Merge pull request #25015 from ClickHouse/fix-wrong-code-in-aggregate-functions

Remove a chunk of wrong code and look what will happen

src/AggregateFunctions/AggregateFunctionArray.cpp

@@ -1,7 +1,7 @@
 #include <AggregateFunctions/AggregateFunctionArray.h>
 #include <AggregateFunctions/AggregateFunctionCombinatorFactory.h>
 #include <Common/typeid_cast.h>
-#include "registerAggregateFunctions.h"
+
 
 namespace DB
 {

src/AggregateFunctions/AggregateFunctionBitwise.cpp

@@ -2,7 +2,6 @@
 #include <AggregateFunctions/AggregateFunctionBitwise.h>
 #include <AggregateFunctions/Helpers.h>
 #include <AggregateFunctions/FactoryHelpers.h>
-#include "registerAggregateFunctions.h"
 
 
 namespace DB

src/AggregateFunctions/AggregateFunctionBoundingRatio.cpp

@@ -1,7 +1,6 @@
 #include <AggregateFunctions/AggregateFunctionFactory.h>
 #include <AggregateFunctions/AggregateFunctionBoundingRatio.h>
 #include <AggregateFunctions/FactoryHelpers.h>
-#include "registerAggregateFunctions.h"
 
 
 namespace DB

src/AggregateFunctions/AggregateFunctionCategoricalInformationValue.cpp

@@ -3,7 +3,6 @@
 #include <AggregateFunctions/AggregateFunctionFactory.h>
 #include <AggregateFunctions/FactoryHelpers.h>
 #include <AggregateFunctions/Helpers.h>
-#include "registerAggregateFunctions.h"
 
 
 namespace DB

src/AggregateFunctions/AggregateFunctionCombinatorFactory.cpp

@@ -1,11 +1,9 @@
 #include <Common/StringUtils/StringUtils.h>
 #include <AggregateFunctions/AggregateFunctionCombinatorFactory.h>
-#include "registerAggregateFunctions.h"
 
 
 namespace DB
 {
-struct Settings;
 
 namespace ErrorCodes
 {

src/AggregateFunctions/AggregateFunctionCount.cpp

@@ -1,7 +1,6 @@
 #include <AggregateFunctions/AggregateFunctionFactory.h>
 #include <AggregateFunctions/AggregateFunctionCount.h>
 #include <AggregateFunctions/FactoryHelpers.h>
-#include "registerAggregateFunctions.h"
 
 
 namespace DB

src/AggregateFunctions/AggregateFunctionCount.h

@@ -100,7 +100,7 @@ public:
     }
 
     /// Reset the state to specified value. This function is not the part of common interface.
-    void set(AggregateDataPtr __restrict place, UInt64 new_count)
+    void set(AggregateDataPtr __restrict place, UInt64 new_count) const
     {
         data(place).count = new_count;
     }

src/AggregateFunctions/AggregateFunctionDistinct.cpp

@@ -2,7 +2,7 @@
 #include <AggregateFunctions/AggregateFunctionCombinatorFactory.h>
 #include <AggregateFunctions/Helpers.h>
 #include <Common/typeid_cast.h>
-#include "registerAggregateFunctions.h"
+
 
 namespace DB
 {

src/AggregateFunctions/AggregateFunctionEntropy.cpp

@@ -2,7 +2,6 @@
 #include <AggregateFunctions/AggregateFunctionEntropy.h>
 #include <AggregateFunctions/FactoryHelpers.h>
 #include <AggregateFunctions/Helpers.h>
-#include "registerAggregateFunctions.h"
 
 
 namespace DB
@@ -17,7 +16,8 @@ namespace ErrorCodes
 namespace
 {
 
-AggregateFunctionPtr createAggregateFunctionEntropy(const std::string & name, const DataTypes & argument_types, const Array & parameters, const Settings *)
+AggregateFunctionPtr createAggregateFunctionEntropy(
+    const std::string & name, const DataTypes & argument_types, const Array & parameters, const Settings *)
 {
     assertNoParameters(name, parameters);
     if (argument_types.empty())

src/AggregateFunctions/AggregateFunctionFactory.cpp

@@ -17,10 +17,10 @@
 #include <Common/CurrentThread.h>
 
 #include <Poco/String.h>
-#include "registerAggregateFunctions.h"
 
 #include <Functions/FunctionFactory.h>
 
+
 namespace DB
 {
 struct Settings;
@@ -95,7 +95,7 @@ AggregateFunctionPtr AggregateFunctionFactory::get(
         // nullability themselves. Another special case is functions from Nothing
         // that are rewritten to AggregateFunctionNothing, in this case
         // nested_function is nullptr.
-        if (nested_function && nested_function->asWindowFunction())
+        if (nested_function && nested_function->isOnlyWindowFunction())
         {
             return nested_function;
         }

src/AggregateFunctions/AggregateFunctionForEach.cpp

@@ -1,12 +1,10 @@
 #include <AggregateFunctions/AggregateFunctionForEach.h>
 #include <AggregateFunctions/AggregateFunctionCombinatorFactory.h>
 #include <Common/typeid_cast.h>
-#include "registerAggregateFunctions.h"
 
 
 namespace DB
 {
-struct Settings;
 
 namespace ErrorCodes
 {

src/AggregateFunctions/AggregateFunctionGroupArray.cpp

@@ -4,7 +4,6 @@
 #include <AggregateFunctions/FactoryHelpers.h>
 #include <DataTypes/DataTypeDate.h>
 #include <DataTypes/DataTypeDateTime.h>
-#include "registerAggregateFunctions.h"
 
 
 namespace DB
@@ -50,7 +49,8 @@ inline AggregateFunctionPtr createAggregateFunctionGroupArrayImpl(const DataType
 }
 
 
-AggregateFunctionPtr createAggregateFunctionGroupArray(const std::string & name, const DataTypes & argument_types, const Array & parameters, const Settings *)
+AggregateFunctionPtr createAggregateFunctionGroupArray(
+    const std::string & name, const DataTypes & argument_types, const Array & parameters, const Settings *)
 {
     assertUnary(name, argument_types);
 

src/AggregateFunctions/AggregateFunctionGroupArrayInsertAt.cpp

@@ -2,7 +2,6 @@
 #include <AggregateFunctions/AggregateFunctionGroupArrayInsertAt.h>
 #include <AggregateFunctions/Helpers.h>
 #include <AggregateFunctions/FactoryHelpers.h>
-#include "registerAggregateFunctions.h"
 
 
 namespace DB
@@ -17,7 +16,8 @@ namespace ErrorCodes
 namespace
 {
 
-AggregateFunctionPtr createAggregateFunctionGroupArrayInsertAt(const std::string & name, const DataTypes & argument_types, const Array & parameters, const Settings *)
+AggregateFunctionPtr createAggregateFunctionGroupArrayInsertAt(
+    const std::string & name, const DataTypes & argument_types, const Array & parameters, const Settings *)
 {
     assertBinary(name, argument_types);
 

src/AggregateFunctions/AggregateFunctionGroupArrayMoving.cpp

@@ -5,7 +5,6 @@
 #include <DataTypes/DataTypeDate.h>
 #include <DataTypes/DataTypeDateTime.h>
 #include <DataTypes/DataTypeDateTime64.h>
-#include "registerAggregateFunctions.h"
 
 
 namespace DB
@@ -58,7 +57,8 @@ inline AggregateFunctionPtr createAggregateFunctionMovingImpl(const std::string
 }
 
 template <template <typename, typename> class Function>
-AggregateFunctionPtr createAggregateFunctionMoving(const std::string & name, const DataTypes & argument_types, const Array & parameters, const Settings *)
+AggregateFunctionPtr createAggregateFunctionMoving(
+    const std::string & name, const DataTypes & argument_types, const Array & parameters, const Settings *)
 {
     assertUnary(name, argument_types);
 

src/AggregateFunctions/AggregateFunctionGroupBitmap.cpp

@@ -2,11 +2,11 @@
 #include <AggregateFunctions/FactoryHelpers.h>
 #include <AggregateFunctions/Helpers.h>
 #include <DataTypes/DataTypeAggregateFunction.h>
-#include "registerAggregateFunctions.h"
 
