Auto-suspend and auto-resume in Snowflake - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is auto-suspend in Snowflake?

Auto-suspend is a feature that automatically pauses a virtual warehouse after a set period of inactivity to save compute costs.

beginner

What does auto-resume do in Snowflake?

Auto-resume automatically restarts a suspended virtual warehouse when a query or operation requires compute resources.

beginner

Why is auto-suspend useful for managing costs?

Because it stops the warehouse when not in use, preventing charges for idle compute time, similar to turning off a machine when not needed.

intermediate

How do you enable auto-suspend and auto-resume on a Snowflake warehouse?

You set the AUTO_SUSPEND parameter to a number of seconds and AUTO_RESUME to TRUE when creating or altering the warehouse.

intermediate

What happens if auto-resume is disabled and the warehouse is suspended?

Queries will fail until the warehouse is manually resumed, causing delays similar to waiting for a machine to be turned back on by hand.

What does setting AUTO_SUSPEND to 300 mean?

A The warehouse suspends immediately

B The warehouse runs for 300 seconds then stops

C The warehouse suspends after 300 seconds of inactivity

D The warehouse resumes every 300 seconds

AUTO_SUSPEND set to 300 means the warehouse will suspend after 5 minutes (300 seconds) of no activity.

If AUTO_RESUME is set to FALSE, what must happen to run queries after suspension?

A Queries run automatically

B Warehouse must be manually resumed

C Queries are queued indefinitely

D Warehouse auto-resumes after 1 minute

With AUTO_RESUME disabled, the warehouse stays suspended until manually resumed.

Why is auto-suspend important for cloud cost management?

A It pauses unused warehouses to save money

B It increases compute power

C It speeds up queries

D It backs up data automatically

Auto-suspend pauses warehouses when idle, avoiding charges for unused compute.

Which Snowflake object is affected by auto-suspend and auto-resume settings?

A Schema

B Database

C User account

D Virtual warehouse

Auto-suspend and auto-resume control the state of virtual warehouses.

What is the default behavior if AUTO_SUSPEND is not set?

A Warehouse suspends after 10 minutes

B Warehouse never suspends automatically

C Warehouse suspends after 1 minute

D Warehouse auto-resumes disabled

The default value for AUTO_SUSPEND is 600 seconds (10 minutes) of inactivity.

Explain how auto-suspend and auto-resume work together to optimize Snowflake warehouse usage and cost.

Think about turning off and on a machine automatically.

Describe the steps to configure a Snowflake warehouse to auto-suspend after 5 minutes and auto-resume on query.

Focus on warehouse parameters.

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