COF-C02 SnowPro Core Certification Exam (COF-C02) Questions and Answers

A materialized view in Snowflake gets suspended when structural changes that could impact the view's integrity are made to the base table, such as B. When a column is dropped from the base table. Dropping a column from the base table on which a materialized view is defined can invalidate the view's data, as the view might rely on the column that is being removed. To maintain data consistency and prevent the materialized view from serving stale or incorrect data, Snowflake automatically suspends the materialized view.

Upon suspension, the materialized view does not reflect changes to the base table until it is refreshed or re-created. This ensures that only accurate and current data is presented to users querying the materialized view.

References:

• Snowflake Documentation on Materialized Views: Materialized Views

Snowflake streams are objects that enable users to track changes (inserts, updates, and deletes) to the data in tables, facilitating real-time data processing and integration workflows. Streams can be created on standard tables, capturing DML changes made to these tables so that downstream processes can consume the changes incrementally. This feature supports efficient data ETL, replication, and real-time analytics by providing a mechanism to process only the data that has changed. Note: The correct options should likely include a distinction between "Standard tables" and another object type such as "External tables" rather than repeating "Standard tables" twice.References: Snowflake Documentation on Streams

The ACCESS_HISTORY view in Snowflake is a powerful tool for enhancing data governance, especially concerning monitoring and auditing data access patterns for both read and write operations. The key ways in which ACCESS_HISTORY enhances overall data governance are:

• B. Provides a unified picture of what data was accessed and when it was accessed: This view logs details about query executions, including the objects (tables, views) accessed and the timestamps of these accesses. It's instrumental in auditing and compliance scenarios, where understanding the access patterns to sensitive data is critical.
• E. Determines whether a given row in a table can be accessed by the user by filtering the data based on a given policy: While this option is a bit of a misinterpretation of what ACCESS_HISTORY directly offers, it indirectly supports data governance by providing the information necessary to analyze access patterns. This analysis can then inform policy decisions, such as implementing Row-Level Security (RLS) to restrict access to specific rows based on user roles or attributes.

ACCESS_HISTORY does not automatically apply data masking or tag columns with personal information. However, the insights derived from analyzing ACCESS_HISTORY can be used to identify sensitive data and inform the application of masking policies or other security measures.

References:

• Snowflake Documentation on ACCESS_HISTORY: Access History

Resource monitors in Snowflake are tools used to track and control the consumption of compute resources, ensuring that usage stays within defined limits. These monitors can be created at the account level, allowing administrators to set overall resource consumption limits for the entire Snowflake account. Additionally, resource monitors can be set at the virtual warehouse level, enabling more granular control over the resources consumed by individual warehouses. This dual-level capability allows organizations to manage their Snowflake usage efficiently, preventing unexpected costs and optimizing performance.References: Snowflake Documentation on Resource Monitors

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When attempting to load large files, such as a 125 GB file, into Snowflake using SnowSQL, the process might encounter limitations related to the maximum execution time for queries or data loading operations. If the loading process exceeds this time limit (typically around 24 hours), it could be aborted without committing any part of the file to the database. This behavior is designed to prevent indefinite resource consumption and to maintain system stability, emphasizing the need for optimizing data load operations, possibly through file segmentation or parallel loading strategies.References: Snowflake Documentation on Data Loading Considerations

For minimizing the cost of large tables that are used to store transitory data, which does not need to be protected against failures because it can be reconstructed outside of Snowflake, the best table type to use is Transient. Transient tables in Snowflake are designed for temporary or transitory data storage and offer reduced storage costs compared to permanent tables. However, unlike temporary tables, they persist across sessions until explicitly dropped.

• Why Transient Tables: Transient tables provide a cost-effective solution for storing data that is temporary but needs to be available longer than a single session. They have lower data storage costs because Snowflake does not maintain historical data (Time Travel) for as long as it does for permanent tables.
• Creating a Transient Table:

CREATE TRANSIENT TABLE my_transient_table (...);

• Use Case Considerations: Transient tables are ideal for scenarios where the data is not critical, can be easily recreated, and where cost optimization is a priority. They are suitable for development, testing, or staging environments where data longevity is not a concern.

https://docs.snowflake.com/en/sql-reference/data-sharing-usage

The Activity area of Snowsight, Snowflake's web interface, allows users to perform several important tasks related to query management and performance analysis. Among the options provided, the correct ones are:

• B. Explore each step of an executed query: Snowsight provides detailed insights into query execution, including the ability to explore the execution plan of a query. This helps users understand how a query was processed, identify performance bottlenecks, and optimize query performance.
• C. Monitor queries executed by users in an account: The Activity area enables users to monitor the queries that have been executed by users within the Snowflake account. This includes viewing the history of queries, their execution times, resources consumed, and other relevant metrics.

These features are crucial for effective query performance tuning and ensuring efficient use of Snowflake's resources.

References:

• Snowflake Documentation on Snowsight: Using Snowsight

Objects in a data share become unavailable to a consumer account if the objects in the data share are deleted or if the permissions on these objects are altered without re-applying the grant permissions systematically. This is because the sharing mechanism in Snowflake relies on explicit grants of permissions on specific objects (like tables, views, or secure views) to the share. If these objects are deleted or if their permissions change without updating the share accordingly, consumers can lose access.

The DATA_RETENTION_TIME_IN_DAYS parameter does not directly affect the availability of shared objects, as it controls how long Snowflake retains historical data for time travel and does not impact data sharing permissions.

Running the GRANT IMPORTED PRIVILEGES command in the consumer account is not related to the availability of shared objects; this command is used to grant privileges on imported objects within the consumer's account and is not a routine maintenance command that would need to be run regularly.

Acquiring a data share through a private data exchange does not inherently make objects unavailable; issues would only arise if there were problems with the share configuration or if the shared objects were deleted or had their permissions altered without re-granting access to the share.

If any compute resources for a virtual warehouse fail to provision during startup, Snowflake will attempt to restart those failed resources. The system is designed to automatically handle transient issues that might occur during the provisioning of compute resources. By restarting the failed resources, Snowflake aims to ensure that the virtual warehouse has the necessary compute capacity to handle the user's workloads without manual intervention.References: Snowflake Documentation on Virtual Warehouses

When a virtual warehouse in Snowflake is suspended, the cache is dropped and is no longer available upon restart. This means that all cached data, including results and temporary data, are cleared from memory. The purpose of this behavior is to conserve resources while the warehouse is not active. Upon restarting the warehouse, it will need to reload any data required for queries from storage, which may result in a slower initial performance until the cache is repopulated. This is a critical consideration for managing performance and cost in Snowflake.

The property mins_to_bypass_network_policy is set at the account level in Snowflake. This setting allows administrators to specify a time frame during which users can bypass network policies that have been set on their account. It is particularly useful in scenarios where temporary access needs to be granted from IPs not covered by the existing network policies. By adjusting this property at the account level, Snowflake administrators can manage and enforce network access controls efficiently across the entire account.

References:

• Snowflake Documentation on Network Policies: Network Policies

In Snowflake, permissions for accessing database objects, including tables, are not granted directly to users but rather to roles. A role encapsulates a collection of privileges on various Snowflake objects. Users are then granted roles, and through those roles, they inherit the permissions necessary to read a table or perform other actions. This approach adheres to the principle of least privilege, allowing for granular control over database access and simplifying the management of user permissions.

