c628fa4e9e
before this change, `scylla sstable shard-of` didn't support tablets, because: - with tablets enabled, data distribution uses the scheduler - this replaces the previous method of mapping based on vnodes and shard numbers - as a result, we can no longer deduce sstable mapping from token ranges in this change, we: - read `system.tablets` table to retrieve tablet information - print the tablet's replica set (list of <host, shard> pairs) - this helps users determine where a given sstable is hosted This approach provides the closest equivalent functionality of `shard-of` in the tablet era. Fixes scylladb/scylladb#16488 Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
105 lines
4.2 KiB
C++
105 lines
4.2 KiB
C++
/*
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* Copyright (C) 2024-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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#include "tools/load_system_tablets.hh"
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#include <seastar/core/thread.hh>
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#include <seastar/util/closeable.hh>
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#include "log.hh"
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#include "data_dictionary/keyspace_metadata.hh"
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#include "db/cql_type_parser.hh"
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#include "db/system_keyspace.hh"
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#include "mutation/mutation.hh"
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#include "readers/combined.hh"
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#include "replica/tablets.hh"
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#include "tools/read_mutation.hh"
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#include "types/list.hh"
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#include "types/tuple.hh"
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namespace {
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logging::logger logger{"load_sys_tablets"};
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future<utils::UUID> get_table_id(std::filesystem::path scylla_data_path,
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std::string_view keyspace_name,
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std::string_view table_name) {
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auto path = co_await get_table_directory(scylla_data_path,
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keyspace_name,
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table_name);
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// the part after "-" is the string representation of the table_id
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// "$scylla_data_path/system/tablets-fd4f7a4696bd3e7391bf99eb77e82a5c"
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auto fn = path.filename().native();
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auto dash_pos = fn.find_last_of('-');
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assert(dash_pos != fn.npos);
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if (dash_pos == fn.size()) {
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throw std::runtime_error(fmt::format("failed parse system.tablets path {}: bad path", path));
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}
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co_return utils::UUID{fn.substr(dash_pos + 1).c_str()};
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}
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tools::tablets_t do_load_system_tablets(const db::config& dbcfg,
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std::filesystem::path scylla_data_path,
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std::string_view keyspace_name,
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std::string_view table_name,
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reader_permit permit) {
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sharded<sstable_manager_service> sst_man;
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sst_man.start(std::ref(dbcfg)).get();
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auto stop_sst_man_service = deferred_stop(sst_man);
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auto schema = db::system_keyspace::tablets();
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auto tablets_table_directory = get_table_directory(scylla_data_path,
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db::system_keyspace::NAME,
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schema->cf_name()).get();
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auto table_id = get_table_id(scylla_data_path, keyspace_name, table_name).get();
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auto mut = read_mutation_from_table_offline(sst_man,
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permit,
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tablets_table_directory,
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db::system_keyspace::NAME,
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db::system_keyspace::tablets,
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data_value(table_id),
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{});
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if (!mut || mut->partition().row_count() == 0) {
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throw std::runtime_error(fmt::format("failed to find tablets for {}.{}", keyspace_name, table_name));
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}
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auto ks = make_lw_shared<data_dictionary::keyspace_metadata>(keyspace_name,
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"org.apache.cassandra.locator.LocalStrategy",
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std::map<sstring, sstring>{},
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std::nullopt, false);
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db::cql_type_parser::raw_builder ut_builder(*ks);
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tools::tablets_t tablets;
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query::result_set result_set{*mut};
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for (auto& row : result_set.rows()) {
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auto last_token = row.get_nonnull<int64_t>("last_token");
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auto replica_set = row.get_data_value("replicas");
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if (replica_set) {
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tablets.emplace(last_token,
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replica::tablet_replica_set_from_cell(*replica_set));
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}
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}
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return tablets;
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}
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} // anonymous namespace
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namespace tools {
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future<tablets_t> load_system_tablets(const db::config &dbcfg,
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std::filesystem::path scylla_data_path,
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std::string_view keyspace_name,
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std::string_view table_name,
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reader_permit permit) {
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return async([=, &dbcfg] {
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return do_load_system_tablets(dbcfg, scylla_data_path, keyspace_name, table_name, permit);
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});
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}
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} // namespace tools
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