Skip sorting step if input stream is globally sorted

src/Core/SortDescription.h

@@ -87,6 +87,13 @@ struct SortColumnDescriptionWithColumnIndex
         : base(std::move(description_)), column_number(column_number_)
     {
     }
+
+    bool operator==(const SortColumnDescriptionWithColumnIndex & other) const
+    {
+        return base == other.base && column_number == other.column_number;
+    }
+
+    bool operator!=(const SortColumnDescriptionWithColumnIndex & other) const { return !(*this == other); }
 };
 
 class CompiledSortDescriptionFunctionHolder;
@@ -102,6 +109,21 @@ public:
     std::shared_ptr<CompiledSortDescriptionFunctionHolder> compiled_sort_description_holder;
     size_t min_count_to_compile_sort_description = 3;
     bool compile_sort_description = false;
+
+    bool operator==(const SortDescription & other) const
+    {
+        if (size() != other.size())
+            return false;
+
+        for (size_t i = 0; i < size(); ++i)
+        {
+            if ((*this)[i] != other[i])
+                return false;
+        }
+        return true;
+    }
+
+    bool operator!=(const SortDescription & other) const { return !(*this == other); }
 };
 
 /** Compile sort description for header_types.

src/Processors/QueryPlan/SortingStep.cpp

@@ -113,6 +113,10 @@ void SortingStep::convertToFinishSorting(SortDescription prefix_description_)
 
 void SortingStep::transformPipeline(QueryPipelineBuilder & pipeline, const BuildQueryPipelineSettings &)
 {
+    if (input_streams.back().sort_mode == DataStream::SortMode::Stream
+        && input_streams.back().sort_description == output_stream->sort_description)
+        return;
+
     if (type == Type::FinishSorting)
     {
         bool need_finish_sorting = (prefix_description.size() < result_description.size());