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tablets: Implement tablet sharder

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This commit is contained in:
Tomasz Grabiec
2023-05-09 11:45:33 +02:00
parent e44e6033d8
commit 22ab100b41
3 changed files with 187 additions and 0 deletions
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78
locator/tablet_sharder.hh Normal file
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@@ -0,0 +1,78 @@
/*
* Copyright (C) 2023-present ScyllaDB
*/
/*
* SPDX-License-Identifier: AGPL-3.0-or-later
*/
#pragma once
#include "locator/tablets.hh"
#include "dht/sharder.hh"
#include "locator/token_metadata.hh"
namespace locator {
/// Implements sharder object which reflects assignment of tablets of a given table to local shards.
/// Token ranges which don't have local tablets are reported to belong to shard 0.
class tablet_sharder : public dht::sharder {
const token_metadata& _tm;
table_id _table;
mutable const tablet_map* _tmap = nullptr;
private:
// Tablet map is lazily initialized to avoid exceptions during effective_replication_map construction
// in case tablet mapping is not yet available in token metadata at the time the table is constructed.
void ensure_tablet_map() const {
if (!_tmap) {
_tmap = &_tm.tablets().get_tablet_map(_table);
}
}
public:
tablet_sharder(const token_metadata& tm, table_id table)
: _tm(tm)
, _table(table)
{ }
virtual ~tablet_sharder() = default;
virtual unsigned shard_of(const dht::token& token) const override {
ensure_tablet_map();
auto tid = _tmap->get_tablet_id(token);
auto shard = _tmap->get_shard(tid, _tm.get_my_id());
tablet_logger.trace("[{}] shard_of({}) = {}, tablet={}", _table, token, shard, tid);
return shard.value_or(0);
}
virtual std::optional<dht::shard_and_token> next_shard(const token& t) const override {
ensure_tablet_map();
auto me = _tm.get_my_id();
std::optional<tablet_id> tb = _tmap->get_tablet_id(t);
while ((tb = _tmap->next_tablet(*tb))) {
auto r = _tmap->get_shard(*tb, me);
auto next = _tmap->get_first_token(*tb);
tablet_logger.trace("[{}] token_for_next_shard({}) = {{{}, {}}}, tablet={}", _table, t, next, r, *tb);
return dht::shard_and_token{r.value_or(0), next};
}
tablet_logger.trace("[{}] token_for_next_shard({}) = null", _table, t);
return std::nullopt;
}
virtual token token_for_next_shard(const token& t, shard_id shard, unsigned spans = 1) const override {
ensure_tablet_map();
auto token = t;
while (auto s_a_t = next_shard(token)) {
token = s_a_t->token;
if (s_a_t->shard == shard) {
if (--spans == 0) {
tablet_logger.trace("[{}] token_for_next_shard({}, {}, {}) = {}", _table, t, shard, spans, s_a_t->token);
return token;
}
}
}
tablet_logger.trace("[{}] token_for_next_shard({}, {}, {}) = null", _table, t, shard, spans);
return dht::maximum_token();
}
};
} // namespace locator

1
locator/tablets.cc
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@@ -8,6 +8,7 @@
#include "locator/tablet_replication_strategy.hh"
#include "locator/tablets.hh"
#include "locator/tablet_sharder.hh"
#include "locator/token_range_splitter.hh"
#include "dht/i_partitioner.hh"
#include "types/types.hh"

