Small Table Cardinality Statistics
For all LT/ST-J1a (Reasonable Indexed Joins) examples, the following row information is given for the small dimension tables:
| Attribute | Cardinality |
|---|---|
| color | 2 |
| size | 10 |
| options | 10 |
Large Table Uniqueness Statistics
The following statistics information is given for the large fact table:
| Column Name | Number of Unique Values |
|---|---|
| color | 10 |
| size | 100 |
| options | 1000 |
Test Query
These examples explain the join plans and estimated time for running the following query, when different types of indexes (primary index, unique secondary index, nonunique secondary index) are created on the join columns (color, size, and options) of the large table.
SELECT … WHERE widgets.color = color.code AND widgets.size = size.code AND widgets.options = options.code;