org.apache.hadoop.hive.ql.optimizer.calcite.rules

Class HiveAggregateReduceFunctionsRule

java.lang.Object

org.apache.calcite.plan.RelOptRule

org.apache.hadoop.hive.ql.optimizer.calcite.rules.HiveAggregateReduceFunctionsRule

public class HiveAggregateReduceFunctionsRule
extends org.apache.calcite.plan.RelOptRule

This rule is a copy of AggregateReduceFunctionsRule that regenerates Hive specific aggregate operators. TODO: When CALCITE-2216 is completed, we should be able to remove much of this code and just override the relevant methods. Planner rule that reduces aggregate functions in Aggregates to simpler forms.

Rewrites:

• AVG(x) → SUM(x) / COUNT(x)
• STDDEV_POP(x) → SQRT( (SUM(x * x) - SUM(x) * SUM(x) / COUNT(x)) / COUNT(x))
• STDDEV_SAMP(x) → SQRT( (SUM(x * x) - SUM(x) * SUM(x) / COUNT(x)) / CASE COUNT(x) WHEN 1 THEN NULL ELSE COUNT(x) - 1 END)
• VAR_POP(x) → (SUM(x * x) - SUM(x) * SUM(x) / COUNT(x)) / COUNT(x)
• VAR_SAMP(x) → (SUM(x * x) - SUM(x) * SUM(x) / COUNT(x)) / CASE COUNT(x) WHEN 1 THEN NULL ELSE COUNT(x) - 1 END

Field Summary

Fields

Modifier and Type	Field and Description
static HiveAggregateReduceFunctionsRule	INSTANCE The singleton.

Fields inherited from class org.apache.calcite.plan.RelOptRule

description, operands, relBuilderFactory

Constructor Summary

Constructors

Constructor and Description
HiveAggregateReduceFunctionsRule() Creates an HiveAggregateReduceFunctionsRule.

Method Summary

Modifier and Type	Method and Description
boolean	matches(org.apache.calcite.plan.RelOptRuleCall call)
protected void	newAggregateRel(org.apache.calcite.tools.RelBuilder relBuilder, org.apache.calcite.rel.core.Aggregate oldAggregate, List<org.apache.calcite.rel.core.AggregateCall> newCalls) Do a shallow clone of oldAggRel and update aggCalls.
void	onMatch(org.apache.calcite.plan.RelOptRuleCall ruleCall)

Methods inherited from class org.apache.calcite.plan.RelOptRule

any, convert, convert, convertList, convertOperand, equals, equals, getOperand, getOperands, getOutConvention, getOutTrait, hashCode, none, operand, operand, operand, operand, operand, some, toString, unordered

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

INSTANCE

public static final HiveAggregateReduceFunctionsRule INSTANCE

The singleton.

Constructor Detail

HiveAggregateReduceFunctionsRule

public HiveAggregateReduceFunctionsRule()

Creates an HiveAggregateReduceFunctionsRule.

Method Detail

matches

public boolean matches(org.apache.calcite.plan.RelOptRuleCall call)

Overrides:

matches in class org.apache.calcite.plan.RelOptRule

onMatch

public void onMatch(org.apache.calcite.plan.RelOptRuleCall ruleCall)

Specified by:

onMatch in class org.apache.calcite.plan.RelOptRule

newAggregateRel

protected void newAggregateRel(org.apache.calcite.tools.RelBuilder relBuilder,
                               org.apache.calcite.rel.core.Aggregate oldAggregate,
                               List<org.apache.calcite.rel.core.AggregateCall> newCalls)

Do a shallow clone of oldAggRel and update aggCalls. Could be refactored into Aggregate and subclasses - but it's only needed for some subclasses.

Parameters:

relBuilder - Builder of relational expressions; at the top of its stack is its input

oldAggregate - LogicalAggregate to clone.

newCalls - New list of AggregateCalls