Snowflake COF-C02 SnowPro Core Certification Exam Exam Practice Test

The MIN_DATA_RETENTION_TIME_IN_DAYS parameter is set at the account level. This parameter determinesthe minimum number of days Snowflake retains historical data for Time Travel operations

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

The LIST and PUT commands are specific to SnowSQL and cannot be executed in the web interface or other SQL clients. LIST is used to display the contents of a stage, and PUT is used to upload files to a stage. 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.

Unstructured data stored in Snowflake can be retrieved by using SQL functions to generate URLs that point to the data. These URLs can then be used to download the data directly to a client

To determine which user has accessed a database object containing sensitive information, a Snowflake administrator can query the ACCESS_HISTORY view in the ACCOUNT_USAGE schema, which provides information about access to database objects3.

The STRIP_NULL_VALUE function in Snowflake is used to convert a JSON null value into aSQL NULL value1.

The Query Profile statistics that indicate intermediate results do not fit in memory are the bytes spilled to local storage and bytes spilled to remote storage2.

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.

 To traverse semi-structured data in Snowflake, a user can insert a colon (:) between the VARIANT column name and any first-level element. This path syntax is used to retrieve elements in a VARIANT column4.

When the data retention period is changed at the schema level, all child objects that do not have an explicit retention period setwill inherit the new retention period from the schema4.

 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

The Statistic output in the Query Profile Overview of Snowflake provides detailed insights into the performance of different parts of the query. Specifically, it highlights the "Most expensive nodes," which are the operations or steps within the query execution that consume the most resources, such as CPU and memory. Identifying these nodes helps in pinpointing performance bottlenecks and optimizing query execution by focusing efforts on the most resource-intensive parts of the query.

The RETURN_ERRORS value in the VALIDATION_MODE option of theCOPY command instructs Snowflake to validate the data files and return errors encountered across all specified files, including those that were partially loaded during an earlier load2. References: [COF-C02] SnowPro Core Certification Exam Study Guide

Snowflake recommends automating key pair rotation to improve security and comply with industry best practices. SSH key pairs are used for key-pair authentication with clients like SnowSQL or Snowpipe.

The ACCESS_HISTORY view in Snowflake provides detailed information about queries executed in the account, including metadata such as the time of execution, the user, and the SQL text of the queries. This view is available in the Snowflake Enterprise edition and higher editions. The Standard edition does not include this feature.

Snowflake Documentation: Access History

Snowflake Editions: Snowflake Pricing

The GET_STAGE_LOCATION function retrieves the full external URL associated with a named stage. It is useful for accessing the storage location of external stages configured in Snowflake.

Snowflake's Data Exchange allows users to create and manage a group of accounts to which they can offer data shares. This platform facilitates secure and governed data sharing within and between organizations.

Data Exchange Setup:Users can set up a Data Exchange and invite other Snowflake accounts to join.

Sharing Data:Within the Data Exchange, users can offer shares to the entire group or to specific accounts.

Governance and Security:Data Exchange provides tools for data governance and security, ensuring that shared data is only accessible to authorized accounts.

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.

The GET command is used to download (i.e., unload) files from a Snowflake internal stage to the local file system. COPY INTO writes to stages, not directly to local disk.

The search optimization service in Snowflake significantly improves the performance of range searches and equality searches. Range searches involve looking for values within a specific range (e.g., BETWEEN, <, >). Equality searches involve looking for values that match a specific value (e.g., =).

Snowflake Documentation: Search Optimization Service

To remove staged files during data loading after they have been successfully loaded, thePURGEcopy option is used in Snowflake.

PURGE Option: This option automatically deletes files from the stage after they have been successfully copied into the target table.

Usage:

FROM @my_stage

FILE_FORMAT = (type = 'csv')

PURGE = TRUE;

Snowflake Documentation on COPY INTO

The function used to determine the kind of value stored in a VARIANT column in Snowflake is TYPEOF.