The CURRENT_TASK_GRAPHS table function is designed to provide information on Directed Acyclic Graphs (DAGs) that are currently scheduled or executing within Snowflake. This function offers insights into the structure and status of task chains, enabling users to monitor and troubleshoot task executions. DAGs in Snowflake represent sequences of tasks with dependencies, and understanding their current state is crucial for managing complex workflows.References: Snowflake Documentation on Task Management

To see the definition of a secure view in Snowflake, the minimum privilege required is OWNERSHIP of the view. Ownership grants the ability to view the definition as well as to modify or drop the view. Secure views are designed to protect sensitive data, and thus the definition of these views is restricted to users with sufficient privileges to ensure data security.

References:

• Snowflake Documentation: Secure Views

The command used to export or unload data from Snowflake to a stage (such as a file in an S3 bucket, Azure Blob Storage, or Google Cloud Storage) is the PUT command. The PUT command is designed to upload data files from a local file system (in the case of SnowSQL or other client) or a virtual warehouse to a specified stage. This functionality is critical for scenarios where data needs to be extracted from Snowflake for use in external systems, backups, or further processing.

The syntax for the PUT command follows the structure: PUT file://<local_file_path> @<stage_name>, where <local_file_path> specifies the path to the file(s) on the local file system that you wish to upload, and <stage_name> specifies the destination stage in Snowflake.

It's important to distinguish that the PUT command is used for exporting data out of Snowflake, whereas the COPY INTO <table> command is used for importing data into Snowflake from a stage. The GET command, on the other hand, is used to download files from a stage to the local file system, essentially the inverse operation of the PUT command.

References:

• Snowflake Documentation on Loading and Unloading Data: [Loading and Unloading Data](https://docs.snowflake.com/en/user-guide/data-load

 In the Snowflake Data Marketplace, the types of data listings available include ‘Vendor’, which refers to the providers of data, and ‘Personalized’, which indicates customized data offerings tailored to specific consumer needs45.

Operations that do not require compute resources are typically those that can leverage previously cached results. However, if no queries have been executed previously, all the given operations would require compute to execute. It’s important to note that certain operations like DDL statements and queries that hit the result cache do not consume compute credits2.

The LOGIN_HISTORY view in the ACCOUNT_USAGE schema provides information about login attempts, including both successful and failed logins. This view can be used to review the failed login attempts of a specific user for the past 30 days. References: [COF-C02] SnowPro Core Certification Exam Study Guide

The graphical representation of warehouse utilization indicates periods of significant queuing, suggesting that the current single cluster cannot efficiently handle all incoming queries. Configuring the warehouse to a multi-cluster warehouse will distribute the load among multiple clusters, reducing queuing times and improving overall performance1.

References = Snowflake Documentation on Multi-cluster Warehouses1

The Query Profile in Snowflake is used to identify performance issues with queries. Common issues that can be found using the Query Profile include identifying inefficient micro-partition pruning (D) and data spilling to a local or remote disk (E). Micro-partition pruning is related to the efficiency of query execution, and data spilling occurs when the memory is insufficient, causing the query to write data to disk, which can slow down the query performance1.

Serverless features in Snowflake are billed based on the time they are used, measured in minutes. The cost is calculated by multiplying the duration of the job by an automatic sizing determined by Snowflake, with a minimum billing increment of one minute. This means that even if a serverless feature is used for less than a minute, it will still be billed for the full minute.

 Scaling out in Snowflake involves adding clusters of the same size to a virtual warehouse, which allows for handling more concurrent queries without affecting the performance of individual queries. Scaling up refers to resizing a virtual warehouse to increase its compute resources, enabling it to handle more complex workloads and larger queries more efficiently.

 In Snowflake, both materialized views and transient tables will incur storage charges because they store data. They will also incur compute charges when queries are run against them, as compute resources are used to process the queries. References: [COF-C02] SnowPro Core Certification Exam Study Guide

 By default, the Snowflake role required to create a share is ACCOUNTADMIN (D). This role has the necessary privileges to perform administrative tasks, including creating shares for data sharing purposes

The ResultSet cache is leveraged to quickly return results for repeated queries. Actions that prevent leveraging this cache include stopping the virtual warehouse that the query is running against (B) and executing the RESULTS_SCAN() table function (D). Stopping the warehouse clears the local disk cache, including the ResultSet cache1. The RESULTS_SCAN() function is used to retrieve the result of a previously executed query, which bypasses the need for the ResultSet cache.

The Search Optimization Service significantly improves the performance of selective point lookup queries on tables by creating and maintaining a persistent data structure called a search access path, which allows some micro-partitions to be skipped when scanning the table

Snowflake supports the use of external stages with Amazon Web Services (AWS), Microsoft Azure Cloud, and Google Cloud Platform (GCP). These platforms allow users to stage data externally and integrate with Snowflake for data loading operations

Snowflake’s data caching features include the ability to clear the least-recently used data when the data cache is full to make room for new data. Additionally, the RESULT_SCAN table function can access and filter the contents of the query result cache, allowing users to retrieve and work with the results of previous queries. The other statements are incorrect: the data cache is not saved on the remote storage layer when a virtual warehouse is suspended, users can access queries from the query result cache that were run by other users, and there is no setting called USE_METADATA_CACHE in Snowflake. References: Caching in the Snowflake Cloud Data Platform, Optimizing the warehouse cache

The features associated with Continuous Data Protection (CDP) that require additional Snowflake-provided data storage are Time Travel and Fail-safe. Time Travel allows users to access historical data within a defined period, while Fail-safe provides an additional layer of data protection beyond the Time Travel period. References: [COF-C02] SnowPro Core Certification Exam Study Guide

 The billable compute time includes the time the warehouse is running queries plus the auto-suspend time after the last query if the warehouse is not manually suspended. In this scenario, the warehouse runs for 3 minutes, suspends after 10 minutes of inactivity, resumes for a 10-second query, and then is manually suspended. The total billable time is the sum of the initial 3 minutes, the 10 minutes of auto-suspend time, and the brief period for the 10-second query, which is rounded up to the next full minute due to Snowflake’s billing practices. References: [COF-C02] SnowPro Core Certification Exam Study Guide

The SQL statement SHOW GRANTS TO ROLE MY_ROLE is used to determine which users and roles have access to a role called MY_ROLE. This statement lists all the privileges granted to the role, including which roles and users can assume MY_ROLE. References: [COF-C02] SnowPro Core Certification Exam Study Guide

 Dynamic data masking is a feature in Snowflake that allows administrators to define masking policies to protect sensitive data. It enables partial visibility of the data to certain roles, such as functional managers, while hiding it from others, like end users

To go back to the first version of a transient table created three days prior, one can use Time Travel if the DATA_RETENTION_TIME_IN_DAYS was set to at least 3 days. This allows the user to access historical data within the specified retention period. References: [COF-C02] SnowPro Core Certification Exam Study Guide

An explain plan is beneficial because it allows for the evaluation of how a query will be processed without the need to actually execute the query. This can help in understanding the query’s performance implications and potential bottlenecks without consuming resources that would be used if the query were run

Data masking policies in Snowflake allow for the obfuscation of specific data within a field, enabling some users to see the full data while limiting others. This feature is particularly useful for handling PII, ensuring that sensitive information is only visible to authorized users1.

