Revert "Function arrayFold for folding over array with accumulator"

docs/en/sql-reference/functions/array-functions.md

@@ -1213,62 +1213,6 @@ SELECT arrayFill(x -> not isNull(x), [1, null, 3, 11, 12, null, null, 5, 6, 14,
 
 Note that the `arrayFill` is a [higher-order function](../../sql-reference/functions/index.md#higher-order-functions). You must pass a lambda function to it as the first argument, and it can’t be omitted.
 
-## arrayFold(func, arr1, …, init) {#array-fold}
-
-Returns an result of [folding](https://en.wikipedia.org/wiki/Fold_(higher-order_function)) arrays and value `init` using function `func`.
-I.e. result of calculation `func(arr1[n], …, func(arr1[n - 1], …, func(…, func(arr1[2], …,  func(arr1[1], …, init)))))`.
-
-Note that the `arrayMap` is a [higher-order function](../../sql-reference/functions/index.md#higher-order-functions). You must pass a lambda function to it as the first argument, and it can’t be omitted.
-
-**Arguments**
-
--   `func` — The lambda function with `n+1` arguments (where `n` is number of input arrays), first `n` arguments are for
-    current elements of input arrays, and last argument is for current value of accumulator.
--   `arr` — Any number of [arrays](../../sql-reference/data-types/array.md).
--   `init` - Initial value of accumulator.
-
-**Returned value**
-
-Final value of accumulator.
-
-**Examples**
-
-The following example shows how to acquire product and sum of elements of array:
-
-``` sql
-SELECT arrayMap(x, accum -> (accum.1 * x, accum.2 + x), [1, 2, 3], (0, 1)) as res;
-```
-
-``` text
-┌─res───────┐
-│ (120, 15) │
-└───────────┘
-```
-
-The following example shows how to reverse elements of array:
-
-``` sql
-SELECT arrayFold(x, acc -> arrayPushFront(acc, x), [1,2,3,4,5], emptyArrayUInt64()) as res;
-```
-
-``` text
-┌─res─────────┐
-│ [5,4,3,2,1] │
-└─────────────┘
-```
-
-Folding may be used to access of already passed elements due to function calculation, for example:
-
-``` sql
-SELECT arrayFold(x, acc -> (x, concat(acc.2, toString(acc.1), ',')), [1,2], (0,''))
-```
-
-``` text
-┌─res────────┐
-│ (2,'0,1,') │
-└────────────┘
-```
-
 ## arrayReverseFill(func, arr1, …) {#array-reverse-fill}
 
 Scan through `arr1` from the last element to the first element and replace `arr1[i]` by `arr1[i + 1]` if `func` returns 0. The last element of `arr1` will not be replaced.

docs/ru/sql-reference/functions/array-functions.md

@@ -1147,62 +1147,6 @@ SELECT arrayReverseFill(x -> not isNull(x), [1, null, 3, 11, 12, null, null, 5,
 
 Функция `arrayReverseFill` является [функцией высшего порядка](../../sql-reference/functions/index.md#higher-order-functions) — в качестве первого аргумента ей нужно передать лямбда-функцию, и этот аргумент не может быть опущен.
 
