SnowPro-Core Snowflake Exam Lab Questions

To unload data from a table into one or more files in a named stage, the COPY INTO <location> 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. The COPY INTO command is versatile, supporting various file formats and compression options for efficient data unloading.

References:

• Snowflake Documentation: COPY INTO Location

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.

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

Snowflake's unique architecture is described as a multi-cluster, shared data architecture that leverages massively parallel processing (MPP). This architecture separates compute and storage resources, enabling Snowflake to scale them independently. It does not use a single cluster or rely solely on symmetric multiprocessing (SMP); rather, it uses a combination of shared-nothing architecture for compute clusters (virtual warehouses) and a centralized storage layer for data, optimizing for both performance and scalability.

References:

• Snowflake Documentation: Snowflake Architecture Overview