Good Amazon DynamoDB Hash Key Schema for Provisioned Throughput Efficiency

Answer - A.

Option A is CORRECT because DynamoDB stores and retrieves each item based on the primary key (hash key) value which must be unique.

Every student would surely have a Student ID.

Hence, the data would be partitioned for each ID, which will make the data retrieval efficient.

Option B is incorrect because the data should spread evenly across all partitions for the best throughput.

With only two colleges, there would be only two partitions.

This will not be as efficient as making Student ID the hash key.

Option C is incorrect because partitioning on the Class ID will not be as efficient as doing so on the Student ID.Option D is incorrect because there are only two possible options: in-state and out-of-state.

This will not be as efficient as making Student ID the hash key.

For more information on DynamoDB tables, please visit the URL:

http://docs.aws.amazon.com/amazondynamodb/latest/developerguide/WorkingWithTables.html

To answer this question, we need to understand how Amazon DynamoDB works and how it handles throughput. Amazon DynamoDB is a NoSQL database that provides consistent, single-digit millisecond latency at any scale. When designing a DynamoDB table, the choice of the partition key or hash key can significantly impact the performance and cost efficiency of the system.

In DynamoDB, data is partitioned across multiple physical storage partitions based on the partition key. Each partition has a maximum throughput limit, which is measured in read and write capacity units (RCUs and WCUs). To achieve optimal performance, it is essential to choose a hash key schema that evenly distributes the data across the partitions and minimizes hot partitions (partitions that receive significantly more requests than others).

Now let's examine each of the options given in the question:

A. Student ID where every student has a unique I. This is a good choice for a hash key as it is unique and evenly distributes the data across the partitions, minimizing the risk of hot partitions.

B. College ID where there are two colleges in the university. This is not a good choice for a hash key, as it will result in only two partitions, and one partition will be much more active than the other, leading to a hot partition.

C. Class ID where every student is in one of the four classes. This is not a good choice for a hash key, as it will result in only four partitions, and one partition will be much more active than the others, leading to a hot partition.

D. Tuition Plan where the vast majority of students are in-state and the rest are out of state. This is not a good choice for a hash key, as it will result in only two partitions, and one partition will be much more active than the other, leading to a hot partition.

Therefore, the correct answer is A. Student ID where every student has a unique ID, as it is unique and evenly distributes the data across the partitions, minimizing the risk of hot partitions, and therefore ensuring provisioned throughput efficiency.