 In Snowflake’s data sharing model, any full Snowflake account can both provide and consume shared data. Additionally, the data consumer pays only for the compute resources used to query the shared data. No actual data is copied or transferred between accounts, and shared data does not take up any storage in a consumer account, so the consumer does not pay for data storage1.

References = Introduction to Secure Data Sharing | Snowflake Documentation

Snowflake supports the VARIANT and ARRAY data types for semi-structured data. VARIANT can store values of any other type, including OBJECT and ARRAY, making it suitable for semi-structured data formats like JSON. ARRAY is used to store an ordered list of elements

 When a pipe is recreated using the CREATE OR REPLACE PIPE command, the load history of the pipe is reset. This means that Snowpipe will consider all files in the stage as new and will attempt to load them, even if they were loaded previously by the old pipe2.

The command USE WAREHOUSE <>; is used to set the virtual warehouse for the current session in Snowflake. This command specifies which virtual warehouse to use for executing queries in that session1.

 When the retention period for an object ends in Snowflake, Time Travel on the historical data is dropped ©. This means that the ability to access historical data via Time Travel is no longer available once the retention period has expired2.

The LATERAL FLATTEN command in Snowflake produces a result set that includes several columns, among which PATH and INDEX are includedPATH indicates the path to the element within a data structure that needs to be flattened, and INDEX represents the index of the element if it is an array2.

To manage compliance with Personal Identifiable Information (PII) requirements, the Virtual Private Snowflake and Business Critical Editions of Snowflake should be used. These editions provide advanced security features necessary for handling sensitive data

Network policies in Snowflake can be set at the user level and at the account level2.

Best practices for using the ACCOUNTADMIN role include ensuring that all users with this role use Multi-factor Authentication (MFA) for added security. Additionally, it is recommended to assign the ACCOUNTADMIN role to at least two users to avoid delays in case of password recovery issues, but to as few users as possible to maintain strict control over account-level operations4.

The list @my_stage command in Snowflake can be used to verify if data has been uploaded to an external stage named my_stage. This command provides a list of files that are present in the specified stage2.

The minimum Snowflake edition required to use Dynamic Data Masking is the Enterprise edition. This feature is not available in the Standard edition2.

The Snowflake storage layer is responsible for storing data in an optimized, compressed, columnar format. This includes micro-partitions, which are the fundamental storage units that contain the actual data stored in Snowflake. Additionally, persisted query results, which are the results of queries that have been materialized and stored for future use, are also kept within this layer. This design allows for efficient data retrieval and management within the Snowflake architecture1.

References:

• [COF-C02] SnowPro Core Certification Exam Study Guide
• Key Concepts & Architecture | Snowflake Documentation2

When a cloned table is replicated to a secondary database in Snowflake, the following occurs:

• C. The physical data is replicated: The actual data of the cloned table is physically replicated to the secondary database. This ensures that the secondary database has its own copy of the data, which can be used for read-only purposes or failover scenarios1.
• E. Metadata pointers to cloned tables are replicated: Along with the physical data, the metadata pointers that refer to the cloned tables are also replicated. This metadata includes information about the structure of the table and any associated properties2.

It’s important to note that while the physical data and metadata are replicated, the secondary database is typically read-only and cannot be used for write operations. Additionally, while there may be additional storage costs associated with the secondary account, this is not a direct result of the replication process but rather a consequence of storing additional data.

References:

• SnowPro Core Exam Prep — Answers to Snowflake’s LEVEL UP: Backup and Recovery
• Snowflake SnowPro Core Certification Exam Questions Set 10

Assigning the custom role to the SYSADMIN role is considered a best practice because it allows the SYSADMIN role to manage objects created by the custom role. This is important for maintaining proper access control and ensuring that the SYSADMIN can perform necessary administrative tasks on objects created by users with the custom role.

References:

• [COF-C02] SnowPro Core Certification Exam Study Guide
• Section 1.3 - SnowPro Core Certification Study Guide1

In Snowflake, Data Shares can be created and managed in two primary ways:

• Via the Snowflake Web Interface (UI): Users can create and manage shares through the graphical interface provided by Snowflake, which allows for a user-friendly experience.
• Via SQL commands: Snowflake also allows the creation and management of shares using SQL commands. This method is more suited for users who prefer scripting or need to automate the process.

 One of the key features of Snowflake’s architecture is its unique approach to eliminating resource contention through the use of virtual warehouses. This is achieved by separating storage and compute resources, allowing multiple virtual warehouses to operate independently on the same data without affecting each other. This means that different workloads, such as loading data, running queries, or performing complex analytics, can be processed simultaneously without any performance degradation due to resource contention.

References:

• Snowflake Documentation on Virtual Warehouses
• SnowPro® Core Certification Study Guide

 In Snowflake, a reader account is a type of account that is intended for consuming shared data rather than performing any data management or DDL operations. The CREATE SHARE command is used to share data from your account with another account, which is not a capability provided to reader accounts. Reader accounts are typically restricted from creating shares, as their primary purpose is to read shared data rather than to share it themselves.

References:

• Snowflake Documentation on Reader Accounts
• SnowPro® Core Certification Study Guide

In Snowflake, to create a materialized view, the user must have the necessary privileges on the schema where the view will be created. These privileges are granted through roles, not directly to individual users. Therefore, the correct process is to grant the role to the user and then grant the privilege to create the materialized view to the role itself.

The statement GRANT ROLE MYROLE TO USER USER1; grants the specified role to the user, allowing them to assume that role and exercise its privileges. The subsequent statement CREATE MATERIALIZED VIEW ON SCHEMA MYDB.MYSCHEMA TO MYROLE; grants the privilege to create a materialized view within the specified schema to the role MYROLE. Any user who has been granted MYROLE can then create materialized views in MYDB.MYSCHEMA.

References:

• Snowflake Documentation on Roles
• Snowflake Documentation on Materialized Views

 The Result cache is used in Snowflake to cache the data output from SQL queries. This feature is designed to improve performance by storing the results of queries for a period of time. When the same or similar query is executed again, Snowflake can retrieve the result from this cache instead of re-computing the result, which saves time and computational resources.

References:

• Snowflake Documentation on Query Results Cache
• SnowPro® Core Certification Study Guide

 Query compilation in Snowflake occurs in the Cloud Services layer. This layer is responsible for coordinating and managing all aspects of the Snowflake service, including authentication, infrastructure management, metadata management, query parsing and optimization, and security. By handling these tasks, the Cloud Services layer enables the Compute layer to focus on executing queries, while the Storage layer is dedicated to persistently storing data.

References:

• [COF-C02] SnowPro Core Certification Exam Study Guide
• Snowflake Documentation on Snowflake Architecture1

 The correct statement to accommodate the request for a marketing co-worker to change the size of their medium virtual warehouse called mktg__WH is to grant the MODIFY privilege on the warehouse to the ROLE MARKETING. This privilege allows the role to change the warehouse size among other properties.

References:

• [COF-C02] SnowPro Core Certification Exam Study Guide
• Snowflake Documentation on Access Control Privileges1

The ACCOUNTADMIN role is the most powerful role in Snowflake and should be limited to a select number of users within an organization. It is responsible for account-level configurations and should not be used for day-to-day object creation or management. Granting a custom role to ACCOUNTADMIN could inadvertently give broad access to users with this role, which is not a recommended security practice.