 // TODO include this last because of a broken roaring header. See the comment inside.
 #include <AggregateFunctions/AggregateFunctionGroupBitmap.h>
 
+
 namespace DB
 {
 struct Settings;
@@ -18,9 +18,8 @@ namespace ErrorCodes
 
 namespace
 {
-
-    template <template <typename, typename> class AggregateFunctionTemplate, template <typename> class Data, typename... TArgs>
-    static IAggregateFunction * createWithIntegerType(const IDataType & argument_type, TArgs && ... args)
+    template <template <typename, typename> class AggregateFunctionTemplate, template <typename> typename Data, typename... TArgs>
+    static IAggregateFunction * createWithIntegerType(const IDataType & argument_type, TArgs &&... args)
     {
         WhichDataType which(argument_type);
         if (which.idx == TypeIndex::UInt8) return new AggregateFunctionTemplate<UInt8, Data<UInt8>>(std::forward<TArgs>(args)...);
@@ -34,8 +33,9 @@ namespace
         return nullptr;
     }
 
-    template <template <typename> class Data>
-    AggregateFunctionPtr createAggregateFunctionBitmap(const std::string & name, const DataTypes & argument_types, const Array & parameters, const Settings *)
+    template <template <typename> typename Data>
+    AggregateFunctionPtr createAggregateFunctionBitmap(
+        const std::string & name, const DataTypes & argument_types, const Array & parameters, const Settings *)
     {
         assertNoParameters(name, parameters);
         assertUnary(name, argument_types);
@@ -57,12 +57,13 @@ namespace
     }
 
     // Additional aggregate functions to manipulate bitmaps.
-    template <template <typename, typename> class AggregateFunctionTemplate>
-    AggregateFunctionPtr
-    createAggregateFunctionBitmapL2(const std::string & name, const DataTypes & argument_types, const Array & parameters, const Settings *)
+    template <template <typename, typename> typename AggregateFunctionTemplate>
+    AggregateFunctionPtr createAggregateFunctionBitmapL2(
+        const std::string & name, const DataTypes & argument_types, const Array & parameters, const Settings *)
     {
         assertNoParameters(name, parameters);
         assertUnary(name, argument_types);
+
         DataTypePtr argument_type_ptr = argument_types[0];
         WhichDataType which(*argument_type_ptr);
         if (which.idx != TypeIndex::AggregateFunction)
@@ -70,11 +71,15 @@ namespace
                 "Illegal type " + argument_types[0]->getName() + " of argument for aggregate function " + name,
                 ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
 
+        /// groupBitmap needs to know about the data type that was used to create bitmaps.
+        /// We need to look inside the type of its argument to obtain it.
         const DataTypeAggregateFunction & datatype_aggfunc = dynamic_cast<const DataTypeAggregateFunction &>(*argument_type_ptr);
         AggregateFunctionPtr aggfunc = datatype_aggfunc.getFunction();
-        argument_type_ptr = aggfunc->getArgumentTypes()[0];
+        DataTypePtr nested_argument_type_ptr = aggfunc->getArgumentTypes()[0];
+
         AggregateFunctionPtr res(createWithIntegerType<AggregateFunctionTemplate, AggregateFunctionGroupBitmapData>(
-            *argument_type_ptr, argument_type_ptr));
+            *nested_argument_type_ptr, argument_type_ptr));
+
         if (!res)
             throw Exception(
                 "Illegal type " + argument_types[0]->getName() + " of argument for aggregate function " + name,

src/AggregateFunctions/AggregateFunctionGroupBitmap.h

@@ -9,15 +9,19 @@
 // TODO include this last because of a broken roaring header. See the comment inside.
 #include <AggregateFunctions/AggregateFunctionGroupBitmapData.h>
 
+
 namespace DB
 {
-struct Settings;
+
 /// Counts bitmap operation on numbers.
 template <typename T, typename Data>
 class AggregateFunctionBitmap final : public IAggregateFunctionDataHelper<Data, AggregateFunctionBitmap<T, Data>>
 {
 public:
-    AggregateFunctionBitmap(const DataTypePtr & type) : IAggregateFunctionDataHelper<Data, AggregateFunctionBitmap<T, Data>>({type}, {}) { }
+    AggregateFunctionBitmap(const DataTypePtr & type)
+        : IAggregateFunctionDataHelper<Data, AggregateFunctionBitmap<T, Data>>({type}, {})
+    {
+    }
 
     String getName() const override { return Data::name(); }
 
@@ -46,6 +50,7 @@ public:
 };
 
 
+/// This aggregate function takes the states of AggregateFunctionBitmap as its argument.
 template <typename T, typename Data, typename Policy>
 class AggregateFunctionBitmapL2 final : public IAggregateFunctionDataHelper<Data, AggregateFunctionBitmapL2<T, Data, Policy>>
 {
@@ -61,6 +66,11 @@ public:
 
     bool allocatesMemoryInArena() const override { return false; }
 
+    DataTypePtr getStateType() const override
+    {
+        return this->argument_types.at(0);
+    }
+
     void add(AggregateDataPtr __restrict place, const IColumn ** columns, size_t row_num, Arena *) const override
     {
         Data & data_lhs = this->data(place);
@@ -105,6 +115,7 @@ public:
     }
 };
 
+
 template <typename Data>
 class BitmapAndPolicy
 {

src/AggregateFunctions/AggregateFunctionGroupBitmapData.h

@@ -1,9 +1,9 @@
 #pragma once
 
 #include <algorithm>
+#include <boost/noncopyable.hpp>
 #include <IO/ReadHelpers.h>
 #include <IO/WriteHelpers.h>
-#include <boost/noncopyable.hpp>
 #include <Common/HashTable/SmallTable.h>
 #include <Common/PODArray.h>
 
@@ -14,9 +14,9 @@
 #include <roaring.hh>
 #include <roaring64map.hh>
 
+
 namespace DB
 {
-struct Settings;
 
 enum BitmapKind
 {
@@ -24,6 +24,7 @@ enum BitmapKind
     Bitmap = 1
 };
 
+
 /**
   * For a small number of values - an array of fixed size "on the stack".
   * For large, roaring bitmap is allocated.

src/AggregateFunctions/AggregateFunctionGroupUniqArray.cpp

@@ -4,7 +4,6 @@
 #include <AggregateFunctions/FactoryHelpers.h>
 #include <DataTypes/DataTypeDate.h>
 #include <DataTypes/DataTypeDateTime.h>
-#include "registerAggregateFunctions.h"
 
 
 namespace DB
@@ -73,7 +72,8 @@ inline AggregateFunctionPtr createAggregateFunctionGroupUniqArrayImpl(const std:
 
