Auto-suspend and auto-resume in Snowflake - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ service_behavior

intermediate

What happens when a Snowflake warehouse with auto-suspend enabled is idle?

A Snowflake warehouse has auto-suspend set to 5 minutes. What will happen if no queries run for 6 minutes?

A The warehouse suspends immediately when the last query finishes.

B The warehouse automatically suspends after 5 minutes of inactivity.

C The warehouse continues running indefinitely until manually suspended.

D The warehouse suspends only if manually triggered by the user.

💡 Hint

Think about what auto-suspend means for idle warehouses.

Auto-suspend automatically stops the warehouse after the specified idle time to save credits.

❓ Configuration

intermediate

Which SQL command enables auto-resume for a Snowflake warehouse?

Choose the correct SQL command to enable auto-resume on a warehouse named MY_WH.

A ALTER WAREHOUSE MY_WH SET AUTO_RESUME = TRUE;

B ALTER WAREHOUSE MY_WH SET AUTO_RESUME = ON;

C ALTER WAREHOUSE MY_WH SET AUTO_RESUME = ENABLED;

D ALTER WAREHOUSE MY_WH SET AUTO_RESUME = 1;

💡 Hint

Check the exact syntax for setting boolean options in Snowflake.

Snowflake uses TRUE or FALSE for boolean settings in ALTER WAREHOUSE commands.

❓ Architecture

advanced

How does auto-resume affect query latency in Snowflake?

Consider a warehouse with auto-suspend enabled after 10 minutes and auto-resume enabled. What is the impact on query latency when a new query arrives after suspension?

A The first query experiences a delay while the warehouse resumes, increasing latency.

B Queries run instantly with no delay because auto-resume is automatic.

C All queries are queued until the warehouse is manually resumed.

D Queries fail if the warehouse is suspended, regardless of auto-resume.

💡 Hint

Think about what happens when a warehouse is suspended and a query arrives.

Auto-resume starts the warehouse when a query arrives, but this startup takes a few seconds, causing initial delay.

❓ security

advanced

What security risk can arise if auto-resume is enabled on a Snowflake warehouse?

Identify a potential security concern related to enabling auto-resume on a warehouse.

A Auto-resume encrypts data less securely during warehouse startup.

B Auto-resume disables user authentication, allowing anonymous access.

C Auto-resume causes warehouses to run with elevated privileges automatically.

D Unauthorized queries can trigger warehouse startup, increasing exposure to data.

💡 Hint

Consider who can run queries and what happens when the warehouse starts automatically.

If unauthorized users can run queries, auto-resume may start the warehouse unexpectedly, potentially increasing data exposure.

✅ Best Practice

expert

Which combination of auto-suspend and auto-resume settings optimizes cost and performance for unpredictable workloads?

You manage a Snowflake warehouse with unpredictable query patterns. Which setting combination best balances cost savings and query responsiveness?

A Auto-suspend set to 60 minutes; auto-resume disabled.

B Auto-suspend disabled; auto-resume disabled.

C Auto-suspend set to 5 minutes; auto-resume enabled.

D Auto-suspend disabled; auto-resume enabled.

💡 Hint

Think about how quickly the warehouse suspends and restarts for cost and speed.

Short auto-suspend with auto-resume saves cost by suspending quickly and resumes automatically to reduce query wait time.

Practice

1. What is the main purpose of the auto-suspend feature in a Snowflake warehouse?

easy

A. To increase the warehouse size during peak hours

B. To automatically start the warehouse when a query is submitted

C. To automatically stop the warehouse after a period of inactivity to save costs

D. To backup warehouse data automatically

Solution

1. Step 1: Understand auto-suspend functionality

   Auto-suspend stops the warehouse when it is idle for a set time to avoid unnecessary charges.

2. Step 2: Differentiate from auto-resume

   Auto-resume starts the warehouse when a query runs, not auto-suspend.

3. Final Answer:

   To automatically stop the warehouse after a period of inactivity to save costs -> Option C

4. Quick Check:

   Auto-suspend = stops warehouse after inactivity [OK]

Hint: Auto-suspend stops idle warehouse to save money [OK]

Common Mistakes:

• Confusing auto-suspend with auto-resume
• Thinking auto-suspend increases warehouse size
• Assuming auto-suspend backs up data

2. Which of the following is the correct way to enable auto-resume for a Snowflake warehouse using SQL?

easy

A. ALTER WAREHOUSE my_wh SET AUTO_RESUME = TRUE;

B. ALTER WAREHOUSE my_wh SET AUTO_SUSPEND = TRUE;

C. CREATE WAREHOUSE my_wh AUTO_RESUME = ON;

D. ALTER WAREHOUSE my_wh ENABLE AUTO_RESUME;

Solution

1. Step 1: Recall correct syntax for enabling auto-resume

   The correct command uses ALTER WAREHOUSE with SET AUTO_RESUME = TRUE.