When loading data into Snowflake, it is recommended to:

• C. Load files that are approximately 100-250 MB (or larger): This size is optimal for parallel processing and can help to maximize throughput. Smaller files can lead to overhead that outweighs the actual data processing time.
• D. Avoid using embedded characters such as commas for numeric data types: Embedded characters can cause issues during data loading as they may be interpreted incorrectly. It’s best to clean the data of such characters to ensure accurate and efficient data loading.

These best practices are designed to optimize the data loading process, ensuring that data is loaded quickly and accurately into Snowflake.

References:

• Snowflake Documentation on Data Loading Considerations
• [COF-C02] SnowPro Core Certification Exam Study Guide

 Snowflake manages various compute resources and features, including Snowpipe and the ability to scale up a warehouse. Snowpipe is Snowflake’s continuous data ingestion service that allows users to load data as soon as it becomes available. Scaling up a warehouse refers to increasing the compute resources allocated to a virtual warehouse to handle larger workloads or improve performance.

References:

• [COF-C02] SnowPro Core Certification Exam Study Guide
• Snowflake Documentation on Snowpipe and Virtual Warehouses1

 When an external stage is dropped in Snowflake, the reference to the external storage location is removed, but the actual files within the external storage (like Amazon S3, Google Cloud Storage, or Microsoft Azure) are not deleted. This means that the data remains intact in the external storage location, and only the stage object in Snowflake is removed.

On the other hand, when an internal stage is dropped, any files that were uploaded to the stage are deleted along with the stage itself. These files are not recoverable once the internal stage is dropped, as they are permanently removed from Snowflake’s storage.

References:

• [COF-C02] SnowPro Core Certification Exam Study Guide
• Snowflake Documentation on Stages

Fail-safe is a feature in Snowflake that provides an additional layer of data protection. After the Time Travel retention period ends, Fail-safe offers a non-configurable 7-day period during which historical data may be recoverable by Snowflake. This period is designed to protect against accidental data loss and is not intended for customer access.

References: Understanding and viewing Fail-safe | Snowflake Documentation

To generate a report listing all Snowflake logins within the last 90 days, the ACCOUNT_USAGE.LOGIN_HISTORY view should be used. This view provides information about login attempts, including successful and unsuccessful logins, and is suitable for security audits4.

Parquet is a columnar storage file format that is optimized for performance in Snowflake. It is designed to be efficient for both storage and query performance, particularly for complex queries on large datasets. Parquet files support efficient compression and encoding schemes, which can lead to significant savings in storage and speed in query processing, making it the most performant file format for loading data into Snowflake.

References:

• [COF-C02] SnowPro Core Certification Exam Study Guide
• Snowflake Documentation on Data Loading1

The ACCOUNTADMIN role is required for a user to create and manage accounts in Snowflake. This role has the highest level of privileges and is responsible for managing all aspects of the Snowflake account, including the ability to create and manage other user accounts1.

https://docs.snowflake.com/en/user-guide/security-access-control-considerations.html

When the COPY INTO command is executed in Snowflake, it processes all files present in the specified stage that have not been ingested before or marked as already loaded. Since the user did not remove the original 10 files after the first load, running the same COPY INTO command again will result in all 20 files being processed. This means that the data from the original 10 files will be appended to the table again, along with the data from the new 10 files, potentially leading to duplicate records for the original data set.

References:

• Snowflake Documentation on Data Loading
• SnowPro® Core Certification Study Guide

 The COPY INTO command is used in Snowflake to unload data from a table into a file in a stage. This command allows for the export of data from Snowflake tables into flat files, which can then be used for further analysis, processing, or storage in external systems.

References:

• Snowflake Documentation on Unloading Data
• Snowflake SnowPro Core: Copy Into Command to Unload Rows to Files in Named Stage

A VARIANT column in Snowflake can store semi-structured data types. This includes:

• B. OBJECT: An object is a collection of key-value pairs in JSON, and a VARIANT column can store this type of data structure.
• D. ARRAY: An array is an ordered list of zero or more values, which can be of any variant-supported data type, including objects or other arrays.

The VARIANT data type is specifically designed to handle semi-structured data like JSON, Avro, ORC, Parquet, or XML, allowing for the storage of nested and complex data structures.

References:

• Snowflake Documentation on Semi-Structured Data Types
• SnowPro® Core Certification Study Guide

 When a query in Snowflake is too large to fit into the available memory, it will start spilling to remote storage. This is an indication that the memory allocated for the query is insufficient for its execution, and as a result, Snowflake uses remote disk storage to handle the overflow. This spill to remote storage can lead to slower query performance due to the additional I/O operations required.

References:

• [COF-C02] SnowPro Core Certification Exam Study Guide
• Snowflake Documentation on Query Profile1
• Snowpro Core Certification Exam Flashcards2

When a Snowflake virtual warehouse is resized, the data cached in the warehouse is not lost. This is because the cache is maintained independently of the warehouse size. Resizing a warehouse, whether scaling up or down, does not affect the cached data, ensuring that query performance is not impacted by such changes.

References:

• [COF-C02] SnowPro Core Certification Exam Study Guide
• Snowflake Documentation on Virtual Warehouse Performance1

The result set cache in Snowflake is invalidated and no longer available when the underlying data of the query results has changed, ensuring that queries return the most current data. Additionally, the cache expires after 24 hours to maintain the efficiency and accuracy of data retrieval1.

 Snowflake’s architecture is designed to handle high concurrency workloads through several features, two of which are particularly effective:

• B. The use of warehouse auto scaling: This feature allows Snowflake to automatically adjust the compute resources allocated to a virtual warehouse in response to the workload. If there is an increase in concurrent queries, Snowflake can scale up the resources to maintain performance.
• D. Use of multi-clustered warehouses: Multi-clustered warehouses enable Snowflake to run multiple clusters of compute resources simultaneously. This allows for the distribution of queries across clusters, thereby reducing the load on any single cluster and improving the system’s ability to handle a high number of concurrent queries.

These features ensure that Snowflake can manage varying levels of demand without manual intervention, providing a seamless experience even during peak usage.

References:

• Snowflake Documentation on Virtual Warehouses
• SnowPro® Core Certification Study Guide

 In the query profiler view, the components that represent areas that can be used to help optimize query performance include ‘Bytes scanned’ and ‘Number of partitions scanned’. ‘Bytes scanned’ indicates the total amount of data the query had to read and is a direct indicator of the query’s efficiency. Reducing the bytes scanned can lead to lower data transfer costs and faster query execution. ‘Number of partitions scanned’ reflects how well the data is clustered; fewer partitions scanned typically means better performance because the system can skip irrelevant data more effectively.

References:

• [COF-C02] SnowPro Core Certification Exam Study Guide
• Snowflake Documentation on Query Profiling1

Semi-structured

JSON, Parquet

Snowflake supports unloading data in several semi-structured file formats, including Parquet and JSON. These formats allow for efficient storage and querying of semi-structured data, which can be loaded directly into Snowflake tables without requiring a predefined schema12.

https://docs.snowflake.com/en/user-guide/data-unload-prepare.html#:~:text=Supported%20File%20Formats,-The%20following%20file &text=Delimited%20(CSV%2C%20TSV%2C%20etc.)

