add filter push down

src/include/binder/expression/expression.h

@@ -76,7 +76,12 @@ class Expression : public std::enable_shared_from_this<Expression> {
 
     inline uint32_t getNumChildren() const { return children.size(); }
 
-    inline std::shared_ptr<Expression> getChild(uint32_t idx) const { return children[idx]; }
+    inline std::shared_ptr<Expression> getChild(common::vector_idx_t idx) const {
+        return children[idx];
+    }
+    inline void setChild(common::vector_idx_t idx, std::shared_ptr<Expression> child) {
+        children[idx] = child;
+    }
 
     inline virtual expression_vector getChildren() const { return children; }
 

src/include/common/constants.h

@@ -129,7 +129,8 @@ struct LoggerConstants {
 };
 
 struct EnumeratorKnobs {
-    static constexpr double PREDICATE_SELECTIVITY = 0.1;
+    static constexpr double NON_EQUALITY_PREDICATE_SELECTIVITY = 0.1;
+    static constexpr double EQUALITY_PREDICATE_SELECTIVITY = 0.01;
     static constexpr double FLAT_PROBE_PENALTY = 10;
 };
 

src/include/common/types/types.h

@@ -25,6 +25,7 @@ using list_header_t = uint32_t;
 using property_id_t = uint32_t;
 constexpr property_id_t INVALID_PROPERTY_ID = UINT32_MAX;
 using vector_idx_t = uint32_t;
+constexpr vector_idx_t INVALID_VECTOR_IDX = UINT32_MAX;
 
 // System representation for a variable-sized overflow value.
 struct overflow_value_t {

src/include/main/kuzu_fwd.h

@@ -6,7 +6,6 @@ namespace testing {
 class ApiTest;
 class BaseGraphTest;
 class TestHelper;
-class TestHelper;
 class TinySnbDDLTest;
 class TinySnbCopyCSVTransactionTest;
 } // namespace testing

src/include/optimizer/filter_push_down_optimizer.h

@@ -0,0 +1,77 @@
+#pragma once
+
+#include "binder/expression/node_expression.h"
+#include "logical_operator_visitor.h"
+#include "planner/logical_plan/logical_plan.h"
+
+namespace kuzu {
+namespace optimizer {
+
+class FilterPushDownOptimizer {
+public:
+    FilterPushDownOptimizer() { predicateSet = std::make_unique<PredicateSet>(); }
+
+    void rewrite(planner::LogicalPlan* plan);
+
+private:
+    std::shared_ptr<planner::LogicalOperator> visitOperator(
+        std::shared_ptr<planner::LogicalOperator> op);
+    // Collect predicates in FILTER
+    std::shared_ptr<planner::LogicalOperator> visitFilterReplace(
+        std::shared_ptr<planner::LogicalOperator> op);
+    // Push primary key lookup into CROSS_PRODUCT
+    // E.g.
+    //      Filter(a.ID=b.ID)
+    //      CrossProduct                   to           IndexNestedLoopJoin(b)
+    //   S(a)           S(b)                            S(a)
+    // This is a temporary solution in the absence of a generic hash join operator.
+    std::shared_ptr<planner::LogicalOperator> visitCrossProductReplace(
+        std::shared_ptr<planner::LogicalOperator> op);
+
+    // Push FILTER before SCAN_NODE_PROPERTY.
+    // Push index lookup into SCAN_NODE_ID.
+    std::shared_ptr<planner::LogicalOperator> visitScanNodePropertyReplace(
+        std::shared_ptr<planner::LogicalOperator> op);
+
+    // Rewrite SCAN_NODE_ID->SCAN_NODE_PROPERTY->FILTER as
+    // SCAN_NODE_ID->(SCAN_NODE_PROPERTY->FILTER)*->SCAN_NODE_PROPERTY
+    // so that filter with higher selectivity is applied before scanning.
+    std::shared_ptr<planner::LogicalOperator> pushDownToScanNode(
+        std::shared_ptr<binder::NodeExpression> node, std::shared_ptr<binder::Expression> predicate,
+        std::shared_ptr<planner::LogicalOperator> child);
+
+    // Finish the current push down optimization by apply remaining predicates as a single filter.
+    // And heuristically reorder equality predicates first in the filter.
+    std::shared_ptr<planner::LogicalOperator> finishPushDown(
+        std::shared_ptr<planner::LogicalOperator> op);
+
+    std::shared_ptr<planner::LogicalOperator> appendScanNodeProperty(
+        std::shared_ptr<binder::NodeExpression> node, binder::expression_vector properties,
+        std::shared_ptr<planner::LogicalOperator> child);
+    std::shared_ptr<planner::LogicalOperator> appendFilter(
+        std::shared_ptr<binder::Expression> predicate,
+        std::shared_ptr<planner::LogicalOperator> child);
+
+    struct PredicateSet {
+        binder::expression_vector equalityPredicates;
+        binder::expression_vector nonEqualityPredicates;
+
+        inline bool isEmpty() const {
+            return equalityPredicates.empty() && nonEqualityPredicates.empty();
+        }
+        inline void clear() {
+            equalityPredicates.clear();
+            nonEqualityPredicates.clear();
+        }
+
+        void addPredicate(std::shared_ptr<binder::Expression> predicate);
+        std::shared_ptr<binder::Expression> popNodePKEqualityComparison(
+            const binder::NodeExpression& node);
+    };
+
+private:
+    std::unique_ptr<PredicateSet> predicateSet;
+};
+
+} // namespace optimizer
+} // namespace kuzu

