diff --git a/dbms/src/DataStreams/GraphiteRollupSortedBlockInputStream.cpp b/dbms/src/DataStreams/GraphiteRollupSortedBlockInputStream.cpp
index 2606658e828..5da53d8eea5 100644
--- a/dbms/src/DataStreams/GraphiteRollupSortedBlockInputStream.cpp
+++ b/dbms/src/DataStreams/GraphiteRollupSortedBlockInputStream.cpp
@@ -182,10 +182,12 @@ void GraphiteRollupSortedBlockInputStream::merge(MutableColumns & merged_columns
 
         /// Within all rows with same key, we should leave only one row with maximum version;
         /// and for rows with same maximum version - only last row.
-        UInt64 next_version = next_cursor->all_columns[version_column_num]->get64(next_cursor->pos);
-        if (is_new_key || next_version >= current_subgroup_max_version)
+        if (is_new_key
+            || next_cursor->all_columns[version_column_num]->compareAt(
+                next_cursor->pos, current_subgroup_newest_row.row_num,
+                *(*current_subgroup_newest_row.columns)[version_column_num],
+                /* nan_direction_hint = */ 1) >= 0)
         {
-            current_subgroup_max_version = next_version;
             setRowRef(current_subgroup_newest_row, next_cursor);
 
             /// Small hack: group and subgroups have the same path, so we can set current_group_path here instead of startNextGroup
@@ -244,7 +246,8 @@ void GraphiteRollupSortedBlockInputStream::finishCurrentGroup(MutableColumns & m
 {
     /// Insert calculated values of the columns `time`, `value`, `version`.
     merged_columns[time_column_num]->insert(UInt64(current_time_rounded));
-    merged_columns[version_column_num]->insert(current_subgroup_max_version);
+    merged_columns[version_column_num]->insertFrom(
+        *(*current_subgroup_newest_row.columns)[version_column_num], current_subgroup_newest_row.row_num);
 
     if (aggregate_state_created)
     {
diff --git a/dbms/src/DataStreams/GraphiteRollupSortedBlockInputStream.h b/dbms/src/DataStreams/GraphiteRollupSortedBlockInputStream.h
index 99d9466408d..c256d27064d 100644
--- a/dbms/src/DataStreams/GraphiteRollupSortedBlockInputStream.h
+++ b/dbms/src/DataStreams/GraphiteRollupSortedBlockInputStream.h
@@ -184,7 +184,6 @@ private:
 
     /// Last row with maximum version for current primary key (time bucket).
     RowRef current_subgroup_newest_row;
-    UInt64 current_subgroup_max_version = 0;
 
     /// Time of last read row
     time_t current_time = 0;
diff --git a/dbms/src/DataStreams/MergingSortedBlockInputStream.h b/dbms/src/DataStreams/MergingSortedBlockInputStream.h
index a8e0c4bf488..6391f52dcd5 100644
--- a/dbms/src/DataStreams/MergingSortedBlockInputStream.h
+++ b/dbms/src/DataStreams/MergingSortedBlockInputStream.h
@@ -105,6 +105,12 @@ protected:
             return !(*this == other);
         }
 
+        void reset()
+        {
+            RowRef empty;
+            swap(empty);
+        }
+
         bool empty() const { return columns == nullptr; }
         size_t size() const { return empty() ? 0 : columns->size(); }
     };
diff --git a/dbms/src/DataStreams/ReplacingSortedBlockInputStream.cpp b/dbms/src/DataStreams/ReplacingSortedBlockInputStream.cpp
index 96ac8a98355..197fac9c22d 100644
--- a/dbms/src/DataStreams/ReplacingSortedBlockInputStream.cpp
+++ b/dbms/src/DataStreams/ReplacingSortedBlockInputStream.cpp
@@ -73,10 +73,6 @@ void ReplacingSortedBlockInputStream::merge(MutableColumns & merged_columns, std
         if (current_key.empty())
             setPrimaryKeyRef(current_key, current);
 
