Push filter down cross join (#5473)

* fix comment

* push down filter through cross join

---------

Co-authored-by: Sophie <84560950+Sophie-Xie@users.noreply.github.com>

src/graph/executor/algo/CartesianProductExecutor.cpp

@@ -5,6 +5,7 @@
 #include "graph/executor/algo/CartesianProductExecutor.h"
 
 #include "graph/planner/plan/Algo.h"
+#include "graph/planner/plan/Query.h"
 
 namespace nebula {
 namespace graph {

src/graph/optimizer/CMakeLists.txt

@@ -10,6 +10,7 @@ nebula_add_library(
     OptGroup.cpp
     OptRule.cpp
     OptContext.cpp
+    rule/PushFilterDownCrossJoinRule.cpp
     rule/PushFilterDownGetNbrsRule.cpp
     rule/RemoveNoopProjectRule.cpp
     rule/CombineFilterRule.cpp

src/graph/optimizer/rule/PushFilterDownCrossJoinRule.cpp

@@ -0,0 +1,139 @@
+/* Copyright (c) 2023 vesoft inc. All rights reserved.
+ *
+ * This source code is licensed under Apache 2.0 License.
+ */
+
+#include "graph/optimizer/rule/PushFilterDownCrossJoinRule.h"
+
+#include "graph/optimizer/OptContext.h"
+#include "graph/optimizer/OptGroup.h"
+#include "graph/planner/plan/PlanNode.h"
+#include "graph/planner/plan/Query.h"
+#include "graph/util/ExpressionUtils.h"
+
+using nebula::graph::CrossJoin;
+using nebula::graph::ExpressionUtils;
+using nebula::graph::Filter;
+using nebula::graph::PlanNode;
+using nebula::graph::QueryContext;
+
+namespace nebula {
+namespace opt {
+
+std::unique_ptr<OptRule> PushFilterDownCrossJoinRule::kInstance =
+    std::unique_ptr<PushFilterDownCrossJoinRule>(new PushFilterDownCrossJoinRule());
+
+PushFilterDownCrossJoinRule::PushFilterDownCrossJoinRule() {
+  RuleSet::QueryRules().addRule(this);
+}
+
+const Pattern& PushFilterDownCrossJoinRule::pattern() const {
+  static Pattern pattern = Pattern::create(
+      PlanNode::Kind::kFilter,
+      {Pattern::create(
+          PlanNode::Kind::kCrossJoin,
+          {Pattern::create(PlanNode::Kind::kUnknown), Pattern::create(PlanNode::Kind::kUnknown)})});
+  return pattern;
+}
+
+StatusOr<OptRule::TransformResult> PushFilterDownCrossJoinRule::transform(
+    OptContext* octx, const MatchedResult& matched) const {
+  auto* filterGroupNode = matched.node;
+  auto* oldFilterNode = filterGroupNode->node();
+  DCHECK_EQ(oldFilterNode->kind(), PlanNode::Kind::kFilter);
+
+  auto* crossJoinNode = matched.planNode({0, 0});
+  DCHECK_EQ(crossJoinNode->kind(), PlanNode::Kind::kCrossJoin);
+  auto* oldCrossJoinNode = static_cast<const CrossJoin*>(crossJoinNode);
+
+  const auto* condition = static_cast<Filter*>(oldFilterNode)->condition();
+  DCHECK(condition);
+
+  const auto& leftResult = matched.result({0, 0, 0});
+  const auto& rightResult = matched.result({0, 0, 1});
+
+  Expression *leftFilterUnpicked = nullptr, *rightFilterUnpicked = nullptr;
+  OptGroup* leftGroup = pushFilterDownChild(octx, leftResult, condition, &leftFilterUnpicked);
+  OptGroup* rightGroup =
+      pushFilterDownChild(octx, rightResult, leftFilterUnpicked, &rightFilterUnpicked);
+
+  if (!leftGroup && !rightGroup) {
+    return TransformResult::noTransform();
+  }
+
+  leftGroup = leftGroup ? leftGroup : const_cast<OptGroup*>(leftResult.node->group());
+  rightGroup = rightGroup ? rightGroup : const_cast<OptGroup*>(rightResult.node->group());
+
+  // produce new CrossJoin node
+  auto* newCrossJoinNode = static_cast<CrossJoin*>(oldCrossJoinNode->clone());
+  auto newJoinGroup = rightFilterUnpicked ? OptGroup::create(octx) : filterGroupNode->group();
+  // TODO(yee): it's too tricky
+  auto newGroupNode = rightFilterUnpicked
+                          ? const_cast<OptGroup*>(newJoinGroup)->makeGroupNode(newCrossJoinNode)
+                          : OptGroupNode::create(octx, newCrossJoinNode, newJoinGroup);
+  newGroupNode->dependsOn(leftGroup);
+  newGroupNode->dependsOn(rightGroup);
+  newCrossJoinNode->setLeftVar(leftGroup->outputVar());
+  newCrossJoinNode->setRightVar(rightGroup->outputVar());
