Add Synchronize operator stub

Reviewers: florijan, msantl

Reviewed By: florijan

Subscribers: pullbot

Differential Revision: https://phabricator.memgraph.io/D1166

src/query/plan/operator.cpp

@@ -2649,6 +2649,19 @@ std::unique_ptr<Cursor> PullRemote::MakeCursor(
   return std::make_unique<PullRemote::PullRemoteCursor>(*this, db);
 }
 
+bool Synchronize::Accept(HierarchicalLogicalOperatorVisitor &visitor) {
+  if (visitor.PreVisit(*this)) {
+    input_->Accept(visitor) && pull_remote_->Accept(visitor);
+  }
+  return visitor.PostVisit(*this);
+}
+
+std::unique_ptr<Cursor> Synchronize::MakeCursor(
+    database::GraphDbAccessor &) const {
+  // TODO: Implement a concrete cursor.
+  return nullptr;
+}
+
 }  // namespace query::plan
 
 BOOST_CLASS_EXPORT_IMPLEMENT(query::plan::Once);
@@ -2685,3 +2698,4 @@ BOOST_CLASS_EXPORT_IMPLEMENT(query::plan::CreateIndex);
 BOOST_CLASS_EXPORT_IMPLEMENT(query::plan::Union);
 BOOST_CLASS_EXPORT_IMPLEMENT(query::plan::ProduceRemote);
 BOOST_CLASS_EXPORT_IMPLEMENT(query::plan::PullRemote);
+BOOST_CLASS_EXPORT_IMPLEMENT(query::plan::Synchronize);

src/query/plan/operator.hpp

@@ -99,6 +99,7 @@ class CreateIndex;
 class Union;
 class ProduceRemote;
 class PullRemote;
+class Synchronize;
 
 using LogicalOperatorCompositeVisitor = ::utils::CompositeVisitor<
     Once, CreateNode, CreateExpand, ScanAll, ScanAllByLabel,
@@ -108,7 +109,7 @@ using LogicalOperatorCompositeVisitor = ::utils::CompositeVisitor<
     ExpandUniquenessFilter<VertexAccessor>,
     ExpandUniquenessFilter<EdgeAccessor>, Accumulate, Aggregate, Skip, Limit,
     OrderBy, Merge, Optional, Unwind, Distinct, Union, ProduceRemote,
-    PullRemote>;
+    PullRemote, Synchronize>;
 
 using LogicalOperatorLeafVisitor = ::utils::LeafVisitor<Once, CreateIndex>;
 
@@ -2317,6 +2318,35 @@ class PullRemote : public LogicalOperator {
   }
 };
 
+/** Operator used to synchronize the execution of master and workers. */
+class Synchronize : public LogicalOperator {
+ public:
+  Synchronize(const std::shared_ptr<LogicalOperator> &input,
+              const std::shared_ptr<PullRemote> &pull_remote,
+              bool advance_command = false)
+      : input_(input),
+        pull_remote_(pull_remote),
+        advance_command_(advance_command) {}
+  bool Accept(HierarchicalLogicalOperatorVisitor &visitor) override;
+  std::unique_ptr<Cursor> MakeCursor(
+      database::GraphDbAccessor &db) const override;
+
+ private:
+  std::shared_ptr<LogicalOperator> input_;
+  std::shared_ptr<PullRemote> pull_remote_;
+  bool advance_command_ = false;
+
+  Synchronize() {}
+
+  friend class boost::serialization::access;
+  template <class TArchive>
+  void serialize(TArchive &ar, const unsigned int) {
+    ar &input_;
+    ar &pull_remote_;
+    ar &advance_command_;
+  }
+};
+
 }  // namespace plan
 }  // namespace query
 
@@ -2353,3 +2383,4 @@ BOOST_CLASS_EXPORT_KEY(query::plan::CreateIndex);
 BOOST_CLASS_EXPORT_KEY(query::plan::Union);
 BOOST_CLASS_EXPORT_KEY(query::plan::ProduceRemote);
 BOOST_CLASS_EXPORT_KEY(query::plan::PullRemote);
+BOOST_CLASS_EXPORT_KEY(query::plan::Synchronize);

tests/unit/distributed_graph_db.cpp

@@ -263,8 +263,8 @@ TEST_F(DistributedGraphDbTest, RemotePullProduceRpc) {
 
   Parameters params;
   std::vector<query::Symbol> symbols{ctx.symbol_table_[*x_ne]};
-  auto remote_pull = [this, plan_id, &params, &symbols](
+  auto remote_pull = [this, &params, &symbols](database::GraphDbAccessor &dba,
-      database::GraphDbAccessor &dba, int worker_id) {
+                                               int worker_id) {
     return master().remote_pull_clients().RemotePull(dba, worker_id, plan_id,
                                                      params, symbols, 3);
   };
@@ -358,9 +358,9 @@ TEST_F(DistributedGraphDbTest, RemotePullProduceRpcWithGraphElements) {
   ctx.symbol_table_[*return_p] = ctx.symbol_table_.CreateSymbol("", true);
   auto produce = MakeProduce(p, return_n_r, return_m, return_p);
 
-  auto check_result = [prop](
+  auto check_result = [prop](int worker_id,
-      int worker_id,
+                             const std::vector<std::vector<query::TypedValue>>
-      const std::vector<std::vector<query::TypedValue>> &frames) {
+                                 &frames) {
     int offset = worker_id * 10;
     ASSERT_EQ(frames.size(), 1);
     auto &row = frames[0];
@@ -387,8 +387,8 @@ TEST_F(DistributedGraphDbTest, RemotePullProduceRpcWithGraphElements) {
   Parameters params;
   std::vector<query::Symbol> symbols{ctx.symbol_table_[*return_n_r],
                                      ctx.symbol_table_[*return_m], p_sym};
-  auto remote_pull = [this, plan_id, &params, &symbols](
+  auto remote_pull = [this, &params, &symbols](database::GraphDbAccessor &dba,
-      database::GraphDbAccessor &dba, int worker_id) {
+                                               int worker_id) {
     return master().remote_pull_clients().RemotePull(dba, worker_id, plan_id,
                                                      params, symbols, 3);
   };