 }
 
-AggregateFunctionPtr createAggregateFunctionGroupUniqArray(const std::string & name, const DataTypes & argument_types, const Array & parameters, const Settings *)
+AggregateFunctionPtr createAggregateFunctionGroupUniqArray(
+    const std::string & name, const DataTypes & argument_types, const Array & parameters, const Settings *)
 {
     assertUnary(name, argument_types);
 

src/AggregateFunctions/AggregateFunctionHistogram.cpp

@@ -4,7 +4,7 @@
 #include <AggregateFunctions/Helpers.h>
 
 #include <Common/FieldVisitors.h>
-#include "registerAggregateFunctions.h"
+
 
 namespace DB
 {

src/AggregateFunctions/AggregateFunctionIf.cpp

@@ -1,12 +1,10 @@
 #include <AggregateFunctions/AggregateFunctionIf.h>
 #include <AggregateFunctions/AggregateFunctionCombinatorFactory.h>
-#include "registerAggregateFunctions.h"
 #include "AggregateFunctionNull.h"
 
 
 namespace DB
 {
-struct Settings;
 
 namespace ErrorCodes
 {

src/AggregateFunctions/AggregateFunctionMLMethod.cpp

@@ -11,7 +11,6 @@
 #include "AggregateFunctionFactory.h"
 #include "FactoryHelpers.h"
 #include "Helpers.h"
-#include "registerAggregateFunctions.h"
 
 
 namespace DB
@@ -25,13 +24,14 @@ namespace ErrorCodes
     extern const int ILLEGAL_TYPE_OF_ARGUMENT;
     extern const int NUMBER_OF_ARGUMENTS_DOESNT_MATCH;
 }
+
 namespace
 {
     using FuncLinearRegression = AggregateFunctionMLMethod<LinearModelData, NameLinearRegression>;
     using FuncLogisticRegression = AggregateFunctionMLMethod<LinearModelData, NameLogisticRegression>;
-    template <class Method>
-    AggregateFunctionPtr
-    createAggregateFunctionMLMethod(const std::string & name, const DataTypes & argument_types, const Array & parameters, const Settings *)
+    template <typename Method>
+    AggregateFunctionPtr createAggregateFunctionMLMethod(
+        const std::string & name, const DataTypes & argument_types, const Array & parameters, const Settings *)
     {
         if (parameters.size() > 4)
             throw Exception(

src/AggregateFunctions/AggregateFunctionMannWhitney.cpp

@@ -1,7 +1,6 @@
 #include <AggregateFunctions/AggregateFunctionFactory.h>
 #include <AggregateFunctions/AggregateFunctionMannWhitney.h>
 #include <AggregateFunctions/FactoryHelpers.h>
-#include "registerAggregateFunctions.h"
 #include <AggregateFunctions/Helpers.h>
 
 
@@ -17,7 +16,8 @@ struct Settings;
 namespace
 {
 
-AggregateFunctionPtr createAggregateFunctionMannWhitneyUTest(const std::string & name, const DataTypes & argument_types, const Array & parameters, const Settings *)
+AggregateFunctionPtr createAggregateFunctionMannWhitneyUTest(
+    const std::string & name, const DataTypes & argument_types, const Array & parameters, const Settings *)
 {
     assertBinary(name, argument_types);
 

src/AggregateFunctions/AggregateFunctionMax.cpp

@@ -1,7 +1,6 @@
 #include <AggregateFunctions/AggregateFunctionFactory.h>
 #include <AggregateFunctions/HelpersMinMaxAny.h>
 #include <AggregateFunctions/FactoryHelpers.h>
-#include "registerAggregateFunctions.h"
 
 
 namespace DB
@@ -11,12 +10,14 @@ struct Settings;
 namespace
 {
 
-AggregateFunctionPtr createAggregateFunctionMax(const std::string & name, const DataTypes & argument_types, const Array & parameters, const Settings * settings)
+AggregateFunctionPtr createAggregateFunctionMax(
+    const std::string & name, const DataTypes & argument_types, const Array & parameters, const Settings * settings)
 {
     return AggregateFunctionPtr(createAggregateFunctionSingleValue<AggregateFunctionsSingleValue, AggregateFunctionMaxData>(name, argument_types, parameters, settings));
 }
 
-AggregateFunctionPtr createAggregateFunctionArgMax(const std::string & name, const DataTypes & argument_types, const Array & parameters, const Settings * settings)
+AggregateFunctionPtr createAggregateFunctionArgMax(
+    const std::string & name, const DataTypes & argument_types, const Array & parameters, const Settings * settings)
 {
     return AggregateFunctionPtr(createAggregateFunctionArgMinMax<AggregateFunctionMaxData>(name, argument_types, parameters, settings));
 }

src/AggregateFunctions/AggregateFunctionMaxIntersections.cpp

@@ -2,7 +2,6 @@
 #include <AggregateFunctions/AggregateFunctionMaxIntersections.h>
 #include <AggregateFunctions/FactoryHelpers.h>
 #include <AggregateFunctions/Helpers.h>
-#include "registerAggregateFunctions.h"
 
 
 namespace DB

src/AggregateFunctions/AggregateFunctionMerge.cpp

@@ -1,12 +1,10 @@
 #include <AggregateFunctions/AggregateFunctionMerge.h>
 #include <AggregateFunctions/AggregateFunctionCombinatorFactory.h>
 #include <DataTypes/DataTypeAggregateFunction.h>
-#include "registerAggregateFunctions.h"
 
 
 namespace DB
 {
-struct Settings;
 
 namespace ErrorCodes
 {

src/AggregateFunctions/AggregateFunctionMerge.h

@@ -50,6 +50,11 @@ public:
         return nested_func->getReturnType();
     }
 
+    DataTypePtr getStateType() const override
+    {
+        return nested_func->getStateType();
+    }
+
     void create(AggregateDataPtr __restrict place) const override
     {
         nested_func->create(place);

src/AggregateFunctions/AggregateFunctionMin.cpp

@@ -1,7 +1,6 @@
 #include <AggregateFunctions/AggregateFunctionFactory.h>
 #include <AggregateFunctions/HelpersMinMaxAny.h>
 #include <AggregateFunctions/FactoryHelpers.h>
-#include "registerAggregateFunctions.h"
 
 
 namespace DB
@@ -11,12 +10,14 @@ struct Settings;
 namespace
 {
 
-AggregateFunctionPtr createAggregateFunctionMin(const std::string & name, const DataTypes & argument_types, const Array & parameters, const Settings * settings)
+AggregateFunctionPtr createAggregateFunctionMin(
+    const std::string & name, const DataTypes & argument_types, const Array & parameters, const Settings * settings)
 {
     return AggregateFunctionPtr(createAggregateFunctionSingleValue<AggregateFunctionsSingleValue, AggregateFunctionMinData>(name, argument_types, parameters, settings));
 }
 
-AggregateFunctionPtr createAggregateFunctionArgMin(const std::string & name, const DataTypes & argument_types, const Array & parameters, const Settings * settings)
+AggregateFunctionPtr createAggregateFunctionArgMin(
+    const std::string & name, const DataTypes & argument_types, const Array & parameters, const Settings * settings)
 {
     return AggregateFunctionPtr(createAggregateFunctionArgMinMax<AggregateFunctionMinData>(name, argument_types, parameters, settings));
 }

src/AggregateFunctions/AggregateFunctionMinMaxAny.h

@@ -700,13 +700,11 @@ template <typename Data>
 class AggregateFunctionsSingleValue final : public IAggregateFunctionDataHelper<Data, AggregateFunctionsSingleValue<Data>>
 {
 private:
-    DataTypePtr type;
     SerializationPtr serialization;
 
 public:
-    AggregateFunctionsSingleValue(const DataTypePtr & type_)
-        : IAggregateFunctionDataHelper<Data, AggregateFunctionsSingleValue<Data>>({type_}, {})
-        , type(this->argument_types[0])
+    AggregateFunctionsSingleValue(const DataTypePtr & type)
+        : IAggregateFunctionDataHelper<Data, AggregateFunctionsSingleValue<Data>>({type}, {})
         , serialization(type->getDefaultSerialization())
     {
         if (StringRef(Data::name()) == StringRef("min")
@@ -722,7 +720,7 @@ public:
 