+
+  if (rightFilterUnpicked) {
+    auto newFilterNode = Filter::make(octx->qctx(), nullptr, rightFilterUnpicked);
+    newFilterNode->setOutputVar(oldFilterNode->outputVar());
+    newFilterNode->setColNames(oldFilterNode->colNames());
+    newFilterNode->setInputVar(newCrossJoinNode->outputVar());
+    newGroupNode = OptGroupNode::create(octx, newFilterNode, filterGroupNode->group());
+    newGroupNode->dependsOn(const_cast<OptGroup*>(newJoinGroup));
+  } else {
+    newCrossJoinNode->setOutputVar(oldFilterNode->outputVar());
+    newCrossJoinNode->setColNames(oldCrossJoinNode->colNames());
+  }
+
+  TransformResult result;
+  result.eraseAll = true;
+  result.newGroupNodes.emplace_back(newGroupNode);
+  return result;
+}
+
+OptGroup* PushFilterDownCrossJoinRule::pushFilterDownChild(OptContext* octx,
+                                                           const MatchedResult& child,
+                                                           const Expression* condition,
+                                                           Expression** unpickedFilter) {
+  if (!condition) return nullptr;
+
+  const auto* childPlanNode = DCHECK_NOTNULL(child.node->node());
+  const auto& colNames = childPlanNode->colNames();
+
+  // split the `condition` based on whether the varPropExpr comes from the left child
+  auto picker = [&colNames](const Expression* e) -> bool {
+    return ExpressionUtils::checkColName(colNames, e);
+  };
+
+  Expression* filterPicked = nullptr;
+  ExpressionUtils::splitFilter(condition, picker, &filterPicked, unpickedFilter);
+  if (!filterPicked) return nullptr;
+
+  auto* newChildPlanNode = childPlanNode->clone();
+  DCHECK_NE(childPlanNode->outputVar(), newChildPlanNode->outputVar());
+  newChildPlanNode->setInputVar(childPlanNode->inputVar());
+  newChildPlanNode->setColNames(childPlanNode->colNames());
+  auto* newChildGroup = OptGroup::create(octx);
+  auto* newChildGroupNode = newChildGroup->makeGroupNode(newChildPlanNode);
+  for (auto* g : child.node->dependencies()) {
+    newChildGroupNode->dependsOn(g);
+  }
+
+  auto* newFilterNode = Filter::make(octx->qctx(), nullptr, filterPicked);
+  newFilterNode->setOutputVar(childPlanNode->outputVar());
+  newFilterNode->setColNames(colNames);
+  newFilterNode->setInputVar(newChildPlanNode->outputVar());
+  auto* group = OptGroup::create(octx);
+  group->makeGroupNode(newFilterNode)->dependsOn(newChildGroup);
+  return group;
+}
+
+std::string PushFilterDownCrossJoinRule::toString() const {
+  return "PushFilterDownCrossJoinRule";
+}
+
+}  // namespace opt
+}  // namespace nebula

src/graph/optimizer/rule/PushFilterDownCrossJoinRule.h

@@ -0,0 +1,37 @@
+/* Copyright (c) 2023 vesoft inc. All rights reserved.
+ *
+ * This source code is licensed under Apache 2.0 License.
+ */
+
+#ifndef GRAPH_OPTIMIZER_RULE_PUSHFILTERDOWNCROSSJOINRULE_H_
+#define GRAPH_OPTIMIZER_RULE_PUSHFILTERDOWNCROSSJOINRULE_H_
+
+#include "graph/optimizer/OptRule.h"
+
+namespace nebula {
+namespace opt {
+
+//  Push down the filter items into the child sub-plan of [[CrossJoin]]
+class PushFilterDownCrossJoinRule final : public OptRule {
+ public:
+  const Pattern &pattern() const override;
+
+  StatusOr<OptRule::TransformResult> transform(OptContext *octx,
+                                               const MatchedResult &matched) const override;
+
+  std::string toString() const override;
+
+ private:
+  PushFilterDownCrossJoinRule();
+  static OptGroup *pushFilterDownChild(OptContext *octx,
+                                       const MatchedResult &child,
+                                       const Expression *condition,
+                                       Expression **unpickedFilter);
+
+  static std::unique_ptr<OptRule> kInstance;
+};
+
+}  // namespace opt
+}  // namespace nebula
+
+#endif  // GRAPH_OPTIMIZER_RULE_PUSHFILTERDOWNCROSSJOINRULE_H_

