diff --git a/dbms/programs/obfuscator/Obfuscator.cpp b/dbms/programs/obfuscator/Obfuscator.cpp
index febe2b286060..5d649b5f1766 100644
--- a/dbms/programs/obfuscator/Obfuscator.cpp
+++ b/dbms/programs/obfuscator/Obfuscator.cpp
@@ -670,13 +670,13 @@ class MarkovModel
 
         while (pos < end)
         {
-            Table::iterator it = table.end();
+            Table::MappedPtr it;
 
             size_t context_size = params.order;
             while (true)
             {
                 it = table.find(hashContext(code_points.data() + code_points.size() - context_size, code_points.data() + code_points.size()));
-                if (table.end() != it && it->getSecond().total + it->getSecond().count_end != 0)
+                if (it && it->total + it->count_end != 0)
                     break;
 
                 if (context_size == 0)
@@ -684,7 +684,7 @@ class MarkovModel
                 --context_size;
             }
 
-            if (table.end() == it)
+            if (!it)
                 throw Exception("Logical error in markov model", ErrorCodes::LOGICAL_ERROR);
 
             size_t offset_from_begin_of_string = pos - data;
@@ -710,7 +710,7 @@ class MarkovModel
             if (num_bytes_after_desired_size > 0)
                 end_probability_multiplier = std::pow(1.25, num_bytes_after_desired_size);
 
-            CodePoint code = it->getSecond().sample(determinator, end_probability_multiplier);
+            CodePoint code = it->sample(determinator, end_probability_multiplier);
 
             if (code == END)
                 break;
diff --git a/dbms/src/Common/ColumnsHashingImpl.h b/dbms/src/Common/ColumnsHashingImpl.h
index 89141f0f4d57..98045eb88437 100644
--- a/dbms/src/Common/ColumnsHashingImpl.h
+++ b/dbms/src/Common/ColumnsHashingImpl.h
@@ -221,20 +221,19 @@ class HashMethodBase
             }
         }
 
-        auto it = data.find(key);
-        bool found = it != data.end();
+        auto mapped_ptr = data.find(key);
 
         if constexpr (consecutive_keys_optimization)
         {
-            cache.found = found;
+            cache.found = mapped_ptr != nullptr;
             cache.empty = false;
 
             if constexpr (has_mapped)
             {
                 cache.value.first = key;
-                if (found)
+                if (mapped_ptr)
                 {
-                    cache.value.second = it->getSecond();
+                    cache.value.second = *mapped_ptr;
                 }
             }
             else
@@ -244,9 +243,9 @@ class HashMethodBase
         }
 
         if constexpr (has_mapped)
-            return FindResult(found ? &it->getSecond() : nullptr, found);
+            return FindResult(mapped_ptr, mapped_ptr != nullptr);
         else
-            return FindResult(found);
+            return FindResult(mapped_ptr != nullptr);
     }
 };
 
diff --git a/dbms/src/Common/HashTable/FixedHashMap.h b/dbms/src/Common/HashTable/FixedHashMap.h
index eb3c798f31d1..f4dbf61fce51 100644
--- a/dbms/src/Common/HashTable/FixedHashMap.h
+++ b/dbms/src/Common/HashTable/FixedHashMap.h
@@ -90,11 +90,11 @@ class FixedHashMap : public FixedHashTable<Key, FixedHashMapCell<Key, Mapped>, A
     {
         for (auto it = this->begin(), end = this->end(); it != end; ++it)
         {
-            decltype(it) res_it = that.find(it->getFirst(), it.getHash());
-            if (res_it == that.end())
+            auto res_it = that.find(it->getFirst(), it.getHash());
+            if (!res_it)
                 func(it->getSecond(), it->getSecond(), false);
             else
-                func(res_it->getSecond(), it->getSecond(), true);
+                func(*res_it, it->getSecond(), true);
         }
     }
 
