Snowflake Updated COF-C03 Exam Questions and Answers by caelan

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 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.

The replication feature in Snowflake provides several benefits, with disaster recovery and database failover and fallback being two of the primary advantages. Replication allows for the continuous copying of data from one Snowflake account to another, ensuring that a secondary copy of the data is available in case of outages or disasters. This capability supports disaster recovery strategies by allowing operations to quickly switch to the replicated data in a different account or region. Additionally, it facilitates database failover and fallback procedures, ensuring business continuity and minimizing downtime.

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.