diff --git a/geocoder/geocoder.cpp b/geocoder/geocoder.cpp
index 266d68c923..ff7603296e 100644
--- a/geocoder/geocoder.cpp
+++ b/geocoder/geocoder.cpp
@@ -15,6 +15,7 @@
 
 #include <algorithm>
 #include <set>
+#include <thread>
 #include <utility>
 
 using namespace std;
@@ -195,13 +196,18 @@ vector<Geocoder::Layer> & Geocoder::Context::GetLayers() { return m_layers; }
 vector<Geocoder::Layer> const & Geocoder::Context::GetLayers() const { return m_layers; }
 
 // Geocoder ----------------------------------------------------------------------------------------
-Geocoder::Geocoder(string const & pathToJsonHierarchy)
-  : Geocoder(HierarchyReader(pathToJsonHierarchy).Read())
+Geocoder::Geocoder(string const & pathToJsonHierarchy, unsigned int loadThreadsCount)
+  : Geocoder{HierarchyReader{pathToJsonHierarchy}.Read(loadThreadsCount), loadThreadsCount}
 {
 }
 
-Geocoder::Geocoder(Hierarchy && hierarchy)
-  : m_hierarchy(move(hierarchy)), m_index(m_hierarchy)
+Geocoder::Geocoder(istream & jsonHierarchy, unsigned int loadThreadsCount)
+  : Geocoder{HierarchyReader{jsonHierarchy}.Read(loadThreadsCount), loadThreadsCount}
+{
+}
+
+Geocoder::Geocoder(Hierarchy && hierarchy, unsigned int loadThreadsCount)
+  : m_hierarchy(move(hierarchy)), m_index(m_hierarchy, loadThreadsCount)
 {
 }
 
diff --git a/geocoder/geocoder.hpp b/geocoder/geocoder.hpp
index 24fcda0b9a..ff6542afdd 100644
--- a/geocoder/geocoder.hpp
+++ b/geocoder/geocoder.hpp
@@ -12,6 +12,7 @@
 
 #include <cstddef>
 #include <string>
+#include <thread>
 #include <unordered_map>
 #include <utility>
 #include <vector>
@@ -118,8 +119,10 @@ public:
     std::vector<Layer> m_layers;
   };
 
-  explicit Geocoder(std::string const & pathToJsonHierarchy);
-  explicit Geocoder(Hierarchy && hierarchy);
+  explicit Geocoder(std::string const & pathToJsonHierarchy,
+      unsigned int loadThreadsCount = std::thread::hardware_concurrency());
+  explicit Geocoder(std::istream & jsonHierarchy,
+      unsigned int loadThreadsCount = std::thread::hardware_concurrency());
 
   void ProcessQuery(std::string const & query, std::vector<Result> & results) const;
 
@@ -128,6 +131,8 @@ public:
   Index const & GetIndex() const;
 
 private:
+  explicit Geocoder(Hierarchy && hierarchy, unsigned int loadThreadsCount);
+
   void Go(Context & ctx, Type type) const;
 
   void FillBuildingsLayer(Context & ctx, Tokens const & subquery, Layer & curLayer) const;
diff --git a/geocoder/hierarchy_reader.cpp b/geocoder/hierarchy_reader.cpp
index c86e60d490..14e06abcc0 100644
--- a/geocoder/hierarchy_reader.cpp
+++ b/geocoder/hierarchy_reader.cpp
@@ -2,6 +2,7 @@
 
 #include "base/logging.hpp"
 
+#include <algorithm>
 #include <queue>
 #include <thread>
 
@@ -41,7 +42,7 @@ HierarchyReader::HierarchyReader(string const & pathToJsonHierarchy)
     MYTHROW(OpenException, ("Failed to open file", pathToJsonHierarchy));
 }
 
-HierarchyReader::HierarchyReader(std::istream & in)
+HierarchyReader::HierarchyReader(istream & in)
   : m_in{in}
 {
 }
@@ -86,7 +87,7 @@ Hierarchy HierarchyReader::Read(unsigned int readersCount)
       ("Entries whose names do not match their most specific addresses:", stats.m_mismatchedNames));
   LOG(LINFO, ("(End of stats.)"));
 
-  return Hierarchy{std::move(entries), true};
+  return Hierarchy{move(entries), true};
 }
 
 vector<Hierarchy::Entry> HierarchyReader::MergeEntries(vector<multimap<base::GeoObjectId, Entry>> & entryParts)
@@ -104,18 +105,18 @@ vector<Hierarchy::Entry> HierarchyReader::MergeEntries(vector<multimap<base::Geo
   using PartReference = reference_wrapper<multimap<base::GeoObjectId, Entry>>;
   struct ReferenceGreater
   {
-    bool operator () (PartReference const & l, PartReference const & r) const noexcept
+    bool operator()(PartReference const & l, PartReference const & r) const noexcept
     { return l.get() > r.get(); }
   };
 