-## arrayFold(func, arr1, …, init) {#array-fold}
-
-Возвращает результат [сворачивания](https://ru.wikipedia.org/wiki/%D0%A1%D0%B2%D1%91%D1%80%D1%82%D0%BA%D0%B0_%D1%81%D0%BF%D0%B8%D1%81%D0%BA%D0%B0) массивов и начального значения `init` с помощью функции `func`.
-Т.е. результат вычисления `func(arr1[n], …, func(arr1[n - 1], …, func(…, func(arr1[2], …,  func(arr1[1], …, init)))))`.
-
-Функция `arrayFold` является [функцией высшего порядка](../../sql-reference/functions/index.md#higher-order-functions) — в качестве первого аргумента ей нужно передать лямбда-функцию, и этот аргумент не может быть опущен.
-
-**Аргументы**
-
--   `func` — лямбда-функция с `n+1` параметром (где `n` это количество входных массивов), причём первые `n` параметров
-    используются для текущих элементов входных массивов, а последний элемент для текущего значения аккумулятора.
--   `arr` — произвольное количество [массивов](../../sql-reference/data-types/array.md).
--   `init` - начальное значение аккумулятора.
-
-**Возвращаемое значение**
-
-Итоговое значение аккумулятора.
-
-**Примеры**
-
-Следующий пример показывает, как вычислить произведение и сумму элементов массива:
-
-``` sql
-SELECT arrayMap(x, accum -> (accum.1 * x, accum.2 + x), [1, 2, 3], (0, 1)) as res;
-```
-
-``` text
-┌─res───────┐
-│ (120, 15) │
-└───────────┘
-```
-
-В этом примере показано, как обратить массив:
-
-``` sql
-SELECT arrayFold(x, acc -> arrayPushFront(acc, x), [1,2,3,4,5], emptyArrayUInt64()) as res;
-```
-
-``` text
-┌─res─────────┐
-│ [5,4,3,2,1] │
-└─────────────┘
-```
-
-Свёртка может быть использована для доступа к уже пройденным в процессе вычисления элементам. Например:
-
-``` sql
-SELECT arrayFold(x, acc -> (x, concat(acc.2, toString(acc.1), ',')), [1,2], (0,''))
-```
-
-``` text
-┌─res────────┐
-│ (2,'0,1,') │
-└────────────┘
-```
-
 ## arraySplit(func, arr1, …) {#array-split}
 
 Разделяет массив `arr1` на несколько. Если `func` возвращает не 0, то массив разделяется, а элемент помещается в левую часть. Массив не разбивается по первому элементу.
@@ -1239,7 +1183,6 @@ SELECT arrayReverseSplit((x, y) -> y, [1, 2, 3, 4, 5], [1, 0, 0, 1, 0]) AS res
 
 Функция `arrayReverseSplit` является [функцией высшего порядка](../../sql-reference/functions/index.md#higher-order-functions) — в качестве первого аргумента ей нужно передать лямбда-функцию, и этот аргумент не может быть опущен.
 
-
 ## arrayExists(\[func,\] arr1, …) {#arrayexistsfunc-arr1}
 
 Возвращает 1, если существует хотя бы один элемент массива `arr`, для которого функция func возвращает не 0. Иначе возвращает 0.