The list command in Snowflake is used to validate and display the list of files in a specified stage. When a user has unloaded data to a stage, running the list @file__stage command will show all the files that have been uploaded to that stage, allowing the user to verify the data that was unloaded.

References:

• Snowflake Documentation on Stages
• SnowPro® Core Certification Study Guide

 To address a high volume of queries queuing in a warehouse, Snowflake recommends two best practices:

• A. Use multi-clustered warehousing to scale out warehouse capacity: This approach allows for the distribution of queries across multiple clusters within a warehouse, effectively managing the load and reducing the queue volume.
• B. Scale up the warehouse size to allow Queries to execute faster: Increasing the size of the warehouse provides more compute resources, which can reduce the time it takes for queries to execute and thus decrease the number of queries waiting in the queue.

These strategies help to optimize the performance of the warehouse by ensuring that resources are scaled appropriately to meet demand.

References:

• Snowflake Documentation on Multi-Cluster Warehousing
• SnowPro Core Certification best practices

 Snowflake supports querying semi-structured data using specific data types that are capable of handling the flexibility and structure of such data. The data types supported for this purpose are:

• A. VARIANT: This is a universal data type that can store values of any other type, including structured and semi-structured types. It is particularly useful for handling JSON, Avro, ORC, Parquet, and XML data formats1.
• B. ARRAY: An array is a list of elements that can be of any data type, including VARIANT, and is used to handle semi-structured data that is naturally represented as a list1.

These data types are part of Snowflake’s built-in support for semi-structured data, allowing for the storage, querying, and analysis of data that does not fit into the traditional row-column format.

References:

• Snowflake Documentation on Semi-Structured Data
• [COF-C02] SnowPro Core Certification Exam Study Guide

To easily transfer data from a production account to a non-production account in Snowflake within the same cloud provider region, creating a data share is the most efficient approach. Data sharing allows for live, read-only access to selected data objects from the production account to the non-production account without the need to duplicate or move the actual data. This method facilitates seamless access to the data for development, testing, or analytics purposes in the non-production environment.

References:

• Snowflake Documentation: Data Sharing

The Cloud Services layer in Snowflake is responsible for a wide range of services that facilitate the management and use of Snowflake, including:

• D. User authentication: This service handles identity and access management, ensuring that only authorized users can access Snowflake resources.
• E. Infrastructure management: This service manages the allocation and scaling of resources to meet user demands, including the management of virtual warehouses, storage, and the orchestration of query execution.

These services are part of Snowflake's fully managed, cloud-based architecture, which abstracts and automates many of the complexities associated with data warehousing.

References:

• Snowflake Documentation: Overview of Snowflake Cloud Services

• Object Name Resolution: When unqualified object names (e.g., table name without schema) are used in a UDF, Snowflake follows a specific hierarchy to resolve them. Here's the order:
• Note: The SEARCH_PATH parameter influences object resolution for queries, not within UDFs.

References:

• Snowflake Documentation (Object Naming Resolution): https://docs.snowflake.com/en/sql-reference/name-resolution.html

The Search Optimization Service in Snowflake is designed to improve the performance of specific types of queries, particularly those involving extensive sets of WHERE conditions. By maintaining a search index on tables, this service can accelerate lookup and analytical queries, making it a valuable feature for optimizing query performance and reducing execution times for complex searches.

References:

• Snowflake Documentation: Search Optimization Service

To obtain the most detailed information about individual table storage details in Snowflake, the TABLE STORAGE METRICS view is the recommended option. This view provides comprehensive metrics on storage usage, including data size, time travel size, fail-safe size, and other relevant storage metrics for each table. This level of detail is invaluable for monitoring, managing, and optimizing storage costs and performance.

References:

• Snowflake Documentation: Information Schema

 Snowflake is designed to optimize query performance by utilizing metadata for certain types of queries. When executing a COUNT query, Snowflake can often fulfill the request by accessing metadata about the table’s row count, rather than scanning the entire table or micro-partitions. This is particularly efficient for large tables like FCT_SALES with a significant number of records. The metadata layer maintains statistics about the table, including the row count, which enables Snowflake to quickly return the result of a COUNT query without the need to perform a full scan.

References:

• Snowflake Documentation on Metadata Management
• SnowPro® Core Certification Study Guide

A cached MFA token is valid for up to four hours. https://docs.snowflake.com/en/user-guide/security-mfa#using-mfa-token-caching-to-minimize-the-number-of-prompts-during-authentication-optional

The VALIDATE table function in Snowflake would typically use a unique identifier, such as a UUID_STRING, as an input argument. This function is designed to validate the data within a table against a set of constraints or conditions, often requiring a specific identifier to reference the particular data or job being validated.

References:

• There is no direct reference to a VALIDATE table function with these specific parameters in Snowflake documentation. It seems like a theoretical example for understanding function arguments. Snowflake documentation on UDFs and system functions can provide guidance on how to create and use custom functions for similar purposes.

Query pruning in Snowflake refers to the optimization technique where the system reduces the amount of data scanned by a query based on the query conditions. This typically involves skipping unnecessary data partitions that do not contribute to the query result. The effectiveness of this technique can be observed through:

• Option A: Partitions scanned. This statistic indicates how many data partitions were actually scanned as a result of query pruning, showing the optimization in action.
• Option C: Bytes scanned. This measures the volume of data physically read during query execution, and a reduction in this number indicates effective query pruning, as fewer bytes are read when unnecessary partitions are skipped.

Options B, D, and E do not directly relate to observing the effects of query pruning. "Partitions total" shows the total available, not the impact of pruning, while "Bytes read from result" and "Bytes written" relate to output rather than the efficiency of data scanning.References: Snowflake documentation on performance tuning and query optimization techniques, specifically how query pruning affects data access.

A materialized view in Snowflake denotes a pre-computed data set derived from a SELECT query specification and stored for later use. Unlike standard views, which dynamically compute the data each time the view is accessed, materialized views store the result of the query at the time it is executed, thereby speeding up access to the data, especially for expensive aggregations on large datasets.

References:

• Snowflake Documentation: Materialized Views

In Snowflake, when setting up a network policy that specifies both allowed and blocked IP address lists, if an IP address appears in both lists, access from that IP address will be denied. The reason is that Snowflake prioritizes security, and the presence of an IP address in the blocked list indicates it should not be allowed regardless of its presence in the allowed list. This ensures that access controls remain stringent and that any potentially unsafe IP addresses are not inadvertently permitted access.

References:

• Snowflake Documentation: Network Policies

A materialized view in Snowflake is a database object derived from a query specification, stored for later use, and can significantly speed up expensive aggregations on large data sets. Materialized views store the result of their underlying query, reducing the need to recompute the result each time the view is accessed. This makes them ideal for improving the performance of read-heavy, aggregate-intensive queries.

References:

• Snowflake Documentation: Using Materialized Views

By default, the ACCOUNTADMIN role in Snowflake has the ability to create a share from a shared database. This role has the highest level of access within a Snowflake account, including the management of all aspects of the account, such as users, roles, warehouses, and databases, as well as the creation and management of shares for secure data sharing with other Snowflake accounts.

