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898cd1d404
Base initial tablets allocation for new table on the dc/rack topology, rather then on the token ring, to remove the dependency on token ownership. We keep the rack ordinal order in each dc to facilitate in-rack pairing of base/view replica pairing, and we apply load-balancing principles by sorting the nodes in each rack by their load (number of tablets allocated to the node), and attempting to fill lease-loaded nodes first. This method is more efficient than circling the token ring and attemting to insert the endpoints to the natural_endpoint_tracker until the replication factor per dc is fulfilled, and it allows an easier way to incrementally allocate more replicas after rf is increased. Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
51 lines
2.0 KiB
C++
51 lines
2.0 KiB
C++
/*
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* Copyright (C) 2023-present ScyllaDB
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*/
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/*
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* SPDX-License-Identifier: AGPL-3.0-or-later
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*/
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#pragma once
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#include "locator/abstract_replication_strategy.hh"
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#include "locator/token_metadata.hh"
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#include "locator/tablets.hh"
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#include <seastar/core/sstring.hh>
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namespace locator {
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/// Trait class which allows replication strategies to work in a mode which
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/// uses tablet-based replication.
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///
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/// Contains common logic, like parsing tablet options,
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/// and creating effective_replication_map for a given table which works with
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/// system's tablet_metadata.
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class tablet_aware_replication_strategy : public per_table_replication_strategy {
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private:
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size_t _initial_tablets = 1;
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protected:
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void validate_tablet_options(const abstract_replication_strategy&, const gms::feature_service&, const replication_strategy_config_options&) const;
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void process_tablet_options(abstract_replication_strategy&, replication_strategy_config_options&, replication_strategy_params);
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std::unordered_set<sstring> recognized_tablet_options() const;
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size_t get_initial_tablets() const { return _initial_tablets; }
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effective_replication_map_ptr do_make_replication_map(table_id,
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replication_strategy_ptr,
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token_metadata_ptr,
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size_t replication_factor) const;
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public:
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/// Generates tablet_map for a new table.
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/// Runs under group0 guard.
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virtual future<tablet_map> allocate_tablets_for_new_table(schema_ptr, token_metadata_ptr, unsigned initial_scale) const = 0;
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/// Generates tablet_map for a new table or when increasing replication factor.
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/// For a new table, cur_tablets is initialized with the tablet_count,
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/// otherwise, cur_tablets is a copy of the current tablet_map.
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/// Runs under group0 guard.
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virtual future<tablet_map> reallocate_tablets(schema_ptr, token_metadata_ptr, tablet_map cur_tablets) const = 0;
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};
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} // namespace locator
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