Statistics-based versus hard-wired selectivity
Derby
determines the selectivity for a WHERE clause in one of two ways.
Selectivity from cardinality statistics
Selectivity from hard-wired assumptions
Parent topic:
Selectivity and cardinality statistics
Related concepts
Determinations of rows scanned from disk for a table scan
Estimations of rows scanned from disk for an index scan
What are cardinality statistics?
Working with cardinality statistics