Exam AWS Certified Solutions Architect - Associate SAA-C03 topic 1 question 337 discussion

i hate this kind of question

Using Cache required huge changes in the application. Several things need to change to use cache in front of the DB in the application. So, option B is not correct. Aurora will help to reduce replication lag for read replica

You need to read the question carefully. The solutions architect must minimize changes to the application code = therefore A If this question without this statement, B will be a better choice.

minimize ongoing operational overhead = Not B Using ElastiCache require app change

AWS Aurora and Native Functions are least application changes while providing better performance and minimum latency. https://aws.amazon.com/rds/aurora/faqs/ B, C, D require lots of changes to the application so relatively speaking A is least code change and least maintenance/operational overhead.

A: Minimal changes to the application code, < 1 second lag B: Does not address the replication lag issue at all, requires code changes and adds overhead C: Moving from managed RDS to self-managed database on EC2 is ADDING, not minimizing, overhead, PLUS it does not address the replication lag issue D: DynamoDB is a NoSQL DB, would require MASSIVE changes to application code and probably even application logic

imho, B is not valid because it involves extra coding and the question specifically mentions no more coding. Therefore, replacing the current db with another one is not considered as more coding.

Migrate the database to Amazon Aurora MySQL. Replace the read replicas with Aurora Replicas, and configure Aurora Auto Scaling. Replace the stored procedures with Aurora MySQL native functions

Migrate the RDS MySQL database to Amazon Aurora MySQL Use Aurora Replicas for read scaling instead of RDS read replicas Configure Aurora Auto Scaling to handle load spikes Replace stored procedures with Aurora MySQL native functions

First, Elasticache involves heavy change on application code. The question mentioned that "he solutions architect must minimize changes to the application code". Therefore B is not suitable and A is more appropriate for the question requirement.

Why not B? Please explain to me.

Option A is the most appropriate solution for reducing replication lag without significant changes to the application code and minimizing ongoing operational overhead. Migrating the database to Amazon Aurora MySQL allows for improved replication performance and higher scalability compared to Amazon RDS for MySQL. Aurora Replicas provide faster replication, reducing the replication lag, and Aurora Auto Scaling ensures that there are enough Aurora Replicas to handle the incoming traffic. Additionally, Aurora MySQL native functions can replace the stored procedures, reducing the load on the database and improving performance. Option B is not the best solution since adding an ElastiCache for Redis cluster does not address the replication lag issue, and the cache may not have the most up-to-date information. Additionally, replacing the stored procedures with AWS Lambda functions adds additional complexity and may not improve performance.

a,b are confusing me.. i would like to go with b..

By using ElastiCache you avoid a lot of common issues you might encounter. ElastiCache is a database caching solution. ElastiCache Redis per se, supports failover and Multi-AZ. And Most of all, ElastiCache is well suited to place in front of RDS. Migrating a database such as option A, requires operational overhead.

Aurora can have up to 15 read replicas - much faster than RDS https://aws.amazon.com/rds/aurora/

Answer - A https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/USER_PostgreSQL.Replication.ReadReplicas.html --------------------------------------------------------------------------------------- You can scale reads for your Amazon RDS for PostgreSQL DB instance by adding read replicas to the instance. As with other Amazon RDS database engines, RDS for PostgreSQL uses the native replication mechanisms of PostgreSQL to keep read replicas up to date with changes on the source DB. For general information about read replicas and Amazon RDS, see Working with read replicas.