Why virtual warehouses control compute independently in Snowflake - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a virtual warehouse with a specific size.

Snowflake

CREATE WAREHOUSE my_warehouse WITH WAREHOUSE_SIZE = '[1]';

Drag options to blanks, or click blank then click option'

AEXTRA_LARGE

BMEDIUM

CLARGE

DSMALL

Attempts:

3 left

💡 Hint

Common Mistakes

Using an invalid warehouse size.

Leaving the size blank.

The warehouse size controls the compute resources allocated. SMALL is a valid size.

2fill in blank

medium

Complete the code to set the warehouse to auto-suspend after inactivity.

Snowflake

ALTER WAREHOUSE my_warehouse SET AUTO_SUSPEND = [1];

Drag options to blanks, or click blank then click option'

A300

BON

CNULL

D0

Attempts:

3 left

💡 Hint

Common Mistakes

Using ON instead of a number.

Setting 0 disables auto-suspend.

Setting AUTO_SUSPEND to 300 means the warehouse suspends after 300 seconds of inactivity.

3fill in blank

hard

Fix the error in the code to resume the warehouse.

Snowflake

RESUME WAREHOUSE [1];

Drag options to blanks, or click blank then click option'

Amy_warehouse

Bmywarehouse

Cmy-warehouse

Dmy warehouse

Attempts:

3 left

💡 Hint

Common Mistakes

Using spaces or dashes in warehouse names.

Misspelling the warehouse name.

Warehouse names cannot have spaces or dashes; underscores are valid.

4fill in blank

hard

Fill both blanks to create a warehouse that auto-resumes and has a specific size.

Snowflake

CREATE WAREHOUSE my_warehouse WITH AUTO_RESUME = [1] WAREHOUSE_SIZE = '[2]';

Drag options to blanks, or click blank then click option'

ATRUE

BFALSE

CMEDIUM

DLARGE

Attempts:

3 left

💡 Hint

Common Mistakes

Setting AUTO_RESUME to FALSE when auto-resume is needed.

Using invalid warehouse sizes.

AUTO_RESUME should be TRUE to enable automatic resume. MEDIUM is a valid warehouse size.

5fill in blank

hard

Fill all three blanks to alter a warehouse to suspend after 600 seconds, set size to LARGE, and enable auto-resume.

Snowflake

ALTER WAREHOUSE my_warehouse SET AUTO_SUSPEND = [1], WAREHOUSE_SIZE = '[2]', AUTO_RESUME = [3];

Drag options to blanks, or click blank then click option'

A300

B600

CLARGE

DTRUE

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong values for AUTO_SUSPEND or AUTO_RESUME.

Incorrect warehouse size spelling.

Setting AUTO_SUSPEND to 600 seconds, size to LARGE, and AUTO_RESUME to TRUE configures the warehouse properly.

Practice

1. Why do virtual warehouses in Snowflake control compute independently?

easy

A. To share compute resources evenly among all users

B. To allow multiple workloads to run without affecting each other

C. To reduce storage costs by combining compute

D. To limit the number of queries that can run simultaneously

Solution

1. Step 1: Understand the role of virtual warehouses

   Virtual warehouses provide compute resources for queries and run independently.

2. Step 2: Identify the benefit of independent control

   Independent control prevents one workload from slowing down others by isolating compute resources.

3. Final Answer:

   To allow multiple workloads to run without affecting each other -> Option B

4. Quick Check:

   Independent compute control = no workload interference [OK]

Hint: Think: separate engines run separately to avoid slowdowns [OK]

Common Mistakes:

• Confusing compute independence with storage sharing
• Assuming warehouses share compute resources
• Thinking compute control reduces storage costs

2. Which of the following is the correct way to suspend a virtual warehouse in Snowflake?

easy

A. ALTER WAREHOUSE my_wh SUSPEND;

B. SUSPEND WAREHOUSE my_wh;

C. ALTER WAREHOUSE my_wh SET SUSPEND = TRUE;

D. ALTER WAREHOUSE my_wh SUSPEND IMMEDIATE;

Solution

1. Step 1: Recall Snowflake syntax for suspending warehouses

   The correct command uses ALTER WAREHOUSE with SUSPEND.