Understanding VARIANT Data Type:

VARIANT is a flexible data type in Snowflake that can store semi-structured data, such as JSON, Avro, and XML.

This data type can hold values of different types, including strings, numbers, objects, arrays, and more.

Using TYPEOF Function:

The TYPEOF function returns the data type of the value stored in a VARIANT column.

It helps in identifying the type of data, which is crucial for processing and transforming semi-structured data accurately.

Example Usage:

SELECT TYPEOF(variant_column)

FROM my_table;

This query retrieves the type of data stored invariant_columnfor each row inmy_table.

Possible return values include 'OBJECT', 'ARRAY', 'STRING', 'NUMBER', etc.

Benefits:

Simplifies data processing: Knowing the data type helps in applying appropriate transformations and validations.

Enhances query accuracy: Ensures that operations on VARIANT columns are performed correctly based on the data type.

Snowflake Documentation: TYPEOF

Snowflake Documentation: VARIANT Data Type

Snowflake supports a variety of subquery types, including both correlated and uncorrelated subqueries. The correct answers are B and E, which highlight Snowflake's flexibility in handling subqueries within SQL queries.

Uncorrelated Scalar Subqueries:These are subqueries that can execute independently of the outer query. They return a single value and can be used anywhere a value expression is allowed, offering great flexibility in SQL queries.

EXISTS, ANY/ALL, and IN Subqueries:These subqueries are used inWHEREclauses to filter the results of the main query based on the presence or absence of matching rows in a subquery. Snowflake supports both correlated and uncorrelated versions of these subqueries, providing powerful tools for complex data analysis scenarios.

Examples and Usage:

Uncorrelated Scalar Subquery:

SELECT*FROMemployeesWHEREsalary > (SELECTAVG(salary)FROMemployees);

Correlated EXISTS Subquery:

SELECT*FROMorders oWHEREEXISTS(SELECT1FROMcustomer cWHEREc.id = o.customer_idANDc.region ='North America');

To handle a large number of complex queries, configuring the warehouse in auto-scale mode by increasing the number of warehouse clusters is recommended. This setup allows Snowflake to dynamically add clusters as demand increases, ensuring better performance and concurrency. Increasing the number of clusters provides scalability for concurrent users and heavy workloads, improving response times without impacting individual query performance.

Snowflake supports several official connectors and drivers, including:

Go Snowflake Driver

Snowflake Connector for Python

Perl, COBOL, and MongoDB drivers are not supported by Snowflake.

Snowflake uses both Discretionary Access Control (DAC) and Role-Based Access Control (RBAC) to manage access control. DAC allows object owners to grant access privileges to other users. RBAC assigns permissions to roles, and roles are then granted to users, making it easier to manage permissions based on user roles within the organization.

Snowflake Documentation: Access Control in Snowflake

Snowsight, Snowflake’s user interface for executing and analyzing queries, supports various types of visualizations to help users understand their data better. Among the supported types, area charts and bar charts are two common options. Area charts are useful for representing quantities through the use of filled areas on the graph, often useful for showing volume changes over time. Bar charts, on the other hand, are versatile for comparing different groups or categories of data. Both chart types are integral to data analysis, enabling users to visualize trends, patterns, and differences in their data effectively.

A materialized view in Snowflake gets suspended when structural changes that could impact the view's integrity are made to the base table, such asB. 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.

With reader accounts, the provider pays for:

Storage of shared data

Compute used by the reader account

The consumer does not pay, as the infrastructure is provisioned and managed by the provider.

Session policies allow account administrators to define rules such as session timeout, requiring users to re-authenticate after inactivity. This is different from password or network policies, which manage login credentials and IP filtering.

TheGET_PRESIGNED_URLfunction in Snowflake generates a pre-signed URL for a file in an internal stage. This URL can be shared with external tools or users who do not have direct access to Snowflake, allowing them to download the file.

Generate Pre-Signed URL:

SELECT GET_PRESIGNED_URL(@my_stage/file.txt);

Share the URL:The generated URL can be shared with external users or applications, enabling them to access the file directly.