src/graph/planner/match/MatchSolver.cpp

@@ -207,8 +207,7 @@ Expression* MatchSolver::makeIndexFilter(const std::string& label,
 
   auto* root = relationals[0];
   for (auto i = 1u; i < relationals.size(); i++) {
-    auto* left = root;
-    root = LogicalExpression::makeAnd(qctx->objPool(), left, relationals[i]);
+    root = LogicalExpression::makeAnd(qctx->objPool(), root, relationals[i]);
   }
 
   return root;

src/graph/planner/match/StartVidFinder.h

@@ -28,7 +28,7 @@ using StartVidFinderInstantiateFunc = std::function<std::unique_ptr<StartVidFind
 // 3. PropIndexSeek finds if a plan could traverse from some vids that could be
 // read from the property indices.
 // MATCH(n:Tag{prop:value}) RETURN n
-// MATCH(n:Tag) WHERE n.prop = value RETURN n
+// MATCH(n:Tag) WHERE n.Tag.prop = value RETURN n
 //
 // 4. LabelIndexSeek finds if a plan could traverse from some vids that could be
 // read from the label indices.

src/graph/planner/plan/Algo.cpp

@@ -139,34 +139,6 @@ std::vector<std::string> CartesianProduct::inputVars() const {
   return varNames;
 }
 
-std::unique_ptr<PlanNodeDescription> CrossJoin::explain() const {
-  return BinaryInputNode::explain();
-}
-
-PlanNode* CrossJoin::clone() const {
-  auto* node = make(qctx_);
-  node->cloneMembers(*this);
-  return node;
-}
-
-void CrossJoin::cloneMembers(const CrossJoin& r) {
-  BinaryInputNode::cloneMembers(r);
-}
-
-CrossJoin::CrossJoin(QueryContext* qctx, PlanNode* left, PlanNode* right)
-    : BinaryInputNode(qctx, Kind::kCrossJoin, left, right) {
-  auto lColNames = left->colNames();
-  auto rColNames = right->colNames();
-  lColNames.insert(lColNames.end(), rColNames.begin(), rColNames.end());
-  setColNames(lColNames);
-}
-
-void CrossJoin::accept(PlanNodeVisitor* visitor) {
-  visitor->visit(this);
-}
-
-CrossJoin::CrossJoin(QueryContext* qctx) : BinaryInputNode(qctx, Kind::kCrossJoin) {}
-
 std::unique_ptr<PlanNodeDescription> Subgraph::explain() const {
   auto desc = SingleInputNode::explain();
   addDescription("src", src_ ? src_->toString() : "", desc.get());

src/graph/planner/plan/Algo.h

@@ -437,32 +437,6 @@ class Subgraph final : public SingleInputNode {
   std::unique_ptr<std::vector<EdgeProp>> edgeProps_;
 };
 
-class CrossJoin final : public BinaryInputNode {
- public:
-  static CrossJoin* make(QueryContext* qctx, PlanNode* left, PlanNode* right) {
-    return qctx->objPool()->makeAndAdd<CrossJoin>(qctx, left, right);
-  }
-
-  std::unique_ptr<PlanNodeDescription> explain() const override;
-
-  PlanNode* clone() const override;
-
-  void accept(PlanNodeVisitor* visitor) override;
-
- private:
-  friend ObjectPool;
-
-  // used for clone only
-  static CrossJoin* make(QueryContext* qctx) {
-    return qctx->objPool()->makeAndAdd<CrossJoin>(qctx);
-  }
-
-  void cloneMembers(const CrossJoin& r);
-
-  CrossJoin(QueryContext* qctx, PlanNode* left, PlanNode* right);
-  // use for clone
-  explicit CrossJoin(QueryContext* qctx);
-};
 }  // namespace graph
 }  // namespace nebula
 #endif  // GRAPH_PLANNER_PLAN_ALGO_H_

src/graph/planner/plan/Query.cpp

@@ -959,6 +959,34 @@ void HashInnerJoin::cloneMembers(const HashInnerJoin& l) {
   HashJoin::cloneMembers(l);
 }
 
