bahman/scylla
1
0
Fork 0
Code Issues Pull Requests Actions 3 Packages Projects Releases Wiki Activity

tablet_allocator: Add initial tablets scale to config

Browse Source 
When allocating tablets for table for the frist time their initial count
is calculated so that each shard in a cluster gets one tablet. It may
happen that more than one initial tablet per shard is better, e.g. perf
tests typically rely on that.

It's possible to specify the initial tablets count when creating a
keyspace, this number doesn't take the cluster topology into
consideration and may also be not very nice.

As a temporary solution (e.g. for perf tests) we may add a configurable
that scales the initial number of calculated tablets by some factor

Signed-off-by: Pavel Emelyanov <xemul@scylladb.com>
This commit is contained in:
Pavel Emelyanov
2024-01-22 17:33:24 +03:00
parent f57b194db0
commit eb3b237e05
6 changed files with 12 additions and 9 deletions
Download Patch File Download Diff File Expand all files Collapse all files

4
locator/network_topology_strategy.cc
View File

@@ -312,10 +312,10 @@ static unsigned calculate_initial_tablets_from_topology(const schema& s, const t
return initial_tablets;
}
future<tablet_map> network_topology_strategy::allocate_tablets_for_new_table(schema_ptr s, token_metadata_ptr tm) const {
future<tablet_map> network_topology_strategy::allocate_tablets_for_new_table(schema_ptr s, token_metadata_ptr tm, unsigned initial_scale) const {
auto tablet_count = get_initial_tablets();
if (tablet_count == 0) {
tablet_count = calculate_initial_tablets_from_topology(*s, tm->get_topology(), _dc_rep_factor);
tablet_count = calculate_initial_tablets_from_topology(*s, tm->get_topology(), _dc_rep_factor) * initial_scale;
}
auto aligned_tablet_count = 1ul << log2ceil(tablet_count);
if (tablet_count != aligned_tablet_count) {

2
locator/network_topology_strategy.hh
View File

@@ -42,7 +42,7 @@ public:
public: // tablet_aware_replication_strategy
virtual effective_replication_map_ptr make_replication_map(table_id, token_metadata_ptr) const override;
virtual future<tablet_map> allocate_tablets_for_new_table(schema_ptr, token_metadata_ptr) const override;
virtual future<tablet_map> allocate_tablets_for_new_table(schema_ptr, token_metadata_ptr, unsigned initial_scale) const override;
protected:
/**
* calculate endpoints in one pass through the tokens by tracking our

2
locator/tablet_replication_strategy.hh
View File

@@ -44,7 +44,7 @@ protected:
public:
/// Generates tablet_map for a new table.
/// Runs under group0 guard.
virtual future<tablet_map> allocate_tablets_for_new_table(schema_ptr, token_metadata_ptr) const = 0;
virtual future<tablet_map> allocate_tablets_for_new_table(schema_ptr, token_metadata_ptr, unsigned initial_scale) const = 0;
};
} // namespace locator

6
service/tablet_allocator.cc
View File

@@ -804,7 +804,9 @@ public:
: _config(std::move(cfg))
, _migration_notifier(mn)
, _db(db) {
(void)_config;
if (_config.initial_tablets_scale == 0) {
throw std::runtime_error("Initial tablets scale must be positive");
}
if (db.get_config().check_experimental(db::experimental_features_t::feature::TABLETS)) {
_migration_notifier.register_listener(this);
}
@@ -831,7 +833,7 @@ public:
auto rs = abstract_replication_strategy::create_replication_strategy(ksm.strategy_name(), params);
if (auto&& tablet_rs = rs->maybe_as_tablet_aware()) {
auto tm = _db.get_shared_token_metadata().get();
auto map = tablet_rs->allocate_tablets_for_new_table(s.shared_from_this(), tm).get0();
auto map = tablet_rs->allocate_tablets_for_new_table(s.shared_from_this(), tm, _config.initial_tablets_scale).get0();
muts.emplace_back(tablet_map_to_mutation(map, s.id(), s.keypace_name(), s.cf_name(), ts).get0());
}
}

1
service/tablet_allocator.hh
View File

@@ -53,6 +53,7 @@ class tablet_allocator_impl;
class tablet_allocator {
public:
struct config {
unsigned initial_tablets_scale = 1;
};
class impl {
public:

6
test/boost/network_topology_strategy_test.cc
View File

@@ -447,7 +447,7 @@ SEASTAR_THREAD_TEST_CASE(NetworkTopologyStrategy_tablets_test) {
.with_column("v", utf8_type)
.build();
auto tmap = tab_awr_ptr->allocate_tablets_for_new_table(s, stm.get()).get0();
auto tmap = tab_awr_ptr->allocate_tablets_for_new_table(s, stm.get(), 1).get0();
full_ring_check(tmap, options323, ars_ptr, stm.get());
///////////////
@@ -464,7 +464,7 @@ SEASTAR_THREAD_TEST_CASE(NetworkTopologyStrategy_tablets_test) {
tab_awr_ptr = ars_ptr->maybe_as_tablet_aware();
BOOST_REQUIRE(tab_awr_ptr);
tmap = tab_awr_ptr->allocate_tablets_for_new_table(s, stm.get()).get0();
tmap = tab_awr_ptr->allocate_tablets_for_new_table(s, stm.get(), 1).get0();
full_ring_check(tmap, options320, ars_ptr, stm.get());
// Test the case of not enough nodes to meet RF in DC 102
@@ -480,7 +480,7 @@ SEASTAR_THREAD_TEST_CASE(NetworkTopologyStrategy_tablets_test) {
tab_awr_ptr = ars_ptr->maybe_as_tablet_aware();
BOOST_REQUIRE(tab_awr_ptr);
tmap = tab_awr_ptr->allocate_tablets_for_new_table(s, stm.get()).get0();
tmap = tab_awr_ptr->allocate_tablets_for_new_table(s, stm.get(), 1).get0();
full_ring_check(tmap, options324, ars_ptr, stm.get());
}