Snowflake uses columnar scanning of partitions to avoid scanning an entire partition when a query filters on a single column.

• A. True
• B. False
• C. Not applicable
• D. It depends on the partition size

Answer: (A)

Snowflake uses micro-partitions with columnar storage and pruning metadata to avoid scanning unnecessary data. Each micro-partition has min/max statistics for its columns. When a query filters on a single column, Snowflake can quickly determine which micro-partitions cannot contain matching rows and skip them, instead scanning only those partitions that might have relevant data. Within the micro-partitions that are read, Snowflake also uses columnar storage to load only the columns needed for the query, further reducing I/O. This means you don’t end up scanning the entire partition just because of a filter on one column. The behavior is generally true regardless of partition size, though the amount of pruning depends on data distribution.