src/Functions/array/arrayFold.cpp

@@ -1,187 +0,0 @@
-#include "FunctionArrayMapped.h"
-#include <Functions/FunctionFactory.h>
-
-
-namespace DB
-{
-
-namespace ErrorCodes
-{
-    extern const int ILLEGAL_COLUMN;
-    extern const int ILLEGAL_TYPE_OF_ARGUMENT;
-    extern const int NUMBER_OF_ARGUMENTS_DOESNT_MATCH;
-    extern const int SIZES_OF_ARRAYS_DOESNT_MATCH;
-    extern const int TYPE_MISMATCH;
-}
-
-
-/** arrayFold(x1,...,xn,accum -> expression, array1,...,arrayn, init_accum) - apply the expression to each element of the array (or set of parallel arrays).
-  */
-class FunctionArrayFold : public IFunction
-{
-public:
-    static constexpr auto name = "arrayFold";
-    static FunctionPtr create(ContextPtr) { return std::make_shared<FunctionArrayFold>(); }
-
-    String getName() const override { return name; }
-    bool isVariadic() const override { return true; }
-    size_t getNumberOfArguments() const override { return 0; }
-
-    void getLambdaArgumentTypes(DataTypes & arguments) const override
-    {
-        if (arguments.size() < 3)
-            throw Exception("Function " + getName() + " needs lambda function, at least one array argument and one accumulator argument.",
-                            ErrorCodes::NUMBER_OF_ARGUMENTS_DOESNT_MATCH);
-
-        DataTypes nested_types(arguments.size() - 1);
-        for (size_t i = 0; i < nested_types.size() - 1; ++i)
-        {
-            const DataTypeArray * array_type = checkAndGetDataType<DataTypeArray>(&*arguments[i + 1]);
-            if (!array_type)
-                throw Exception("Argument " + toString(i + 2) + " of function " + getName() + " must be array. Found "
-                                + arguments[i + 1]->getName() + " instead.", ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
-            nested_types[i] = recursiveRemoveLowCardinality(array_type->getNestedType());
-        }
-        nested_types[nested_types.size() - 1] = arguments[arguments.size() - 1];
-
-        const DataTypeFunction * function_type = checkAndGetDataType<DataTypeFunction>(arguments[0].get());
-        if (!function_type || function_type->getArgumentTypes().size() != nested_types.size())
-            throw Exception("First argument for this overload of " + getName() + " must be a function with "
-                            + toString(nested_types.size()) + " arguments. Found "
-                            + arguments[0]->getName() + " instead.", ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
-
-        arguments[0] = std::make_shared<DataTypeFunction>(nested_types);
-    }
-
-    DataTypePtr getReturnTypeImpl(const ColumnsWithTypeAndName & arguments) const override
-    {
-        if (arguments.size() < 2)
-            throw Exception("Function " + getName() + " needs at least 2 arguments; passed "
-                            + toString(arguments.size()) + ".",
-                            ErrorCodes::NUMBER_OF_ARGUMENTS_DOESNT_MATCH);
-        const auto * data_type_function = checkAndGetDataType<DataTypeFunction>(arguments[0].type.get());
-        if (!data_type_function)
-            throw Exception("First argument for function " + getName() + " must be a function.",
-                ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
-
-        auto const accumulator_type = arguments.back().type;
-        auto const lambda_type = data_type_function->getReturnType();
-        if (! accumulator_type->equals(*lambda_type))
-            throw Exception("Return type of lambda function must be the same as the accumulator type. "
-                            "Inferred type of lambda " + lambda_type->getName() + ", "
-                            + "inferred type of accumulator " + accumulator_type->getName() + ".",
-                ErrorCodes::TYPE_MISMATCH);
-
-        return DataTypePtr(accumulator_type);
-    }
-
-    ColumnPtr executeImpl(const ColumnsWithTypeAndName & arguments, const DataTypePtr &, size_t /*input_rows_count*/) const override
-    {
-        const auto & column_with_type_and_name = arguments[0];
-
-        if (!column_with_type_and_name.column)
-            throw Exception("First argument for function " + getName() + " must be a function.",
-                ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
-
-        const auto * column_function = typeid_cast<const ColumnFunction *>(column_with_type_and_name.column.get());
-
-        if (!column_function)
-            throw Exception("First argument for function " + getName() + " must be a function.",
-                ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
-
-        ColumnPtr offsets_column;
-        ColumnPtr column_first_array_ptr;
-        const ColumnArray * column_first_array = nullptr;
-        ColumnsWithTypeAndName arrays;
-        arrays.reserve(arguments.size() - 1);
-
-        for (size_t i = 1; i < arguments.size() - 1; ++i)
-        {