Snowflake Streams are used to track and record Data Manipulation Language (DML) changes made to a table. Streams capture changes such as inserts, updates, and deletes, which can then be processed by other Snowflake objects or external applications.

Creating a Stream:

CREATE OR REPLACE STREAM my_stream ON TABLE my_table;

Using Streams:Streams provide a way to process changes incrementally, making it easier to build efficient data pipelines.

Consuming Stream Data:The captured changes can be consumed using SQL queries or Snowflake tasks.

When SINGLE = FALSE is set during COPY INTO, Snowflake writes multiple output files, enabling parallelism. Setting SINGLE = TRUE forces one output file, reducing parallel processing.

 Snowflake recommends creating separate warehouses for each workload to resolve performance issues caused by shared virtual warehouses. This ensures that the resources are not being overutilized by one user’s activities, thereby affecting the performance of another user’s activities4.

 The REST API used with unstructured data in Snowflake is GET /api/files/, which retrieves (downloads) a data file from an internal or external stage4.

 The VALIDATION_MODE parameter can be used with the COPY command to verify data files without loading them into the specified table. This parameter allows users to check for errors in the files

In Snowflake, a tabular User-Defined Function (UDF) is defined with a return clause that includes the keyword “TABLE.” This indicates that the UDF will return a set of rows, which can be used in the FROM clause of a query. References: Based on my internal knowledge as of 2021.

Credit charges for Snowflake virtual warehouses are calculated based on the size of the virtual warehouse and the length of time the warehouse is running. The size determines the compute resources available, and charges are incurred for the time these resources are utilized

Snowflake’s documentation recommends producing the largest files possible for data loading, as larger files reduce the number of files to process and the overhead associated with handling many small files. Thisapproach can maximize the load performance by leveraging Snowflake’s ability to ingest large files efficiently1. References: [COF-C02] SnowPro Core Certification Exam Study Guide

A scoped URL expires when the persisted query result period ends, which is typically after the results cache expires. This is currently set to 24 hours

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 viewis refreshed

 To change permissions for new objects in a managed access schema, a user should be granted the MANAGE GRANTS global privilege. This privilege allows the user to manage access control through grants on all securable objects within Snowflake2. References: [COF-C02] SnowPro Core Certification Exam Study Guide

The Snowflake feature that allows for small volumes of data to be continuously loaded into Snowflake and incrementally made available for analysis is Snowpipe. Snowpipe is designed for near-real-time data loading, enabling data to be loaded as soon as it’s available in the storage layer3

Snowflake supports reader accounts, which are a type of account that allows data providers to share data with consumers who are not Snowflake customers. However, for data sharing to occur, the consumer needs to become a licensed Snowflake customer because data sharing is only supported between Snowflake accounts. References: Introduction to Secure Data Sharing | Snowflake Documentation2.

Snowflake recommends using columns with very high cardinality and those that are most actively used in selective filters as clustering keys. High cardinality columns have a wide range of unique values, which helps in evenly distributing the data across micro-partitions. Columns used in selective filters help in pruning the number of micro-partitions to scan, thus improving query performance. References: Based on general database optimization principles.

 The OBJECT_CONSTRUCT function is used in Snowflake to create a JSON object from relational data, which is useful when unloading semi-structured data. The SINGLE = TRUE parameter is used when unloading data to ensure that the data is exported as a single file, which can be up to 5 GB in size. References: [COF-C02] SnowPro Core Certification Exam Study Guide

 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’sregion and on their cloud platform, facilitating seamless data sharing. References: Sharing data securely across regions and cloud platforms | Snowflake Documentation

When a database is cloned in Snowflake, it does not retain any privileges that were granted on the source object. The clone will need to have privileges reassigned as necessary for users to access it. References: [COF-C02] SnowPro Core Certification Exam Study Guide

 Snowflake recommends using the COPY command for bulk loading data batches from files already available in cloud storage. This command allows for efficient and large-scale data loading operations from files staged in cloud storage into Snowflake tables3.