2. Step 2: Eliminate incorrect options

   ALTER WAREHOUSE my_wh SET AUTO_SUSPEND = TRUE; sets auto_suspend, not auto_resume. CREATE WAREHOUSE my_wh AUTO_RESUME = ON; uses wrong syntax for CREATE. ALTER WAREHOUSE my_wh ENABLE AUTO_RESUME; uses invalid command.

3. Final Answer:

   ALTER WAREHOUSE my_wh SET AUTO_RESUME = TRUE; -> Option A

4. Quick Check:

   Enable auto-resume with SET AUTO_RESUME = TRUE [OK]

Hint: Use ALTER WAREHOUSE ... SET AUTO_RESUME = TRUE to enable [OK]

Common Mistakes:

• Confusing AUTO_RESUME with AUTO_SUSPEND
• Using CREATE instead of ALTER for existing warehouse
• Using invalid commands like ENABLE AUTO_RESUME

3. Given this SQL command sequence:

ALTER WAREHOUSE my_wh SET AUTO_SUSPEND = 300;
ALTER WAREHOUSE my_wh SET AUTO_RESUME = TRUE;
-- Warehouse is currently suspended
SELECT CURRENT_WAREHOUSE();

What happens when the SELECT query runs?

medium

A. The warehouse automatically resumes and the query runs successfully

B. The query fails because the warehouse is suspended

C. The warehouse remains suspended and query waits indefinitely

D. The warehouse resumes but the query returns NULL

Solution

1. Step 1: Understand auto-resume behavior

   With AUTO_RESUME = TRUE, the warehouse starts automatically when a query runs.

2. Step 2: Apply to the SELECT query

   The warehouse is suspended but will resume automatically before executing the SELECT.

3. Final Answer:

   The warehouse automatically resumes and the query runs successfully -> Option A

4. Quick Check:

   Auto-resume starts warehouse on query run [OK]

Hint: Auto-resume starts suspended warehouse on query execution [OK]

Common Mistakes:

• Assuming query fails if warehouse is suspended
• Thinking warehouse stays suspended during query
• Believing query returns NULL when warehouse resumes

4. You set AUTO_SUSPEND = 0 and AUTO_RESUME = TRUE on a warehouse. What issue might occur?

medium

A. The warehouse suspends and resumes repeatedly every second

B. The warehouse suspends immediately and never resumes

C. The warehouse suspends after default 60 seconds

D. The warehouse never suspends, causing continuous charges

Solution

1. Step 1: Understand AUTO_SUSPEND = 0 meaning

   Setting AUTO_SUSPEND to 0 disables auto-suspend, so warehouse stays running.

2. Step 2: Consider AUTO_RESUME effect

   AUTO_RESUME = TRUE allows auto-start but does not suspend warehouse automatically.

3. Final Answer:

   The warehouse never suspends, causing continuous charges -> Option D

4. Quick Check:

   AUTO_SUSPEND=0 disables suspend, warehouse runs always [OK]

Hint: AUTO_SUSPEND=0 means warehouse never suspends [OK]

Common Mistakes:

• Thinking AUTO_SUSPEND=0 suspends immediately
• Assuming warehouse suspends after default time
• Believing warehouse cycles suspend/resume every second

5. You want to minimize costs by suspending a warehouse after 5 minutes of inactivity but ensure it resumes automatically when needed. Which configuration is best?

hard

A. Set AUTO_SUSPEND = 60 and AUTO_RESUME = FALSE

B. Set AUTO_SUSPEND = 300 and AUTO_RESUME = TRUE

C. Set AUTO_SUSPEND = 0 and AUTO_RESUME = FALSE

D. Set AUTO_SUSPEND = 600 and AUTO_RESUME = TRUE

Solution

1. Step 1: Choose auto-suspend time for 5 minutes

   5 minutes equals 300 seconds, so AUTO_SUSPEND = 300 is correct.

2. Step 2: Enable auto-resume for automatic start

   Setting AUTO_RESUME = TRUE ensures warehouse starts when queries run.

3. Final Answer:

   Set AUTO_SUSPEND = 300 and AUTO_RESUME = TRUE -> Option B

4. Quick Check:

   5 min suspend + auto-resume = AUTO_SUSPEND=300 & AUTO_RESUME=TRUE [OK]

Hint: Use 300 seconds for 5 min suspend and enable auto-resume [OK]

Common Mistakes:

• Using 0 for AUTO_SUSPEND disables suspend
• Disabling AUTO_RESUME causes manual start
• Setting suspend time too short or too long