-            const auto & array_with_type_and_name = arguments[i];
-            ColumnPtr column_array_ptr = array_with_type_and_name.column;
-            const auto * column_array = checkAndGetColumn<ColumnArray>(column_array_ptr.get());
-            const DataTypePtr & array_type_ptr = array_with_type_and_name.type;
-            const auto * array_type = checkAndGetDataType<DataTypeArray>(array_type_ptr.get());
-            if (!column_array)
-            {
-                const ColumnConst * column_const_array = checkAndGetColumnConst<ColumnArray>(column_array_ptr.get());
-                if (!column_const_array)
-                    throw Exception("Expected array column, found " + column_array_ptr->getName(), ErrorCodes::ILLEGAL_COLUMN);
-                column_array_ptr = recursiveRemoveLowCardinality(column_const_array->convertToFullColumn());
-                column_array = checkAndGetColumn<ColumnArray>(column_array_ptr.get());
-            }
-            if (!array_type)
-                throw Exception("Expected array type, found " + array_type_ptr->getName(), ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
-            if (!offsets_column)
-            {
-                offsets_column = column_array->getOffsetsPtr();
-            }
-            else
-            {
-                /// The first condition is optimization: do not compare data if the pointers are equal.
-                if (column_array->getOffsetsPtr() != offsets_column
-                    && column_array->getOffsets() != typeid_cast<const ColumnArray::ColumnOffsets &>(*offsets_column).getData())
-                    throw Exception("Arrays passed to " + getName() + " must have equal size", ErrorCodes::SIZES_OF_ARRAYS_DOESNT_MATCH);
-            }
-            if (i == 1)
-            {
-                column_first_array_ptr = column_array_ptr;
-                column_first_array = column_array;
-            }
-            arrays.emplace_back(ColumnWithTypeAndName(column_array->getDataPtr(),
-                                                      recursiveRemoveLowCardinality(array_type->getNestedType()),
-                                                      array_with_type_and_name.name));
-        }
-        arrays.emplace_back(arguments.back());
-
-        MutableColumnPtr result = arguments.back().column->convertToFullColumnIfConst()->cloneEmpty();
-        size_t arr_cursor = 0;
-        for (size_t irow = 0; irow < column_first_array->size(); ++irow) // for each row of result
-        {
-            // Make accumulator column for this row. We initialize it
-            // with the starting value given as the last argument.
-            ColumnWithTypeAndName accumulator_column = arguments.back();
-            ColumnPtr acc(accumulator_column.column->cut(irow, 1));
-            auto accumulator = ColumnWithTypeAndName(acc,
-                                                     accumulator_column.type,
-                                                     accumulator_column.name);
-            ColumnPtr res(acc);
-            size_t const arr_next = column_first_array->getOffsets()[irow]; // when we do folding
-            for (size_t iter = 0; arr_cursor < arr_next; ++iter, ++arr_cursor)
-            {
-                // Make slice of input arrays and accumulator for lambda
-                ColumnsWithTypeAndName iter_arrays;
-                iter_arrays.reserve(arrays.size() + 1);
-                for (size_t icolumn = 0; icolumn < arrays.size() - 1; ++icolumn)
-                {
-                    auto const & arr = arrays[icolumn];
-                    iter_arrays.emplace_back(ColumnWithTypeAndName(arr.column->cut(arr_cursor, 1),
-                                                                   arr.type,
-                                                                   arr.name));
-                }
-                iter_arrays.emplace_back(accumulator);
-                // Calculate function on arguments
-                auto replicated_column_function_ptr = IColumn::mutate(column_function->replicate(ColumnArray::Offsets(column_first_array->getOffsets().size(), 1)));
-                auto * replicated_column_function = typeid_cast<ColumnFunction *>(replicated_column_function_ptr.get());
-                replicated_column_function->appendArguments(iter_arrays);
-                auto lambda_result = replicated_column_function->reduce().column;
-                if (lambda_result->lowCardinality())
-                    lambda_result = lambda_result->convertToFullColumnIfLowCardinality();
-                res = lambda_result->cut(0, 1);
-                accumulator.column = res;
-            }
-            result->insert((*res)[0]);
-        }
-        return result;
-    }
-};
-
-
-void registerFunctionArrayFold(FunctionFactory & factory)
-{
-    factory.registerFunction<FunctionArrayFold>();
-}
-
-
-}
-

