42a1ced73b
The expression system uses managed_bytes_opt for values, but result_set uses bytes_opt. This means that processing values from the result set in expressions requires a copy. Out of the two, managed_bytes_opt is the better choice, since it prevents large contiguous allocations for large blobs. So we switch result_set to use managed_bytes_opt. Users of the result_set API are adjusted. The db::function interface is not modified to limit churn; instead we convert the types on entry and exit. This will be adjusted in a following patch.
62 lines
1.8 KiB
C++
62 lines
1.8 KiB
C++
/*
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* Modified by ScyllaDB
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* Copyright (C) 2015-present ScyllaDB
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*/
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/*
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* SPDX-License-Identifier: (AGPL-3.0-or-later and Apache-2.0)
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*/
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#include "abstract_function_selector.hh"
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#include "cql3/functions/aggregate_function.hh"
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#pragma once
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namespace cql3 {
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namespace selection {
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class aggregate_function_selector : public abstract_function_selector_for<functions::aggregate_function> {
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const db::functions::stateless_aggregate_function& _aggregate;
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bytes_opt _accumulator;
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public:
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virtual bool is_aggregate() const override {
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return true;
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}
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virtual void add_input(result_set_builder& rs) override {
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// Aggregation of aggregation is not supported
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size_t m = _arg_selectors.size();
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_args[0] = std::move(_accumulator);
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for (size_t i = 0; i < m; ++i) {
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auto&& s = _arg_selectors[i];
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s->add_input(rs);
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_args[i + 1] = to_bytes_opt(s->get_output());
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s->reset();
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}
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_accumulator = _aggregate.aggregation_function->execute(_args);
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}
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virtual managed_bytes_opt get_output() override {
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return to_managed_bytes_opt(
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_aggregate.state_to_result_function
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? _aggregate.state_to_result_function->execute(std::span(&_accumulator, 1))
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: std::move(_accumulator));
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}
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virtual void reset() override {
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_accumulator = _aggregate.initial_state;
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}
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aggregate_function_selector(shared_ptr<functions::function> func,
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std::vector<shared_ptr<selector>> arg_selectors)
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: abstract_function_selector_for<functions::aggregate_function>(
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dynamic_pointer_cast<functions::aggregate_function>(func), std::move(arg_selectors), true)
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, _aggregate(fun()->get_aggregate())
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, _accumulator(_aggregate.initial_state) {
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}
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};
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}
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}
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