diff --git a/dbms/src/Common/HashTable/FixedHashTable.h b/dbms/src/Common/HashTable/FixedHashTable.h
index 67af43d197b5..fd0e05b72fb5 100644
--- a/dbms/src/Common/HashTable/FixedHashTable.h
+++ b/dbms/src/Common/HashTable/FixedHashTable.h
@@ -143,6 +143,7 @@ class FixedHashTable : private boost::noncopyable, protected Allocator, protecte
     using key_type = Key;
     using value_type = typename Cell::value_type;
     using MappedPtr = typename Cell::mapped_type *;
+    using ConstMappedPtr = const typename Cell::mapped_type *;
 
     size_t hash(const Key & x) const { return x; }
 
@@ -289,24 +290,24 @@ class FixedHashTable : private boost::noncopyable, protected Allocator, protecte
         return res;
     }
 
-    iterator ALWAYS_INLINE find(Key x)
+    MappedPtr ALWAYS_INLINE find(Key x)
     {
-        return !buf[x].isZero(*this) ? iterator(this, &buf[x]) : end();
+        return !buf[x].isZero(*this) ? buf[x].getMapped() : nullptr;
     }
 
-    const_iterator ALWAYS_INLINE find(Key x) const
+    ConstMappedPtr ALWAYS_INLINE find(Key x) const
     {
-        return !buf[x].isZero(*this) ? const_iterator(this, &buf[x]) : end();
+        return const_cast<std::decay_t<decltype(*this)> *>(this)->find(x);
     }
 
-    iterator ALWAYS_INLINE find(Key, size_t hash_value)
+    MappedPtr ALWAYS_INLINE find(Key, size_t hash_value)
     {
-        return !buf[hash_value].isZero(*this) ? iterator(this, &buf[hash_value]) : end();
+        return !buf[hash_value].isZero(*this) ? buf[hash_value].getMapped() : nullptr;
     }
 
-    const_iterator ALWAYS_INLINE find(Key, size_t hash_value) const
+    ConstMappedPtr ALWAYS_INLINE find(Key key, size_t hash_value) const
     {
-        return !buf[hash_value].isZero(*this) ? const_iterator(this, &buf[hash_value]) : end();
+        return const_cast<std::decay_t<decltype(*this)> *>(this)->find(key, hash_value);
     }
 
     bool ALWAYS_INLINE has(Key x) const { return !buf[x].isZero(*this); }
diff --git a/dbms/src/Common/HashTable/HashMap.h b/dbms/src/Common/HashTable/HashMap.h
index c90f91c2d89a..b833a9dbd805 100644
--- a/dbms/src/Common/HashTable/HashMap.h
+++ b/dbms/src/Common/HashTable/HashMap.h
@@ -173,11 +173,11 @@ class HashMapTable : public HashTable<Key, Cell, Hash, Grower, Allocator>
     {
         for (auto it = this->begin(), end = this->end(); it != end; ++it)
         {
-            decltype(it) res_it = that.find(it->getFirst(), it.getHash());
-            if (res_it == that.end())
+            auto res_it = that.find(it->getFirst(), it.getHash());
+            if (!res_it)
                 func(it->getSecond(), it->getSecond(), false);
             else
-                func(res_it->getSecond(), it->getSecond(), true);
+                func(*res_it, it->getSecond(), true);
         }
     }
 
diff --git a/dbms/src/Common/HashTable/HashTable.h b/dbms/src/Common/HashTable/HashTable.h
index b8e5a7e11dec..eeb314e80501 100644
--- a/dbms/src/Common/HashTable/HashTable.h
+++ b/dbms/src/Common/HashTable/HashTable.h
@@ -484,6 +484,7 @@ class HashTable :
     using key_type = Key;
     using value_type = typename Cell::value_type;
     using MappedPtr = typename Cell::mapped_type *;
+    using ConstMappedPtr = const typename Cell::mapped_type *;
 
     size_t hash(const Key & x) const { return Hash::operator()(x); }
 
@@ -796,48 +797,35 @@ class HashTable :
             resize();
     }
 
-    iterator ALWAYS_INLINE find(Key x)
-    {
-        if (Cell::isZero(x, *this))
-            return this->hasZero() ? iteratorToZero() : end();
-
-        size_t hash_value = hash(x);
-        size_t place_value = findCell(x, hash_value, grower.place(hash_value));
-        return !buf[place_value].isZero(*this) ? iterator(this, &buf[place_value]) : end();
-    }
-
 