 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 reader account compute will be billed to the provider account. Very Comprehensive Explanation: In Snowflake, when a provider creates a reader account for a consumer who does not have a Snowflake account, the compute resources used by the reader account are billed to the provider’s account. This allows the consumer to query the shared data without incurring any costs. References: [COF-C02] SnowPro Core Certification Exam Study Guide

The minimum privilege required on an external stage for any role to access unstructured data files using a file URL in the GET REST API is READ. This allows the role to retrieve or download data files from the stage.

 Periodic rekeying of micro-partitions is a feature that requires the Enterprise Edition of Snowflake or higher. This feature is part of Snowflake’s comprehensive approach to encryption key management, ensuring data security through regular rekeying1. References: [COF-C02] SnowPro Core Certification Exam Study Guide

A data consumer who has a pre-signed URL can access data files using Snowflake until the expiration time is exceeded. The expiration time is set when the pre-signed URL is generated and determines how long the URL remains valid3.

A Snowflake Data Exchange allows groups of accounts to share data privately among the accounts (B), and it supports bidirectional sharing, meaning an account can be both a provider and a consumer of data (E). This facilitates secure and governed data collaboration withina selected group3.

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

 Snowsight automatically detects if a target account is in a different region and enables cross-cloud auto-fulfillment when using a paid listing on the Snowflake Marketplace. This feature allows Snowflake to manage the replication of data products to consumer regions as needed, without manual intervention1.

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

The Parquet file format is known for preserving the precision of floating-point numberswhen data is unloaded, preventing truncation of the values3.

The query that contains a Snowflake hosted file URL in a directory table for a stage named bronzestage is select * from directory(@bronzestage). This query retrieves a list of all files on the stage along with metadata, including the Snowflake file URL for each file3.

Snowflake uses a technique called pruning to limit the number of micro-partitions scanned by each query. Pruning effectively filters out unnecessary micro-partitions based on the query’s filter conditions, which can significantly improve query performance by reducing theamount of data scanned1.

 Scaling up the virtual warehouse in Snowflake involves increasing the compute resources available for a single warehouse, which can improve the performance of large and complex queries by providing more CPU and memory resources. References: Based on general cloud data warehousing knowledge as of 2021.

 Snowflake supports three types of internal stages: Named, User, and Table stages. These stages are used for staging data files to be loaded into Snowflake tables. Schema, Stream, and Database stages are not supported as internal stages inSnowflake. References: Snowflake Documentation1.

Snowflake’s architecture is divided into three layers: database storage, query processing, and cloud services. The metadata, which includes information about the structure of the data, the SQL operations performed, and the service-level policies, is stored in the cloud services layer. This layer acts as the brain of the Snowflake environment, managing metadata, query optimization, and transaction coordination.

 Multi-Factor Authentication (MFA) token caching is typically supported for clients that maintain a persistent connection or session with Snowflake, such as the ODBC driver and Python connector, to reduce the need for repeated MFA challenges. References: Based on general security practices in cloud services as of 2021.

 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

 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.

Snowflake supports storing unstructured data and provides native support for semi-structured file formats such as JSON, Avro, Parquet, ORC, and XML1. GeoJSON, being a type of JSON, and XML are among the formats that can be stored in Snowflake. References: [COF-C02] SnowPro Core Certification Exam Study Guide

 The kind of Snowflake table that stores file-level metadata for each file in a stage is a directory table. A directory table is an implicit object layered ona stage and stores file-level metadata about the data files in the stage3.

Snowflake retains information in the ACCESS HISTORY view for 365 days. This allows users to query the access history of Snowflake objects within the last year1.