-  auto partsQueue = priority_queue<PartReference, std::vector<PartReference>, ReferenceGreater>
-                      (entryParts.begin(), entryParts.end());
+  auto partsQueue = priority_queue<PartReference, vector<PartReference>, ReferenceGreater>(
+      entryParts.begin(), entryParts.end());
   while (!partsQueue.empty())
   {
     auto & minPart = partsQueue.top().get();
     partsQueue.pop();
 
-    while (minPart.size() && (partsQueue.empty() || minPart <= partsQueue.top().get()))
+    while (!minPart.empty() && (partsQueue.empty() || minPart <= partsQueue.top().get()))
     {
       entries.emplace_back(move(minPart.begin()->second));
       minPart.erase(minPart.begin());
diff --git a/geocoder/hierarchy_reader.hpp b/geocoder/hierarchy_reader.hpp
index 54b38073a5..e34b8c1a12 100644
--- a/geocoder/hierarchy_reader.hpp
+++ b/geocoder/hierarchy_reader.hpp
@@ -10,6 +10,7 @@
 #include <map>
 #include <mutex>
 #include <string>
+#include <thread>
 #include <vector>
 
 namespace geocoder
@@ -23,10 +24,10 @@ public:
   DECLARE_EXCEPTION(OpenException, RootException);
 
   explicit HierarchyReader(std::string const & pathToJsonHierarchy);
-  explicit HierarchyReader(std::istream & in);
+  explicit HierarchyReader(std::istream & jsonHierarchy);
 
   // Read hierarchy file/stream concurrency in |readersCount| threads.
-  Hierarchy Read(unsigned int readersCount = 4);
+  Hierarchy Read(unsigned int readersCount = std::thread::hardware_concurrency());
 
 private:
   void ReadEntryMap(std::multimap<base::GeoObjectId, Entry> & entries, ParsingStats & stats);
diff --git a/geocoder/index.cpp b/geocoder/index.cpp
index 7117805040..60c565bf49 100644
--- a/geocoder/index.cpp
+++ b/geocoder/index.cpp
@@ -23,17 +23,17 @@ size_t const kLogBatch = 100000;
 
 namespace geocoder
 {
-Index::Index(Hierarchy const & hierarchy, unsigned int processingThreadsCount)
-    : m_docs(hierarchy.GetEntries()), m_processingThreadsCount{processingThreadsCount}
+Index::Index(Hierarchy const & hierarchy, unsigned int loadThreadsCount)
+  : m_docs(hierarchy.GetEntries())
 {
   if (auto hardwareConcurrency = thread::hardware_concurrency())
-    m_processingThreadsCount = min(hardwareConcurrency, m_processingThreadsCount);
-  m_processingThreadsCount = max(1U, m_processingThreadsCount);
+    loadThreadsCount = min(hardwareConcurrency, loadThreadsCount);
+  loadThreadsCount = max(1U, loadThreadsCount);
 
   LOG(LINFO, ("Indexing hierarchy entries..."));
   AddEntries();
   LOG(LINFO, ("Indexing houses..."));
-  AddHouses();
+  AddHouses(loadThreadsCount);
 }
 
 Index::Doc const & Index::GetDoc(DocId const id) const
@@ -94,12 +94,12 @@ void Index::AddStreet(DocId const & docId, Index::Doc const & doc)
   }
 }
 
-void Index::AddHouses()
+void Index::AddHouses(unsigned int loadThreadsCount)
 {
   atomic<size_t> numIndexed{0};
-  std::mutex mutex;
+  mutex mutex;
 
-  vector<thread> threads(m_processingThreadsCount);
+  vector<thread> threads(loadThreadsCount);
   CHECK_GREATER(threads.size(), 0, ());
 
   for (size_t t = 0; t < threads.size(); ++t)
diff --git a/geocoder/index.hpp b/geocoder/index.hpp
index a2c96dc1ca..35e9e8d6cb 100644
--- a/geocoder/index.hpp
+++ b/geocoder/index.hpp
@@ -6,6 +6,7 @@
 
 #include <cstdint>
 #include <string>
+#include <thread>
 #include <unordered_map>
 #include <vector>
 
@@ -20,7 +21,8 @@ public:
   // that the index was constructed from.
   using DocId = std::vector<Doc>::size_type;
 
-  explicit Index(Hierarchy const & hierarchy, unsigned int processingThreadsCount = 4);
+  explicit Index(Hierarchy const & hierarchy,
+      unsigned int loadThreadsCount = std::thread::hardware_concurrency());
 
   Doc const & GetDoc(DocId const id) const;
 
@@ -66,7 +68,7 @@ private:
   void AddStreet(DocId const & docId, Doc const & e);
 
   // Fills the |m_buildingsOnStreet| field.
-  void AddHouses();
+  void AddHouses(unsigned int loadThreadsCount);
 
   std::vector<Doc> const & m_docs;
 
@@ -74,7 +76,5 @@ private:
 
   // Lists of houses grouped by the streets they belong to.
   std::unordered_map<DocId, std::vector<DocId>> m_buildingsOnStreet;
-
-  unsigned int m_processingThreadsCount;
 };
 }  // namespace geocoder