-    const_iterator ALWAYS_INLINE find(Key x) const
+    MappedPtr ALWAYS_INLINE find(Key x)
     {
         if (Cell::isZero(x, *this))
-            return this->hasZero() ? iteratorToZero() : end();
+            return this->hasZero() ? this->zeroValue()->getMapped() : nullptr;
 
         size_t hash_value = hash(x);
         size_t place_value = findCell(x, hash_value, grower.place(hash_value));
-        return !buf[place_value].isZero(*this) ? const_iterator(this, &buf[place_value]) : end();
+        return !buf[place_value].isZero(*this)
+                ? buf[place_value].getMapped()
+                : nullptr;
     }
 
-
-    iterator ALWAYS_INLINE find(Key x, size_t hash_value)
+    ConstMappedPtr ALWAYS_INLINE find(Key x) const
     {
-        if (Cell::isZero(x, *this))
-            return this->hasZero() ? iteratorToZero() : end();
-
-        size_t place_value = findCell(x, hash_value, grower.place(hash_value));
-        return !buf[place_value].isZero(*this) ? iterator(this, &buf[place_value]) : end();
+        return const_cast<std::decay_t<decltype(*this)> *>(this)->find(x);
     }
 
-
-    const_iterator ALWAYS_INLINE find(Key x, size_t hash_value) const
+    MappedPtr ALWAYS_INLINE find(Key x, size_t hash_value)
     {
         if (Cell::isZero(x, *this))
-            return this->hasZero() ? iteratorToZero() : end();
+            return this->hasZero() ? this->zeroValue()->getMapped() : nullptr;
 
         size_t place_value = findCell(x, hash_value, grower.place(hash_value));
-        return !buf[place_value].isZero(*this) ? const_iterator(this, &buf[place_value]) : end();
+        return !buf[place_value].isZero(*this)
+                ? buf[place_value].getMapped()
+                : nullptr;
     }
 
-
     bool ALWAYS_INLINE has(Key x) const
     {
         if (Cell::isZero(x, *this))
diff --git a/dbms/src/Common/HashTable/TwoLevelHashTable.h b/dbms/src/Common/HashTable/TwoLevelHashTable.h
index 2d90276bfe42..4b1fed6e0d5f 100644
--- a/dbms/src/Common/HashTable/TwoLevelHashTable.h
+++ b/dbms/src/Common/HashTable/TwoLevelHashTable.h
@@ -84,6 +84,7 @@ class TwoLevelHashTable :
     using key_type = typename Impl::key_type;
     using value_type = typename Impl::value_type;
     using MappedPtr = typename Impl::MappedPtr;
+    using ConstMappedPtr = typename Impl::ConstMappedPtr;
 
     Impl impls[NUM_BUCKETS];
 
@@ -255,31 +256,19 @@ class TwoLevelHashTable :
         it = impl_it;
     }
 
-
-    iterator ALWAYS_INLINE find(Key x, size_t hash_value)
+    MappedPtr ALWAYS_INLINE find(Key x, size_t hash_value)
     {
         size_t buck = getBucketFromHash(hash_value);
-
-        typename Impl::iterator found = impls[buck].find(x, hash_value);
-        return found != impls[buck].end()
-            ? iterator(this, buck, found)
-            : end();
+        return impls[buck].find(x, hash_value);
     }
 
-
-    const_iterator ALWAYS_INLINE find(Key x, size_t hash_value) const
+    ConstMappedPtr ALWAYS_INLINE find(Key x, size_t hash_value) const
     {
-        size_t buck = getBucketFromHash(hash_value);
-
-        typename Impl::const_iterator found = impls[buck].find(x, hash_value);
-        return found != impls[buck].end()
-            ? const_iterator(this, buck, found)
-            : end();
+        return const_cast<std::decay_t<decltype(*this)> *>(this)->find(x, hash_value);
     }
 
