Designing for segmentation

You segment projections using hash segmentation. Hash segmentation allows you to segment a projection based on a built-in hash function that provides even distribution of data across multiple nodes, resulting in optimal query execution. In a projection, the data to be hashed consists of one or more column values, each having a large number of unique values and an acceptable amount of skew in the value distribution. Primary key columns that meet the criteria could be an excellent choice for hash segmentation.

When segmenting projections, determine which columns to use to segment the projection. Choose one or more columns that have a large number of unique data values and acceptable skew in their data distribution. Primary key columns are an excellent choice for hash segmentation. The columns must be unique across all the tables being used in a query.