enhancement/pattern-expression

fix pattern apply executor

add pattern predicate executor

add pattern predicate flag

fix edge cases

fix unused rollup apply

remove unnecessary project before PatternApply

small rename

fix anti-predicate

fix anti-predicate

fix where planner

fix not flattened expression

src/graph/context/ast/CypherAstContext.h

@@ -83,6 +83,10 @@ struct Path final {
   // "(v)-[:like]->()" in (v)-[:like]->()
   std::string collectVariable;
 
+  // Flag for pattern predicate
+  bool isPred{false};
+  bool isAntiPred{false};
+
   enum PathType : int8_t { kDefault, kAllShortest, kSingleShortest };
   PathType pathType{PathType::kDefault};
 };

src/graph/executor/CMakeLists.txt

@@ -40,6 +40,7 @@ nebula_add_library(
     query/TraverseExecutor.cpp
     query/AppendVerticesExecutor.cpp
     query/RollUpApplyExecutor.cpp
+    query/PatternApplyExecutor.cpp
     query/GetDstBySrcExecutor.cpp
     algo/BFSShortestPathExecutor.cpp
     algo/MultiShortestPathExecutor.cpp

src/graph/executor/Executor.cpp

@@ -80,6 +80,7 @@
 #include "graph/executor/query/LeftJoinExecutor.h"
 #include "graph/executor/query/LimitExecutor.h"
 #include "graph/executor/query/MinusExecutor.h"
+#include "graph/executor/query/PatternApplyExecutor.h"
 #include "graph/executor/query/ProjectExecutor.h"
 #include "graph/executor/query/RollUpApplyExecutor.h"
 #include "graph/executor/query/SampleExecutor.h"
@@ -542,6 +543,9 @@ Executor *Executor::makeExecutor(QueryContext *qctx, const PlanNode *node) {
     case PlanNode::Kind::kRollUpApply: {
       return pool->makeAndAdd<RollUpApplyExecutor>(node, qctx);
     }
+    case PlanNode::Kind::kPatternApply: {
+      return pool->makeAndAdd<PatternApplyExecutor>(node, qctx);
+    }
     case PlanNode::Kind::kArgument: {
       return pool->makeAndAdd<ArgumentExecutor>(node, qctx);
     }

