58eb21aa5d
Now that all aggregate functions are derived from stateless_aggregate_function_adapter, we can just fold its functionality into the base class. This exposes stateless_aggregate_function to all users of aggregate_function, so they can begin to benefit from the transformation, though this patch doesn't touch those users. The aggregate_function base class is partiallly devirtualized since there is just a single implementation now.
36 lines
1010 B
C++
36 lines
1010 B
C++
// Copyright (C) 2023-present ScyllaDB
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// SPDX-License-Identifier: (AGPL-3.0-or-later and Apache-2.0)
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#pragma once
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#include "scalar_function.hh"
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#include "function_name.hh"
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#include <optional>
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namespace db::functions {
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struct stateless_aggregate_function final {
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function_name name;
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std::optional<sstring> column_name_override; // if unset, column name is synthesized from name and argument names
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data_type state_type;
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data_type result_type;
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std::vector<data_type> argument_types;
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bytes_opt initial_state;
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// aggregates another input
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// signature: (state_type, argument_types...) -> state_type
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shared_ptr<scalar_function> aggregation_function;
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// converts the state type to a result
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// signature: (state_type) -> result_type
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shared_ptr<scalar_function> state_to_result_function;
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// optional: reduces states computed in parallel
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// signature: (state_type, state_type) -> state_type
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shared_ptr<scalar_function> state_reduction_function;
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};
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}
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