src/Functions/registerFunctionsHigherOrder.cpp

@@ -4,7 +4,6 @@ namespace DB
 class FunctionFactory;
 
 void registerFunctionArrayMap(FunctionFactory & factory);
-void registerFunctionArrayFold(FunctionFactory & factory);
 void registerFunctionArrayFilter(FunctionFactory & factory);
 void registerFunctionArrayCount(FunctionFactory & factory);
 void registerFunctionArrayExists(FunctionFactory & factory);
@@ -23,7 +22,6 @@ void registerFunctionArrayDifference(FunctionFactory & factory);
 void registerFunctionsHigherOrder(FunctionFactory & factory)
 {
     registerFunctionArrayMap(factory);
-    registerFunctionArrayFold(factory);
     registerFunctionArrayFilter(factory);
     registerFunctionArrayCount(factory);
     registerFunctionArrayExists(factory);

src/Functions/ya.make

@@ -144,7 +144,6 @@ SRCS(
     array/arrayFirst.cpp
     array/arrayFirstIndex.cpp
     array/arrayFlatten.cpp
-    array/arrayFold.cpp
     array/arrayIntersect.cpp
     array/arrayJoin.cpp
     array/arrayMap.cpp

tests/performance/array_fold_small.xml

@@ -1,4 +0,0 @@
-<test>
-    <query>SELECT arrayFold(x, acc -> acc + 1, range(100000), toUInt64(0))</query> <!-- count -->
-    <query>SELECT arrayFold(x, acc -> acc + x, range(100000), toUInt64(0))</query> <!-- sum   -->
-</test>

tests/queries/0_stateless/01811_array_fold.reference

@@ -1,8 +0,0 @@
-23
-3
-101
-269
-[1,2,3,4]
-[4,3,2,1]
-([4,3,2,1],[1,2,3,4])
-([1,3,5],[2,4,6])

tests/queries/0_stateless/01811_array_fold.sql

@@ -1,8 +0,0 @@
-SELECT arrayFold(x,acc -> acc + x * 2, [1,2,3,4], toInt64(3));
-SELECT arrayFold(x,acc -> acc + x * 2, emptyArrayInt64(), toInt64(3));
-SELECT arrayFold(x,y,acc -> acc + x * 2 + y * 3, [1,2,3,4], [5,6,7,8], toInt64(3));
-SELECT arrayFold(x,y,z,acc -> acc + x * 2 + y * 3 + z * 4, [1,2,3,4], [5,6,7,8], [9,10,11,12], toInt64(3));
-SELECT arrayFold(x,acc -> arrayPushBack(acc,x),  [1,2,3,4], emptyArrayInt64());
-SELECT arrayFold(x,acc -> arrayPushFront(acc,x), [1,2,3,4], emptyArrayInt64());
-SELECT arrayFold(x,acc -> (arrayPushFront(acc.1,x), arrayPushBack(acc.2,x)), [1,2,3,4], (emptyArrayInt64(), emptyArrayInt64()));
-SELECT arrayFold(x,acc -> x % 2 ? (arrayPushBack(acc.1,x), acc.2): (acc.1, arrayPushBack(acc.2,x)), [1,2,3,4,5,6], (emptyArrayInt64(), emptyArrayInt64()));

tests/queries/0_stateless/01812_array_fold_data_from_tables.reference

@@ -1,80 +0,0 @@
-0
-0
-1
-3
-6
-10
-15
-21
-28
-36
-0
-1
-3
-6
-10
-15
-21
-28
-36
-45
-[]
-[0]
-[1,0]
-[2,1,0]
-[3,2,1,0]
-[4,3,2,1,0]
-[5,4,3,2,1,0]
-[6,5,4,3,2,1,0]
-[7,6,5,4,3,2,1,0]
-[8,7,6,5,4,3,2,1,0]
-[]
-[0]
-[1,0]
-[1,0,2]
-[3,1,0,2]
-[3,1,0,2,4]
-[5,3,1,0,2,4]
-[5,3,1,0,2,4,6]
-[7,5,3,1,0,2,4,6]
-[7,5,3,1,0,2,4,6,8]
-(0,0)
-(0,0)
-(1,-1)
-(3,-3)
-(6,-6)
-(10,-10)
-(15,-15)
-(21,-21)
-(28,-28)
-(36,-36)
-(0,0)
-(0,0)
-(1,-1)
-(3,-3)
-(6,-6)
-(10,-10)
-(15,-15)
-(21,-21)
-(28,-28)
-(36,-36)
-[(0,0)]
-[(0,1),(0,0)]
-[(1,2),(0,1),(0,0)]
-[(2,3),(1,2),(0,1),(0,0)]
-[(3,4),(2,3),(1,2),(0,1),(0,0)]
-[(4,5),(3,4),(2,3),(1,2),(0,1),(0,0)]
-[(5,6),(4,5),(3,4),(2,3),(1,2),(0,1),(0,0)]
-[(6,7),(5,6),(4,5),(3,4),(2,3),(1,2),(0,1),(0,0)]
-[(7,8),(6,7),(5,6),(4,5),(3,4),(2,3),(1,2),(0,1),(0,0)]
-[(8,9),(7,8),(6,7),(5,6),(4,5),(3,4),(2,3),(1,2),(0,1),(0,0)]
-[]
-['0']
-['0','1']
-['0','1','2']
-['0','1','2','3']
-['0','1','2','3','4']
-['0','1','2','3','4','5']
-['0','1','2','3','4','5','6']
-['0','1','2','3','4','5','6','7']
-['0','1','2','3','4','5','6','7','8']