2. Step 2: Check each option's syntax

   Invalid syntax includes extra keywords like IMMEDIATE, missing ALTER, or incorrect SET usage. The correct syntax is ALTER WAREHOUSE my_wh SUSPEND;.

3. Final Answer:

   ALTER WAREHOUSE my_wh SUSPEND; -> Option A

4. Quick Check:

   Correct suspend syntax = ALTER WAREHOUSE ... SUSPEND [OK]

Hint: Remember: ALTER WAREHOUSE ... SUSPEND is correct [OK]

Common Mistakes:

• Using SUSPEND without ALTER WAREHOUSE
• Trying to set SUSPEND as a property
• Using unnecessary keywords like IMMEDIATE

3. Given two virtual warehouses, WH1 and WH2, running queries simultaneously, what happens if WH1 is resized larger while WH2 continues running?

medium

A. WH2's compute resources are reduced automatically

B. Both warehouses share the new combined compute power

C. WH1's resize does not affect WH2's compute resources

D. WH2 is suspended until WH1 finishes resizing

Solution

1. Step 1: Understand independent compute control

   Each warehouse controls its own compute resources independently.

2. Step 2: Analyze the effect of resizing one warehouse

   Resizing WH1 affects only WH1; WH2 continues unaffected.

3. Final Answer:

   WH1's resize does not affect WH2's compute resources -> Option C

4. Quick Check:

   Independent compute means resizing one doesn't impact others [OK]

Hint: Resize affects only targeted warehouse, others run normally [OK]

Common Mistakes:

• Assuming compute resources are shared dynamically
• Thinking resizing pauses other warehouses
• Believing compute is pooled automatically

4. You tried to resume a suspended warehouse with the command RESUME WAREHOUSE my_wh; but got an error. What is the likely cause?

medium

A. The correct command is ALTER WAREHOUSE my_wh RESUME;

B. Warehouse names cannot contain underscores

C. You must use ALTER WAREHOUSE my_wh RESUME WAREHOUSE;

D. The warehouse is already running and cannot be resumed

Solution

1. Step 1: Check Snowflake syntax for resuming warehouses

   The correct command uses ALTER WAREHOUSE with RESUME keyword.

2. Step 2: Identify the error in the given command

   RESUME WAREHOUSE alone is invalid; must use ALTER WAREHOUSE my_wh RESUME;

3. Final Answer:

   The correct command is ALTER WAREHOUSE my_wh RESUME; -> Option A

4. Quick Check:

   Resume warehouse syntax = ALTER WAREHOUSE ... RESUME [OK]

Hint: Use ALTER WAREHOUSE ... RESUME to restart suspended warehouse [OK]

Common Mistakes:

• Using RESUME WAREHOUSE alone as a command
• Misnaming warehouses with invalid characters
• Trying to resume an already running warehouse

5. You have three virtual warehouses: WH_A, WH_B, and WH_C. WH_A is running a heavy ETL job, WH_B is idle, and WH_C runs light queries. To optimize costs and performance, which approach best uses independent compute control?

hard

A. Suspend WH_A and WH_C, run all queries on WH_B

B. Resize all warehouses to the same size to balance compute

C. Merge all warehouses into one to share compute and reduce costs

D. Resize WH_A larger, suspend WH_B, and keep WH_C small and running

Solution

1. Step 1: Use independent compute control to match workload needs

   Resize WH_A larger for heavy ETL, suspend idle WH_B to save costs, keep WH_C small for light queries.

2. Step 2: Avoid resizing all equally or merging warehouses

   Balancing sizes wastes resources; merging loses independent control benefits.

3. Final Answer:

   Resize WH_A larger, suspend WH_B, and keep WH_C small and running -> Option D

4. Quick Check:

   Match warehouse size to workload independently for best cost/performance [OK]

Hint: Adjust each warehouse size and state based on its workload [OK]

Common Mistakes:

• Making all warehouses the same size regardless of workload
• Suspending warehouses that are actively needed
• Trying to merge warehouses to save costs