/**
* Shifts a filter originating from the right child of the JoinRel to the right, to reflect the
* filter now being applied on the resulting MultiJoinRel.
*
* @param joinRel the original JoinRel
* @param left the left child of the JoinRel
* @param right the right child of the JoinRel
* @param rightFilter the filter originating from the right child
* @return the adjusted right filter
*/
private RexNode shiftRightFilter(
JoinRel joinRel, RelNode left, MultiJoinRel right, RexNode rightFilter) {
if (rightFilter == null) {
return null;
}
int nFieldsOnLeft = left.getRowType().getFields().length;
int nFieldsOnRight = right.getRowType().getFields().length;
int[] adjustments = new int[nFieldsOnRight];
for (int i = 0; i < nFieldsOnRight; i++) {
adjustments[i] = nFieldsOnLeft;
}
rightFilter =
rightFilter.accept(
new RelOptUtil.RexInputConverter(
joinRel.getCluster().getRexBuilder(),
right.getRowType().getFields(),
joinRel.getRowType().getFields(),
adjustments));
return rightFilter;
}
// implement RelOptRule
public void onMatch(RelOptRuleCall call) {
FilterRel filterRel = call.rel(0);
MultiJoinRel multiJoinRel = call.rel(1);
MultiJoinRel newMultiJoinRel =
new MultiJoinRel(
multiJoinRel.getCluster(),
multiJoinRel.getInputs(),
multiJoinRel.getJoinFilter(),
multiJoinRel.getRowType(),
multiJoinRel.isFullOuterJoin(),
multiJoinRel.getOuterJoinConditions(),
multiJoinRel.getJoinTypes(),
multiJoinRel.getProjFields(),
multiJoinRel.getJoinFieldRefCountsMap(),
filterRel.getCondition());
call.transformTo(newMultiJoinRel);
}