     DataTypePtr getReturnType() const override
     {
-        return type;
+        return this->argument_types.at(0);
     }
 
     void add(AggregateDataPtr __restrict place, const IColumn ** columns, size_t row_num, Arena * arena) const override

src/AggregateFunctions/AggregateFunctionNull.cpp

@@ -4,12 +4,10 @@
 #include <AggregateFunctions/AggregateFunctionCount.h>
 #include <AggregateFunctions/AggregateFunctionState.h>
 #include <AggregateFunctions/AggregateFunctionCombinatorFactory.h>
-#include "registerAggregateFunctions.h"
 
 
 namespace DB
 {
-struct Settings;
 
 namespace ErrorCodes
 {

src/AggregateFunctions/AggregateFunctionOrFill.cpp

@@ -1,12 +1,11 @@
 #include <AggregateFunctions/AggregateFunctionOrFill.h>
 
 #include <AggregateFunctions/AggregateFunctionCombinatorFactory.h>
-#include "registerAggregateFunctions.h"
 
 
 namespace DB
 {
-struct Settings;
+
 namespace
 {
 

src/AggregateFunctions/AggregateFunctionQuantile.cpp

@@ -4,7 +4,7 @@
 #include <AggregateFunctions/Helpers.h>
 
 #include <Core/Field.h>
-#include "registerAggregateFunctions.h"
+
 
 namespace DB
 {
@@ -84,7 +84,8 @@ static constexpr bool supportBigInt()
 }
 
 template <template <typename, bool> class Function>
-AggregateFunctionPtr createAggregateFunctionQuantile(const std::string & name, const DataTypes & argument_types, const Array & params, const Settings *)
+AggregateFunctionPtr createAggregateFunctionQuantile(
+    const std::string & name, const DataTypes & argument_types, const Array & params, const Settings *)
 {
     /// Second argument type check doesn't depend on the type of the first one.
     Function<void, true>::assertSecondArg(argument_types);

src/AggregateFunctions/AggregateFunctionRankCorrelation.cpp

@@ -1,13 +1,12 @@
 #include <AggregateFunctions/AggregateFunctionFactory.h>
 #include <AggregateFunctions/AggregateFunctionRankCorrelation.h>
 #include <AggregateFunctions/FactoryHelpers.h>
-#include "registerAggregateFunctions.h"
 #include <AggregateFunctions/Helpers.h>
 
 
 namespace ErrorCodes
 {
-extern const int NOT_IMPLEMENTED;
+    extern const int NOT_IMPLEMENTED;
 }
 
 namespace DB
@@ -17,7 +16,8 @@ struct Settings;
 namespace
 {
 
-AggregateFunctionPtr createAggregateFunctionRankCorrelation(const std::string & name, const DataTypes & argument_types, const Array & parameters, const Settings *)
+AggregateFunctionPtr createAggregateFunctionRankCorrelation(
+    const std::string & name, const DataTypes & argument_types, const Array & parameters, const Settings *)
 {
     assertBinary(name, argument_types);
     assertNoParameters(name, parameters);

src/AggregateFunctions/AggregateFunctionResample.cpp

@@ -1,12 +1,10 @@
 #include <AggregateFunctions/AggregateFunctionResample.h>
 
 #include <AggregateFunctions/AggregateFunctionCombinatorFactory.h>
-#include "registerAggregateFunctions.h"
 
 
 namespace DB
 {
-struct Settings;
 
 namespace ErrorCodes
 {

src/AggregateFunctions/AggregateFunctionRetention.cpp

@@ -2,7 +2,6 @@
 #include <AggregateFunctions/AggregateFunctionRetention.h>
 #include <AggregateFunctions/Helpers.h>
 #include <AggregateFunctions/FactoryHelpers.h>
-#include "registerAggregateFunctions.h"
 
 
 namespace DB

src/AggregateFunctions/AggregateFunctionSequenceMatch.cpp

@@ -6,7 +6,6 @@
 #include <DataTypes/DataTypeDateTime.h>
 
 #include <ext/range.h>
-#include "registerAggregateFunctions.h"
 
 namespace DB
 {
@@ -23,8 +22,9 @@ namespace ErrorCodes
 namespace
 {
 
-template <template <typename, typename> class AggregateFunction, template <typename> class Data>
-AggregateFunctionPtr createAggregateFunctionSequenceBase(const std::string & name, const DataTypes & argument_types, const Array & params, const Settings *)
+template <template <typename, typename> typename AggregateFunction, template <typename> typename Data>
+AggregateFunctionPtr createAggregateFunctionSequenceBase(
+    const std::string & name, const DataTypes & argument_types, const Array & params, const Settings *)
 {
     if (params.size() != 1)
         throw Exception{"Aggregate function " + name + " requires exactly one parameter.",

src/AggregateFunctions/AggregateFunctionState.cpp

@@ -2,17 +2,10 @@
 #include <AggregateFunctions/AggregateFunctionMerge.h>
 #include <AggregateFunctions/AggregateFunctionCombinatorFactory.h>
 #include <DataTypes/DataTypeAggregateFunction.h>
-#include "registerAggregateFunctions.h"
 
 
 namespace DB
 {
-struct Settings;
-
-namespace ErrorCodes
-{
-    extern const int BAD_ARGUMENTS;
-}
 
 namespace
 {
@@ -44,36 +37,4 @@ void registerAggregateFunctionCombinatorState(AggregateFunctionCombinatorFactory
     factory.registerCombinator(std::make_shared<AggregateFunctionCombinatorState>());
 }
 
-
-DataTypePtr AggregateFunctionState::getReturnType() const
-{
-    auto ptr = std::make_shared<DataTypeAggregateFunction>(nested_func, arguments, params);
-
-    /// Special case: it is -MergeState combinator.
-    /// We must return AggregateFunction(agg, ...) instead of AggregateFunction(aggMerge, ...)
-    if (typeid_cast<const AggregateFunctionMerge *>(ptr->getFunction().get()))
-    {
-        if (arguments.size() != 1)
-            throw Exception("Combinator -MergeState expects only one argument", ErrorCodes::BAD_ARGUMENTS);
-
-        if (!typeid_cast<const DataTypeAggregateFunction *>(arguments[0].get()))
-            throw Exception("Combinator -MergeState expects argument with AggregateFunction type", ErrorCodes::BAD_ARGUMENTS);
-
-        return arguments[0];
-    }
-    if (!arguments.empty())
-    {
-        DataTypePtr argument_type_ptr = arguments[0];
-        WhichDataType which(*argument_type_ptr);
-        if (which.idx == TypeIndex::AggregateFunction)
-        {
-            if (arguments.size() != 1)
-                throw Exception("Nested aggregation expects only one argument", ErrorCodes::BAD_ARGUMENTS);
-            return arguments[0];
-        }
-    }
-
-    return ptr;
-}
-
 }

src/AggregateFunctions/AggregateFunctionState.h

@@ -33,7 +33,15 @@ public:
         return nested_func->getName() + "State";
     }
 
