ADA-C01 Question 414
Single answerCalculate and minimize IDLE time costA Snowflake administrator reviews warehouse usage and notices that the ETL_WH virtual warehouse runs many short ELT jobs during business hours. Query performance is acceptable, but the monthly credit report shows a large amount of cost attributed to warehouse IDLE time. The warehouse is configured as MEDIUM, AUTO_SUSPEND = 600 seconds, AUTO_RESUME = TRUE, and is used only by scheduled jobs every 10 to 20 minutes. Which configuration change would most directly reduce IDLE time cost while preserving unattended job execution?
- A
Reduce AUTO_SUSPEND from 600 seconds to a smaller value such as 60 seconds and keep AUTO_RESUME enabled
- B
Disable AUTO_RESUME so the warehouse stays suspended until an administrator manually starts it
- C
Resize the warehouse from MEDIUM to SMALL while keeping AUTO_SUSPEND at 600 seconds
- D
Enable multi-cluster mode with a higher maximum cluster count so jobs finish faster
Show answer and explanation
Correct answer: A
Explanation
To minimize warehouse IDLE cost, administrators should focus on how long a warehouse stays running after work completes. In Snowflake, virtual warehouses consume credits while running, including periods when they are idle. AUTO_SUSPEND is the primary control for reducing unnecessary runtime, and AUTO_RESUME allows workloads to restart the warehouse automatically when new queries arrive. For intermittent scheduled workloads, setting a shorter AUTO_SUSPEND value is a common best practice to reduce wasted credits without affecting automation. Warehouse resizing and multi-cluster configuration address performance and concurrency considerations, but they do not directly solve excessive idle runtime. This aligns with Snowflake guidance on managing warehouse cost through suspension behavior, auto-resume, and right-sizing based on actual workload patterns.
- A. Correct.
Correct. IDLE cost occurs when a warehouse remains running but is not executing queries. With jobs arriving every 10 to 20 minutes, an AUTO_SUSPEND value of 600 seconds can leave the warehouse running unnecessarily between job runs. Lowering AUTO_SUSPEND reduces the amount of billable idle time. Keeping AUTO_RESUME enabled ensures scheduled jobs can still start the warehouse automatically without manual intervention.
- B. Incorrect.
Incorrect. Disabling AUTO_RESUME might reduce costs only by keeping the warehouse suspended until someone starts it, but it would not preserve unattended execution for scheduled jobs. This introduces operational risk and job failures because scheduled workloads would not automatically resume the warehouse when needed.
- C. Incorrect.
Incorrect. Resizing to SMALL may reduce compute cost per running second if performance remains acceptable, but it does not directly address the specific issue of IDLE time. The warehouse could still remain running and idle for the same 600-second interval between jobs. This option targets warehouse size, not idle duration.
- D. Incorrect.
Incorrect. Multi-cluster warehouses help manage concurrency by adding clusters when many queries run at the same time. They do not directly minimize idle time cost for a warehouse running periodic short jobs. In fact, increasing cluster capacity could increase cost if concurrency is not the problem.