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6d5bfc8c6f
* Better code [#CLICKHOUSE-2]. * Addition to prev. revision [#CLICKHOUSE-2]. * Addition to prev. revision [#CLICKHOUSE-2]. * Addition to prev. revision [#CLICKHOUSE-2].
188 lines
5.1 KiB
C++
188 lines
5.1 KiB
C++
#pragma once
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#include <DB/IO/VarInt.h>
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#include <array>
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#include <DB/DataTypes/DataTypesNumber.h>
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#include <DB/DataTypes/DataTypeNullable.h>
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#include <DB/AggregateFunctions/INullaryAggregateFunction.h>
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#include <DB/AggregateFunctions/IUnaryAggregateFunction.h>
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#include <DB/Columns/ColumnNullable.h>
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namespace DB
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{
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struct AggregateFunctionCountData
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{
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UInt64 count = 0;
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};
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/// Simply count number of calls.
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class AggregateFunctionCount final : public INullaryAggregateFunction<AggregateFunctionCountData, AggregateFunctionCount>
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{
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public:
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String getName() const override { return "count"; }
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void setArguments(const DataTypes & arguments) override
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{
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/// You may pass some arguments. All of them are ignored.
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}
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DataTypePtr getReturnType() const override
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{
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return std::make_shared<DataTypeUInt64>();
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}
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void addImpl(AggregateDataPtr place) const
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{
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++data(place).count;
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}
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void merge(AggregateDataPtr place, ConstAggregateDataPtr rhs, Arena * arena) const override
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{
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data(place).count += data(rhs).count;
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}
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void serialize(ConstAggregateDataPtr place, WriteBuffer & buf) const override
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{
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writeVarUInt(data(place).count, buf);
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}
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void deserialize(AggregateDataPtr place, ReadBuffer & buf, Arena *) const override
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{
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readVarUInt(data(place).count, buf);
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}
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void insertResultInto(ConstAggregateDataPtr place, IColumn & to) const override
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{
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static_cast<ColumnUInt64 &>(to).getData().push_back(data(place).count);
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}
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/// May be used for optimization.
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void addDelta(AggregateDataPtr place, UInt64 x) const
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{
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data(place).count += x;
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}
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};
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/// Simply count number of not-NULL values.
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class AggregateFunctionCountNotNullUnary final : public IUnaryAggregateFunction<AggregateFunctionCountData, AggregateFunctionCountNotNullUnary>
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{
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public:
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String getName() const override { return "count"; }
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DataTypePtr getReturnType() const override
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{
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return std::make_shared<DataTypeUInt64>();
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}
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void addImpl(AggregateDataPtr place, const IColumn & column, size_t row_num, Arena * arena) const
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{
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data(place).count += !static_cast<const ColumnNullable &>(column).isNullAt(row_num);
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}
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void setArgument(const DataTypePtr & argument)
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{
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if (!argument->isNullable() && !argument->isNull())
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throw Exception("Not Nullable argument passed to aggregate function count", ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
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}
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void merge(AggregateDataPtr place, ConstAggregateDataPtr rhs, Arena * arena) const override
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{
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data(place).count += data(rhs).count;
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}
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void serialize(ConstAggregateDataPtr place, WriteBuffer & buf) const override
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{
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writeVarUInt(data(place).count, buf);
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}
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void deserialize(AggregateDataPtr place, ReadBuffer & buf, Arena *) const override
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{
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readVarUInt(data(place).count, buf);
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}
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void insertResultInto(ConstAggregateDataPtr place, IColumn & to) const override
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{
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static_cast<ColumnUInt64 &>(to).getData().push_back(data(place).count);
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}
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};
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/// Count number of calls where all arguments are not NULL.
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class AggregateFunctionCountNotNullVariadic final : public IAggregateFunctionHelper<AggregateFunctionCountData>
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{
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public:
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String getName() const override { return "count"; }
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DataTypePtr getReturnType() const override
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{
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return std::make_shared<DataTypeUInt64>();
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}
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void setArguments(const DataTypes & arguments) override
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{
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number_of_arguments = arguments.size();
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if (number_of_arguments == 1)
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throw Exception("Logical error: single argument is passed to AggregateFunctionCountNotNullVariadic", ErrorCodes::LOGICAL_ERROR);
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if (number_of_arguments > MAX_ARGS)
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throw Exception("Maximum number of arguments for aggregate function with Nullable types is " + toString(MAX_ARGS),
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ErrorCodes::NUMBER_OF_ARGUMENTS_DOESNT_MATCH);
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for (size_t i = 0; i < number_of_arguments; ++i)
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is_nullable[i] = arguments[i]->isNullable() || arguments[i]->isNull();
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}
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void add(AggregateDataPtr place, const IColumn ** columns, size_t row_num, Arena * arena) const override
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{
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for (size_t i = 0; i < number_of_arguments; ++i)
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if (is_nullable[i] && static_cast<const ColumnNullable &>(*columns[i]).isNullAt(row_num))
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return;
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++data(place).count;
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}
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static void addFree(const IAggregateFunction * that, AggregateDataPtr place,
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const IColumn ** columns, size_t row_num, Arena * arena)
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{
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return static_cast<const AggregateFunctionCountNotNullVariadic &>(*that).add(place, columns, row_num, arena);
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}
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AddFunc getAddressOfAddFunction() const override
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{
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return &addFree;
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}
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void merge(AggregateDataPtr place, ConstAggregateDataPtr rhs, Arena * arena) const override
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{
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data(place).count += data(rhs).count;
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}
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void serialize(ConstAggregateDataPtr place, WriteBuffer & buf) const override
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{
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writeVarUInt(data(place).count, buf);
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}
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void deserialize(AggregateDataPtr place, ReadBuffer & buf, Arena *) const override
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{
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readVarUInt(data(place).count, buf);
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}
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void insertResultInto(ConstAggregateDataPtr place, IColumn & to) const override
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{
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static_cast<ColumnUInt64 &>(to).getData().push_back(data(place).count);
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}
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private:
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enum { MAX_ARGS = 8 };
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size_t number_of_arguments = 0;
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std::array<char, MAX_ARGS> is_nullable; /// Plain array is better than std::vector due to one indirection less.
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};
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}
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