One of the security features of Snowflake includes the periodic rekeying of encrypted data, which is available with the Snowflake Enterprise edition and higher2. This ensures that the encryption keys are rotated regularly to maintain a high level of security. References: [COF-C02] SnowPro Core Certification Exam Study Guide

In Snowflake, when queries begin to queue in a multi-cluster virtual warehouse, an additional compute cluster starts immediately if the warehouse is set to auto-scale mode. This mode allowsSnowflake to automatically add or resume additional clusters as soon as the workload increases, and similarly, shut down or pause the additional clusters when the load decreases

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

 Snowflake automatically rotates the Account and Table master keys when they are more than 30 days old. Active keys are retired, and new keys are created, ensuring robust security through frequent key changes1

 Snowflake maintains a result cache that stores the results of every query for 24 hours. If the same query is executed again within this time frame and the data has not changed, Snowflake will retrieve the data from the result cache instead of using a virtual warehouse to recompute the results2.

 In theInformation Schema and Account Usage, the column that identifies whether a view is secure or not is IS_SECURE2.

Snowflake recommends creating objects with a role that has the necessary privileges and is not overly permissive. SYSADMIN is typically used for managing system-level objects and operations. Creating objects with a custom role and granting this role to SYSADMIN allows for more granular control and adherence to the principle of least privilege. References: Based on best practices for database object ownership and role management.

 A schema in Snowflake is a logical grouping of database objects, such as tables and views, that belongs to a single database. Each schema is part of a namespace in Snowflake, which is inferred from the current database and schema in use for the session5

The details section of a Query Profile in Snowflake provides users with various statistics and information about the execution of a query. One of the key pieces of information that can be determined from this section is the total duration of the query, which helps in understanding the performance and identifying potential bottlenecks. References: [COF-C02] SnowPro Core Certification Exam Study Guide

SnowCD (Snowflake Connectivity Diagnostic Tool) is used to diagnose and troubleshoot network connections to Snowflake. It runs a series of connection checks to evaluate the network connection to Snowflake

 Snowflake reorganizes data into its internal optimized, compressed, columnar format in the Database Storage layer. This process is part of how Snowflake manages data storage, ensuring efficient data retrieval and query performance

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:

Current Schema: Snowflake first checks if an object with the given name exists in the schema currently in use for the session.

PUBLIC Schema: If the object isn't found in the current schema, Snowflake looks in the PUBLIC schema of the current database.

Note: TheSEARCH_PATHparameter influences object resolution for queries, not within UDFs.

Snowflake bills virtual warehouse usage in one-minute increments, rounding up to the nearest minute for any partial minute of compute time used. If a virtual warehouse runs for 61 seconds and then, after being shut down, restarts and runs for an additional 30 seconds, the total time billed would be 120 seconds or 2 minutes. The first 61 seconds are rounded up to 2 minutes, and the subsequent 30 seconds are within a new minute, which is also rounded up to the nearest minute.

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.

Scalar functions in Snowflake (and SQL in general) are designed to return a single value for each invocation. They operate on a single value and return a single result, making them suitable for a wide range of data transformations and calculations within queries.

TheREVOKE ROLEcommand is used to remove a role from another role or a user in Snowflake. This command is part of Snowflake's role-based access control system, allowing administrators to manage permissions and access to database objects efficiently by adding or removing roles from users or other roles.

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

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.

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.

When dealing with semi-structured data in Snowflake, and the specific types of operations to be performed on the data are not yet determined, Snowflake recommends using the VARIANT data type. The VARIANT type is highly flexible and capable of storing data in multiple formats, including JSON, AVRO, BSON, and more, within a single column. This flexibility allows users to perform various operations on the data, including querying and manipulation of nested data structures without predefined schemas.

Snowflake supports a variety of file formats for unloading semi-structured data, among which Parquet and Newline Delimited JSON (NDJSON) are two widely used formats.

B. Binary file in Parquet: Parquet is a columnar storage file format optimized for large-scale data processing and analysis. It is especially suited for complex nested data structures.

D. Newline Delimited JSON (NDJSON): This format represents JSON records separated by newline characters, facilitating the storage and processing of multiple, separate JSON objects in a single file.

These formats are chosen for their efficiency and compatibility with data analytics tools and ecosystems, enabling seamless integration and processing of exported data.

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.