-        UInt64 version = version_column_number != -1
-            ? current->all_columns[version_column_number]->get64(current->pos)
-            : 0;
-
         setPrimaryKeyRef(next_key, current);
 
         bool key_differs = next_key != current_key;
@@ -89,9 +85,9 @@ void ReplacingSortedBlockInputStream::merge(MutableColumns & merged_columns, std
 
         if (key_differs)
         {
-            max_version = 0;
             /// Write the data for the previous primary key.
             insertRow(merged_columns, merged_rows);
+            selected_row.reset();
             current_key.swap(next_key);
         }
 
@@ -101,9 +97,13 @@ void ReplacingSortedBlockInputStream::merge(MutableColumns & merged_columns, std
             current_row_sources.emplace_back(current.impl->order, true);
 
         /// A non-strict comparison, since we select the last row for the same version values.
-        if (version >= max_version)
+        if (version_column_number == -1
+            || selected_row.empty()
+            || current->all_columns[version_column_number]->compareAt(
+                current->pos, selected_row.row_num,
+                *(*selected_row.columns)[version_column_number],
+                /* nan_direction_hint = */ 1) >= 0)
         {
-            max_version = version;
             max_pos = current_pos;
             setRowRef(selected_row, current);
         }
diff --git a/dbms/src/DataStreams/ReplacingSortedBlockInputStream.h b/dbms/src/DataStreams/ReplacingSortedBlockInputStream.h
index e64100b2207..b8592a0e5b6 100644
--- a/dbms/src/DataStreams/ReplacingSortedBlockInputStream.h
+++ b/dbms/src/DataStreams/ReplacingSortedBlockInputStream.h
@@ -43,8 +43,6 @@ private:
     RowRef next_key;
     /// Last row with maximum version for current primary key.
     RowRef selected_row;
-    /// Max version for current primary key.
-    UInt64 max_version = 0;
     /// The position (into current_row_sources) of the row with the highest version.
     size_t max_pos = 0;
 
diff --git a/dbms/src/Storages/MergeTree/MergeTreeData.cpp b/dbms/src/Storages/MergeTree/MergeTreeData.cpp
index db830d77bf5..6a8b2f5deed 100644
--- a/dbms/src/Storages/MergeTree/MergeTreeData.cpp
+++ b/dbms/src/Storages/MergeTree/MergeTreeData.cpp
@@ -111,7 +111,8 @@ MergeTreeData::MergeTreeData(
     data_parts_by_info(data_parts_indexes.get<TagByInfo>()),
     data_parts_by_state_and_info(data_parts_indexes.get<TagByStateAndInfo>())
 {
-    merging_params.check(columns);
+    /// NOTE: using the same columns list as is read when performing actual merges.
+    merging_params.check(getColumnsList());
 
     if (!primary_expr_ast)
         throw Exception("Primary key cannot be empty", ErrorCodes::BAD_ARGUMENTS);
@@ -355,10 +356,11 @@ void MergeTreeData::MergingParams::check(const NamesAndTypesList & columns) cons
         {
             if (column.name == version_column)
             {
-                if (!column.type->isUnsignedInteger() && !column.type->isDateOrDateTime())
-                    throw Exception("Version column (" + version_column + ")"
-                            " for storage " + storage + " must have type of UInt family or Date or DateTime."
-                            " Provided column of type " + column.type->getName() + ".", ErrorCodes::BAD_TYPE_OF_FIELD);
+                if (!column.type->canBeUsedAsVersion())
+                    throw Exception("The column " + version_column +
+                        " cannot be used as a version column for storage " + storage +
+                        " because it is of type " + column.type->getName() +
+                        " (must use an integer or Date or DateTime)", ErrorCodes::BAD_TYPE_OF_FIELD);
                 miss_column = false;
                 break;
             }