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/
87 lines
3.4 KiB
C++
87 lines
3.4 KiB
C++
/*
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* Modified by ScyllaDB
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* Copyright (C) 2023-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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// Scylla includes.
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#include "db/commitlog/commitlog.hh"
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#include "db/commitlog/commitlog_entry.hh"
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#include "db/hints/internal/common.hh"
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#include "utils/loading_shared_values.hh"
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// STD.
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#include <filesystem>
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/// This file is supposed to gather meta information about data structures
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/// and types related to storing hints.
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///
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/// Under the hood, commitlog is used for managing, storing, and reading
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/// hints from disk.
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namespace db::hints {
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namespace internal {
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using node_to_hint_store_factory_type = utils::loading_shared_values<endpoint_id, db::commitlog>;
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using hints_store_ptr = node_to_hint_store_factory_type::entry_ptr;
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using hint_entry_reader = commitlog_entry_reader;
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/// \brief Rebalance hints segments among all present shards.
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///
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/// The difference between the number of segments on every two shard will not be
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/// greater than 1 after the rebalancing.
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///
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/// Removes the subdirectories of \ref hint_directory that correspond to shards that
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/// are not relevant anymore (in the case of re-sharding to a lower shard number).
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///
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/// Complexity: O(N+K), where N is a total number of present hint segments and
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/// K = <number of shards during the previous boot> * <number of endpoints
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/// for which hints where ever created>
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///
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/// \param hint_directory A hint directory to rebalance
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/// \return A future that resolves when the operation is complete.
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future<> rebalance_hints(std::filesystem::path hint_directory);
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class hint_directory_manager {
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private:
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std::map<locator::host_id, gms::inet_address> _mappings;
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public:
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// Inserts a new mapping and returns it.
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// If either the host ID or the IP is already in the map, the function inserts nothings
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// and returns the existing mapping instead.
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std::pair<locator::host_id, gms::inet_address> insert_mapping(const locator::host_id& host_id,
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const gms::inet_address& ip);
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// Returns the corresponding IP for a given host ID if a mapping is present in the directory manager.
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// Otherwise, an empty optional is returned.
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[[nodiscard]] std::optional<gms::inet_address> get_mapping(const locator::host_id& host_id) const noexcept;
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// Returns the corresponding host ID for a given IP if a mapping is present in the directory manager.
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// Otherwise, an empty optional is returned.
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[[nodiscard]] std::optional<locator::host_id> get_mapping(const gms::inet_address& ip) const noexcept;
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// Returns a mapping corresponding to either the passed host ID, or the passed IP if the mapping exists.
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// Otherwise, an empty optional is returned.
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[[nodiscard]] std::optional<std::pair<locator::host_id, gms::inet_address>> get_mapping(
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const locator::host_id& host_id, const gms::inet_address& ip) const noexcept;
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// Removes a mapping corresponding to the passed host ID if the mapping exists.
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void remove_mapping(const locator::host_id& host_id) noexcept;
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// Removes a mapping corresponding to the passed IP if the mapping exists.
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void remove_mapping(const gms::inet_address& ip) noexcept;
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bool has_mapping(const locator::host_id& host_id) const noexcept;
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bool has_mapping(const gms::inet_address& ip) const noexcept;
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// Removes all of the mappings.
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void clear() noexcept;
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};
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} // namespace internal
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} // namespace db::hints
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