src/graph/executor/query/PatternApplyExecutor.cpp

@@ -0,0 +1,155 @@
+/* Copyright (c) 2022 vesoft inc. All rights reserved.
+ *
+ * This source code is licensed under Apache 2.0 License.
+ */
+
+#include "graph/executor/query/PatternApplyExecutor.h"
+
+#include "graph/context/Iterator.h"
+#include "graph/context/QueryExpressionContext.h"
+#include "graph/planner/plan/Query.h"
+
+namespace nebula {
+namespace graph {
+
+folly::Future<Status> PatternApplyExecutor::execute() {
+  SCOPED_TIMER(&execTime_);
+  return patternApply();
+}
+
+Status PatternApplyExecutor::checkBiInputDataSets() {
+  auto* patternApply = asNode<PatternApply>(node());
+  lhsIter_ = ectx_->getResult(patternApply->leftInputVar()).iter();
+  DCHECK(!!lhsIter_);
+  if (lhsIter_->isGetNeighborsIter() || lhsIter_->isDefaultIter()) {
+    std::stringstream ss;
+    ss << "PatternApply executor does not support " << lhsIter_->kind();
+    return Status::Error(ss.str());
+  }
+  rhsIter_ = ectx_->getResult(patternApply->rightInputVar()).iter();
+  DCHECK(!!rhsIter_);
+  if (rhsIter_->isGetNeighborsIter() || rhsIter_->isDefaultIter()) {
+    std::stringstream ss;
+    ss << "PatternApply executor does not support " << rhsIter_->kind();
+    return Status::Error(ss.str());
+  }
+  isAntiPred_ = patternApply->isAntiPredicate();
+
+  return Status::OK();
+}
+
+void PatternApplyExecutor::collectValidKeys(const std::vector<Expression*>& keyCols,
+                                            Iterator* iter,
+                                            std::unordered_set<List>& validKeys) const {
+  QueryExpressionContext ctx(ectx_);
+  for (; iter->valid(); iter->next()) {
+    List list;
+    list.values.reserve(keyCols.size());
+    for (auto& col : keyCols) {
+      Value val = col->eval(ctx(iter));
+      list.values.emplace_back(std::move(val));
+    }
+    validKeys.emplace(std::move(list));
+  }
+}
+
+void PatternApplyExecutor::collectValidKey(Expression* keyCol,
+                                           Iterator* iter,
+                                           std::unordered_set<Value>& validKey) const {
+  QueryExpressionContext ctx(ectx_);
+  for (; iter->valid(); iter->next()) {
+    auto& val = keyCol->eval(ctx(iter));
+    validKey.emplace(val);
+  }
+}
+
+DataSet PatternApplyExecutor::applyZeroKey(Iterator* appliedIter, const bool allValid) {
+  DataSet ds;
+  ds.rows.reserve(appliedIter->size());
+  QueryExpressionContext ctx(ectx_);
+  for (; appliedIter->valid(); appliedIter->next()) {
+    Row row = mv_ ? appliedIter->moveRow() : *appliedIter->row();
+    if (allValid) {
+      ds.rows.emplace_back(std::move(row));
+    }
+  }
+  return ds;
+}
+
+DataSet PatternApplyExecutor::applySingleKey(Expression* appliedKey,
+                                             Iterator* appliedIter,
+                                             const std::unordered_set<Value>& validKey) {
+  DataSet ds;
+  ds.rows.reserve(appliedIter->size());
+  QueryExpressionContext ctx(ectx_);
+  for (; appliedIter->valid(); appliedIter->next()) {
+    auto& val = appliedKey->eval(ctx(appliedIter));
+    bool applyFlag = (validKey.find(val) != validKey.end()) ^ isAntiPred_;
+    if (applyFlag) {
+      Row row = mv_ ? appliedIter->moveRow() : *appliedIter->row();
+      ds.rows.emplace_back(std::move(row));
+    }
+  }
+  return ds;
+}
+
+DataSet PatternApplyExecutor::applyMultiKey(std::vector<Expression*> appliedKeys,
+                                            Iterator* appliedIter,
+                                            const std::unordered_set<List>& validKeys) {
+  DataSet ds;
+  ds.rows.reserve(appliedIter->size());
+  QueryExpressionContext ctx(ectx_);
+  for (; appliedIter->valid(); appliedIter->next()) {
+    List list;
+    list.values.reserve(appliedKeys.size());
+    for (auto& col : appliedKeys) {
+      Value val = col->eval(ctx(appliedIter));
+      list.values.emplace_back(std::move(val));
+    }
+
+    bool applyFlag = (validKeys.find(list) != validKeys.end()) ^ isAntiPred_;
+    if (applyFlag) {
+      Row row = mv_ ? appliedIter->moveRow() : *appliedIter->row();
+      ds.rows.emplace_back(std::move(row));
+    }
+  }
+  return ds;
+}
+
+folly::Future<Status> PatternApplyExecutor::patternApply() {
+  auto* patternApplyNode = asNode<PatternApply>(node());
+  NG_RETURN_IF_ERROR(checkBiInputDataSets());
+
+  DataSet result;
+  mv_ = movable(node()->inputVars()[0]);
+  auto keyCols = patternApplyNode->keyCols();
+  if (keyCols.size() == 0) {
+    // Reverse the valid flag if the pattern predicate is an anti-predicate
+    applyZeroKey(lhsIter_.get(), (rhsIter_->size() > 0) ^ isAntiPred_);
+  } else if (keyCols.size() == 1) {
+    std::unordered_set<Value> validKey;
+    collectValidKey(keyCols[0]->clone(), rhsIter_.get(), validKey);
+    result = applySingleKey(keyCols[0]->clone(), lhsIter_.get(), validKey);
+  } else {
+    // Copy the keyCols to refresh the inside propIndex_ cache
+    auto cloneExpr = [](std::vector<Expression*> exprs) {
+      std::vector<Expression*> applyColsCopy;
+      applyColsCopy.reserve(exprs.size());
+      for (auto& expr : exprs) {
+        applyColsCopy.emplace_back(expr->clone());
+      }
+      return applyColsCopy;
+    };
+
+    std::unordered_set<List> validKeys;
+    collectValidKeys(cloneExpr(keyCols), rhsIter_.get(), validKeys);
+    result = applyMultiKey(cloneExpr(keyCols), lhsIter_.get(), validKeys);
+  }
+
+  // FIXME(czp): remove pattern expression columns
+  result.colNames = patternApplyNode->colNames();
+  return finish(ResultBuilder().value(Value(std::move(result))).build());
+}
+
+}  // namespace graph
+}  // namespace nebula

