Snowflake Certification Practice Test

True or False: Cluster keys should be defined with high cardinality columns.

1. True

2. False

The correct answer is: False

Defining cluster keys with high cardinality columns is generally not advisable because it can lead to a less effective clustering strategy. Cluster keys are used in Snowflake to optimize query performance by organizing data in a way that minimizes the amount of data scanned during queries. High cardinality columns, which have many unique values, may lead to fragmented data distribution. This fragmentation can counteract the benefits of clustering, as it becomes harder for Snowflake to effectively group the data for fast access. Choosing low cardinality columns for clustering often provides better results. These columns can create larger contiguous data segments, resulting in a more efficient organization of data. This, in turn, can improve query performance, as it promotes better data locality and reduces the amount of data that needs to be scanned. Thus, defining cluster keys with low or moderate cardinality allows for a more beneficial clustering mechanism in Snowflake.