References:

• Snowflake Documentation: Roles

In Snowflake, semi-structured data is optimally stored using specific data types that are designed to handle the flexibility and complexity of such data. The VARIANT data type can store structured and semi-structured data types, including JSON, Avro, ORC, Parquet, or XML, in a single column. The ARRAY data type, on the other hand, is suitable for storing ordered sequences of elements, which can be particularly useful for semi-structured data types like JSON arrays. These data types provide the necessary flexibility to store and query semi-structured data efficiently in Snowflake.

References:

• Snowflake Documentation: Semi-structured Data Types

To utilize the search optimization service in Snowflake, the correct syntax for granting privileges to a role involves specific commands that include adding search optimization capabilities:

• Option C: GRANT ADD SEARCH OPTIMIZATION ON SCHEMA TO ROLE . This command grants the specified role the ability to implement search optimization at the schema level, which is essential for enhancing search capabilities within that schema.

Options A and B do not include the correct verb "ADD," which is necessary for this specific type of grant command in Snowflake. Option D incorrectly mentions the database level, as search optimization privileges are typically configured at the schema level, not the database level.References: Snowflake documentation on the use of GRANT statements for configuring search optimization.

The ORGADMIN role in Snowflake is an organizational-level role that provides administrative capabilities across the entire organization, rather than being limited to a single Snowflake account. Users with this role can:

• A. Create an account for an organization: The ORGADMIN role has the privilege to create new Snowflake accounts within the organization, allowing for the expansion and management of the organization's resources.
• D. View usage information for all accounts in an organization: This role also has access to comprehensive usage and activity data across all accounts within the organization. This is crucial for monitoring, cost management, and optimization at the organizational level.

References:

• Snowflake Documentation: Understanding Role-Based Access Control

The OBJECT_CONSTRUCT function in Snowflake is used to convert rows in a relational table into a single VARIANT column that represents each row as a JSON object. This function dynamically creates a JSON object from a list of key-value pairs, where each key is a column name and each value is the corresponding column value for a row. This is particularly useful for aggregating and transforming structured data into semi-structured JSON format for further processing or analysis.

References:

• Snowflake Documentation: Semi-structured Data Functions

The Fail-safe period for a transient table in Snowflake, regardless of the edition (including Enterprise edition and higher), is 0 days. Fail-safe is a data protection feature that provides additional retention beyond the Time Travel period for recovering data in case of accidental deletion or corruption. However, transient tables are designed for temporary or short-term use and do not benefit from the Fail-safe feature, meaning that once their Time Travel period expires, data cannot be recovered.

References:

• Snowflake Documentation: Understanding Fail-safe

The SYSTEM$GET_PRIVATELINK function in Snowflake provides proxy information necessary for configuring PrivateLink connections, which can protect Snowsight as well as other Snowflake services. PrivateLink enhances security by allowing Snowflake to be accessed via a private connection within a cloud provider’s network, reducing exposure to the public internet.

References:

• Snowflake Documentation: PrivateLink Setup

The TABLE_STORAGE_METRICS view can be used to determine if a table has frequent row updates or deletes. This view provides detailed metrics on the storage utilization of tables within Snowflake, including metrics that reflect the impact of DML operations such as updates and deletes on table storage. For example, metrics related to the number of active and deleted rows can help identify tables that experience high levels of row modifications, indicating frequent updates or deletions.

References:

• Snowflake Documentation: TABLE_STORAGE_METRICS View

The VARIANT data type in Snowflake is used to store JSON key-value pairs along with other semi-structured data formats like AVRO, BSON, and XML. The VARIANT data type allows for flexible and dynamic data structures within a single column, accommodating complex and nested data. This data type is crucial for handling semi-structured data in Snowflake, enabling users to perform SQL operations on JSON objects and arrays directly.

References:

• Snowflake Documentation: Semi-structured Data Types

In the Query Profile of Snowflake, the TableScan operator represents the access to a single table. This operator indicates that the query execution involved reading data from a table stored in Snowflake. TableScan is a fundamental operation in query execution plans, showing how the database engine retrieves data directly from tables as part of processing a query.

References:

• Snowflake Documentation: Understanding the Query Profile

When unloading floating-point number columns to CSV or JSON files, Snowflake truncates the values to approximately 15 significant digits with 9 digits following the decimal point, which can be represented as (15,9). This ensures a balance between accuracy and efficiency in representing floating-point numbers in text-based formats, which is essential for data interchange and processing applications that consume these files.

References:

• Snowflake Documentation: Data Unloading Considerations

To extract the URL of a directory table on an external stage for further transformation in Snowflake, the GET_ABSOLUTE_PATH function can be used. This function returns the full path of a file or directory within a specified stage, enabling users to dynamically construct URLs for accessing or processing data stored in external stages.

References:

• Snowflake Documentation: Working with Stages

UTF-8 is the only supported character set for loading and unloading data from all supported file formats in Snowflake. UTF-8 is a widely used encoding that supports a large range of characters from various languages, making it suitable for internationalization and ensuring data compatibility across different systems and platforms.

References:

• Snowflake Documentation: Data Loading and Unloading

Temporary tables in Snowflake do not consume storage costs. They are designed for transient data that is needed only for the duration of a session. Data stored in temporary tables is held in the virtual warehouse's cache and does not persist beyond the session's lifetime, thereby not incurring any storage charges.

References:

• Snowflake Documentation: Temporary Tables

When unloading data, the Parquet file format is known for its efficiency in preserving the data values for floating-point number columns. Parquet is a columnar storage file format that offers high compression ratios and efficient data encoding schemes. It is especially effective for floating-point data, as it maintains high precision and supports efficient querying and analysis.

References:

• Snowflake Documentation: Using the Parquet File Format for Unloading Data

When data is loaded into Snowflake, it undergoes a reorganization process where the data is stored in a columnar format and compressed. The columnar storage format enables efficient querying and data retrieval, as it allows for reading only the necessary columns for a query, thereby reducing IO operations. Additionally, Snowflake uses advanced compression techniques to minimize storage costs and improve performance. This combination of columnar storage and compression is key to Snowflake's data warehousing capabilities.

References:

• Snowflake Documentation: Data Storage and Organization

When a Snowflake user increases the size of a suspended virtual warehouse, the changes to compute resources are queued but do not take immediate effect. The provisioning of additional compute resources occurs only when the warehouse is resumed. This ensures that resources are allocated efficiently, aligning with Snowflake's commitment to cost-effective and on-demand scalability.

References:

• Snowflake Documentation: Virtual Warehouses

In Snowflake, the maximum number of clusters that can be provisioned within a multi-cluster virtual warehouse is 10. This allows for significant scalability and performance management by enabling Snowflake to handle varying levels of query load by adjusting the number of active clusters within the warehouse.References: Snowflake documentation on virtual warehouses, particularly the scalability options available in multi-cluster configurations.

The layer of Snowflake's architecture associated with virtual warehouses is the Query Processing layer. Virtual warehouses in Snowflake are dedicated compute clusters that execute SQL queries against the stored data. This layer is responsible for the entire query execution process, including parsing, optimization, and the actual computation. It operates independently of the storage layer, enabling Snowflake to scale compute and storage resources separately for efficiency and cost-effectiveness.