To get the most detailed information about individual table storage details in Snowflake, theTABLE STORAGE METRICSview should be used. This Information Schema view provides granular storage metrics for tables within Snowflake, including data related to the size of the table, the amount of data stored, and storage usage over time. It's an essential tool for administrators and users looking to monitor and optimize storage consumption and costs.

Tri-secret secure encryption is a security model employed by Snowflake that involves combining a customer-managed key with a Snowflake-managed key to create a composite key for encrypting data. This model enhances data security by requiring both the customer-managed key and the Snowflake-managed key to decrypt data, thus ensuring that neither party can access the data independently. It represents a balanced approach to key management, leveraging both customer control and Snowflake's managed services for robust data encryption.

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.

The worksheet and database explorer feature in Snowsight allows users to tag frequently accessed worksheets for ease of access. This functionality helps users organize and quickly navigate to the worksheets they use most often, enhancing productivity and streamlining the data exploration and analysis process within Snowsight, Snowflake's web-based query and visualization interface.

A clustering key can be defined when a table is created by appending a CLUSTER Where each clustering key consists of one or more table columns/expressions, which can be of any data type, except GEOGRAPHY, VARIANT, OBJECT, or ARRAYhttps://docs.snowflake.com/en/user-guide/tables-clustering-keys

TheOBJECT_CONSTRUCTfunction 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.

Valid sub-clauses to theOVERclause for a window function in SQL are:

C. ORDER BY: This clause specifies the order in which the rows in a partition are processed by the window function. It is essential for functions that depend on the row order, such as ranking functions.

D. PARTITION BY: This clause divides the result set into partitions to which the window function is applied. Each partition is processed independently of other partitions, making it crucial for functions that compute values across sets of rows that share common characteristics.

These clauses are fundamental to defining the scope and order of data over which the window function operates, enabling complex analytical computations within SQL queries.

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.

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.

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.

When creating a CSV file format in Snowflake and the requirement is to wrap columns by single quotes or double quotes, theFIELD_OPTIONALLY_ENCLOSED_BYparameter should be used in the file format specification. This parameter allows you to define a character (either a single quote or a double quote) that can optionally enclose each field in the CSV file, providing flexibility in handling fields that contain special characters or delimiters as part of their data.

Snowflake recommends enhancing the granularity and management of privileges by creating and utilizing custom roles. When additional privileges are needed beyond those provided by the system-defined roles for a virtual warehouse or any other resource, these privileges should be granted to a custom role. This approach allows for more precise control over access rights and the ability to tailor permissions to the specific needs of different user groups or applications within the organization, while also maintaining the integrity and security model of system-defined roles.

The Query Profile in Snowflake provides a graphical representation and statistics for each component of the query's execution plan. This includes details such as the execution time, the number of rows processed, and the amount of data scanned for each operation within the query. The Query Profile is a crucial tool for understanding and optimizing the performance of queries, as it helps identify potential bottlenecks and inefficiencies.

Snowflake's architecture is unique in that it combines elements of both traditional shared-disk and shared-nothing database architectures. This hybrid approach allows Snowflake to offer the scalability and performance benefits of a shared-nothing architecture (with compute and storage separated) while maintaining the simplicity and flexibility of a shared-disk architecture in managing data across all nodes in the system. This results in an architecture that provides on-demand scalability, both vertically and horizontally, without sacrificing performance or data cohesion.

A Snowflake user would decide to use a materialized view instead of a regular view primarily when the base tables do not change frequently. Materialized views store the result of the view query and update it as the underlying data changes, making them ideal for situations where the data is relatively static and query performance is critical. By precomputing and storing the query results, materialized views can significantly reduce query execution times for complex aggregations, joins, and calculations.

Transient tables in Snowflake are designed for temporary or intermediate workloads with the following characteristics:

B. Transient tables can be cloned to permanent tables: This feature allows users to create copies of transient tables for permanent use, providing flexibility in managing data lifecycles.