src/graph/executor/query/PatternApplyExecutor.h

@@ -0,0 +1,52 @@
+/* Copyright (c) 2022 vesoft inc. All rights reserved.
+ *
+ * This source code is licensed under Apache 2.0 License.
+ */
+
+#pragma once
+
+#include "graph/executor/Executor.h"
+
+namespace nebula {
+namespace graph {
+
+class PatternApplyExecutor : public Executor {
+ public:
+  PatternApplyExecutor(const PlanNode* node, QueryContext* qctx)
+      : Executor("PatternApplyExecutor", node, qctx) {}
+
+  folly::Future<Status> execute() override;
+
+ protected:
+  Status checkBiInputDataSets();
+
+  void collectValidKeys(const std::vector<Expression*>& keyCols,
+                        Iterator* iter,
+                        std::unordered_set<List>& validKeys) const;
+
+  void collectValidKey(Expression* keyCol,
+                       Iterator* iter,
+                       std::unordered_set<Value>& validKey) const;
+
+  DataSet applyZeroKey(Iterator* appliedIter, const bool allValid);
+
+  DataSet applySingleKey(Expression* appliedCol,
+                         Iterator* appliedIter,
+                         const std::unordered_set<Value>& validKey);
+
+  DataSet applyMultiKey(std::vector<Expression*> appliedKeys,
+                        Iterator* appliedIter,
+                        const std::unordered_set<List>& validKeys);
+
+  folly::Future<Status> patternApply();
+  std::unique_ptr<Iterator> lhsIter_;
+  std::unique_ptr<Iterator> rhsIter_;
+
+  // Should apply the reverse when the pattern is an anti-predicate
+  bool isAntiPred_{false};
+  // Check if the apply side dataset movable
+  bool mv_{false};
+};
+
+}  // namespace graph
+}  // namespace nebula

src/graph/optimizer/rule/RemoveNoopProjectRule.cpp

@@ -61,6 +61,7 @@ namespace opt {
     PlanNode::Kind::kBiInnerJoin,
     PlanNode::Kind::kBiCartesianProduct,
     PlanNode::Kind::kRollUpApply,
+    PlanNode::Kind::kPatternApply,
     PlanNode::Kind::kArgument};
 
 std::unique_ptr<OptRule> RemoveNoopProjectRule::kInstance =

src/graph/planner/match/MatchPathPlanner.cpp

@@ -97,7 +97,11 @@ StatusOr<SubPlan> MatchPathPlanner::transform(
                             subplan,
                             nodeAliasesSeenInPattern));
 
-  MatchSolver::buildProjectColumns(qctx, path, subplan);
+  // No need to actually build path if the path is just a predicate
+  if (!path.isPred) {
+    MatchSolver::buildProjectColumns(qctx, path, subplan);
+  }
+
   return subplan;
 }
 

src/graph/planner/match/SegmentsConnector.cpp

@@ -90,12 +90,34 @@ SubPlan SegmentsConnector::cartesianProduct(QueryContext* qctx,
   return newPlan;
 }
 
+/*static*/ SubPlan SegmentsConnector::patternApply(QueryContext* qctx,
+                                                   const SubPlan& left,
+                                                   const std::vector<std::string>& inputColNames,
+                                                   const SubPlan& right,
+                                                   const std::vector<std::string>& keyCols,
+                                                   bool isAntiPred) {
+  SubPlan newPlan = left;
+  std::vector<Expression*> keyProps;
+  for (const auto& col : keyCols) {
+    keyProps.emplace_back(FunctionCallExpression::make(
+        qctx->objPool(), "id", {InputPropertyExpression::make(qctx->objPool(), col)}));
+  }
+  auto* patternApply = PatternApply::make(
+      qctx, left.root, DCHECK_NOTNULL(right.root), std::move(keyProps), isAntiPred);
+  // Left side input may be nullptr, which will be filled later
+  std::vector<std::string> colNames = left.root != nullptr ? left.root->colNames() : inputColNames;
+  patternApply->setColNames(std::move(colNames));
+  newPlan.root = patternApply;
+  newPlan.tail = (newPlan.tail == nullptr ? patternApply : newPlan.tail);
+  return newPlan;
+}
+
 SubPlan SegmentsConnector::addInput(const SubPlan& left, const SubPlan& right, bool copyColNames) {
   if (left.root == nullptr) {
     return right;
   }
   SubPlan newPlan = left;
-  DCHECK(left.root->isSingleInput());
+  // DCHECK(left.root->isSingleInput());
   if (left.tail->isSingleInput()) {
     auto* mutableLeft = const_cast<PlanNode*>(left.tail);
     auto* siLeft = static_cast<SingleInputNode*>(mutableLeft);

