Snowflake recommends considering adding a clustering key to a table when its size reaches1 Terabyte (TB)or larger. Clustering keys help optimize the storage and query performance by organizing the data in a table based on the specified columns. This is particularly beneficial for large tables where data retrieval can become inefficient without proper clustering.

Why Clustering Keys Are Important:Clustering keys ensure that data stored in Snowflake is physically ordered in a way that aligns with the most frequent access patterns, thereby reducing the amount of scanned data during queries and improving performance.

Recommendation Basis:The recommendation for tables of size 1 TB or larger is based on the observation that smaller tables generally do not benefit as much from clustering, given Snowflake's architecture. However, as tables grow in size, the benefits of clustering become more pronounced.

Implementing Clustering Keys:

To set a clustering key for a table, you can use theCLUSTER BYclause during table creation or alter an existing table to add it:

CREATETABLEmy_table (... ) CLUSTERBY(column1, column2);

Or for an existing table:

ALTERTABLEmy_table CLUSTERBY(column1, column2);