Snowflake COF-C02 Exam Practice Test Instant Access

Question 1

Which Query Profile metrics will provide information that can be used to improve query performance? (Select TWO).

ASynchronization

BRemote disk IO

CLocal disk IO

DPruning

ESpillage

Answer : B, D

Two key metrics in Snowflake's Query Profile that provide insights for performance improvement are:

Remote Disk IO: This measures the time the query spends waiting on remote disk access, indicating potential performance issues related to I/O bottlenecks.

Pruning: This metric reflects how effectively Snowflake's micro-partition pruning is reducing the data scanned. Better pruning (more partitions excluded) leads to faster query performance, as fewer micro-partitions need to be processed.

These metrics are essential for identifying and addressing inefficiencies in data retrieval and storage access, optimizing overall query performance.

Question 2

Which type of Snowflake virtual warehouse provides 16 times the memory for each node and is recommended for larger workloads like Machine Learning (ML) training?

AA size 6XL warehouse

BA standard warehouse

CA multi-cluster warehouse

DA Snowpark-optimized warehouse

Answer : D

The Snowpark-optimized warehouse is designed with significantly higher memory per node, making it ideal for machine learning (ML) training and other memory-intensive workloads. Snowpark-optimized warehouses provide the necessary computational power and memory for complex, large-scale data processing tasks.

Standard and multi-cluster warehouses do not offer the same memory advantage, while the 6XL warehouse is large but not specifically optimized for memory-intensive operations.

Question 3

What does the Remote Disk I/O statistic in the Query Profile indicate?

ATime spent reading from the result cache.

BTime spent reading from the virtual warehouse cache.

CTime when the query processing was blocked by remote disk access.

DThe level of network activity between the Cloud Services layer and the virtual warehouse.

Answer : C

The Remote Disk I/O statistic in the Query Profile reflects time spent waiting on remote disk access, which can occur when data needs to be retrieved from external storage (remote). This metric is crucial for identifying bottlenecks related to I/O delays, often suggesting a need for performance optimization in data retrieval paths.

The other options relate to caching and network activity, but Remote Disk I/O specifically measures the wait time for data access from remote storage locations.

Question 4

When working with table MY_TABLE that contains 10 rows, which sampling query will always return exactly 5 rows?

ASELECT * FROM MY_TABLE SAMPLE SYSTEM (5);

BSELECT * FROM MY_TABLE SAMPLE BERNOULLI (5);

CSELECT * FROM MY_TABLE SAMPLE (5 ROWS);

DSELECT * FROM MY_TABLE SAMPLE SYSTEM (1) SEED (5);

Answer : C

In Snowflake, SAMPLE (5 ROWS) ensures an exact count of 5 rows is returned from MY_TABLE, regardless of table size. This is different from SAMPLE SYSTEM or SAMPLE BERNOULLI, which use percentage-based sampling, potentially returning varying row counts based on probabilistic methods.

The ROWS option is deterministic and does not depend on percentage, making it ideal when an exact row count is required.

Question 5

How does the search optimization service improve query performance?

ABy clustering the tables

BBy creating a persistent data structure

CBy using caching

DBy optimizing the use of micro-partitions

Answer : B

The Search Optimization Service in Snowflake enhances query performance by creating a persistent data structure that enables faster access to specific data, particularly for queries with selective filters on columns not often used in clustering. This persistent structure accelerates data retrieval without depending on clustering or caching, thereby improving response times for targeted queries.

Snowflake's micro-partitioning automatically manages table structure, but search optimization allows further enhancement for certain high-frequency, specific access patterns.

Question 6

When unloading data, which combination of parameters should be used to differentiate between empty strings and NULL values? (Select TWO).

AESCAPE_UNENCLOSED_FIELD

BREPLACE_INVALID_CHARACTERS

CFIELD_OPTIONALLY_ENCLOSED_BY

DEMPTY_FIELD_AS_NULL

ESKIP_BLANK_LINES

Answer : C, D

When unloading data in Snowflake, it is essential to differentiate between empty strings and NULL values to preserve data integrity. The parameters FIELD_OPTIONALLY_ENCLOSED_BY and EMPTY_FIELD_AS_NULL are used together to address this:

FIELD_OPTIONALLY_ENCLOSED_BY: This parameter specifies the character used to enclose fields, which can differentiate between empty strings (as enclosed fields) and NULLs.

EMPTY_FIELD_AS_NULL: By setting this parameter, Snowflake interprets empty fields as NULL values when unloading data, ensuring accurate representation of NULLs versus empty strings.

These parameters are crucial when exporting data for systems that need explicit differentiation between NULL and empty string values.

Question 7

What activities can a user with the ORGADMIN role perform? (Select TWO).

ACreate information_schema in a database

BView usage information for all accounts in the organization.

CEnable database cloning for an account in the organization.

DEnable database replication for an account in the organization.

EView micro-partition information for all accounts in the organization.

Answer : B, D

The ORGADMIN role in Snowflake is designed to manage organization-level activities. This role can perform several tasks that span across multiple accounts within the organization.

View Usage Information: The ORGADMIN role can view usage statistics and billing information for all accounts within the organization.

-- Example: Viewing usage information

SELECT *

FROM organization_usage_history;

Enable Database Replication: The ORGADMIN role has the authority to enable and manage database replication for accounts within the organization.

-- Example: Enabling database replication

ALTER DATABASE my_database ENABLE REPLICATION TO ACCOUNT other_account;

Snowflake Documentation: Organization Administration

Snowflake Documentation: Replication

Snowflake COF-C02 SnowPro Core Certification Exam Practice Test