COF-C03 Question 81
Single answerAuto-SuspendA data engineering team uses a Snowflake virtual warehouse named ETL_WH to run scheduled transformation jobs every 15 minutes. Between runs, the warehouse is often idle for 10-12 minutes. The team wants to reduce compute cost without significantly increasing job start time. Which warehouse configuration change best meets this requirement?
- A
Set AUTO_SUSPEND to 60 seconds and keep AUTO_RESUME enabled
- B
Set AUTO_SUSPEND to 0 so the warehouse stays available for the next scheduled run
- C
Disable AUTO_RESUME and manually resume the warehouse before each job
- D
Increase the warehouse size so each job finishes faster and the warehouse can suspend sooner
Show answer and explanation
Correct answer: A
Explanation
AUTO_SUSPEND controls how long a virtual warehouse waits while idle before shutting down, and AUTO_RESUME allows it to restart automatically when a new query arrives. For periodic workloads with predictable idle gaps, a short AUTO_SUSPEND value is a Snowflake best practice to minimize wasted compute credits while preserving usability. Setting AUTO_SUSPEND to a low value such as 60 seconds is especially effective when idle periods are much longer than the suspend threshold. By contrast, setting AUTO_SUSPEND to 0 disables auto-suspend entirely. This question tests practical warehouse cost management, a key SnowPro Core skill. Refer to Snowflake documentation on virtual warehouses, specifically warehouse properties for AUTO_SUSPEND and AUTO_RESUME, and cost optimization guidance for idle warehouses.
- A. Correct.
Correct. Setting AUTO_SUSPEND to 60 seconds allows the warehouse to shut down shortly after becoming idle, which reduces compute charges during the 10-12 minute gaps between scheduled jobs. Keeping AUTO_RESUME enabled ensures the next scheduled query can automatically restart the warehouse with minimal operational overhead. This is a common cost-optimization pattern for intermittent workloads.
- B. Incorrect.
Incorrect. An AUTO_SUSPEND value of 0 disables automatic suspension, so the warehouse would continue running during idle periods. In this scenario, that would waste credits during the 10-12 minutes between job runs, which is the opposite of the stated goal.
- C. Incorrect.
Incorrect. Disabling AUTO_RESUME would require operational processes or external orchestration to resume the warehouse before every job. While this could work, it does not best meet the requirement to reduce cost without significantly increasing startup complexity or risking job failures when the warehouse is not manually resumed in time.
- D. Incorrect.
Incorrect. A larger warehouse may reduce query runtime, but it does not directly address the cost of idle time between executions. In some cases, increasing size can increase compute consumption. AUTO_SUSPEND is the relevant setting for controlling how long an idle warehouse remains running.