org.apache.calcite.rel.rules

Class SpatialRules

java.lang.Object

org.apache.calcite.rel.rules.SpatialRules

@Value.Enclosing
public abstract class SpatialRules
extends Object

Collection of planner rules that convert calls to spatial functions into more efficient expressions.

The rules allow Calcite to use spatial indexes. For example the following query:

SELECT ... FROM Restaurants AS r WHERE ST_DWithin(ST_Point(10, 20), ST_Point(r.longitude, r.latitude), 5)

is rewritten to

SELECT ... FROM Restaurants AS r WHERE (r.h BETWEEN 100 AND 150 OR r.h BETWEEN 170 AND 185) AND ST_DWithin(ST_Point(10, 20), ST_Point(r.longitude, r.latitude), 5)

if there is the constraint

CHECK (h = Hilbert(8, r.longitude, r.latitude))

If the Restaurants table is sorted on h then the latter query can be answered using two limited range-scans, and so is much more efficient.

Note that the original predicate ST_DWithin(ST_Point(10, 20), ST_Point(r.longitude, r.latitude), 5) is still present, but is evaluated after the approximate predicate has eliminated many potential matches.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	SpatialRules.FilterHilbertRule Rule that converts ST_DWithin in a Filter condition into a predicate on a Hilbert curve.

Field Summary

Fields

Modifier and Type	Field and Description
static RelOptRule	INSTANCE

Method Summary

Methods inherited from class java.lang.Object

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

Field Detail

INSTANCE

public static final RelOptRule INSTANCE