+std::unique_ptr<PlanNodeDescription> CrossJoin::explain() const {
+  return BinaryInputNode::explain();
+}
+
+PlanNode* CrossJoin::clone() const {
+  auto* node = make(qctx_);
+  node->cloneMembers(*this);
+  return node;
+}
+
+void CrossJoin::cloneMembers(const CrossJoin& r) {
+  BinaryInputNode::cloneMembers(r);
+}
+
+CrossJoin::CrossJoin(QueryContext* qctx, PlanNode* left, PlanNode* right)
+    : BinaryInputNode(qctx, Kind::kCrossJoin, left, right) {
+  auto lColNames = left->colNames();
+  auto rColNames = right->colNames();
+  lColNames.insert(lColNames.end(), rColNames.begin(), rColNames.end());
+  setColNames(lColNames);
+}
+
+void CrossJoin::accept(PlanNodeVisitor* visitor) {
+  visitor->visit(this);
+}
+
+CrossJoin::CrossJoin(QueryContext* qctx) : BinaryInputNode(qctx, Kind::kCrossJoin) {}
+
 std::unique_ptr<PlanNodeDescription> RollUpApply::explain() const {
   auto desc = BinaryInputNode::explain();
   addDescription("compareCols", folly::toJson(util::toJson(compareCols_)), desc.get());

src/graph/planner/plan/Query.h

@@ -1899,6 +1899,33 @@ class HashInnerJoin final : public HashJoin {
   void cloneMembers(const HashInnerJoin&);
 };
 
+class CrossJoin final : public BinaryInputNode {
+ public:
+  static CrossJoin* make(QueryContext* qctx, PlanNode* left, PlanNode* right) {
+    return qctx->objPool()->makeAndAdd<CrossJoin>(qctx, left, right);
+  }
+
+  std::unique_ptr<PlanNodeDescription> explain() const override;
+
+  PlanNode* clone() const override;
+
+  void accept(PlanNodeVisitor* visitor) override;
+
+ private:
+  friend ObjectPool;
+
+  // used for clone only
+  static CrossJoin* make(QueryContext* qctx) {
+    return qctx->objPool()->makeAndAdd<CrossJoin>(qctx);
+  }
+
+  void cloneMembers(const CrossJoin& r);
+
+  CrossJoin(QueryContext* qctx, PlanNode* left, PlanNode* right);
+  // use for clone
+  explicit CrossJoin(QueryContext* qctx);
+};
+
 // Roll Up Apply two results from two inputs.
 class RollUpApply : public BinaryInputNode {
  public:

tests/tck/features/optimizer/PushFilterDownCrossJoinRule.feature

@@ -0,0 +1,32 @@
+# Copyright (c) 2023 vesoft inc. All rights reserved.
+#
+# This source code is licensed under Apache 2.0 License.
+Feature: Push Filter down HashInnerJoin rule
+
+  Background:
+    Given a graph with space named "nba"
+
+  Scenario: push filter down HashInnerJoin
+    When profiling query:
+      """
+      with ['Tim Duncan', 'Tony Parker'] as id_list
+      match (v1:player)-[e]-(v2:player)
+      where id(v1) in ['Tim Duncan', 'Tony Parker'] AND id(v2) in ['Tim Duncan', 'Tony Parker']
+      return count(e)
+      """
+    Then the result should be, in any order:
+      | count(e) |
+      | 8        |
+    And the execution plan should be:
+      | id | name           | dependencies | operator info                                                                                                          |
+      | 11 | Aggregate      | 14           |                                                                                                                        |
+      | 14 | CrossJoin      | 1,16         |                                                                                                                        |
+      | 1  | Project        | 2            |                                                                                                                        |
+      | 2  | Start          |              |                                                                                                                        |
+      | 16 | Project        | 15           |                                                                                                                        |
+      | 15 | Filter         | 18           | {"condition": "((id($-.v1) IN [\"Tim Duncan\",\"Tony Parker\"]) AND (id($-.v2) IN [\"Tim Duncan\",\"Tony Parker\"]))"} |
+      | 18 | AppendVertices | 17           |                                                                                                                        |
+      | 17 | Traverse       | 4            |                                                                                                                        |
+      | 4  | Dedup          | 3            |                                                                                                                        |
+      | 3  | PassThrough    | 5            |                                                                                                                        |
+      | 5  | Start          |              |                                                                                                                        |