Snowflake Certification Practice Test

What does high cardinality mean in the context of Snowflake?

1. A column with a vast number of distinct values

2. A column with repetitive values

3. A column that is not used often

4. A column that contains null values

The correct answer is: A column with a vast number of distinct values

High cardinality in the context of Snowflake refers to a column that has a vast number of distinct values. This means that the values in that column are unique or near-unique, which can be beneficial for performance in certain types of queries, particularly those involving filtering and searching through large datasets. High cardinality columns can improve query performance by allowing for more efficient indexing and partitioning strategies, as the database can utilize the uniqueness of those values to optimize data retrieval. In contrast, columns with repetitive values would be categorized as having low cardinality. Low cardinality columns typically have a small set of distinct values, which can lead to inefficiencies in certain types of queries because they may not narrow down the search effectively. Columns that are not used often or that contain null values do not directly relate to the concept of cardinality, as those attributes are based more on usage and data presence rather than the distinctness of values. Thus, the notion of high cardinality is primarily concerned with the quantity and variety of distinct values within a given column.