Exam AWS Certified Database - Specialty topic 1 question 288 discussion

Exam question from Amazon's AWS Certified Database - Specialty

Question #: 288
Topic #: 1

[All AWS Certified Database - Specialty Questions]

A company uses Amazon DynamoDB as a data store for multi-tenant data. Approximately 70% of the reads by the company's application are strongly consistent. The current key schema for the DynamoDB table is as follows:

Partition key: OrgID -

Sort key: TenantID#Version -

Due to a change in design and access patterns, the company needs to support strongly consistent lookups based on the new schema below:

Partition key: OrgID#TenantID -

Sort key: Version -

How can the database specialist implement this change?

A. Create a global secondary index (GSI) on the existing table with the specified partition and sort key.
B. Create a local secondary index (LSI) on the existing table with the specified partition and sort key.
C. Create a new table with the specified partition and sort key. Create an AWS Glue ETL job to perform the transformation and write the transformed data to the new table.
D. Create a new table with the specified partition and sort key. Use AWS Database Migration Service (AWS DMS) to migrate the data to the new table.

Show Suggested Answer

Suggested Answer: C 🗳️

by rdiaz at March 29, 2023, 6:17 p.m.

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Comments

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aviathor

Highly Voted 2 years ago

Selected Answer: C

xA. Create a global secondary index (GSI) on the existing table with the specified partition and sort key. - GSI does not support strongly consistent searches xB. Create a local secondary index (LSI) on the existing table with the specified partition and sort key. - the secondary index only contains the sort key, it does not help for the partition key, and it cannot be added after the table has been created. C. Create a new table with the specified partition and sort key. Create an AWS Glue ETL job to perform the transformation and write the transformed data to the new table. - by elimination, this has to be the correct answer xD. Create a new table with the specified partition and sort key. Use AWS Database Migration Service (AWS DMS) to migrate the data to the new table. - DMS only supports DynamoDB as a target

upvoted 6 times

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rn30

Most Recent 1 year, 10 months ago

C you can not update the sort key after the table is provisioned. However, you can create a new table and put the existing data in the newly created table, and delete the old table.

upvoted 1 times

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mawsman

2 years, 1 month ago

Selected Answer: C

GSI uses the same data and is eventually consistent - we need to combine two columns to create new primary key, plus it needs to be strongly consistent. Hence new table and glue, but a bit of a trick question none the less, since it asks for LEAST effort.

upvoted 1 times

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Mintwater

2 years, 1 month ago

A. Create a global secondary index (GSI) on the existing table with the specified partition and sort key. https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/GSI.html#GSI.scenario "By creating a GSI with the new partition and sort key, the existing table can continue to be used, and there is no need to create a new table or migrate the data. This approach can support strongly consistent lookups for the new access pattern while maintaining the existing access pattern. A GSI is ideal for handling queries with different access patterns without changing the primary key of the table."

upvoted 1 times

Mintwater

2 years, 1 month ago

A maybe not the right answer -- "Data synchronization between tables and Global Secondary Indexes DynamoDB automatically synchronizes each global secondary index with its base table. When an application writes or deletes items in a table, any global secondary indexes on that table are updated asynchronously, using an eventually consistent model. Applications never write directly to an index.

upvoted 1 times

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rdiaz

2 years, 2 months ago

Selected Answer: C

A. KO - GSI is not strongly consistent. B. KO - LSI cannot be created once the table exists. C. OK - New table + glue D. KO - Dynamo is not a compatible source for DMS: https://docs.aws.amazon.com/dms/latest/userguide/CHAP_Source.html

upvoted 3 times

Mintwater

2 years, 1 month ago

GLUE is complex. I prefer D

upvoted 1 times

Mintwater

2 years, 1 month ago

You are right. Dynamo is not the source for DMS.

upvoted 1 times

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