org.apache.calcite.rel.rules

Class DateRangeRules

java.lang.Object

org.apache.calcite.rel.rules.DateRangeRules

public abstract class DateRangeRules
extends Object

Collection of planner rules that convert EXTRACT(timeUnit FROM dateTime) = constant, FLOOR(dateTime to timeUnit = constant} and CEIL(dateTime to timeUnit = constant} to dateTime BETWEEN lower AND upper.

The rules allow conversion of queries on time dimension tables, such as

SELECT ... FROM sales JOIN time_by_day USING (time_id) WHERE time_by_day.the_year = 1997 AND time_by_day.the_month IN (4, 5, 6)

into

SELECT ... FROM sales JOIN time_by_day USING (time_id) WHERE the_date BETWEEN DATE '2016-04-01' AND DATE '2016-06-30'

and is especially useful for Druid, which has a single timestamp column.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
private static class	DateRangeRules.ExtractFinder Visitor that searches for calls to EXTRACT, FLOOR or CEIL, building a list of distinct time units.
(package private) static class	DateRangeRules.ExtractShuttle Walks over an expression, replacing calls to EXTRACT, FLOOR and CEIL with date ranges.
static class	DateRangeRules.FilterDateRangeRule Rule that converts EXTRACT, FLOOR and CEIL in a Filter into a date range.

Field Summary

Fields

Modifier and Type	Field and Description
static RelOptRule	FILTER_INSTANCE
private static com.google.common.base.Predicate<Filter>	FILTER_PREDICATE
private static Map<org.apache.calcite.avatica.util.TimeUnitRange,Integer>	TIME_UNIT_CODES
private static Map<org.apache.calcite.avatica.util.TimeUnitRange,org.apache.calcite.avatica.util.TimeUnitRange>	TIME_UNIT_PARENTS

Constructor Summary

Constructors

Modifier	Constructor and Description
private	DateRangeRules()

Method Summary

Modifier and Type	Method and Description
(package private) static com.google.common.collect.ImmutableSortedSet<org.apache.calcite.avatica.util.TimeUnitRange>	extractTimeUnits(RexNode e) Tests whether an expression contains one or more calls to the EXTRACT function, and if so, returns the time units used.
static RexNode	replaceTimeUnits(RexBuilder rexBuilder, RexNode e, String timeZone) Replaces calls to EXTRACT, FLOOR and CEIL in an expression.

Methods inherited from class java.lang.Object

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

Field Detail

FILTER_PREDICATE

private static final com.google.common.base.Predicate<Filter> FILTER_PREDICATE

FILTER_INSTANCE

public static final RelOptRule FILTER_INSTANCE

TIME_UNIT_CODES

private static final Map<org.apache.calcite.avatica.util.TimeUnitRange,Integer> TIME_UNIT_CODES

TIME_UNIT_PARENTS

private static final Map<org.apache.calcite.avatica.util.TimeUnitRange,org.apache.calcite.avatica.util.TimeUnitRange> TIME_UNIT_PARENTS

Constructor Detail

DateRangeRules

private DateRangeRules()

Method Detail

extractTimeUnits

static com.google.common.collect.ImmutableSortedSet<org.apache.calcite.avatica.util.TimeUnitRange> extractTimeUnits(RexNode e)

Tests whether an expression contains one or more calls to the EXTRACT function, and if so, returns the time units used.

The result is an immutable set in natural order. This is important, because code relies on the collection being sorted (so YEAR comes before MONTH before HOUR) and unique. A predicate on MONTH is not useful if there is no predicate on YEAR. Then when we apply the predicate on DAY it doesn't generate hundreds of ranges we'll later throw away.

replaceTimeUnits

public static RexNode replaceTimeUnits(RexBuilder rexBuilder,
                                       RexNode e,
                                       String timeZone)

Replaces calls to EXTRACT, FLOOR and CEIL in an expression.