ADA-C01 Question 508
Single answerDifferentiate the use cases for primary and secondary databasesA global retailer uses database replication between Snowflake accounts in different regions. The production account in AWS us-east-1 hosts the SALES database, which is the source for business-critical ETL and reporting. The company also maintains a replicated copy of SALES in a separate account in AWS us-west-2 for disaster recovery and limited read-only reporting during regional outages. An administrator is asked to recommend the correct operational model for the two databases. Which statement best describes the appropriate use of the primary and secondary databases in this scenario?
- A
Keep SALES in us-east-1 as the primary database for all read and write activity, and use the replicated SALES database in us-west-2 as a secondary database that can be refreshed from the primary and used mainly for read-only access or failover.
- B
Convert the replicated SALES database in us-west-2 to the primary database so that both regions can accept concurrent writes, improving availability without requiring failover.
- C
Use the secondary database in us-west-2 as the main ETL target because secondary databases support independent writes as long as replication is scheduled frequently.
- D
Designate both databases as primary databases so each account can replicate changes back to the other, creating active-active bidirectional replication for the SALES data.
Show answer and explanation
Correct answer: A
Explanation
Snowflake database replication distinguishes clearly between primary and secondary databases. The primary database is the authoritative, writable source. Secondary databases are read-only replicas used for disaster recovery, business continuity, migration support, and certain read-only access patterns. In real-world administration, this means production ETL and transactional updates should continue against the primary until a failover event requires promotion of a secondary. Snowflake replication is not an active-active bidirectional database write architecture. This aligns with Snowflake documentation on replication and failover, which describes secondaries as replicated, read-only copies that can be refreshed from the primary and promoted when needed for recovery.
- A. Correct.
Correct. In Snowflake replication, the primary database is the writable source database. A secondary database is a read-only replicated copy created from the primary and refreshed through replication. This makes the primary appropriate for ongoing production writes, while the secondary is appropriate for disaster recovery, business continuity, and read-only use cases such as reporting. If needed during a failover event, the secondary can be promoted to become writable.
- B. Incorrect.
Incorrect. A secondary database is not used for concurrent write activity alongside the primary. Snowflake database replication is not an active-active write model. To make the west region database writable, it would need to be promoted during failover or failover/failback operations, not used simultaneously for bidirectional production writes.
- C. Incorrect.
Incorrect. This reflects a common misconception that frequent refreshes make a secondary database suitable for near-real-time ETL writes. Secondary databases remain read-only while they are secondaries. They are intended for replicated access and recovery scenarios, not as independent writable ETL targets.
- D. Incorrect.
Incorrect. Snowflake does not support designating both copies as primaries for the same replicated database in a bidirectional active-active pattern. Replication is based on a single writable primary source and one or more read-only secondary databases. Administrators use failover groups and promotion when shifting write responsibility, not simultaneous dual-primary replication.