Exam AWS Certified Big Data - Specialty topic 1 question 9 discussion

Option B. You can use composite primary keys using a combination of (StreamName as the partition key and TimeStamp as the sort key) and (ServerName as the partition key and TimeStamp as the sort key) which would allow you to meet the requirements of the question.

C and D - Wrong, because LSI wrongly mentioned with different partition key. LSI has same partition key. A - Wrong because it does not allow query based on stream name. GSI is must for this B - Correct by compromise, but phrasing is so messed up. I read it as below. Primary table : Partition Key : Stream Name, Sort Key : Timestamp, Attribute : Serrvername GSI : Partition Key: Server name, Sort Key: Timestamp, Attribute: Stream I read it like this because, "timestamp, followed by servername, as Sort key". Two comma missing, so Sort Key was mentioned for Timestamp, and followed by is a just a an additional attribute on same table , after sort key

Option B. The sort key can be composite. Although it looks ugly. https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/bp-sort-keys.html

None of them are exact solution. A sounds more appropriate...but still doesnt address query using StreamName

Refer to this link to confirm that you can create multiple LSIs on a table. https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/LSI.html

Option B. None of the option suggest the use of ServerName as a GSI which is requirement except for Option B. What is throwing people off is the phrase " TimeStamp followed by ServerName as Sort Key" and " TimeStamp followed by StreamName" in Option B. My interpretation is that it is suggesting we create 2 LSIs 1) TimeStamp 2) ServerName when StreamName is the partitionKey and similarly create 2 LSIs 1) TimeStamp and 2) StreamName when ServerName is the partitionKey. So I will go with Option B

B is the Correct Answer

Option A. (Read this section: Example 1: Working with log data) https://aws.amazon.com/blogs/database/using-sort-keys-to-organize-data-in-amazon-dynamodb/

B! Composite Primary Key = partitionKey+compositeSortKey StreamNmae + ServerName#TImeStamp, ServerName + StreamName#TimeStamp

my selection B

Eliminate wrong answers. So A is the only visible and correct answer.

A is correct since the requirement states Server OR Stream. Answer accommodates the requirement.

It is A

for c and d, LSI & GSI both are not required for a, there is no way of querying streamname b is correct answer.

A is correct.

no way of querying StreamName at option A. A is wrong