diff --git a/src/Processors/QueryPlan/AggregatingStep.cpp b/src/Processors/QueryPlan/AggregatingStep.cpp
index f31de80b22d..8a5ed7fde65 100644
--- a/src/Processors/QueryPlan/AggregatingStep.cpp
+++ b/src/Processors/QueryPlan/AggregatingStep.cpp
@@ -134,7 +134,6 @@ AggregatingStep::AggregatingStep(
     {
         output_stream->sort_description = group_by_sort_description;
         output_stream->sort_scope = DataStream::SortScope::Global;
-        output_stream->has_single_port = true;
     }
 }
 
@@ -147,7 +146,6 @@ void AggregatingStep::applyOrder(SortDescription sort_description_for_merging_,
     {
         output_stream->sort_description = group_by_sort_description;
         output_stream->sort_scope = DataStream::SortScope::Global;
-        output_stream->has_single_port = true;
     }
 
     explicit_sorting_required_for_aggregation_in_order = false;
diff --git a/src/Processors/QueryPlan/DistinctStep.cpp b/src/Processors/QueryPlan/DistinctStep.cpp
index a481454139d..b1c24fc01ce 100644
--- a/src/Processors/QueryPlan/DistinctStep.cpp
+++ b/src/Processors/QueryPlan/DistinctStep.cpp
@@ -10,6 +10,11 @@
 namespace DB
 {
 
+namespace ErrorCodes
+{
+    extern const int LOGICAL_ERROR;
+}
+
 static ITransformingStep::Traits getTraits(bool pre_distinct)
 {
     const bool preserves_number_of_streams = pre_distinct;
@@ -90,7 +95,8 @@ void DistinctStep::transformPipeline(QueryPipelineBuilder & pipeline, const Buil
             /// final distinct for sorted stream (sorting inside and among chunks)
             if (input_stream.sort_scope == DataStream::SortScope::Global)
             {
-                assert(input_stream.has_single_port);
+                if (pipeline.getNumStreams() != 1)
+                    throw Exception(ErrorCodes::LOGICAL_ERROR, "DistinctStep with in-order expects single input");
 
                 if (distinct_sort_desc.size() < columns.size())
                 {
diff --git a/src/Processors/QueryPlan/FillingStep.cpp b/src/Processors/QueryPlan/FillingStep.cpp
index 65c9cf11661..81622389ada 100644
--- a/src/Processors/QueryPlan/FillingStep.cpp
+++ b/src/Processors/QueryPlan/FillingStep.cpp
@@ -39,12 +39,13 @@ FillingStep::FillingStep(
     , interpolate_description(interpolate_description_)
     , use_with_fill_by_sorting_prefix(use_with_fill_by_sorting_prefix_)
 {
-    if (!input_stream_.has_single_port)
-        throw Exception(ErrorCodes::LOGICAL_ERROR, "FillingStep expects single input");
 }
 
 void FillingStep::transformPipeline(QueryPipelineBuilder & pipeline, const BuildQueryPipelineSettings &)
 {
+    if (pipeline.getNumStreams() != 1)
+        throw Exception(ErrorCodes::LOGICAL_ERROR, "FillingStep expects single input");
+
     pipeline.addSimpleTransform([&](const Block & header, QueryPipelineBuilder::StreamType stream_type) -> ProcessorPtr
     {
         if (stream_type == QueryPipelineBuilder::StreamType::Totals)
@@ -69,9 +70,6 @@ void FillingStep::describeActions(JSONBuilder::JSONMap & map) const
 
 void FillingStep::updateOutputStream()
 {
-    if (!input_streams.front().has_single_port)
-        throw Exception(ErrorCodes::LOGICAL_ERROR, "FillingStep expects single input");
-
     output_stream = createOutputStream(
         input_streams.front(), FillingTransform::transformHeader(input_streams.front().header, sort_description), getDataStreamTraits());
 }
diff --git a/src/Processors/QueryPlan/IQueryPlanStep.h b/src/Processors/QueryPlan/IQueryPlanStep.h
index daca88fcceb..44eb7ea0c59 100644
--- a/src/Processors/QueryPlan/IQueryPlanStep.h
+++ b/src/Processors/QueryPlan/IQueryPlanStep.h
@@ -28,9 +28,6 @@ class DataStream
 public:
     Block header;
 
-    /// QueryPipeline has single port. Totals or extremes ports are not counted.
-    bool has_single_port = false;
-
     /// Sorting scope. Please keep the mutual order (more strong mode should have greater value).
     enum class SortScope : uint8_t
     {
@@ -51,8 +48,7 @@ public:
 
     bool hasEqualPropertiesWith(const DataStream & other) const
     {
-        return has_single_port == other.has_single_port
-            && sort_description == other.sort_description
+        return sort_description == other.sort_description
             && (sort_description.empty() || sort_scope == other.sort_scope);
     }
 
diff --git a/src/Processors/QueryPlan/ITransformingStep.cpp b/src/Processors/QueryPlan/ITransformingStep.cpp
index 9ecfdb0af22..3fa9d1b8308 100644
--- a/src/Processors/QueryPlan/ITransformingStep.cpp
+++ b/src/Processors/QueryPlan/ITransformingStep.cpp
@@ -20,9 +20,6 @@ DataStream ITransformingStep::createOutputStream(
 {
     DataStream output_stream{.header = std::move(output_header)};
 
-    output_stream.has_single_port = stream_traits.returns_single_stream
-                                     || (input_stream.has_single_port && stream_traits.preserves_number_of_streams);
-
     if (stream_traits.preserves_sorting)
     {
         output_stream.sort_description = input_stream.sort_description;
diff --git a/src/Processors/QueryPlan/ReadNothingStep.cpp b/src/Processors/QueryPlan/ReadNothingStep.cpp
index 253f3a5b980..3037172bbd4 100644
--- a/src/Processors/QueryPlan/ReadNothingStep.cpp
+++ b/src/Processors/QueryPlan/ReadNothingStep.cpp
@@ -6,7 +6,7 @@ namespace DB
 {
 
 ReadNothingStep::ReadNothingStep(Block output_header)
-    : ISourceStep(DataStream{.header = std::move(output_header), .has_single_port = true})
+    : ISourceStep(DataStream{.header = std::move(output_header)})
 {
 }