-    DataTypePtr getReturnType() const override;
+    DataTypePtr getReturnType() const override
+    {
+        return getStateType();
+    }
+
+    DataTypePtr getStateType() const override
+    {
+        return nested_func->getStateType();
+    }
 
     void create(AggregateDataPtr __restrict place) const override
     {

src/AggregateFunctions/AggregateFunctionStatistics.cpp

@@ -2,7 +2,6 @@
 #include <AggregateFunctions/Helpers.h>
 #include <AggregateFunctions/FactoryHelpers.h>
 #include <AggregateFunctions/AggregateFunctionStatistics.h>
-#include "registerAggregateFunctions.h"
 
 
 namespace DB
@@ -17,8 +16,9 @@ namespace ErrorCodes
 namespace
 {
 
-template <template <typename> class FunctionTemplate>
-AggregateFunctionPtr createAggregateFunctionStatisticsUnary(const std::string & name, const DataTypes & argument_types, const Array & parameters, const Settings *)
+template <template <typename> typename FunctionTemplate>
+AggregateFunctionPtr createAggregateFunctionStatisticsUnary(
+    const std::string & name, const DataTypes & argument_types, const Array & parameters, const Settings *)
 {
     assertNoParameters(name, parameters);
     assertUnary(name, argument_types);
@@ -31,8 +31,9 @@ AggregateFunctionPtr createAggregateFunctionStatisticsUnary(const std::string &
     return res;
 }
 
-template <template <typename, typename> class FunctionTemplate>
-AggregateFunctionPtr createAggregateFunctionStatisticsBinary(const std::string & name, const DataTypes & argument_types, const Array & parameters, const Settings *)
+template <template <typename, typename> typename FunctionTemplate>
+AggregateFunctionPtr createAggregateFunctionStatisticsBinary(
+    const std::string & name, const DataTypes & argument_types, const Array & parameters, const Settings *)
 {
     assertNoParameters(name, parameters);
     assertBinary(name, argument_types);

src/AggregateFunctions/AggregateFunctionStatisticsSimple.cpp

@@ -2,7 +2,6 @@
 #include <AggregateFunctions/Helpers.h>
 #include <AggregateFunctions/FactoryHelpers.h>
 #include <AggregateFunctions/AggregateFunctionStatisticsSimple.h>
-#include "registerAggregateFunctions.h"
 
 
 namespace DB
@@ -17,8 +16,9 @@ namespace ErrorCodes
 namespace
 {
 
-template <template <typename> class FunctionTemplate>
-AggregateFunctionPtr createAggregateFunctionStatisticsUnary(const std::string & name, const DataTypes & argument_types, const Array & parameters, const Settings *)
+template <template <typename> typename FunctionTemplate>
+AggregateFunctionPtr createAggregateFunctionStatisticsUnary(
+    const std::string & name, const DataTypes & argument_types, const Array & parameters, const Settings *)
 {
     assertNoParameters(name, parameters);
     assertUnary(name, argument_types);
@@ -36,8 +36,9 @@ AggregateFunctionPtr createAggregateFunctionStatisticsUnary(const std::string &
     return res;
 }
 
-template <template <typename, typename> class FunctionTemplate>
-AggregateFunctionPtr createAggregateFunctionStatisticsBinary(const std::string & name, const DataTypes & argument_types, const Array & parameters, const Settings *)
+template <template <typename, typename> typename FunctionTemplate>
+AggregateFunctionPtr createAggregateFunctionStatisticsBinary(
+    const std::string & name, const DataTypes & argument_types, const Array & parameters, const Settings *)
 {
     assertNoParameters(name, parameters);
     assertBinary(name, argument_types);

src/AggregateFunctions/AggregateFunctionStudentTTest.cpp

@@ -3,8 +3,6 @@
 #include <AggregateFunctions/FactoryHelpers.h>
 #include <AggregateFunctions/Moments.h>
 
-#include "registerAggregateFunctions.h"
-
 
 namespace ErrorCodes
 {
@@ -57,7 +55,8 @@ struct StudentTTestData : public TTestMoments<Float64>
     }
 };
 
-AggregateFunctionPtr createAggregateFunctionStudentTTest(const std::string & name, const DataTypes & argument_types, const Array & parameters, const Settings *)
+AggregateFunctionPtr createAggregateFunctionStudentTTest(
+    const std::string & name, const DataTypes & argument_types, const Array & parameters, const Settings *)
 {
     assertBinary(name, argument_types);
     assertNoParameters(name, parameters);

src/AggregateFunctions/AggregateFunctionSum.cpp

@@ -2,7 +2,6 @@
 #include <AggregateFunctions/AggregateFunctionSum.h>
 #include <AggregateFunctions/Helpers.h>
 #include <AggregateFunctions/FactoryHelpers.h>
-#include "registerAggregateFunctions.h"
 
 
 namespace DB

src/AggregateFunctions/AggregateFunctionSumCount.cpp

@@ -2,7 +2,7 @@
 #include <AggregateFunctions/AggregateFunctionSumCount.h>
 #include <AggregateFunctions/Helpers.h>
 #include <AggregateFunctions/FactoryHelpers.h>
-#include "registerAggregateFunctions.h"
+
 
 namespace DB
 {

src/AggregateFunctions/AggregateFunctionSumMap.cpp

@@ -4,7 +4,6 @@
 #include <AggregateFunctions/FactoryHelpers.h>
 #include <Functions/FunctionHelpers.h>
 #include <IO/WriteHelpers.h>
-#include "registerAggregateFunctions.h"
 
 
 namespace DB

src/AggregateFunctions/AggregateFunctionUniq.cpp

@@ -11,12 +11,12 @@
 
 namespace DB
 {
+
 struct Settings;
 
 namespace ErrorCodes
 {
     extern const int NUMBER_OF_ARGUMENTS_DOESNT_MATCH;
-    extern const int ILLEGAL_TYPE_OF_ARGUMENT;
 }
 
 
@@ -38,12 +38,6 @@ AggregateFunctionPtr createAggregateFunctionUniq(const std::string & name, const
 
     bool use_exact_hash_function = !isAllArgumentsContiguousInMemory(argument_types);
 
-    const WhichDataType t(argument_types[0]);
-    if (t.isAggregateFunction())
-        throw Exception(
-            "Illegal type " + argument_types[0]->getName() + " of argument for aggregate function " + name,
-            ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
-
     if (argument_types.size() == 1)
     {
         const IDataType & argument_type = *argument_types[0];
@@ -86,12 +80,6 @@ AggregateFunctionPtr createAggregateFunctionUniq(const std::string & name, const
         throw Exception("Incorrect number of arguments for aggregate function " + name,
             ErrorCodes::NUMBER_OF_ARGUMENTS_DOESNT_MATCH);
 
