Read replicas for performance in AWS - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a read replica in cloud databases?

A read replica is a copy of the main database that handles read requests to reduce load on the main database and improve performance.

beginner

How do read replicas improve application performance?

By directing read queries to replicas, the main database can focus on writes, reducing delays and improving overall speed.

beginner

Can read replicas be used for write operations?

No, read replicas are designed only for read operations. All writes must go to the primary database to keep data consistent.

intermediate

What happens if the primary database fails when using read replicas?

You can promote a read replica to become the new primary database to maintain availability and reduce downtime.

intermediate

Why is replication lag important in read replicas?

Replication lag is the delay between the primary database and replicas. High lag means replicas may serve outdated data, affecting accuracy.

What is the main purpose of a read replica?

A To process write operations faster

B To store backups of the database

C To replace the primary database permanently

D To handle read requests and reduce load on the primary database

Read replicas handle read requests to improve performance and reduce load on the primary database.

Can you write data directly to a read replica?

A Yes, always

B Only during maintenance

C No, writes must go to the primary database

D Only if replication lag is zero

Read replicas are read-only; all writes must be done on the primary database to keep data consistent.

What is replication lag?

A The delay between data updates on primary and replicas

B The time it takes to create a read replica

C The speed of the primary database

D The network speed between users and database

Replication lag is the delay between when data is updated on the primary and when it appears on the read replicas.

How can read replicas help during a primary database failure?

A They can be promoted to primary to restore service

B They stop serving any requests

C They delete all data to prevent errors

D They automatically become the new primary without any action

Read replicas can be promoted to primary to maintain availability if the original primary fails.

Which workload benefits most from read replicas?

A Heavy write operations

B Heavy read operations

C Backup storage

D Data encryption

Read replicas improve performance mainly for workloads with many read operations.

Explain how read replicas improve database performance and availability.

Think about how splitting reads and writes helps.

Describe the limitations and considerations when using read replicas.

Consider what read replicas cannot do and what to watch out for.