src/include/planner/join_order_enumerator.h

@@ -73,12 +73,6 @@ class JoinOrderEnumerator {
     void planTableScan();
 
     void planNodeScan(uint32_t nodePos);
-    // Filter push down for node table.
-    void planFiltersForNode(binder::expression_vector& predicates,
-        std::shared_ptr<NodeExpression> node, LogicalPlan& plan);
-    // Property push down for node table.
-    void planPropertyScansForNode(std::shared_ptr<NodeExpression> node, LogicalPlan& plan);
-
     void planRelScan(uint32_t relPos);
 
     void planExtendAndFilters(std::shared_ptr<RelExpression> rel, common::RelDirection direction,
@@ -105,8 +99,6 @@ class JoinOrderEnumerator {
     void planFiltersForHashJoin(binder::expression_vector& predicates, LogicalPlan& plan);
 
     void appendScanNode(std::shared_ptr<NodeExpression>& node, LogicalPlan& plan);
-    void appendIndexScanNode(std::shared_ptr<NodeExpression>& node,
-        std::shared_ptr<Expression> indexExpression, LogicalPlan& plan);
 
     bool needExtendToNewGroup(
         RelExpression& rel, NodeExpression& boundNode, common::RelDirection direction);
@@ -126,8 +118,6 @@ class JoinOrderEnumerator {
         std::vector<std::unique_ptr<LogicalPlan>>& buildPlans);
     static void appendCrossProduct(LogicalPlan& probePlan, LogicalPlan& buildPlan);
 
-    binder::expression_vector getPropertiesForVariable(
-        Expression& expression, Expression& variable);
     uint64_t getExtensionRate(
         const RelExpression& rel, const NodeExpression& boundNode, common::RelDirection direction);
 

src/include/planner/query_planner.h

@@ -63,7 +63,8 @@ class QueryPlanner {
     static void appendFlattens(const f_group_pos_set& groupsPos, LogicalPlan& plan);
     static void appendFlattenIfNecessary(f_group_pos groupPos, LogicalPlan& plan);
 
-    void appendFilter(const std::shared_ptr<Expression>& expression, LogicalPlan& plan);
+    void appendFilters(const binder::expression_vector& predicates, LogicalPlan& plan);
+    void appendFilter(const std::shared_ptr<Expression>& predicate, LogicalPlan& plan);
 
     void appendScanNodePropIfNecessary(const expression_vector& propertyExpressions,
         std::shared_ptr<NodeExpression> node, LogicalPlan& plan);

src/optimizer/CMakeLists.txt

@@ -2,7 +2,7 @@ add_library(kuzu_optimizer
         OBJECT
         asp_optimizer.cpp
         factorization_rewriter.cpp
-        index_nested_loop_join_optimizer.cpp
+        filter_push_down_optimizer.cpp
         logical_operator_collector.cpp
         logical_operator_visitor.cpp
         optimizer.cpp