-    const WhichDataType t(argument_types[0]);
-    if (t.isAggregateFunction())
-        throw Exception(
-            "Illegal type " + argument_types[0]->getName() + " of argument for aggregate function " + name,
-            ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
-
     /// We use exact hash function if the user wants it;
     /// or if the arguments are not contiguous in memory, because only exact hash function have support for this case.
     bool use_exact_hash_function = is_exact || !isAllArgumentsContiguousInMemory(argument_types);

src/AggregateFunctions/AggregateFunctionUniqCombined.cpp

@@ -13,13 +13,13 @@
 
 namespace DB
 {
+
 struct Settings;
 
 namespace ErrorCodes
 {
     extern const int NUMBER_OF_ARGUMENTS_DOESNT_MATCH;
     extern const int ARGUMENT_OUT_OF_BOUND;
-    extern const int ILLEGAL_TYPE_OF_ARGUMENT;
 }
 
 namespace
@@ -105,11 +105,6 @@ namespace
 
         if (argument_types.empty())
             throw Exception("Incorrect number of arguments for aggregate function " + name, ErrorCodes::NUMBER_OF_ARGUMENTS_DOESNT_MATCH);
-        const WhichDataType t(argument_types[0]);
-        if (t.isAggregateFunction())
-            throw Exception(
-                "Illegal type " + argument_types[0]->getName() + " of argument for aggregate function " + name,
-                ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
 
         switch (precision)
         {

src/AggregateFunctions/AggregateFunctionUniqUpTo.cpp

@@ -10,13 +10,13 @@
 
 namespace DB
 {
+
 struct Settings;
 
 namespace ErrorCodes
 {
     extern const int NUMBER_OF_ARGUMENTS_DOESNT_MATCH;
     extern const int ARGUMENT_OUT_OF_BOUND;
-    extern const int ILLEGAL_TYPE_OF_ARGUMENT;
 }
 
 
@@ -47,11 +47,6 @@ AggregateFunctionPtr createAggregateFunctionUniqUpTo(const std::string & name, c
     if (argument_types.empty())
         throw Exception("Incorrect number of arguments for aggregate function " + name,
             ErrorCodes::NUMBER_OF_ARGUMENTS_DOESNT_MATCH);
-    const WhichDataType t(argument_types[0]);
-    if (t.isAggregateFunction())
-        throw Exception(
-            "Illegal type " + argument_types[0]->getName() + " of argument for aggregate function " + name,
-            ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
 
     bool use_exact_hash_function = !isAllArgumentsContiguousInMemory(argument_types);
 

src/AggregateFunctions/AggregateFunctionWelchTTest.cpp

@@ -3,8 +3,6 @@
 #include <AggregateFunctions/FactoryHelpers.h>
 #include <AggregateFunctions/Moments.h>
 
-#include "registerAggregateFunctions.h"
-
 
 namespace ErrorCodes
 {
@@ -54,7 +52,8 @@ struct WelchTTestData : public TTestMoments<Float64>
     }
 };
 
-AggregateFunctionPtr createAggregateFunctionWelchTTest(const std::string & name, const DataTypes & argument_types, const Array & parameters, const Settings *)
+AggregateFunctionPtr createAggregateFunctionWelchTTest(
+    const std::string & name, const DataTypes & argument_types, const Array & parameters, const Settings *)
 {
     assertBinary(name, argument_types);
     assertNoParameters(name, parameters);

src/AggregateFunctions/CMakeLists.txt

@@ -2,6 +2,7 @@ include("${ClickHouse_SOURCE_DIR}/cmake/dbms_glob_sources.cmake")
 add_headers_and_sources(clickhouse_aggregate_functions .)
 
 list(REMOVE_ITEM clickhouse_aggregate_functions_sources
+    IAggregateFunction.cpp
     AggregateFunctionFactory.cpp
     AggregateFunctionCombinatorFactory.cpp
     AggregateFunctionCount.cpp

src/AggregateFunctions/IAggregateFunction.cpp

@@ -0,0 +1,13 @@
+#include <AggregateFunctions/IAggregateFunction.h>
+#include <DataTypes/DataTypeAggregateFunction.h>
+
+
+namespace DB
+{
+
+DataTypePtr IAggregateFunction::getStateType() const
+{
+    return std::make_shared<DataTypeAggregateFunction>(shared_from_this(), argument_types, parameters);
+}
+
+}

src/AggregateFunctions/IAggregateFunction.h

@@ -38,7 +38,7 @@ using AggregateDataPtr = char *;
 using ConstAggregateDataPtr = const char *;
 
 class IAggregateFunction;
-using AggregateFunctionPtr = std::shared_ptr<IAggregateFunction>;
+using AggregateFunctionPtr = std::shared_ptr<const IAggregateFunction>;
 struct AggregateFunctionProperties;
 
 /** Aggregate functions interface.
@@ -49,7 +49,7 @@ struct AggregateFunctionProperties;
   *  (which can be created in some memory pool),
   *  and IAggregateFunction is the external interface for manipulating them.
   */
-class IAggregateFunction
+class IAggregateFunction : public std::enable_shared_from_this<IAggregateFunction>
 {
 public:
     IAggregateFunction(const DataTypes & argument_types_, const Array & parameters_)
@@ -61,6 +61,9 @@ public:
     /// Get the result type.
     virtual DataTypePtr getReturnType() const = 0;
 
+    /// Get the data type of internal state. By default it is AggregateFunction(name(params), argument_types...).
+    virtual DataTypePtr getStateType() const;
+
     /// Get type which will be used for prediction result in case if function is an ML method.
     virtual DataTypePtr getReturnTypeToPredict() const
     {
@@ -236,9 +239,7 @@ public:
     // aggregate functions implement IWindowFunction interface and so on. This
     // would be more logically correct, but more complex. We only have a handful
     // of true window functions, so this hack-ish interface suffices.
-    virtual IWindowFunction * asWindowFunction() { return nullptr; }
-    virtual const IWindowFunction * asWindowFunction() const
-    { return const_cast<IAggregateFunction *>(this)->asWindowFunction(); }
+    virtual bool isOnlyWindowFunction() const { return false; }
 
 protected:
     DataTypes argument_types;

src/AggregateFunctions/ya.make

@@ -61,6 +61,7 @@ SRCS(
     AggregateFunctionUniqUpTo.cpp
     AggregateFunctionWelchTTest.cpp
     AggregateFunctionWindowFunnel.cpp
+    IAggregateFunction.cpp
     UniqCombinedBiasData.cpp
     UniqVariadicHash.cpp
     parseAggregateFunctionParameters.cpp

src/CMakeLists.txt

@@ -111,6 +111,7 @@ list (APPEND dbms_sources Functions/IFunction.cpp Functions/FunctionFactory.cpp
 list (APPEND dbms_headers Functions/IFunction.h Functions/FunctionFactory.h Functions/FunctionHelpers.h Functions/extractTimeZoneFromFunctionArguments.h Functions/replicate.h Functions/FunctionsLogical.h)
 
 list (APPEND dbms_sources
+    AggregateFunctions/IAggregateFunction.cpp
     AggregateFunctions/AggregateFunctionFactory.cpp
     AggregateFunctions/AggregateFunctionCombinatorFactory.cpp
     AggregateFunctions/AggregateFunctionState.cpp

src/Columns/ColumnAggregateFunction.cpp

@@ -167,7 +167,7 @@ MutableColumnPtr ColumnAggregateFunction::predictValues(const ColumnsWithTypeAnd
     MutableColumnPtr res = func->getReturnTypeToPredict()->createColumn();
     res->reserve(data.size());
 
-    auto * machine_learning_function = func.get();
+    const auto * machine_learning_function = func.get();
     if (machine_learning_function)
     {
         if (data.size() == 1)
@@ -485,7 +485,7 @@ Arena & ColumnAggregateFunction::createOrGetArena()
 }
 
 
-static void pushBackAndCreateState(ColumnAggregateFunction::Container & data, Arena & arena, IAggregateFunction * func)
+static void pushBackAndCreateState(ColumnAggregateFunction::Container & data, Arena & arena, const IAggregateFunction * func)
 {
     data.push_back(arena.alignedAlloc(func->sizeOfData(), func->alignOfData()));
     try

src/DataTypes/DataTypeAggregateFunction.cpp

@@ -100,7 +100,7 @@ bool DataTypeAggregateFunction::equals(const IDataType & rhs) const
 