C. Transient tables persist until they are explicitly dropped: Unlike temporary tables that exist for the duration of a session, transient tables remain in the database until explicitly removed by a user, offering more durability for short-term data storage needs.

To temporarily bypass a network policy by configuring the user object property MINS_TO_BYPASS_NETWORK_POLICY, the USERADMIN role should be used. This role has the necessary privileges to modify user properties, including setting a temporarybypass for network policies, which can be crucial for enabling access under specific circumstances without permanently altering the network security configuration.

Characteristics of reader accounts in Snowflake include:

A. Reader account users cannot add new data to the account: Reader accounts are intended for data consumption only. Users of these accounts can query and analyze the data shared with them but cannot upload or add new data to the account.

E. Reader accounts enable data consumers to access and query data shared by the provider: One of the primary purposes of reader accounts is to allow data consumers to access and perform queries on the data shared by another Snowflake account, facilitating secure and controlled data sharing.

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.

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.

The Virtual Private Snowflake (VPS) edition offers the highest level of security for organizations with the strictest security requirements. This edition provides a dedicated andisolated instance of Snowflake, including enhanced security features and compliance certifications to meet the needs of highly regulated industries or any organization requiring the utmost in data protection and privacy.

In Snowflake, semi-structured data is optimally stored using specific data types that are designed to handle the flexibility and complexity of such data. TheVARIANTdata type can store structured and semi-structured data types, including JSON, Avro, ORC, Parquet, or XML, in a single column. TheARRAYdata 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.

In the Snowflake Web Interface (UI), the Query History page displays the history of queries executed in Snowflake for up to 14 days. This allows users to review and analyze their query performance, troubleshoot issues, and understand their query patterns over a two-week period. The Query History page is a critical tool for monitoring and optimizing the use of Snowflake.

The command to list all the file formats for which a user has access privileges in Snowflake isSHOW FILE FORMATS. This command provides a list of all file formats defined in the user's current session or specified database/schema, along with details such as the name, type, and creation time of each file format. It is a valuable tool for users to understand and manage the file formats available for data loading and unloading operations.

In Snowflake, overloading refers to the creation of multiple User-Defined Functions (UDFs) with the same name but differing in the number or types of their arguments. This feature allows for more flexible function usage, as Snowflake can differentiate between functions based on the context of their invocation, such as the types or the number of arguments passed. Overloading helps to create more adaptable and readable code, as the same function name can be used for similar operations on different types of data.

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.

Characteristics of Snowsight worksheets in Snowflake include:

A. Worksheets can be grouped under folders, and a folder of folders: This organizational feature allows users to efficiently manage and categorize their worksheets within Snowsight, Snowflake's web-based UI, enhancing the user experience by keeping related worksheets together.

E. Users can import worksheets and share them with other users: Snowsight supports the sharing of worksheets among users, fostering collaboration by allowing users to share queries, analyses, and findings. This feature is crucial for collaborative data exploration and analysis workflows.

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.

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.

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.

A Pre-signed URL provides access to files stored in Snowflake without requiring authorization at the time of access. This feature allows users to generate a URL with a limited validity period that grants temporary access to a file in a secure manner. It's particularly useful for sharing data with external parties or applications without the need for them to authenticate directly with Snowflake.

In Snowflake, the query history and the results of queries executed by a user are accessible based on the roles and permissions. If User1 executed a query with the SYSADMIN role, User2 would be able to view the result set of that query executed by User1 only if User2 has the ACCOUNTADMIN role. The ACCOUNTADMIN role has the broadest set of privileges, including the ability to access all aspects of the account's operation, data, and query history, thus enabling User2 to view the results of queries executed by other users.

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.

The default value for auto-suspending a Virtual Warehouse in the Snowflake Web Interface (UI) is 10 minutes. This setting helps manage compute costs by automatically suspending warehouses that are not in use, ensuring that compute resources are efficiently allocated and not wasted on idle warehouses.