References:

• Snowflake Documentation: Snowflake Architecture

 In a Query Profile, the statistical information that indicates a query is too large to fit in memory includes bytes spilled to local cache and bytes spilled to local storage. These metrics suggest that the working data set of the query exceeded the memory available on the warehouse nodes, causing intermediate results to be written to disk

Network policies in Snowflake are defined as a set of rules that manage the network-level access to Snowflake accounts. These rules specify which IP addresses or IP ranges are permitted to connect to Snowflake, enhancing the security of Snowflake accounts by preventing unauthorized access. Network policies are an essential aspect of Snowflake's security model, allowing administrators to enforce access controls based on network locations.

References:

• Snowflake Documentation: Network Policies

 Snowflake allows data providers to share data with consumers across different cloud platforms and regions through database replication. The data provider must replicate the database to a secondary account in the target region or cloud platform within the same organization, and then create a share to the data consumer’s account. This process ensures that the data is available in the consumer’s region and on their cloud platform, facilitating seamless data sharing. References: Sharing data securely across regions and cloud platforms | Snowflake Documentation

To execute a series of SQL statements using a task, a user would use a stored procedure that contains multiple SQL statements and invoke this stored procedure from the task. References: Snowflake Documentation2.

 To show all privileges granted to a specific schema, the command SHOW GRANTS ON SCHEMA  should be used3. In this case, it would be SHOW GRANTS ON SCHEMA ANALYTICS_DW.MARKETING. References: [COF-C02] SnowPro Core Certification Exam Study Guide

Disabling auto-suspend for a virtual warehouse is recommended when there is a steady workload, which ensures that compute resources are always available. Additionally, it is advisable to disable auto-suspend when immediate availability of compute resources is critical, eliminating any startup delay

To access a JSON object in Snowflake, dot notation is used where the path to the object is specified after the column name containing the JSON data. Both lowercase and uppercase can be used for attribute names, so both “name” and “Name” are valid. References: [COF-C02] SnowPro Core Certification Exam Study Guide

 SnowCD (Snowflake Connectivity Diagnostic Tool) is the best tool provided by Snowflake for troubleshooting network connectivity issues. It helps diagnose and resolve issues related to connecting to Snowflake services

https://docs.snowflake.com/en/user-guide/snowcd.html#:~:text=SnowCD%20(i.e.%20Snowflake%20Connectivity%20Diagnostic,their%20network%20connection%20to%20Snowflake .

 Snowpark is designed to bring the data programmability to Snowflake, enabling developers to write code in familiar languages like Scala, Java, and Python. It allows for the execution of these codes directly within Snowflake’s virtual warehouses, eliminating the need for a separate cluster. Additionally, Snowpark’s compatibility with Spark allows users to leverage their existing Spark code with minimal changes1.

 To use Partner Connect, the ACCOUNTADMIN role is required. Partner Connect allows account administrators to easily create trial accounts with selected Snowflake business partners and integrate these accounts with Snowflake

The user property ‘MINS TO BYPASS MFA’ in Snowflake allows temporary bypass of MFA for a user, which can be set by an account administrator without contacting Snowflake Support2.

The Snowflake edition that enables data sharing only through Snowflake Support is the Virtual Private Snowflake (VPS). By default, VPS does not permit data sharing outside of the VPS environment, but it can be enabled through Snowflake Support4.

In Snowflake, to change the columns referenced in a view, the view must be recreated with the required changes. The ALTER VIEW command does not allow changing the definition of a view; it can only be used to rename a view, convert it to or from a secure view, or add, overwrite, or remove a comment for a view. Therefore, the correct approach is to drop the existing view and create a new one with the desired column references. 

The Snowflake Cloud Services layer coordinates activities within the Snowflake account. It is responsible for tasks such as authentication, infrastructure management, metadata management, query parsing and optimization, and access control. References: Based on general cloud database architecture knowledge.

 In Snowflake, a User-Defined Table Function (UDTF) can be accessed in the FROM clause of a query. UDTFs return a set of rows with one or more columns, which can be queried like a regular table

The cloud services layer of Snowflake architecture handles various aspects including security functions, authentication of user sessions, and access control, ensuring that only authorized users can access the data and services23.

A characteristic of a materialized view is that the data accessed through it can be stale. This is because the data in a materialized view may not reflect the latest changes in the base tables until the view is refreshed

The WAIT_FOR_COMPLETION = TRUE parameter in an ALTER WAREHOUSE command ensures that the command does not return until the warehouse has completed resizing. This means that the command will wait until all the necessary compute resources have been provisioned and the warehouse size has been changed. References: [COF-C02] SnowPro Core Certification Exam Study Guide

The Snowflake Account_Usage.Metering_History view is used to gather the hourly credit usage for an account. This view provides details on the credits consumed by various services within Snowflake for the last 365 days1.

 Snowflake supports several semi-structured data formats for loading data. The supported formats include JSON, Avro, and Parquet12. These formats allow for efficient storage and querying of data that does not conform to a traditional relational database schema.

Pruning in Snowflake refers to the process of filtering or disregarding micro-partitions that are not needed to satisfy the conditions of a query. This optimization technique helps reduce the amount of data scanned, thereby improving query performance

 Directory tables in Snowflake are used to store metadata about data files in a stage. They are not separate database objects but are conceptually similar to external tables. Directory tables do not have grantable privileges of their own

 When a view is defined on a permanent table, and a temporary table with the same name is created in the same schema, the query from the view will return the data from the permanent table. Temporary tables are session-specific and do not affect the data returned by views defined on permanent tables2.

 In a multi-cluster warehouse with an economy scaling policy, queries will wait in the queue for 2 minutes before another cluster is started. This is to minimize costs by allowing queries to queue up for a short period before adding additional compute resources. References: [COF-C02] SnowPro Core Certification Exam Study Guide

The Snowflake PUT command is used to upload files from a local file system to Snowflake stages, specifically the user stage, table stage, and internal named stage. These stages are where the data files are temporarily stored before being loaded into Snowflake tables

When file format options are specified in multiple locations, the load operation applies the options in the following order of precedence: first, the COPY INTO TABLE statement; second, the stage definition; and third, the table definition1

Clones in Snowflake have the advantage of being created almost instantly and saving space by not duplicating storage. This is due to Snowflake’s zero-copy cloning feature, which allows for the creation of object clones without the additional storage costs typically associated with data duplication23. Clones are independent of the original table and do not stay in sync with it, nor do they inherently have better query performance. However, they do inherit the time travel history from the original table at the time of cloning

 In Snowflake, schema objects include Pipes and File formats. Pipes are used for continuous data loading, and File formats specify the format of data files used in loading and unloading operations within Snowflake

The bulk data load history available after a COPY statement is stored in the metadata of the pipe and is retained for 64 days1.

The SQL command GET_DDL can be used to retrieve the CREATE definition of a masking policy in Snowflake. This command generates the DDL statement required to recreate the masking policy

The parameter that prevents streams on tables from becoming stale is MAXDATAEXTENSIONTIMEINDAYS. This parameter specifies the maximum number of days for which Snowflake can extend the data retention period for the table to prevent streams on the table from becoming stale4.

The STRIP NULL_VALUES file format option, when set to TRUE, removes object or array elements that contain null values during the loading process of semi-structured data files into Snowflake. This ensures that the data loaded into Snowflake tables does not contain these null elements, which can be useful when the “null” values in files indicate missing values and have no other special meaning2.