-
-    iterator ALWAYS_INLINE find(Key x) { return find(x, hash(x)); }
-    const_iterator ALWAYS_INLINE find(Key x) const { return find(x, hash(x)); }
+    MappedPtr ALWAYS_INLINE find(Key x) { return find(x, hash(x)); }
+    ConstMappedPtr ALWAYS_INLINE find(Key x) const { return find(x, hash(x)); }
 
 
     void write(DB::WriteBuffer & wb) const
diff --git a/dbms/src/Common/SpaceSaving.h b/dbms/src/Common/SpaceSaving.h
index da7e9293723c..860f19da1758 100644
--- a/dbms/src/Common/SpaceSaving.h
+++ b/dbms/src/Common/SpaceSaving.h
@@ -366,10 +366,10 @@ class SpaceSaving
     Counter * findCounter(const TKey & key, size_t hash)
     {
         auto it = counter_map.find(key, hash);
-        if (it == counter_map.end())
+        if (!it)
             return nullptr;
 
-        return it->getSecond();
+        return *it;
     }
 
     void rebuildCounterMap()
diff --git a/dbms/src/Common/tests/parallel_aggregation.cpp b/dbms/src/Common/tests/parallel_aggregation.cpp
index 97e7a5a2cd06..11029793e41a 100644
--- a/dbms/src/Common/tests/parallel_aggregation.cpp
+++ b/dbms/src/Common/tests/parallel_aggregation.cpp
@@ -135,10 +135,10 @@ void aggregate3(Map & local_map, Map & global_map, Mutex & mutex, Source::const_
 
     for (auto it = begin; it != end; ++it)
     {
-        Map::iterator found = local_map.find(*it);
+        auto found = local_map.find(*it);
 
-        if (found != local_map.end())
-            ++found->getSecond();
+        if (found)
+            ++*found;
         else if (local_map.size() < threshold)
             ++local_map[*it];    /// TODO You could do one lookup, not two.
         else
@@ -195,10 +195,10 @@ void aggregate4(Map & local_map, MapTwoLevel & global_map, Mutex * mutexes, Sour
         {
             for (; it != block_end; ++it)
             {
-                Map::iterator found = local_map.find(*it);
+                auto found = local_map.find(*it);
 
-                if (found != local_map.end())
-                    ++found->getSecond();
+                if (found)
+                    ++*found;
                 else
                 {
                     size_t hash_value = global_map.hash(*it);
diff --git a/dbms/src/DataTypes/DataTypeEnum.h b/dbms/src/DataTypes/DataTypeEnum.h
index b99e2383860b..521d105ebfe5 100644
--- a/dbms/src/DataTypes/DataTypeEnum.h
+++ b/dbms/src/DataTypes/DataTypeEnum.h
@@ -77,11 +77,11 @@ class DataTypeEnum final : public IDataTypeEnum
 
     FieldType getValue(StringRef field_name) const
     {
-        const auto it = name_to_value_map.find(field_name);
-        if (it == std::end(name_to_value_map))
+        const auto value = name_to_value_map.find(field_name);
+        if (!value)
             throw Exception{"Unknown element '" + field_name.toString() + "' for type " + getName(), ErrorCodes::LOGICAL_ERROR};
 
