/**
* Combines the join filters from the left and right inputs (if they are MultiJoinRels) with the
* join filter in the joinrel into a single AND'd join filter, unless the inputs correspond to
* null generating inputs in an outer join
*
* @param joinRel join rel
* @param left left child of the joinrel
* @param right right child of the joinrel
* @return combined join filters AND'd together
*/
private RexNode combineJoinFilters(JoinRel joinRel, RelNode left, RelNode right) {
RexBuilder rexBuilder = joinRel.getCluster().getRexBuilder();
JoinRelType joinType = joinRel.getJoinType();
// first need to adjust the RexInputs of the right child, since
// those need to shift over to the right
RexNode rightFilter = null;
if (canCombine(right, joinType.generatesNullsOnRight())) {
MultiJoinRel multiJoin = (MultiJoinRel) right;
rightFilter = shiftRightFilter(joinRel, left, multiJoin, multiJoin.getJoinFilter());
}
// AND the join condition if this isn't a left or right outer join;
// in those cases, the outer join condition is already tracked
// separately
RexNode newFilter = null;
if ((joinType != JoinRelType.LEFT) && (joinType != JoinRelType.RIGHT)) {
newFilter = joinRel.getCondition();
}
if (canCombine(left, joinType.generatesNullsOnLeft())) {
RexNode leftFilter = ((MultiJoinRel) left).getJoinFilter();
newFilter = RelOptUtil.andJoinFilters(rexBuilder, newFilter, leftFilter);
}
newFilter = RelOptUtil.andJoinFilters(rexBuilder, newFilter, rightFilter);
return newFilter;
}
public void onMatch(RelOptRuleCall call) {
JoinRel origJoinRel = (JoinRel) call.rels[0];
RelNode left = call.rels[1];
RelNode right = call.rels[2];
// combine the children MultiJoinRel inputs into an array of inputs
// for the new MultiJoinRel
List<BitSet> projFieldsList = new ArrayList<BitSet>();
List<int[]> joinFieldRefCountsList = new ArrayList<int[]>();
RelNode[] newInputs =
combineInputs(origJoinRel, left, right, projFieldsList, joinFieldRefCountsList);
// combine the outer join information from the left and right
// inputs, and include the outer join information from the current
// join, if it's a left/right outer join
RexNode[] newOuterJoinConds = new RexNode[newInputs.length];
JoinRelType[] joinTypes = new JoinRelType[newInputs.length];
combineOuterJoins(origJoinRel, newInputs, left, right, newOuterJoinConds, joinTypes);
// pull up the join filters from the children MultiJoinRels and
// combine them with the join filter associated with this JoinRel to
// form the join filter for the new MultiJoinRel
RexNode newJoinFilter = combineJoinFilters(origJoinRel, left, right);
// add on the join field reference counts for the join condition
// associated with this JoinRel
Map<Integer, int[]> newJoinFieldRefCountsMap = new HashMap<Integer, int[]>();
addOnJoinFieldRefCounts(
newInputs,
origJoinRel.getRowType().getFieldCount(),
origJoinRel.getCondition(),
joinFieldRefCountsList,
newJoinFieldRefCountsMap);
RexNode newPostJoinFilter = combinePostJoinFilters(origJoinRel, left, right);
RelNode multiJoin =
new MultiJoinRel(
origJoinRel.getCluster(),
newInputs,
newJoinFilter,
origJoinRel.getRowType(),
(origJoinRel.getJoinType() == JoinRelType.FULL),
newOuterJoinConds,
joinTypes,
projFieldsList.toArray(new BitSet[projFieldsList.size()]),
newJoinFieldRefCountsMap,
newPostJoinFilter);
call.transformTo(multiJoin);
}
// implement RelOptRule
public void onMatch(RelOptRuleCall call) {
ProjectRel origProj = call.rel(0);
JoinRel joinRel = call.rel(1);
// locate all fields referenced in the projection and join condition;
// determine which inputs are referenced in the projection and
// join condition; if all fields are being referenced and there are no
// special expressions, no point in proceeding any further
PushProjector pushProject =
new PushProjector(origProj, joinRel.getCondition(), joinRel, preserveExprCondition);
if (pushProject.locateAllRefs()) {
return;
}
// create left and right projections, projecting only those
// fields referenced on each side
RelNode leftProjRel = pushProject.createProjectRefsAndExprs(joinRel.getLeft(), true, false);
RelNode rightProjRel = pushProject.createProjectRefsAndExprs(joinRel.getRight(), true, true);
// convert the join condition to reference the projected columns
RexNode newJoinFilter = null;
int[] adjustments = pushProject.getAdjustments();
if (joinRel.getCondition() != null) {
List<RelDataTypeField> projJoinFieldList = new ArrayList<RelDataTypeField>();
projJoinFieldList.addAll(joinRel.getSystemFieldList());
projJoinFieldList.addAll(leftProjRel.getRowType().getFieldList());
projJoinFieldList.addAll(rightProjRel.getRowType().getFieldList());
newJoinFilter =
pushProject.convertRefsAndExprs(joinRel.getCondition(), projJoinFieldList, adjustments);
}
// create a new joinrel with the projected children
JoinRel newJoinRel =
new JoinRel(
joinRel.getCluster(),
leftProjRel,
rightProjRel,
newJoinFilter,
joinRel.getJoinType(),
Collections.<String>emptySet(),
joinRel.isSemiJoinDone(),
joinRel.getSystemFieldList());
// put the original project on top of the join, converting it to
// reference the modified projection list
ProjectRel topProject = pushProject.createNewProject(newJoinRel, adjustments);
call.transformTo(topProject);
}
public void onMatch(RelOptRuleCall call) {
JoinRel join = (JoinRel) call.rels[0];
List<RexNode> expList = new ArrayList<RexNode>(Arrays.asList(join.getChildExps()));
if (reduceExpressions(join, expList)) {
call.transformTo(
new JoinRel(
join.getCluster(),
join.getLeft(),
join.getRight(),
expList.get(0),
join.getJoinType(),
join.getVariablesStopped()));
// New plan is absolutely better than old plan.
call.getPlanner().setImportance(join, 0.0);
}
}
/**
* Combines the post-join filters from the left and right inputs (if they are MultiJoinRels) into
* a single AND'd filter.
*
* @param joinRel the original JoinRel
* @param left left child of the JoinRel
* @param right right child of the JoinRel
* @return combined post-join filters AND'd together
*/
private RexNode combinePostJoinFilters(JoinRel joinRel, RelNode left, RelNode right) {
RexNode rightPostJoinFilter = null;
if (right instanceof MultiJoinRel) {
rightPostJoinFilter =
shiftRightFilter(
joinRel, left, (MultiJoinRel) right, ((MultiJoinRel) right).getPostJoinFilter());
}
RexNode leftPostJoinFilter = null;
if (left instanceof MultiJoinRel) {
leftPostJoinFilter = ((MultiJoinRel) left).getPostJoinFilter();
}
if ((leftPostJoinFilter == null) && (rightPostJoinFilter == null)) {
return null;
} else {
return RelOptUtil.andJoinFilters(
joinRel.getCluster().getRexBuilder(), leftPostJoinFilter, rightPostJoinFilter);
}
}
/**
* 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;
}