References: [COF-C02] SnowPro Core Certification Exam Study Guide

The query acceleration service in Snowflake is designed to benefit queries that involve large scans and selective filters. This service can offload portions of the query processing work to shared compute resources, which can handle these types of workloads more efficiently by performing more work in parallel and reducing the wall-clock time spent in scanning and filtering2. References: [COF-C02] SnowPro Core Certification Exam Study Guide

Running a virtual warehouse is required when loading data into a table and when unloading data from a table because these operations require compute resources that are provided by the virtual warehouse23.

The TABLE_STORAGE_METRICS metadata table stores the storage utilization information, including for tables that have been dropped but are still incurring storage costs2.

The minimum Snowflake Edition that supports secure storage of Protected Health Information (PHI) data is the Business Critical Edition. This edition offers enhanced security features necessary for compliance with regulations such as HIPAA and HITRUST CSF4.

When a tag object is assigned to a table, using the statement CREATE TABLE <table_name> AS SELECT * FROM TABLE_A will automatically assign the TABLE_A tag to the newly created table2.

The purpose of the Snowflake SPLIT_TO_TABLE function is to split a string based on a specified delimiter and flatten the results into rows. This table function is useful for transforming a delimited string into a set of rows that can be further processed or queried5.

The Snowflake command to unload the result of a query to a single file is COPY INTO with SINGLE = TRUE followed by a GET command to download the file. This command unloads the query result into a single file in the specified internal stage

 Snowflake supports the storage of semi-structured data using the ARRAY and VARIANT data types. The ARRAY data type can directly contain VARIANT, and thus indirectly contain any other data type, including itself. The VARIANT data type can store a value of any other type, including OBJECT and ARRAY, and is often used to represent semi-structured data formats like JSON, Avro, ORC, Parquet, or XML34.

References: [COF-C02] SnowPro Core Certification Exam Study Guide

In Snowflake, to extract a specific value from a VARIANT column, you use the column name followed by a colon and then the key. The keys are case-sensitive. Therefore, to extract the employee’s name from the “Data” column, the correct syntax is data:employee.name.

 The factors that impact storage costs in Snowflake include the account type (Capacity or On Demand) and the cloud region used by the account. These factors determine the rate at which storage is billed, with different regions potentially having different rates3.

The SECURITYADMIN role in Snowflake can manage any object grant globally, including modifying and revoking grants. This role has the necessary privileges to oversee and control access to all securable objects within the Snowflake environment4.

Micro-partitioning is a Snowflake function that is maintained separately from the data and supports features such as Time Travel, Secure Data Sharing, and pruning. It allows Snowflake to efficiently manage and query large datasets by organizing them into micro-partitions1.

 A Query Profile provides detailed execution information for a query, which can be used to analyze the performance and behavior of queries. This information can help users optimize and right-size their virtual warehouses for better efficiency. References: [COF-C02] SnowPro Core Certification Exam Study Guide

 In Snowflake, if a temporary table and a permanent table have the same name within the same schema, the temporary table takes precedence over the permanent table within the session where the temporary table was created4.

The BUILD_STAGE_FILE_URL function generates a Snowflake-hosted file URL to a staged file using the stage name and relative file path as inputs2.

Snowflake’s Time Travel feature is used for the maintenance of historical data, allowing users to access and restore data that has been changed or deleted within a defined period4.

The DATA_SHARING_USAGE schema includes views that display information about listings published in the Snowflake Marketplace or a data exchange, which includes DATA_TRANSFER_HISTORY and LISTING_TELEMETRY_DAILY2.

A directory table in Snowflake is used to store file-level metadata about the data files in a stage. It is conceptually similar to an external table and provides information such as file size, last modified timestamp, and file URL. References: [COF-C02] SnowPro Core Certification Exam Study Guide

Snowflake’s Data Exchange feature provides a data hub for secure data collaboration. It allows providers to publish data that can be discovered and accessed by a selected group of invited members, facilitating secure and controlled data sharing within a collaborative environment3. References: [COF-C02] SnowPro Core Certification Exam Study Guide

Snowflake external tables are read-only, which means data manipulation language (DML) operations like INSERT, RENAME, or ALTER cannot be performed on them. However, external tables can be used for query and join operations3.

References: [COF-C02] SnowPro Core Certification Exam Study Guide

When using the ALLOW_CLIENT_MFA_CACHING parameter, a cached Multi-Factor Authentication (MFA) token is valid for up to 4 hours. This allows for continuous, secure connectivity without users needing to respond to an MFA prompt at the start of each connection attempt to Snowflake within this timeframe2.

Snowflake stores metadata for rows in micro-partitions, including the range of values for each column and the number of distinct values1.

 To view and modify resource monitors, the least privileges needed are MONITOR and MODIFY. These privileges allow a user to monitor credit usage and make changes to resource monitors3.

Dynamic Data Masking in Snowflake supports tables and views. These objects can have masking policies applied to their columns to dynamically mask data at query time3.

The ACCESS_HISTORY view in Snowflake is utilized to support compliance auditing. It provides detailed information on data access within Snowflake, including reads and writes by user queries. This view is essential for regulatory compliance auditing as it offers insights into the usage of tables and columns, and maintains a direct link between the user, the query, and the accessed data1.

References: [COF-C02] SnowPro Core Certification Exam Study Guide

The statistics that can be used to identify queries with inefficient pruning are ‘Partitions scanned’ and ‘Partitions total’. These statistics indicate how much of the data was actually needed and scanned versus the total available, which can highlight inefficiencies in data pruning34.

 Tags in Snowflake allow users to track sensitive data for compliance, discovery, protection, and resource usage. They enable the categorization and tracking of data, supporting compliance with privacy regulations678. References: [COF-C02] SnowPro Core Certification Exam Study Guide

 The TO_JSON function is used to convert a VARIANT value into a string containing the JSON representation of the value. This function is suitable for unloading data from a relational table to JSON format. References: [COF-C02] SnowPro Core Certification Exam Study Guide

To reduce data spilling in Snowflake, using a larger virtual warehouse is effective because it provides more memory and local disk space, which can accommodate larger data operations and minimize the need to spill data to disk or remote storage1. References: [COF-C02] SnowPro Core Certification Exam Study Guide

The primary factor that determines the cost of using a virtual warehouse in Snowflake is D. The length of time the compute resources in each cluster run. Snowflake's pricing model for compute usage is based on the concept of Snowflake credits, which are consumed based on the time virtual warehouses are running and the size of the warehouses. The more compute resources are utilized and the longer they run, the more credits are consumed, which directly impacts the cost.

References:

• Snowflake Documentation on Virtual Warehouses: Understanding and Managing Warehouse Credit Usage

The correct function to use with the COPY INTO <location> statement to convert rows from a relational table into a single variant column and to unload rows into a JSON file is TO VARIANT. The TO VARIANT function is used to explicitly convert a value of any supported data type into a VARIANT data type. This is particularly useful when needing to aggregate multiple columns or complex data structures into a single JSON-formatted string, which can then be unloaded into a file.

In the context of unloading data, the COPY INTO <location> statement combined with TO VARIANT enables the conversion of structured data from Snowflake tables into a semi-structured VARIANT format, typically JSON, which can then be efficiently exported and stored. This approach is often utilized for data integration scenarios, backups, or when data needs to be shared in a format that is easily consumed by various applications or services that support JSON.

References:

• Snowflake Documentation on Data Unloading: Unloading Data
• Snowflake Documentation on VARIANT Data Type: Working with JSON