/**
* Combines the outer join conditions and join types from the left and right join inputs. If the
* join itself is either a left or right outer join, then the join condition corresponding to the
* join is also set in the position corresponding to the null-generating input into the join. The
* join type is also set.
*
* @param joinRel join rel
* @param combinedInputs the combined inputs to the join
* @param left left child of the joinrel
* @param right right child of the joinrel
* @param combinedConds the array containing the combined join conditions
* @param joinTypes the array containing the combined join types
* @return combined join filters AND'd together
*/
private RexNode[] combineOuterJoins(
JoinRel joinRel,
RelNode[] combinedInputs,
RelNode left,
RelNode right,
RexNode[] combinedConds,
JoinRelType[] joinTypes) {
JoinRelType joinType = joinRel.getJoinType();
int nCombinedInputs = combinedInputs.length;
boolean leftCombined = canCombine(left, joinType.generatesNullsOnLeft());
boolean rightCombined = canCombine(right, joinType.generatesNullsOnRight());
if (joinType == JoinRelType.LEFT) {
if (leftCombined) {
copyOuterJoinInfo((MultiJoinRel) left, combinedConds, joinTypes, 0, 0, null, null);
} else {
joinTypes[0] = JoinRelType.INNER;
}
combinedConds[nCombinedInputs - 1] = joinRel.getCondition();
joinTypes[nCombinedInputs - 1] = joinType;
} else if (joinType == JoinRelType.RIGHT) {
if (rightCombined) {
copyOuterJoinInfo(
(MultiJoinRel) right,
combinedConds,
joinTypes,
1,
left.getRowType().getFieldCount(),
right.getRowType().getFields(),
joinRel.getRowType().getFields());
} else {
joinTypes[nCombinedInputs - 1] = JoinRelType.INNER;
}
combinedConds[0] = joinRel.getCondition();
joinTypes[0] = joinType;
} else {
int nInputsLeft;
if (leftCombined) {
nInputsLeft = left.getInputs().length;
copyOuterJoinInfo((MultiJoinRel) left, combinedConds, joinTypes, 0, 0, null, null);
} else {
nInputsLeft = 1;
joinTypes[0] = JoinRelType.INNER;
}
if (rightCombined) {
copyOuterJoinInfo(
(MultiJoinRel) right,
combinedConds,
joinTypes,
nInputsLeft,
left.getRowType().getFieldCount(),
right.getRowType().getFields(),
joinRel.getRowType().getFields());
} else {
joinTypes[nInputsLeft] = JoinRelType.INNER;
}
}
return combinedConds;
}
// 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);
}
/**
* 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);
}
/** Variant of {@link #trimFields(RelNode, BitSet, Set)} for {@link JoinRel}. */
public TrimResult trimFields(JoinRel join, BitSet fieldsUsed, Set<RelDataTypeField> extraFields) {
final RelDataType rowType = join.getRowType();
final int fieldCount = rowType.getFieldCount();
final RexNode conditionExpr = join.getCondition();
final int systemFieldCount = join.getSystemFieldList().size();
// Add in fields used in the condition.
BitSet fieldsUsedPlus = (BitSet) fieldsUsed.clone();
final Set<RelDataTypeField> combinedInputExtraFields =
new LinkedHashSet<RelDataTypeField>(extraFields);
RelOptUtil.InputFinder inputFinder =
new RelOptUtil.InputFinder(fieldsUsedPlus, combinedInputExtraFields);
conditionExpr.accept(inputFinder);
// If no system fields are used, we can remove them.
int systemFieldUsedCount = 0;
for (int i = 0; i < systemFieldCount; ++i) {
if (fieldsUsed.get(i)) {
++systemFieldUsedCount;
}
}
final int newSystemFieldCount;
if (systemFieldUsedCount == 0) {
newSystemFieldCount = 0;
} else {
newSystemFieldCount = systemFieldCount;
}
int offset = systemFieldCount;
int changeCount = 0;
int newFieldCount = newSystemFieldCount;
List<RelNode> newInputs = new ArrayList<RelNode>(2);
List<Mapping> inputMappings = new ArrayList<Mapping>();
List<Integer> inputExtraFieldCounts = new ArrayList<Integer>();
for (RelNode input : join.getInputs()) {
final RelDataType inputRowType = input.getRowType();
final int inputFieldCount = inputRowType.getFieldCount();
// Compute required mapping.
BitSet inputFieldsUsed = new BitSet(inputFieldCount);
for (int bit : Util.toIter(fieldsUsedPlus)) {
if (bit >= offset && bit < offset + inputFieldCount) {
inputFieldsUsed.set(bit - offset);
}
}
// If there are system fields, we automatically use the
// corresponding field in each input.
if (newSystemFieldCount > 0) {
// calling with newSystemFieldCount == 0 should be safe but hits
// http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6222207
inputFieldsUsed.set(0, newSystemFieldCount);
}
// FIXME: We ought to collect extra fields for each input
// individually. For now, we assume that just one input has
// on-demand fields.
Set<RelDataTypeField> inputExtraFields =
input.getRowType().getField("_extra") == null
? Collections.<RelDataTypeField>emptySet()
: combinedInputExtraFields;
inputExtraFieldCounts.add(inputExtraFields.size());
TrimResult trimResult = trimChild(join, input, inputFieldsUsed, inputExtraFields);
newInputs.add(trimResult.left);
if (trimResult.left != input) {
++changeCount;
}
final Mapping inputMapping = trimResult.right;
inputMappings.add(inputMapping);
// Move offset to point to start of next input.
offset += inputFieldCount;
newFieldCount += inputMapping.getTargetCount() + inputExtraFields.size();
}
Mapping mapping = Mappings.create(MappingType.InverseSurjection, fieldCount, newFieldCount);
for (int i = 0; i < newSystemFieldCount; ++i) {
mapping.set(i, i);
}
offset = systemFieldCount;
int newOffset = newSystemFieldCount;
for (int i = 0; i < inputMappings.size(); i++) {
Mapping inputMapping = inputMappings.get(i);
for (IntPair pair : inputMapping) {
mapping.set(pair.source + offset, pair.target + newOffset);
}
offset += inputMapping.getSourceCount();
newOffset += inputMapping.getTargetCount() + inputExtraFieldCounts.get(i);
}
if (changeCount == 0 && mapping.isIdentity()) {
return new TrimResult(join, Mappings.createIdentity(fieldCount));
}
// Build new join.
final RexVisitor<RexNode> shuttle =
new RexPermuteInputsShuttle(mapping, newInputs.get(0), newInputs.get(1));
RexNode newConditionExpr = conditionExpr.accept(shuttle);
final JoinRel newJoin =
join.copy(join.getTraitSet(), newConditionExpr, newInputs.get(0), newInputs.get(1));
return new TrimResult(newJoin, mapping);
}