COF-C02 Exam Dumps - SnowPro Core Certification Exam

Two key metrics in Snowflake’sQuery Profilethat provide insights for performance improvement are:

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

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

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

A Directory Table stores metadata about unstructured data files in a stage, such as size, last-modified timestamp, and file URL. This metadata helps query or track files without ingesting them into a table.

The Merge operator is considered a DML (Data Manipulation Language) operator in Snowflake. DML operators are used to modify data in tables, and the Merge operator specifically allows for conditional updates, inserts, or deletes in a target table based on the results of a join with a source table.

Snowflake Documentation: Query Profile Overview

Snowflake Documentation: MERGE Statement

In Snowflake, the default access level for any securable object (such as a table, view, or schema) is "No access" until explicit access is granted. This means that when an object is created, only the owner of the object and roles with the necessary privileges can access it. Other users or roles will not have any form of access to the object until it is explicitly granted.

This design adheres to the principle of least privilege, ensuring that access to data is tightly controlled and that users and roles only have the access necessary for their functions. To grant access, the owner of the object or a role with the GRANT option can use the GRANT statement to provide specific privileges to other users or roles.

For example, to grant SELECT access on a table to a specific role, you would use a command similar to:

GRANTSELECTONTABLEmy_tableTOROLE my_role;

Column-level security in Snowflake enhances data protection by restricting access and applying masking policies to sensitive data at the column level.

Limiting Access Based on User Privileges:

Column-level security allows administrators to define which users or roles have access to specific columns within a table.

This ensures that sensitive data is only accessible to authorized personnel, thereby reducing the risk of data breaches.

Application of Masking Policies:

Masking policies can be applied to columns to obfuscate sensitive data.

For example, credit card numbers can be masked to show only the last four digits, protecting the full number from being exposed.

Snowflake Documentation: Column-Level Security

Snowflake Documentation: Dynamic Data Masking