-        return it->getSecond();
+        return *value;
     }
 
     Field castToName(const Field & value_or_name) const override;
diff --git a/dbms/src/Dictionaries/ComplexKeyCacheDictionary.h b/dbms/src/Dictionaries/ComplexKeyCacheDictionary.h
index 7c2ba75ba176..2c74dc8a7f1b 100644
--- a/dbms/src/Dictionaries/ComplexKeyCacheDictionary.h
+++ b/dbms/src/Dictionaries/ComplexKeyCacheDictionary.h
@@ -469,7 +469,7 @@ class ComplexKeyCacheDictionary final : public IDictionaryBase
         {
             const StringRef key = keys_array[row];
             const auto it = map.find(key);
-            const auto string_ref = it != std::end(map) ? it->getSecond() : get_default(row);
+            const auto string_ref = it ? *it : get_default(row);
             out->insertData(string_ref.data, string_ref.size);
         }
     }
diff --git a/dbms/src/Dictionaries/ComplexKeyHashedDictionary.cpp b/dbms/src/Dictionaries/ComplexKeyHashedDictionary.cpp
index 586fc5e89f97..a4904e8fc585 100644
--- a/dbms/src/Dictionaries/ComplexKeyHashedDictionary.cpp
+++ b/dbms/src/Dictionaries/ComplexKeyHashedDictionary.cpp
@@ -357,7 +357,7 @@ void ComplexKeyHashedDictionary::updateData()
             {
                 const auto s_key = placeKeysInPool(i, saved_key_column_ptrs, keys, temp_key_pool);
                 auto it = update_key_hash.find(s_key);
-                if (it != std::end(update_key_hash))
+                if (it)
                     filter[i] = 0;
                 else
                     filter[i] = 1;
@@ -561,7 +561,7 @@ void ComplexKeyHashedDictionary::getItemsImpl(
         const auto key = placeKeysInPool(i, key_columns, keys, temporary_keys_pool);
 
         const auto it = attr.find(key);
-        set_value(i, it != attr.end() ? static_cast<OutputType>(it->getSecond()) : get_default(i));
+        set_value(i, it ? static_cast<OutputType>(*it) : get_default(i));
 
         /// free memory allocated for the key
         temporary_keys_pool.rollback(key.size);
@@ -672,7 +672,7 @@ void ComplexKeyHashedDictionary::has(const Attribute & attribute, const Columns
         const auto key = placeKeysInPool(i, key_columns, keys, temporary_keys_pool);
 
         const auto it = attr.find(key);
-        out[i] = it != attr.end();
+        out[i] = static_cast<bool>(it);
 
         /// free memory allocated for the key
         temporary_keys_pool.rollback(key.size);
diff --git a/dbms/src/Dictionaries/HashedDictionary.cpp b/dbms/src/Dictionaries/HashedDictionary.cpp
index 9b853ac2df54..92538dd47878 100644
--- a/dbms/src/Dictionaries/HashedDictionary.cpp
+++ b/dbms/src/Dictionaries/HashedDictionary.cpp
@@ -72,8 +72,8 @@ void HashedDictionary::isInImpl(const ChildType & child_ids, const AncestorType
         while (id != null_value && id != ancestor_id)
         {
             auto it = attr.find(id);
-            if (it != std::end(attr))
-                id = it->getSecond();
+            if (it)
+                id = *it;
             else
                 break;
         }
@@ -555,7 +555,7 @@ void HashedDictionary::getItemsImpl(
     for (const auto i : ext::range(0, rows))
     {
         const auto it = attr.find(ids[i]);
-        set_value(i, it != attr.end() ? static_cast<OutputType>(it->getSecond()) : get_default(i));
+        set_value(i, it ? static_cast<OutputType>(*it) : get_default(i));
     }
 
     query_count.fetch_add(rows, std::memory_order_relaxed);
@@ -631,7 +631,7 @@ void HashedDictionary::has(const Attribute & attribute, const PaddedPODArray<Key
     const auto rows = ext::size(ids);
 
     for (const auto i : ext::range(0, rows))
-        out[i] = attr.find(ids[i]) != std::end(attr);
+        out[i] = static_cast<bool>(attr.find(ids[i]));
 