src/graph/planner/match/SegmentsConnector.h

@@ -46,6 +46,13 @@ class SegmentsConnector final {
                              const std::vector<std::string>& compareCols,
                              const std::string& collectCol);
 
+  static SubPlan patternApply(QueryContext* qctx,
+                              const SubPlan& left,
+                              const std::vector<std::string>& inputColNames,
+                              const SubPlan& right,
+                              const std::vector<std::string>& keyCols,
+                              bool isAntiPred = false);
+
   /*
    * left->right
    */

src/graph/planner/match/WhereClausePlanner.cpp

@@ -19,34 +19,47 @@ StatusOr<SubPlan> WhereClausePlanner::transform(CypherClauseContextBase* ctx) {
   }
 
   auto* wctx = static_cast<WhereClauseContext*>(ctx);
-  SubPlan wherePlan;
-  if (wctx->filter) {
-    auto* newFilter = MatchSolver::doRewrite(wctx->qctx, wctx->aliasesAvailable, wctx->filter);
-    wherePlan.root = Filter::make(wctx->qctx, nullptr, newFilter, needStableFilter_);
-    wherePlan.tail = wherePlan.root;
-
-    SubPlan subPlan;
-    // Build plan for pattern from expression
+  SubPlan plan;
+  if (!wctx->paths.empty()) {
+    SubPlan pathsPlan;
+    // Build plan for pattern expression
     for (auto& path : wctx->paths) {
       auto pathPlan = std::make_unique<MatchPathPlanner>()->transform(
           wctx->qctx, wctx->space.id, nullptr, wctx->aliasesAvailable, {}, path);
       NG_RETURN_IF_ERROR(pathPlan);
       auto pathplan = std::move(pathPlan).value();
-      subPlan = SegmentsConnector::rollUpApply(wctx->qctx,
-                                               subPlan,
-                                               wctx->inputColNames,
-                                               pathplan,
-                                               path.compareVariables,
-                                               path.collectVariable);
-    }
-    if (subPlan.root != nullptr) {
-      wherePlan = SegmentsConnector::addInput(wherePlan, subPlan, true);
+      if (path.isPred) {
+        // Build plan for pattern predicates
+        pathsPlan = SegmentsConnector::patternApply(wctx->qctx,
+                                                    pathsPlan,
+                                                    wctx->inputColNames,
+                                                    pathplan,
+                                                    path.compareVariables,
+                                                    path.isAntiPred);
+      } else {
+        pathsPlan = SegmentsConnector::rollUpApply(wctx->qctx,
+                                                   pathsPlan,
+                                                   wctx->inputColNames,
+                                                   pathplan,
+                                                   path.compareVariables,
+                                                   path.collectVariable);
+      }
     }
+    plan = pathsPlan;
+  }
 
-    return wherePlan;
+  if (wctx->filter) {
+    SubPlan wherePlan;
+    auto* newFilter = MatchSolver::doRewrite(wctx->qctx, wctx->aliasesAvailable, wctx->filter);
+    wherePlan.root = Filter::make(wctx->qctx, nullptr, newFilter, needStableFilter_);
+    wherePlan.tail = wherePlan.root;
+    if (plan.root == nullptr) {
+      return wherePlan;
+    }
+    plan = SegmentsConnector::addInput(wherePlan, plan, true);
   }
 
-  return wherePlan;
+  return plan;
 }
 }  // namespace graph
 }  // namespace nebula

src/graph/planner/plan/PlanNode.cpp

@@ -300,6 +300,8 @@ const char* PlanNode::toString(PlanNode::Kind kind) {
       return "Argument";
     case Kind::kRollUpApply:
       return "RollUpApply";
+    case Kind::kPatternApply:
+      return "PatternApply";
     case Kind::kGetDstBySrc:
       return "GetDstBySrc";
       // no default so the compiler will warning when lack