io.prestosql.sql.planner.iterative.rule

Class ExtractSpatialJoins

java.lang.Object

io.prestosql.sql.planner.iterative.rule.ExtractSpatialJoins

public class ExtractSpatialJoins
extends Object

Applies to broadcast spatial joins, inner and left, expressed via ST_Contains, ST_Intersects and ST_Distance functions.

For example:

• SELECT ... FROM a, b WHERE ST_Contains(b.geometry, a.geometry)
• SELECT ... FROM a, b WHERE ST_Intersects(b.geometry, a.geometry)
• SELECT ... FROM a, b WHERE ST_Distance(b.geometry, a.geometry) <= 300
• SELECT ... FROM a, b WHERE 15.5 > ST_Distance(b.geometry, a.geometry)

Joins expressed via ST_Contains and ST_Intersects functions must match all of the following criteria:

- arguments of the spatial function are non-scalar expressions; - one of the arguments uses symbols from left side of the join, the other from right.

Joins expressed via ST_Distance function must use less than or less than or equals operator to compare ST_Distance value with a radius and must match all of the following criteria:

- arguments of the spatial function are non-scalar expressions; - one of the arguments uses symbols from left side of the join, the other from right; - radius is either scalar expression or uses symbols only from the right (build) side of the join.

For inner join, replaces cross join node and a qualifying filter on top with a single spatial join node.

For both inner and left joins, pushes non-trivial expressions of the spatial function arguments and radius into projections on top of join child nodes.

Examples:

 Point-in-polygon inner join
      ST_Contains(ST_GeometryFromText(a.wkt), ST_Point(b.longitude, b.latitude))
 becomes a spatial join
      ST_Contains(st_geometryfromtext, st_point)
 with st_geometryfromtext -> 'ST_GeometryFromText(a.wkt)' and
 st_point -> 'ST_Point(b.longitude, b.latitude)' projections on top of child nodes.

 Distance query
      ST_Distance(ST_Point(a.lon, a.lat), ST_Point(b.lon, b.lat)) <= 10 / (111.321 * cos(radians(b.lat)))
 becomes a spatial join
      ST_Distance(st_point_a, st_point_b) <= radius
 with st_point_a -> 'ST_Point(a.lon, a.lat)', st_point_b -> 'ST_Point(b.lon, b.lat)'
 and radius -> '10 / (111.321 * cos(radians(b.lat)))' projections on top of child nodes.
 

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	ExtractSpatialJoins.ExtractSpatialInnerJoin
static class	ExtractSpatialJoins.ExtractSpatialLeftJoin

Constructor Summary

Constructors

Constructor and Description
ExtractSpatialJoins(Metadata metadata, SplitManager splitManager, PageSourceManager pageSourceManager, TypeAnalyzer typeAnalyzer)

Method Summary

Modifier and Type	Method and Description
Set<Rule<?>>	rules()

Methods inherited from class java.lang.Object

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

Constructor Detail

ExtractSpatialJoins

public ExtractSpatialJoins(Metadata metadata,
                           SplitManager splitManager,
                           PageSourceManager pageSourceManager,
                           TypeAnalyzer typeAnalyzer)

Method Detail

rules

public Set<Rule<?>> rules()