To access a file URL from an external stage in Snowflake, the minimum permission required is USAGE on the stage object. USAGE permission allows a user to reference the stage in SQL commands, necessary for actions like listing files or loading data from the stage, but does not permit the user to alter or drop the stage.

To unload data from a table into one or more files in a named stage, theCOPY INTO command should be used. This command exports the result of a query, such as selecting all rows from a table, into files stored in the specified stage. TheCOPY INTOcommand is versatile, supporting various file formats and compression options for efficient data unloading.

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.

 The COPY command is used in Snowflake to load data from files located in an external stage into a table. This command allows for efficient and parallelized data loading from various file formats1.

References = [COF-C02] SnowPro Core Certification Exam Study Guide, Snowflake Documentation

 For loading data into Snowflake via Snowpipe, the recommended compressed file size is between 100-250 MB. This size range is optimal for balancing the performance of parallel processing and minimizing the overhead associated with handling many small files2.

 To ensure that additional multi-clusters are resumed with no delay, a virtual warehouse should be configured to a size larger than generally required. This configuration allows for immediate availability of additional resources when needed, without waiting for new clusters to start up

Snowflake recommends file sizes between 100-250 MB compressed when loading data to optimize parallel processing. Smaller, compressed files can be loaded in parallel, which maximizes the efficiency of the virtual warehouses and speeds up the data loading process

The Enterprise edition of Snowflake allows for a dedicated metadata store, providing additional features designed for large-scale enterprises

A multi-cluster warehouse should be used in auto-scaling mode when there is a need to handle a large number of concurrent queries. Auto-scaling allows Snowflake to automatically add or remove compute clusters to balance the load, ensuring that performance remains consistent during varying levels of demand

 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.

 Users are responsible for data storage costs in Snowflake until the data expires from the Fail-safe period. Fail-safe is the final stage in the data lifecycle, following Time Travel, and provides additional protection against accidental data loss. Once data exits the Fail-safe state, users are no longer billed for its storage

 Snowflake’s architecture is described as a multi-cluster, shared data architecture. This design combines the simplicity of a shared-disk architecture with the performance and scale-out benefits of a shared-nothing architecture, using a central repository accessiblefrom all compute nodes2.

References = [COF-C02] SnowPro Core Certification Exam Study Guide, Snowflake Documentation

The Snowflake Search Optimization Service is designed to support improved performance for selective point lookup queries. These are queries that retrieve specific records from a database, often based on a unique identifier or a small set of criteria3.

The Snowflake Enterprise edition includes database replication and failoverfor business continuity and disaster recovery, as well as extended time travel capabilities for longer data retention periods1.

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

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

 In Snowflake, a schema is a logical grouping of database objects, which can include streams and external tables. A stream is an object that allows users to query data that has changed in specified tables or views, and an external table is a table that references data stored outside of Snowflake. Roles, warehouses, users, and shares are not contained within a schema. References: SHOW OBJECTS, Database, Schema, & Share DDL

 For a temporary table, the maximum total Continuous Data Protection (CDP) charges incurred are forthe duration of the session in which the table was created, which does not exceed 24 hours2.

References = [COF-C02] SnowPro Core Certification Exam Study Guide, Snowflake Documentation2

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, to extract a specific element from a JSON stored in a VARIANT column, the correct syntax is to use the dot notation. Therefore, the query select src.dealership from car_sales; will return the dealership information contained within each JSON object in the src column.

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

 Snowflake supports unloading data in JSON and delimited file formats such as CSV and TSV. These formats are commonly used for data interchange and are supported by Snowflake for unloading operations

The parse_json() function in Snowflake interprets an input string as a JSON document and produces a VARIANT value containing the JSON document. This function is specifically designed for parsing strings that contain valid JSON information3.

A well-clustered table in Snowflake means that the data is organized in such a way that related data points are stored close to each other within the micro-partitions. This optimizes query performance by reducing the amount of scanned data. The diagram indicated by option C shows a well-clustered table, as it likely represents a more evenly distributed range of values across the micro-partitions1.

References = Snowflake Micro-partitions & TableClustering