tests/queries/0_stateless/01812_array_fold_data_from_tables.sql

@@ -1,8 +0,0 @@
-SELECT arrayFold(x,acc -> acc+x, range(number), toInt64(0)) FROM system.numbers LIMIT 10;
-SELECT arrayFold(x,acc -> acc+x, range(number), number) FROM system.numbers LIMIT 10;
-SELECT arrayFold(x,acc -> arrayPushFront(acc, x), range(number), emptyArrayUInt64()) FROM system.numbers LIMIT 10;
-SELECT arrayFold(x,acc -> x % 2 ? arrayPushFront(acc, x) : arrayPushBack(acc, x), range(number), emptyArrayUInt64()) FROM system.numbers LIMIT 10;
-SELECT arrayFold(x,acc -> (acc.1+x, acc.2-x), range(number), (toInt64(0), toInt64(0))) FROM system.numbers LIMIT 10;
-SELECT arrayFold(x,acc -> (acc.1+x.1, acc.2-x.2), arrayZip(range(number), range(number)), (toInt64(0), toInt64(0))) FROM system.numbers LIMIT 10;
-SELECT arrayFold(x,acc -> arrayPushFront(acc, (x, x+1)), range(number), [(toUInt64(0),toUInt64(0))]) FROM system.numbers LIMIT 10;
-SELECT arrayFold(x, acc -> concat(acc, arrayMap(z -> toString(x), [number])) , range(number), CAST([] as Array(String))) FROM system.numbers LIMIT 10;

tests/queries/0_stateless/01813_array_fold_errors.sql

@@ -1,12 +0,0 @@
-SELECT arrayFold([]); -- { serverError 42 }
-SELECT arrayFold([1,2,3]); -- { serverError 42 }
-SELECT arrayFold([1,2,3], [4,5,6]); -- { serverError 43 }
-SELECT arrayFold(1234); -- { serverError 42 }
-SELECT arrayFold(x, acc -> acc + x, 10, 20); -- { serverError 43 }
-SELECT arrayFold(x, acc -> acc + x, 10, [20, 30, 40]); -- { serverError 43 }
-SELECT arrayFold(x -> x * 2, [1,2,3,4], toInt64(3)); -- { serverError 43 }
-SELECT arrayFold(x,acc -> acc+x, number, toInt64(0)) FROM system.numbers LIMIT 10; -- { serverError 43 }
-SELECT arrayFold(x,y,acc -> acc + x * 2 + y * 3, [1,2,3,4], [5,6,7], toInt64(3)); -- { serverError 190 }
-SELECT arrayFold(x,acc -> acc + x * 2 + y * 3, [1,2,3,4], [5,6,7,8], toInt64(3)); -- { serverError 47 }
-SELECT arrayFold(x,acc -> acc + x * 2, [1,2,3,4], [5,6,7,8], toInt64(3)); -- { serverError 43 }
-SELECT arrayFold(x,acc -> concat(acc,', ', x), [1, 2, 3, 4], '0') -- { serverError 44 }