Replace unordered_map with map in storage v2

Summary:
`std::unordered_map` is 56 bytes in size, `std::map` is 48 bytes in size.
Also, `std::map` doesn't require the key type to be hashable.

Reviewers: mtomic, teon.banek

Reviewed By: teon.banek

Subscribers: pullbot

Differential Revision: https://phabricator.memgraph.io/D2218

src/storage/v2/edge.hpp

@@ -1,7 +1,7 @@
 #pragma once
 
 #include <limits>
-#include <unordered_map>
+#include <map>
 
 #include "utils/spin_lock.hpp"
 
@@ -20,7 +20,7 @@ struct Edge {
 
   Gid gid;
 
-  std::unordered_map<uint64_t, storage::PropertyValue> properties;
+  std::map<uint64_t, storage::PropertyValue> properties;
 
   utils::SpinLock lock;
   bool deleted;

src/storage/v2/edge_accessor.cpp

@@ -90,9 +90,8 @@ Result<PropertyValue> EdgeAccessor::GetProperty(uint64_t property, View view) {
   return Result<PropertyValue>{std::move(value)};
 }
 
-Result<std::unordered_map<uint64_t, PropertyValue>> EdgeAccessor::Properties(
-    View view) {
-  std::unordered_map<uint64_t, PropertyValue> properties;
+Result<std::map<uint64_t, PropertyValue>> EdgeAccessor::Properties(View view) {
+  std::map<uint64_t, PropertyValue> properties;
   bool deleted = false;
   Delta *delta = nullptr;
   {
@@ -137,11 +136,9 @@ Result<std::unordered_map<uint64_t, PropertyValue>> EdgeAccessor::Properties(
         }
       });
   if (deleted) {
-    return Result<std::unordered_map<uint64_t, PropertyValue>>{
-        Error::DELETED_OBJECT};
+    return Result<std::map<uint64_t, PropertyValue>>{Error::DELETED_OBJECT};
   }
-  return Result<std::unordered_map<uint64_t, PropertyValue>>{
-      std::move(properties)};
+  return Result<std::map<uint64_t, PropertyValue>>{std::move(properties)};
 }
 
 }  // namespace storage

src/storage/v2/edge_accessor.hpp

@@ -37,7 +37,7 @@ class EdgeAccessor final {
 
   Result<PropertyValue> GetProperty(uint64_t property, View view);
 
-  Result<std::unordered_map<uint64_t, PropertyValue>> Properties(View view);
+  Result<std::map<uint64_t, PropertyValue>> Properties(View view);
 
   Gid Gid() const { return edge_->gid; }
 

src/storage/v2/vertex.hpp

@@ -1,8 +1,8 @@
 #pragma once
 
 #include <limits>
+#include <map>
 #include <tuple>
-#include <unordered_map>
 #include <vector>
 
 #include "utils/spin_lock.hpp"
@@ -22,7 +22,7 @@ struct Vertex {
   Gid gid;
 
   std::vector<uint64_t> labels;
-  std::unordered_map<uint64_t, storage::PropertyValue> properties;
+  std::map<uint64_t, storage::PropertyValue> properties;
 
   std::vector<std::tuple<uint64_t, Vertex *, Edge *>> in_edges;
   std::vector<std::tuple<uint64_t, Vertex *, Edge *>> out_edges;

src/storage/v2/vertex_accessor.cpp

@@ -250,9 +250,9 @@ Result<PropertyValue> VertexAccessor::GetProperty(uint64_t property,
   return Result<PropertyValue>{std::move(value)};
 }
 
-Result<std::unordered_map<uint64_t, PropertyValue>> VertexAccessor::Properties(
+Result<std::map<uint64_t, PropertyValue>> VertexAccessor::Properties(
     View view) {
-  std::unordered_map<uint64_t, PropertyValue> properties;
+  std::map<uint64_t, PropertyValue> properties;
   bool deleted = false;
   Delta *delta = nullptr;
   {
@@ -297,11 +297,9 @@ Result<std::unordered_map<uint64_t, PropertyValue>> VertexAccessor::Properties(
         }
       });
   if (deleted) {
-    return Result<std::unordered_map<uint64_t, PropertyValue>>{
-        Error::DELETED_OBJECT};
+    return Result<std::map<uint64_t, PropertyValue>>{Error::DELETED_OBJECT};
   }
-  return Result<std::unordered_map<uint64_t, PropertyValue>>{
-      std::move(properties)};
+  return Result<std::map<uint64_t, PropertyValue>>{std::move(properties)};
 }
 
 Result<std::vector<EdgeAccessor>>

src/storage/v2/vertex_accessor.hpp

@@ -37,7 +37,7 @@ class VertexAccessor final {
 
   Result<PropertyValue> GetProperty(uint64_t property, View view);
 
-  Result<std::unordered_map<uint64_t, PropertyValue>> Properties(View view);
+  Result<std::map<uint64_t, PropertyValue>> Properties(View view);
 
   Result<std::vector<EdgeAccessor>>
   InEdges(const std::vector<uint64_t> &edge_types, View view);