com.lucidera.lcs
Class LcsIndexAggRule

java.lang.Object
  org.eigenbase.relopt.RelOptRule
      com.lucidera.lcs.LcsIndexAggRule

public class LcsIndexAggRule
extends RelOptRule

A rule for directly aggregating off of an unclustered index scan.

Version:

$Id: //open/dev/farrago/src/com/lucidera/lcs/LcsIndexAggRule.java#14 $

Author:

John Pham

Field Summary

static LcsIndexAggRule	instanceNormalizer
static LcsIndexAggRule	instanceRowScan The singletons

Fields inherited from class org.eigenbase.relopt.RelOptRule

ANY, description, operands

Constructor Summary

LcsIndexAggRule(RelOptRuleOperand operand, String id)
Creates an LcsIndexAggRule.

Method Summary

CallingConvention	getOutConvention() Returns the calling convention of the result of firing this rule, null if not known.
void	onMatch(RelOptRuleCall call) Receives notification about a rule match.
private boolean	projectionSatisfiesGroupBy(Integer[] proj, int groupCount) Determines whether a projection from an index scan can meet the group by requirements of an aggregate.

Methods inherited from class org.eigenbase.relopt.RelOptRule

convert, equals, equals, getOperand, getOperands, getOutTrait, hashCode, matches, mergeTraitsAndConvert, mergeTraitsAndConvert, toString

Methods inherited from class java.lang.Object

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

Field Detail

instanceRowScan

public static final LcsIndexAggRule instanceRowScan

The singletons

TODO: handle CalcRel after sort order has been cleaned up

instanceNormalizer

public static final LcsIndexAggRule instanceNormalizer

Constructor Detail

LcsIndexAggRule

public LcsIndexAggRule(RelOptRuleOperand operand,
                       String id)

Creates an LcsIndexAggRule.

Parameters:

operand - Root operand, must not be null

id - Description of rule

Method Detail

getOutConvention

public CallingConvention getOutConvention()

Description copied from class: RelOptRule

Returns the calling convention of the result of firing this rule, null if not known.

Overrides:

getOutConvention in class RelOptRule

onMatch

public void onMatch(RelOptRuleCall call)

Description copied from class: RelOptRule

Receives notification about a rule match. At the time that this method is called, call.rels holds the set of relational expressions which match the operands to the rule; call.rels[0] is the root expression.

Typically a rule would check that the nodes are valid matches, creates a new expression, then calls back RelOptRuleCall.transformTo(org.eigenbase.rel.RelNode) to register the expression.

Specified by:

onMatch in class RelOptRule

Parameters:

call - Rule call

See Also:

RelOptRule.matches(RelOptRuleCall)

projectionSatisfiesGroupBy

private boolean projectionSatisfiesGroupBy(Integer[] proj,
                                           int groupCount)

Determines whether a projection from an index scan can meet the group by requirements of an aggregate. The index scan columns are sorted in order, and the group by columns are required to be sorted in order, so the index scan projection should be a prefix of the index scan: 0, 1, 2, ... etc.

Parameters:

proj - the projection from an index

groupCount - the number of columns to be grouped. the columns are assumed to be the prefix of input to the aggregate

Returns:

whether the projection can meet the group by requirements of an aggregate