Package org.apache.drill.exec.store.base.filter

Class ExprNode.OrNode

java.lang.Object

org.apache.drill.exec.store.base.filter.ExprNode

org.apache.drill.exec.store.base.filter.ExprNode.ListNode

org.apache.drill.exec.store.base.filter.ExprNode.OrNode

Enclosing class:

ExprNode

public static class ExprNode.OrNode
extends ExprNode.ListNode

Represents a set of OR'ed expressions in Disjunctive Normal Form (CNF). Or'ed expresssions often cannot be pushed down except in the special case of a series of expressions on the same column, which can sometimes be handled as a series of requests, each for a different disjunct.

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.drill.exec.store.base.filter.ExprNode

ExprNode.AndNode, ExprNode.ColRelOpConstNode, ExprNode.ColumnTypeNode, ExprNode.ListNode, ExprNode.OrNode, ExprNode.RelOpNode

Field Summary

Fields inherited from class org.apache.drill.exec.store.base.filter.ExprNode.ListNode

children

Constructor Summary

Constructors

Constructor	Description
OrNode(List<ExprNode> children)

Method Summary

Modifier and Type	Method	Description
double	selectivity()	Compute the selectivity of this DNF (OR) clause.

Methods inherited from class org.apache.drill.exec.store.base.filter.ExprNode

rexNode, tag

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

OrNode

public OrNode(List<ExprNode> children)

Method Details

selectivity

public double selectivity()

Compute the selectivity of this DNF (OR) clause. Drill assumes the selectivity of = is 0.15. An OR is a series of equal statements, so selectivity is n * 0.15. However, limit total selectivity to 0.9 (that is, if there are more than 6 clauses in the DNF, assume at least some reduction.)

Specified by:

selectivity in class ExprNode

Returns:

the estimated selectivity of this DNF clause