 SerializationPtr DataTypeAggregateFunction::doGetDefaultSerialization() const
 {
-    return std::make_shared<SerializationAggregateFunction>(function);
+    return std::make_shared<SerializationAggregateFunction>(function, getName());
 }
 
 

src/DataTypes/Serializations/SerializationAggregateFunction.cpp

@@ -20,19 +20,16 @@ namespace DB
 
 void SerializationAggregateFunction::serializeBinary(const Field & field, WriteBuffer & ostr) const
 {
-    const String & s = get<const String &>(field);
-    writeVarUInt(s.size(), ostr);
-    writeString(s, ostr);
+    const AggregateFunctionStateData & state = get<const AggregateFunctionStateData &>(field);
+    writeBinary(state.data, ostr);
 }
 
 void SerializationAggregateFunction::deserializeBinary(Field & field, ReadBuffer & istr) const
 {
-    UInt64 size;
-    readVarUInt(size, istr);
-    field = String();
-    String & s = get<String &>(field);
-    s.resize(size);
-    istr.readStrict(s.data(), size);
+    field = AggregateFunctionStateData();
+    AggregateFunctionStateData & s = get<AggregateFunctionStateData &>(field);
+    readBinary(s.data, istr);
+    s.name = type_name;
 }
 
 void SerializationAggregateFunction::serializeBinary(const IColumn & column, size_t row_num, WriteBuffer & ostr) const

src/DataTypes/Serializations/SerializationAggregateFunction.h

@@ -12,11 +12,13 @@ class SerializationAggregateFunction final : public ISerialization
 {
 private:
     AggregateFunctionPtr function;
+    String type_name;
 
 public:
     static constexpr bool is_parametric = true;
 
-    SerializationAggregateFunction(const AggregateFunctionPtr & function_): function(function_) {}
+    SerializationAggregateFunction(const AggregateFunctionPtr & function_, String type_name_)
+        : function(function_), type_name(std::move(type_name_)) {}
 
     /// NOTE These two functions for serializing single values are incompatible with the functions below.
     void serializeBinary(const Field & field, WriteBuffer & ostr) const override;

src/Functions/array/arrayReduce.cpp

@@ -107,7 +107,7 @@ DataTypePtr FunctionArrayReduce::getReturnTypeImpl(const ColumnsWithTypeAndName
 
 ColumnPtr FunctionArrayReduce::executeImpl(const ColumnsWithTypeAndName & arguments, const DataTypePtr & result_type, size_t input_rows_count) const
 {
-    IAggregateFunction & agg_func = *aggregate_function;
+    const IAggregateFunction & agg_func = *aggregate_function;
     std::unique_ptr<Arena> arena = std::make_unique<Arena>();
 
     /// Aggregate functions do not support constant columns. Therefore, we materialize them.
@@ -178,9 +178,9 @@ ColumnPtr FunctionArrayReduce::executeImpl(const ColumnsWithTypeAndName & argume
     });
 
     {
-        auto * that = &agg_func;
+        const auto * that = &agg_func;
         /// Unnest consecutive trailing -State combinators
-        while (auto * func = typeid_cast<AggregateFunctionState *>(that))
+        while (const auto * func = typeid_cast<const AggregateFunctionState *>(that))
             that = func->getNestedFunction().get();
 
         that->addBatchArray(input_rows_count, places.data(), 0, aggregate_arguments, offsets->data(), arena.get());

src/Functions/array/arrayReduceInRanges.cpp

@@ -123,9 +123,10 @@ DataTypePtr FunctionArrayReduceInRanges::getReturnTypeImpl(const ColumnsWithType
 }
 
 
-ColumnPtr FunctionArrayReduceInRanges::executeImpl(const ColumnsWithTypeAndName & arguments, const DataTypePtr & result_type, size_t input_rows_count) const
+ColumnPtr FunctionArrayReduceInRanges::executeImpl(
+    const ColumnsWithTypeAndName & arguments, const DataTypePtr & result_type, size_t input_rows_count) const
 {
-    IAggregateFunction & agg_func = *aggregate_function;
+    const IAggregateFunction & agg_func = *aggregate_function;
     std::unique_ptr<Arena> arena = std::make_unique<Arena>();
 
     /// Aggregate functions do not support constant columns. Therefore, we materialize them.
@@ -257,9 +258,9 @@ ColumnPtr FunctionArrayReduceInRanges::executeImpl(const ColumnsWithTypeAndName
                 agg_func.destroy(places[j]);
         });
 
-        auto * true_func = &agg_func;
+        const auto * true_func = &agg_func;
         /// Unnest consecutive trailing -State combinators
-        while (auto * func = typeid_cast<AggregateFunctionState *>(true_func))
+        while (const auto * func = typeid_cast<const AggregateFunctionState *>(true_func))
             true_func = func->getNestedFunction().get();
 
         /// Pre-aggregate to the initial level

src/Functions/initializeAggregation.cpp

@@ -44,6 +44,7 @@ public:
     ColumnPtr executeImpl(const ColumnsWithTypeAndName & arguments, const DataTypePtr & result_type, size_t input_rows_count) const override;
 
 private:
+    /// TODO Rewrite with FunctionBuilder.
     mutable AggregateFunctionPtr aggregate_function;
 };
 
@@ -89,7 +90,7 @@ DataTypePtr FunctionInitializeAggregation::getReturnTypeImpl(const ColumnsWithTy
 
 ColumnPtr FunctionInitializeAggregation::executeImpl(const ColumnsWithTypeAndName & arguments, const DataTypePtr & result_type, size_t input_rows_count) const
 {
-    IAggregateFunction & agg_func = *aggregate_function;
+    const IAggregateFunction & agg_func = *aggregate_function;
     std::unique_ptr<Arena> arena = std::make_unique<Arena>();
 
     const size_t num_arguments_columns = arguments.size() - 1;
@@ -138,9 +139,9 @@ ColumnPtr FunctionInitializeAggregation::executeImpl(const ColumnsWithTypeAndNam
     });
 
     {
-        auto * that = &agg_func;
+        const auto * that = &agg_func;
         /// Unnest consecutive trailing -State combinators
-        while (auto * func = typeid_cast<AggregateFunctionState *>(that))
+        while (const auto * func = typeid_cast<const AggregateFunctionState *>(that))
             that = func->getNestedFunction().get();
         that->addBatch(input_rows_count, places.data(), 0, aggregate_arguments, arena.get());
     }

src/Interpreters/Aggregator.cpp

@@ -651,7 +651,7 @@ void Aggregator::prepareAggregateInstructions(Columns columns, AggregateColumns
         aggregate_functions_instructions[i].arguments = aggregate_columns[i].data();
         aggregate_functions_instructions[i].state_offset = offsets_of_aggregate_states[i];
 
-        auto * that = aggregate_functions[i];
+        const auto * that = aggregate_functions[i];
         /// Unnest consecutive trailing -State combinators
         while (const auto * func = typeid_cast<const AggregateFunctionState *>(that))
             that = func->getNestedFunction().get();

src/Interpreters/Aggregator.h

@@ -959,7 +959,7 @@ public:
     using AggregateColumns = std::vector<ColumnRawPtrs>;
     using AggregateColumnsData = std::vector<ColumnAggregateFunction::Container *>;
     using AggregateColumnsConstData = std::vector<const ColumnAggregateFunction::Container *>;
-    using AggregateFunctionsPlainPtrs = std::vector<IAggregateFunction *>;
+    using AggregateFunctionsPlainPtrs = std::vector<const IAggregateFunction *>;
 
