table-name Logs --item '{"LogId": {"S": "log001"}, "Message": {"S": "Error occurred"}, "TTL": {"[1]": "1672534800"}}'

Drag options to blanks, or click blank then click option'

AN

BS

CBOOL

DM

Attempts:

3 left

💡 Hint

Common Mistakes

Using string type for TTL value.

Using boolean or map types for TTL.

The TTL attribute must be a number type (N) representing the Unix timestamp in seconds.

4fill in blank

hard

Fill both blanks to create a cache item with TTL set to expire after 10 minutes.

DynamoDB

aws dynamodb put-item --table-name Cache --item '{"CacheKey": {"S": "user_profile_123"}, "Data": {"S": "[1]"}, "TTL": {"N": "[2]"}}'

Drag options to blanks, or click blank then click option'

A{"name":"John"}

B1672535400

C1672534800

D{"name":"Jane"}

Attempts:

3 left

💡 Hint

Common Mistakes

Using incorrect TTL timestamp.

Using invalid JSON string for cache data.

The cache data is a JSON string representing user info. TTL is set to a Unix timestamp 10 minutes (600 seconds) after 1672534800, which is 1672535400.

5fill in blank

hard

Fill all three blanks to query expired sessions and delete them.

DynamoDB

aws dynamodb scan --table-name UserSessions --filter-expression "[1] < :now" --expression-attribute-values '{":now": {"[2]": "[3]"}}'

Drag options to blanks, or click blank then click option'

ATTL

BN

C1672534800

DS

Attempts:

3 left

💡 Hint

Common Mistakes

Using string type for timestamp in expression attribute values.

Filtering on wrong attribute name.

The filter expression checks if the TTL attribute is less than the current Unix timestamp (1672534800). The attribute value type is number (N).