     query_count.fetch_add(rows, std::memory_order_relaxed);
 }
diff --git a/dbms/src/Dictionaries/RangeHashedDictionary.cpp b/dbms/src/Dictionaries/RangeHashedDictionary.cpp
index ab67ce593715..fa0ef57bf243 100644
--- a/dbms/src/Dictionaries/RangeHashedDictionary.cpp
+++ b/dbms/src/Dictionaries/RangeHashedDictionary.cpp
@@ -124,10 +124,10 @@ void RangeHashedDictionary::getString(
     for (const auto i : ext::range(0, ids.size()))
     {
         const auto it = attr.find(ids[i]);
-        if (it != std::end(attr))
+        if (it)
         {
             const auto date = dates[i];
-            const auto & ranges_and_values = it->getSecond();
+            const auto & ranges_and_values = *it;
             const auto val_it
                 = std::find_if(std::begin(ranges_and_values), std::end(ranges_and_values), [date](const Value<StringRef> & v)
                   {
@@ -395,10 +395,10 @@ void RangeHashedDictionary::getItemsImpl(
     for (const auto i : ext::range(0, ids.size()))
     {
         const auto it = attr.find(ids[i]);
-        if (it != std::end(attr))
+        if (it)
         {
             const auto date = dates[i];
-            const auto & ranges_and_values = it->getSecond();
+            const auto & ranges_and_values = *it;
             const auto val_it
                 = std::find_if(std::begin(ranges_and_values), std::end(ranges_and_values), [date](const Value<AttributeType> & v)
                   {
@@ -423,9 +423,9 @@ void RangeHashedDictionary::setAttributeValueImpl(Attribute & attribute, const K
     auto & map = *std::get<Ptr<T>>(attribute.maps);
     const auto it = map.find(id);
 
-    if (it != map.end())
+    if (it)
     {
-        auto & values = it->getSecond();
+        auto & values = *it;
 
         const auto insert_it
             = std::lower_bound(std::begin(values), std::end(values), range, [](const Value<T> & lhs, const Range & rhs_range)
@@ -496,9 +496,9 @@ void RangeHashedDictionary::setAttributeValue(Attribute & attribute, const Key i
 
             const auto it = map.find(id);
 
-            if (it != map.end())
+            if (it)
             {
-                auto & values = it->getSecond();
+                auto & values = *it;
 
                 const auto insert_it = std::lower_bound(
                     std::begin(values), std::end(values), range, [](const Value<StringRef> & lhs, const Range & rhs_range)
diff --git a/dbms/src/Functions/array/arrayDistinct.cpp b/dbms/src/Functions/array/arrayDistinct.cpp
index aa4e8aec4f14..4bcd5100b268 100644
--- a/dbms/src/Functions/array/arrayDistinct.cpp
+++ b/dbms/src/Functions/array/arrayDistinct.cpp
@@ -173,7 +173,7 @@ bool FunctionArrayDistinct::executeNumber(
             if (nullable_col && (*src_null_map)[j])
                 continue;
 
-            if (set.find(values[j]) == set.end())
+            if (!set.find(values[j]))
             {
                 res_data.emplace_back(values[j]);
                 set.insert(values[j]);
@@ -229,7 +229,7 @@ bool FunctionArrayDistinct::executeString(
 
             StringRef str_ref = src_data_concrete->getDataAt(j);
 
-            if (set.find(str_ref) == set.end())
+            if (!set.find(str_ref))
             {
                 set.insert(str_ref);
                 res_data_column_string.insertData(str_ref.data, str_ref.size);
@@ -279,7 +279,7 @@ void FunctionArrayDistinct::executeHashed(
             src_data.updateHashWithValue(j, hash_function);
             hash_function.get128(reinterpret_cast<char *>(&hash));
 