     /// Process one block. Return false if the processing should be aborted (with group_by_overflow_mode = 'break').
     bool executeOnBlock(const Block & block, AggregatedDataVariants & result,

src/Interpreters/ExecuteScalarSubqueriesVisitor.cpp

@@ -3,7 +3,6 @@
 #include <Columns/ColumnTuple.h>
 #include <DataStreams/IBlockInputStream.h>
 #include <DataStreams/materializeBlock.h>
-#include <DataTypes/DataTypeAggregateFunction.h>
 #include <DataTypes/DataTypeTuple.h>
 #include <IO/WriteHelpers.h>
 #include <Interpreters/Context.h>

src/Interpreters/InterpreterSelectQuery.cpp

@@ -1742,7 +1742,7 @@ void InterpreterSelectQuery::executeFetchColumns(QueryProcessingStage::Enum proc
         && processing_stage == QueryProcessingStage::FetchColumns
         && query_analyzer->hasAggregation()
         && (query_analyzer->aggregates().size() == 1)
-        && typeid_cast<AggregateFunctionCount *>(query_analyzer->aggregates()[0].function.get());
+        && typeid_cast<const AggregateFunctionCount *>(query_analyzer->aggregates()[0].function.get());
 
     if (optimize_trivial_count)
     {
@@ -1766,7 +1766,7 @@ void InterpreterSelectQuery::executeFetchColumns(QueryProcessingStage::Enum proc
 
         if (num_rows)
         {
-            AggregateFunctionCount & agg_count = static_cast<AggregateFunctionCount &>(*func);
+            const AggregateFunctionCount & agg_count = static_cast<const AggregateFunctionCount &>(*func);
 
             /// We will process it up to "WithMergeableState".
             std::vector<char> state(agg_count.sizeOfData());

src/Interpreters/examples/hash_map.cpp

@@ -68,7 +68,7 @@ int main(int argc, char ** argv)
     using namespace DB;
 
     using Key = UInt64;
-    using Value = std::vector<IAggregateFunction*>;
+    using Value = std::vector<const IAggregateFunction*>;
 
     size_t n = argc < 2 ? 10000000 : std::stol(argv[1]);
     //size_t m = std::stol(argv[2]);

src/Processors/Merges/Algorithms/Graphite.h

@@ -5,7 +5,7 @@ namespace DB
 {
 
 class IAggregateFunction;
-using AggregateFunctionPtr = std::shared_ptr<IAggregateFunction>;
+using AggregateFunctionPtr = std::shared_ptr<const IAggregateFunction>;
 
 }
 

src/Processors/Transforms/WindowTransform.cpp

@@ -215,7 +215,9 @@ WindowTransform::WindowTransform(const Block & input_header_,
         }
         workspace.argument_columns.assign(f.argument_names.size(), nullptr);
 
-        workspace.window_function_impl = aggregate_function->asWindowFunction();
+        /// Currently we have slightly wrong mixup of the interfaces of Window and Aggregate functions.
+        workspace.window_function_impl = dynamic_cast<IWindowFunction *>(const_cast<IAggregateFunction *>(aggregate_function.get()));
+
         if (!workspace.window_function_impl)
         {
             workspace.aggregate_function_state.reset(
@@ -1343,13 +1345,12 @@ struct WindowFunction
 {
     std::string name;
 
-    WindowFunction(const std::string & name_, const DataTypes & argument_types_,
-               const Array & parameters_)
+    WindowFunction(const std::string & name_, const DataTypes & argument_types_, const Array & parameters_)
         : IAggregateFunctionHelper<WindowFunction>(argument_types_, parameters_)
         , name(name_)
     {}
 
-    IWindowFunction * asWindowFunction() override { return this; }
+    bool isOnlyWindowFunction() const override { return true; }
 
     [[noreturn]] void fail() const
     {

tests/queries/0_stateless/01882_uniqueState_over_uniqueState.sh

@@ -1,20 +0,0 @@
-#!/usr/bin/env bash
-
-export CLICKHOUSE_CLIENT_SERVER_LOGS_LEVEL=fatal
-
-CURDIR=$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)
-# shellcheck source=../shell_config.sh
-. "$CURDIR"/../shell_config.sh
-
-
-function check()
-{
-    $CLICKHOUSE_CLIENT -q "SELECT id, $1(s) FROM ( SELECT number % 10 as id, uniqState(number) as s FROM ( SELECT number FROM system.numbers LIMIT 100 ) GROUP BY number ) GROUP BY id" 2>&1 | grep -v -P '^(Received exception from server|Code: 43)' ||:
-}
-
-stateFunctions=("uniqState" "uniqExactState" "uniqHLL12State" "uniqCombinedState" "uniqUpToState")  # "uniqThetaState" not tested because its availability depends on compilation options
-
-for i1 in "${stateFunctions[@]}"
-do
-    check "$i1"
-done

tests/queries/0_stateless/01890_state_of_state.sql

@@ -0,0 +1,22 @@
+SELECT uniqExact(x) FROM (SELECT uniqState(number) AS x FROM numbers(100));
+SELECT uniqExact(x) FROM (SELECT uniqState(number) AS x FROM numbers(1000));
+SELECT hex(toString(uniqExactState(x))) FROM (SELECT uniqState(number) AS x FROM numbers(1000));
+SELECT hex(toString(uniqExactState(x))) FROM (SELECT quantileState(number) AS x FROM numbers(1000));
+SELECT toTypeName(uniqExactState(x)) FROM (SELECT quantileState(number) AS x FROM numbers(1000));
+SELECT toTypeName(initializeAggregation('uniqExact', 0));
+SELECT toTypeName(initializeAggregation('uniqExactState', 0));
+SELECT toTypeName(initializeAggregation('uniqExactState', initializeAggregation('quantileState', 0)));
+SELECT hex(toString(initializeAggregation('quantileState', 0)));
+SELECT toTypeName(initializeAggregation('sumState', initializeAggregation('quantileState', 0))); -- { serverError 43 }
+SELECT toTypeName(initializeAggregation('anyState', initializeAggregation('quantileState', 0)));
+SELECT toTypeName(initializeAggregation('anyState', initializeAggregation('uniqState', 0)));
+SELECT hex(toString(initializeAggregation('uniqState', initializeAggregation('uniqState', 0))));
+SELECT hex(toString(initializeAggregation('uniqState', initializeAggregation('quantileState', 0))));
+SELECT hex(toString(initializeAggregation('anyLastState', initializeAggregation('uniqState', 0))));
+SELECT hex(toString(initializeAggregation('anyState', initializeAggregation('uniqState', 0))));
+SELECT hex(toString(initializeAggregation('maxState', initializeAggregation('uniqState', 0)))); -- { serverError 43 }
+SELECT hex(toString(initializeAggregation('uniqExactState', initializeAggregation('uniqState', 0))));
+SELECT finalizeAggregation(initializeAggregation('uniqExactState', initializeAggregation('uniqState', 0)));
+SELECT toTypeName(quantileState(x)) FROM (SELECT uniqState(number) AS x FROM numbers(1000)); -- { serverError 43 }
+SELECT hex(toString(quantileState(x))) FROM (SELECT uniqState(number) AS x FROM numbers(1000)); -- { serverError 43 }
+SELECT hex(toString(anyState(x))), hex(toString(any(x))) FROM (SELECT uniqState(number) AS x FROM numbers(1000)) FORMAT Vertical;