ADA-C01 Question 410
Single answerCalculate warehouse usage and credit consumptionA Snowflake administrator is reviewing warehouse costs for the last week. The ETL_WH warehouse is configured as MEDIUM, AUTO_SUSPEND = 60 seconds, and AUTO_RESUME = TRUE. On Tuesday, it resumed 12 separate times to run short ETL tasks. Each task ran for about 90 seconds, and there was enough idle time between tasks for the warehouse to suspend after each run. No resizing or multi-cluster scaling occurred. Based on Snowflake warehouse billing behavior, which statement best describes the credits charged for ETL_WH on Tuesday?
- A
The warehouse is charged only for the total active query execution time, so about 18 minutes of MEDIUM warehouse usage is billed.
- B
The warehouse is charged in 1-second increments with a 60-second minimum each time it resumes, so the total billed time is approximately 18 minutes plus 12 separate minimum-charge considerations.
- C
The warehouse is charged by rounding each resume period up to the nearest full hour, so 12 hours of MEDIUM warehouse usage is billed.
- D
The warehouse is charged only once for the first resume of the day, and subsequent resumes on the same day do not incur another minimum charge.
Show answer and explanation
Correct answer: B
Explanation
The key concept is that Snowflake bills virtual warehouses per second while they are running, but applies a 60-second minimum every time a warehouse is started or resumed. In this scenario, the MEDIUM warehouse resumed 12 times, and each run lasted about 90 seconds. Because each run exceeded 60 seconds, each interval is billed for about 90 seconds rather than being reduced to only query execution time or rounded to an hour. The practical takeaway for administrators is that frequent suspend/resume cycles for short jobs can materially affect credit consumption, especially when workloads are shorter than or close to the minimum billing interval. This is why tuning AUTO_SUSPEND requires balancing responsiveness against cost efficiency. Refer to Snowflake documentation on virtual warehouse credit usage and billing, especially the per-second billing model and the minimum charge applied on resume/start.
- A. Incorrect.
Incorrect. Snowflake does not bill strictly by summed query execution time. Warehouse billing is based on warehouse runtime while started, not just the time queries actively execute. In this scenario, each warehouse start/resume event can trigger minimum billing behavior, so simply totaling the 12 x 90-second tasks misses how credit consumption is actually calculated.
- B. Correct.
Correct. Snowflake virtual warehouses are billed per-second while running, with a 60-second minimum each time the warehouse starts or resumes. Because ETL_WH resumed 12 separate times and suspended between runs, each resume is a distinct billing event subject to the minimum. Since each task ran about 90 seconds, each run already exceeds the 60-second minimum, so billing would be approximately 12 x 90 seconds of MEDIUM warehouse runtime, with the important understanding that each resume is independently subject to the minimum-charge rule.
- C. Incorrect.
Incorrect. Snowflake does not round warehouse usage to the nearest full hour. Modern warehouse billing is per-second, subject to the warehouse-start minimum charge. This option reflects an outdated or incorrect mental model of compute billing.
- D. Incorrect.
Incorrect. The 60-second minimum is not a once-per-day charge. It applies each time a warehouse is started or resumed. Administrators often miss this when warehouses frequently auto-suspend and auto-resume for short workloads, which can increase effective cost.