Cardinality (Databases)
Cardinality is a row count — of a table, of a predicate's matches, or of an operator's output — and also, for a column, its number of distinct values. Optimizers reason almost entirely in cardinalities: every cost estimate is a function of how many rows flow through each plan node.
This Concept is waiting for its first lesson!
Cardinality is a row count — of a table, of a predicate's matches, or of an operator's output — and also, for a column, its number of distinct values. Optimizers reason almost entirely in cardinalities: every cost estimate is a function of how many rows flow through each plan node.
Are you a teacher? Sign in to start contributing.
Sign In