-            if (set.find(hash) == set.end())
+            if (!set.find(hash))
             {
                 set.insert(hash);
                 res_data_col.insertFrom(src_data, j);
diff --git a/dbms/src/Functions/transform.cpp b/dbms/src/Functions/transform.cpp
index bac5adbb7b9f..9882a7f3d9fd 100644
--- a/dbms/src/Functions/transform.cpp
+++ b/dbms/src/Functions/transform.cpp
@@ -507,8 +507,8 @@ class FunctionTransform : public IFunction
         for (size_t i = 0; i < size; ++i)
         {
             auto it = table.find(src[i]);
-            if (it != table.end())
-                memcpy(&dst[i], &it->getSecond(), sizeof(dst[i]));    /// little endian.
+            if (it)
+                memcpy(&dst[i], it, sizeof(dst[i]));    /// little endian.
             else
                 dst[i] = dst_default;
         }
@@ -523,8 +523,8 @@ class FunctionTransform : public IFunction
         for (size_t i = 0; i < size; ++i)
         {
             auto it = table.find(src[i]);
-            if (it != table.end())
-                memcpy(&dst[i], &it->getSecond(), sizeof(dst[i]));    /// little endian.
+            if (it)
+                memcpy(&dst[i], it, sizeof(dst[i]));    /// little endian.
             else
                 dst[i] = dst_default[i];
         }
@@ -539,8 +539,8 @@ class FunctionTransform : public IFunction
         for (size_t i = 0; i < size; ++i)
         {
             auto it = table.find(src[i]);
-            if (it != table.end())
-                memcpy(&dst[i], &it->getSecond(), sizeof(dst[i]));
+            if (it)
+                memcpy(&dst[i], it, sizeof(dst[i]));
             else
                 dst[i] = src[i];
         }
@@ -557,7 +557,7 @@ class FunctionTransform : public IFunction
         for (size_t i = 0; i < size; ++i)
         {
             auto it = table.find(src[i]);
-            StringRef ref = it != table.end() ? it->getSecond() : dst_default;
+            StringRef ref = it ? *it : dst_default;
             dst_data.resize(current_dst_offset + ref.size);
             memcpy(&dst_data[current_dst_offset], ref.data, ref.size);
             current_dst_offset += ref.size;
@@ -580,8 +580,8 @@ class FunctionTransform : public IFunction
             auto it = table.find(src[i]);
             StringRef ref;
 
-            if (it != table.end())
-                ref = it->getSecond();
+            if (it)
+                ref = *it;
             else
             {
                 ref.data = reinterpret_cast<const char *>(&dst_default_data[current_dst_default_offset]);
@@ -610,8 +610,8 @@ class FunctionTransform : public IFunction
             StringRef ref{&src_data[current_src_offset], src_offsets[i] - current_src_offset};
             current_src_offset = src_offsets[i];
             auto it = table.find(ref);
-            if (it != table.end())
-                memcpy(&dst[i], &it->getSecond(), sizeof(dst[i]));
+            if (it)
+                memcpy(&dst[i], it, sizeof(dst[i]));
             else
                 dst[i] = dst_default;
         }
@@ -631,8 +631,8 @@ class FunctionTransform : public IFunction
             StringRef ref{&src_data[current_src_offset], src_offsets[i] - current_src_offset};
             current_src_offset = src_offsets[i];
             auto it = table.find(ref);
-            if (it != table.end())
-                memcpy(&dst[i], &it->getSecond(), sizeof(dst[i]));
+            if (it)
+                memcpy(&dst[i], it, sizeof(dst[i]));
             else
                 dst[i] = dst_default[i];
         }
@@ -655,7 +655,7 @@ class FunctionTransform : public IFunction
 
             auto it = table.find(src_ref);
 
-            StringRef dst_ref = it != table.end() ? it->getSecond() : (with_default ? dst_default : src_ref);
+            StringRef dst_ref = it ? *it : (with_default ? dst_default : src_ref);
             dst_data.resize(current_dst_offset + dst_ref.size);
             memcpy(&dst_data[current_dst_offset], dst_ref.data, dst_ref.size);
             current_dst_offset += dst_ref.size;
@@ -696,8 +696,8 @@ class FunctionTransform : public IFunction
             auto it = table.find(src_ref);
             StringRef dst_ref;
 
