f3eade2f62
Drop the AGPL license in favor of a source-available license. See the blog post [1] for details. [1] https://www.scylladb.com/2024/12/18/why-were-moving-to-a-source-available-license/
66 lines
2.5 KiB
C++
66 lines
2.5 KiB
C++
/*
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* Copyright (C) 2012-present ScyllaDB
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*/
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/*
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* SPDX-License-Identifier: LicenseRef-ScyllaDB-Source-Available-1.0
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*/
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#pragma once
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#include "schema/schema_fwd.hh"
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#include "dht/ring_position.hh"
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#include "readers/mutation_reader_fwd.hh"
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#include "readers/mutation_reader.hh"
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class reader_permit;
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struct combined_reader_statistics;
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class reader_selector {
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protected:
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schema_ptr _s;
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dht::ring_position_view _selector_position;
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size_t _max_reader_count;
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public:
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reader_selector(schema_ptr s, dht::ring_position_view rpv, size_t max_reader_count) noexcept
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: _s(std::move(s)), _selector_position(std::move(rpv)), _max_reader_count(max_reader_count) {}
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virtual ~reader_selector() = default;
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// Call only if has_new_readers() returned true.
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virtual std::vector<mutation_reader> create_new_readers(const std::optional<dht::ring_position_view>& pos) = 0;
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virtual std::vector<mutation_reader> fast_forward_to(const dht::partition_range& pr) = 0;
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// Can be false-positive but never false-negative!
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bool has_new_readers(const std::optional<dht::ring_position_view>& pos) const noexcept {
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dht::ring_position_comparator cmp(*_s);
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return !_selector_position.is_max() && (!pos || cmp(*pos, _selector_position) >= 0);
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}
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size_t max_reader_count() const {
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return _max_reader_count;
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}
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};
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// Creates a mutation reader which combines data return by supplied readers.
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// Returns mutation of the same schema only when all readers return mutations
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// of the same schema.
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mutation_reader make_combined_reader(schema_ptr schema,
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reader_permit permit,
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std::vector<mutation_reader>,
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streamed_mutation::forwarding fwd_sm = streamed_mutation::forwarding::no,
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mutation_reader::forwarding fwd_mr = mutation_reader::forwarding::yes,
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combined_reader_statistics* statistics = nullptr);
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mutation_reader make_combined_reader(schema_ptr schema,
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reader_permit permit,
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std::unique_ptr<reader_selector>,
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streamed_mutation::forwarding,
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mutation_reader::forwarding,
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combined_reader_statistics* statistics = nullptr);
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mutation_reader make_combined_reader(schema_ptr schema,
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reader_permit permit,
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mutation_reader&& a,
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mutation_reader&& b,
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streamed_mutation::forwarding fwd_sm = streamed_mutation::forwarding::no,
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mutation_reader::forwarding fwd_mr = mutation_reader::forwarding::yes,
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combined_reader_statistics* statistics = nullptr);
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