com.lucidera.lcs
Class LcsIndexSemiJoinRule

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

public class LcsIndexSemiJoinRule
extends RelOptRule

LcsIndexSemiJoinRule implements the rule for converting a semijoin expression into the actual operations used to execute the semijoin. Specfically,

 SemiJoinRel(LcsRowScanRel, D) ->
     LcsRowScanRel(
         LcsIndexMergeRel(
             LcsIndexSearchRel(
                 LcsFennelSortRel(
                     AggregateRel(
                         ProjectRel(D))))))
 

Note that this rule assumes that no projections have been pushed into the LcsRowScanRels.

Version:

$Id: //open/dev/farrago/src/com/lucidera/lcs/LcsIndexSemiJoinRule.java#26 $

Author:

Zelaine Fong

Field Summary

Fields inherited from class org.eigenbase.relopt.RelOptRule

ANY, description, operands

Constructor Summary

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

Method Summary

private static RelNode[]	addNewIndexAccessRel(RelOptRuleCall call, int rowScanRelPosInCall, FennelSortRel sort, FemLocalIndex index, Double indexSelectivity)
private RexNode[]	castJoinKeys(List<Integer> leftKeys, RelDataTypeField[] leftFields, int nKeys, List<Integer> keyOrder, RexBuilder rexBuilder, RexNode[] rhsExps, FarragoTypeFactory typeFactory) Casts the types of the join keys from the right hand side of the join to the types of the left hand side
void	onMatch(RelOptRuleCall call) Receives notification about a rule match.
private void	transformSemiJoin(SemiJoinRel semiJoin, LcsRowScanRel origRowScan, FemLocalIndex index, List<Integer> keyOrder, RelNode rightRel, RelOptRuleCall call) Converts the semijoin expression once a valid index has been found

Methods inherited from class org.eigenbase.relopt.RelOptRule

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

Methods inherited from class java.lang.Object

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

Constructor Detail

LcsIndexSemiJoinRule

public LcsIndexSemiJoinRule(RelOptRuleOperand operand,
                            String id)

Creates an LcsIndexSemiJoinRule.

Parameters:

operand - Root operand, must not be null

id - Description of rule

Method Detail

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)

transformSemiJoin

private void transformSemiJoin(SemiJoinRel semiJoin,
                               LcsRowScanRel origRowScan,
                               FemLocalIndex index,
                               List<Integer> keyOrder,
                               RelNode rightRel,
                               RelOptRuleCall call)

Converts the semijoin expression once a valid index has been found

Parameters:

semiJoin - the semijoin expression to be converted

origRowScan - original row scan on the left hand side of the semijoin

index - index to be used to scan the left hand side of the semijoin

keyOrder - positions of the keys that match the index, in the order of match

rightRel - right hand side of the semijoin

call - rule call

castJoinKeys

private RexNode[] castJoinKeys(List<Integer> leftKeys,
                               RelDataTypeField[] leftFields,
                               int nKeys,
                               List<Integer> keyOrder,
                               RexBuilder rexBuilder,
                               RexNode[] rhsExps,
                               FarragoTypeFactory typeFactory)

Casts the types of the join keys from the right hand side of the join to the types of the left hand side

Parameters:

leftKeys - left hand side join keys

leftFields - fields corresponding to the left hand side of the join

nKeys - number of keys to be cast

keyOrder - positions of the keys that match the index, in the order of match

rexBuilder - rex builder from right hand side of join

rhsExps - right hand side expressions that need to be cast

typeFactory - type factory

Returns:

cast expression

addNewIndexAccessRel

private static RelNode[] addNewIndexAccessRel(RelOptRuleCall call,
                                              int rowScanRelPosInCall,
                                              FennelSortRel sort,
                                              FemLocalIndex index,
                                              Double indexSelectivity)

Parameters:

call - call this rule is matched against

rowScanRelPosInCall - the position(start from 0) of the LcsRowScanRel in the sequence of rels matched by this rule

sort - input to the index search rel to be created

index - the index to use in the index search rel

indexSelectivity - selectivity of the index being added

Returns:

the new input rels, after adding the new index search rel, to the row scan rel.