-            if (it != table.end())
-                dst_ref = it->getSecond();
+            if (it)
+                dst_ref = *it;
             else
             {
                 dst_ref.data = reinterpret_cast<const char *>(&dst_default_data[current_dst_default_offset]);
diff --git a/dbms/src/Interpreters/tests/hash_map_lookup.cpp b/dbms/src/Interpreters/tests/hash_map_lookup.cpp
index 62dbd690d936..6310f3a254c4 100644
--- a/dbms/src/Interpreters/tests/hash_map_lookup.cpp
+++ b/dbms/src/Interpreters/tests/hash_map_lookup.cpp
@@ -63,7 +63,7 @@ void NO_INLINE bench(const std::vector<UInt16> & data, const char * name)
     for (size_t i = 0, size = data.size(); i < size; ++i)
     {
         auto it = map.find(data[i]);
-        ++it->getSecond();
+        ++*it;
     }
     watch.stop();
     std::cerr << std::fixed << std::setprecision(2) << "HashMap (" << name << "). Size: " << map.size()
diff --git a/dbms/src/Processors/Formats/Impl/JSONEachRowRowInputFormat.cpp b/dbms/src/Processors/Formats/Impl/JSONEachRowRowInputFormat.cpp
index 9730ae3f3cca..99db3b317196 100644
--- a/dbms/src/Processors/Formats/Impl/JSONEachRowRowInputFormat.cpp
+++ b/dbms/src/Processors/Formats/Impl/JSONEachRowRowInputFormat.cpp
@@ -64,9 +64,9 @@ inline size_t JSONEachRowRowInputFormat::columnIndex(const StringRef & name, siz
 
     if (prev_positions.size() > key_index
         && prev_positions[key_index] != name_map.end()
-        && name == prev_positions[key_index]->getFirst())
+        && name == prev_positions[key_index]->first)
     {
-        return prev_positions[key_index]->getSecond();
+        return prev_positions[key_index]->second;
     }
     else
     {
@@ -77,7 +77,7 @@ inline size_t JSONEachRowRowInputFormat::columnIndex(const StringRef & name, siz
             if (key_index < prev_positions.size())
                 prev_positions[key_index] = it;
 
-            return it->getSecond();
+            return it->second;
         }
         else
             return UNKNOWN_FIELD;
diff --git a/dbms/src/Processors/Formats/Impl/JSONEachRowRowInputFormat.h b/dbms/src/Processors/Formats/Impl/JSONEachRowRowInputFormat.h
index 17711b5f27d0..0ecf5d73d32b 100644
--- a/dbms/src/Processors/Formats/Impl/JSONEachRowRowInputFormat.h
+++ b/dbms/src/Processors/Formats/Impl/JSONEachRowRowInputFormat.h
@@ -58,7 +58,7 @@ class JSONEachRowRowInputFormat : public IRowInputFormat
     std::vector<UInt8> read_columns;
 
     /// Hash table match `field name -> position in the block`. NOTE You can use perfect hash map.
-    using NameMap = HashMap<StringRef, size_t, StringRefHash>;
+    using NameMap = std::unordered_map<StringRef, size_t, StringRefHash>;
     NameMap name_map;
 
     /// Cached search results for previous row (keyed as index in JSON object) - used as a hint.
diff --git a/dbms/src/Processors/Formats/Impl/TSKVRowInputFormat.cpp b/dbms/src/Processors/Formats/Impl/TSKVRowInputFormat.cpp
index 35a0b4b7a7c7..b0181d2807d8 100644
--- a/dbms/src/Processors/Formats/Impl/TSKVRowInputFormat.cpp
+++ b/dbms/src/Processors/Formats/Impl/TSKVRowInputFormat.cpp
@@ -118,7 +118,7 @@ bool TSKVRowInputFormat::readRow(MutableColumns & columns, RowReadExtension & ex
                 /// and quickly checking for the next expected field, instead of searching the hash table.
 
                 auto it = name_map.find(name_ref);
-                if (name_map.end() == it)
+                if (!it)
                 {
                     if (!format_settings.skip_unknown_fields)
                         throw Exception("Unknown field found while parsing TSKV format: " + name_ref.toString(), ErrorCodes::INCORRECT_DATA);
@@ -129,7 +129,7 @@ bool TSKVRowInputFormat::readRow(MutableColumns & columns, RowReadExtension & ex
                 }
                 else
                 {
-                    index = it->getSecond();
+                    index = *it;
 
                     if (read_columns[index])
                         throw Exception("Duplicate field found while parsing TSKV format: " + name_ref.toString(), ErrorCodes::INCORRECT_DATA);