108
test/boost/tablets_test.cc
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@@ -17,7 +17,9 @@
#include "replica/tablets.hh"
#include "locator/tablets.hh"
#include "locator/tablet_sharder.hh"
#include "locator/tablet_replication_strategy.hh"
#include "utils/fb_utilities.hh"
using namespace locator;
using namespace replica;
@@ -263,6 +265,112 @@ SEASTAR_TEST_CASE(test_get_shard) {
}, tablet_cql_test_config());
}
SEASTAR_TEST_CASE(test_sharder) {
return do_with_cql_env_thread([] (cql_test_env& e) {
auto h1 = host_id(utils::UUID_gen::get_time_UUID());
auto h2 = host_id(utils::UUID_gen::get_time_UUID());
auto h3 = host_id(utils::UUID_gen::get_time_UUID());
auto table1 = table_id(utils::UUID_gen::get_time_UUID());
token_metadata tokm(token_metadata::config{});
tokm.get_topology().add_or_update_endpoint(utils::fb_utilities::get_broadcast_address(), h1);
std::vector<tablet_id> tablet_ids;
{
tablet_map tmap(4);
auto tid = tmap.first_tablet();
tablet_ids.push_back(tid);
tmap.set_tablet(tid, tablet_info {
tablet_replica_set {
tablet_replica {h1, 3},
tablet_replica {h3, 5},
}
});
tid = *tmap.next_tablet(tid);
tablet_ids.push_back(tid);
tmap.set_tablet(tid, tablet_info {
tablet_replica_set {
tablet_replica {h2, 3},
tablet_replica {h3, 1},
}
});
tid = *tmap.next_tablet(tid);
tablet_ids.push_back(tid);
tmap.set_tablet(tid, tablet_info {
tablet_replica_set {
tablet_replica {h3, 2},
tablet_replica {h1, 1},
}
});
tmap.set_tablet_transition_info(tid, tablet_transition_info {
tablet_replica_set {
tablet_replica {h1, 1},
tablet_replica {h2, 3},
},
tablet_replica {h2, 3}
});
tid = *tmap.next_tablet(tid);
tablet_ids.push_back(tid);
tmap.set_tablet(tid, tablet_info {
tablet_replica_set {
tablet_replica {h3, 7},
tablet_replica {h2, 3},
}
});
tablet_metadata tm;
tm.set_tablet_map(table1, std::move(tmap));
tokm.set_tablets(std::move(tm));
}
auto& tm = tokm.tablets().get_tablet_map(table1);
tablet_sharder sharder(tokm, table1);
BOOST_REQUIRE_EQUAL(sharder.shard_of(tm.get_last_token(tablet_ids[0])), 3);
BOOST_REQUIRE_EQUAL(sharder.shard_of(tm.get_last_token(tablet_ids[1])), 0); // missing
BOOST_REQUIRE_EQUAL(sharder.shard_of(tm.get_last_token(tablet_ids[2])), 1);
BOOST_REQUIRE_EQUAL(sharder.shard_of(tm.get_last_token(tablet_ids[3])), 0); // missing
BOOST_REQUIRE_EQUAL(sharder.token_for_next_shard(tm.get_last_token(tablet_ids[1]), 0), tm.get_first_token(tablet_ids[3]));
BOOST_REQUIRE_EQUAL(sharder.token_for_next_shard(tm.get_last_token(tablet_ids[1]), 1), tm.get_first_token(tablet_ids[2]));
BOOST_REQUIRE_EQUAL(sharder.token_for_next_shard(tm.get_last_token(tablet_ids[1]), 3), dht::maximum_token());
BOOST_REQUIRE_EQUAL(sharder.token_for_next_shard(tm.get_first_token(tablet_ids[1]), 0), tm.get_first_token(tablet_ids[3]));
BOOST_REQUIRE_EQUAL(sharder.token_for_next_shard(tm.get_first_token(tablet_ids[1]), 1), tm.get_first_token(tablet_ids[2]));
BOOST_REQUIRE_EQUAL(sharder.token_for_next_shard(tm.get_first_token(tablet_ids[1]), 3), dht::maximum_token());
{
auto shard_opt = sharder.next_shard(tm.get_last_token(tablet_ids[0]));
BOOST_REQUIRE(shard_opt);
BOOST_REQUIRE_EQUAL(shard_opt->shard, 0);
BOOST_REQUIRE_EQUAL(shard_opt->token, tm.get_first_token(tablet_ids[1]));
}
{
auto shard_opt = sharder.next_shard(tm.get_last_token(tablet_ids[1]));
BOOST_REQUIRE(shard_opt);
BOOST_REQUIRE_EQUAL(shard_opt->shard, 1);
BOOST_REQUIRE_EQUAL(shard_opt->token, tm.get_first_token(tablet_ids[2]));
}
{
auto shard_opt = sharder.next_shard(tm.get_last_token(tablet_ids[2]));
BOOST_REQUIRE(shard_opt);
BOOST_REQUIRE_EQUAL(shard_opt->shard, 0);
BOOST_REQUIRE_EQUAL(shard_opt->token, tm.get_first_token(tablet_ids[3]));
}
{
auto shard_opt = sharder.next_shard(tm.get_last_token(tablet_ids[3]));
BOOST_REQUIRE(!shard_opt);
}
}, tablet_cql_test_config());
}
SEASTAR_TEST_CASE(test_large_tablet_metadata) {
return do_with_cql_env_thread([] (cql_test_env& e) {
tablet_metadata tm;