Files
scylladb/counters.cc
Tomasz Grabiec 9dbae279ad mutation: Make counter cell difference consistent with apply
The case when both cells are dead was not handled properly, the diff
was always empty, whereas the cell with higher timestamp should win.

Caused test_mutation_diff_with_random_generator to fail.
2017-05-23 13:16:03 +02:00

297 lines
10 KiB
C++

/*
* Copyright (C) 2016 ScyllaDB
*/
/*
* This file is part of Scylla.
*
* Scylla is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* Scylla is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with Scylla. If not, see <http://www.gnu.org/licenses/>.
*/
#include "service/storage_service.hh"
#include "counters.hh"
#include "mutation.hh"
#include "combine.hh"
counter_id counter_id::local()
{
return counter_id(service::get_local_storage_service().get_local_id());
}
std::ostream& operator<<(std::ostream& os, const counter_id& id) {
return os << id.to_uuid();
}
std::ostream& operator<<(std::ostream& os, counter_shard_view csv) {
return os << "{global_shard id: " << csv.id() << " value: " << csv.value()
<< " clock: " << csv.logical_clock() << "}";
}
std::ostream& operator<<(std::ostream& os, counter_cell_view ccv) {
return os << "{counter_cell timestamp: " << ccv.timestamp() << " shards: {" << ::join(", ", ccv.shards()) << "}}";
}
static bool apply_in_place(atomic_cell_or_collection& dst, atomic_cell_or_collection& src)
{
auto dst_ccmv = counter_cell_mutable_view(dst.as_mutable_atomic_cell());
auto src_ccmv = counter_cell_mutable_view(src.as_mutable_atomic_cell());
auto dst_shards = dst_ccmv.shards();
auto src_shards = src_ccmv.shards();
auto dst_it = dst_shards.begin();
auto src_it = src_shards.begin();
while (src_it != src_shards.end()) {
while (dst_it != dst_shards.end() && dst_it->id() < src_it->id()) {
++dst_it;
}
if (dst_it == dst_shards.end() || dst_it->id() != src_it->id()) {
// Fast-path failed. Revert and fall back to the slow path.
if (dst_it == dst_shards.end()) {
--dst_it;
}
while (src_it != src_shards.begin()) {
--src_it;
while (dst_it->id() != src_it->id()) {
--dst_it;
}
src_it->swap_value_and_clock(*dst_it);
}
return false;
}
if (dst_it->logical_clock() < src_it->logical_clock()) {
dst_it->swap_value_and_clock(*src_it);
} else {
src_it->set_value_and_clock(*dst_it);
}
++src_it;
}
auto dst_ts = dst_ccmv.timestamp();
auto src_ts = src_ccmv.timestamp();
dst_ccmv.set_timestamp(std::max(dst_ts, src_ts));
src_ccmv.set_timestamp(dst_ts);
src.as_mutable_atomic_cell().set_counter_in_place_revert(true);
return true;
}
static void revert_in_place_apply(atomic_cell_or_collection& dst, atomic_cell_or_collection& src)
{
assert(dst.can_use_mutable_view() && src.can_use_mutable_view());
auto dst_ccmv = counter_cell_mutable_view(dst.as_mutable_atomic_cell());
auto src_ccmv = counter_cell_mutable_view(src.as_mutable_atomic_cell());
auto dst_shards = dst_ccmv.shards();
auto src_shards = src_ccmv.shards();
auto dst_it = dst_shards.begin();
auto src_it = src_shards.begin();
while (src_it != src_shards.end()) {
while (dst_it != dst_shards.end() && dst_it->id() < src_it->id()) {
++dst_it;
}
assert(dst_it != dst_shards.end() && dst_it->id() == src_it->id());
dst_it->swap_value_and_clock(*src_it);
++src_it;
}
auto dst_ts = dst_ccmv.timestamp();
auto src_ts = src_ccmv.timestamp();
dst_ccmv.set_timestamp(src_ts);
src_ccmv.set_timestamp(dst_ts);
src.as_mutable_atomic_cell().set_counter_in_place_revert(false);
}
bool counter_cell_view::apply_reversibly(atomic_cell_or_collection& dst, atomic_cell_or_collection& src)
{
auto dst_ac = dst.as_atomic_cell();
auto src_ac = src.as_atomic_cell();
if (!dst_ac.is_live() || !src_ac.is_live()) {
if (dst_ac.is_live() || (!src_ac.is_live() && compare_atomic_cell_for_merge(dst_ac, src_ac) < 0)) {
std::swap(dst, src);
return true;
}
return false;
}
if (dst_ac.is_counter_update() && src_ac.is_counter_update()) {
auto src_v = src_ac.counter_update_value();
auto dst_v = dst_ac.counter_update_value();
dst = atomic_cell::make_live_counter_update(std::max(dst_ac.timestamp(), src_ac.timestamp()),
src_v + dst_v);
return true;
}
assert(!dst_ac.is_counter_update());
assert(!src_ac.is_counter_update());
if (counter_cell_view(dst_ac).shard_count() >= counter_cell_view(src_ac).shard_count()
&& dst.can_use_mutable_view() && src.can_use_mutable_view()) {
if (apply_in_place(dst, src)) {
return true;
}
}
src.as_mutable_atomic_cell().set_counter_in_place_revert(false);
auto dst_shards = counter_cell_view(dst_ac).shards();
auto src_shards = counter_cell_view(src_ac).shards();
counter_cell_builder result;
combine(dst_shards.begin(), dst_shards.end(), src_shards.begin(), src_shards.end(),
result.inserter(), counter_shard_view::less_compare_by_id(), [] (auto& x, auto& y) {
return x.logical_clock() < y.logical_clock() ? y : x;
});
auto cell = result.build(std::max(dst_ac.timestamp(), src_ac.timestamp()));
src = std::exchange(dst, atomic_cell_or_collection(cell));
return true;
}
void counter_cell_view::revert_apply(atomic_cell_or_collection& dst, atomic_cell_or_collection& src)
{
if (dst.as_atomic_cell().is_counter_update()) {
auto src_v = src.as_atomic_cell().counter_update_value();
auto dst_v = dst.as_atomic_cell().counter_update_value();
dst = atomic_cell::make_live(dst.as_atomic_cell().timestamp(),
long_type->decompose(dst_v - src_v));
} else if (src.as_atomic_cell().is_counter_in_place_revert_set()) {
revert_in_place_apply(dst, src);
} else {
std::swap(dst, src);
}
}
stdx::optional<atomic_cell> counter_cell_view::difference(atomic_cell_view a, atomic_cell_view b)
{
assert(!a.is_counter_update());
assert(!b.is_counter_update());
if (!b.is_live() || !a.is_live()) {
if (b.is_live() || (!a.is_live() && compare_atomic_cell_for_merge(b, a) < 0)) {
return atomic_cell(a);
}
return { };
}
auto a_shards = counter_cell_view(a).shards();
auto b_shards = counter_cell_view(b).shards();
auto a_it = a_shards.begin();
auto a_end = a_shards.end();
auto b_it = b_shards.begin();
auto b_end = b_shards.end();
counter_cell_builder result;
while (a_it != a_end) {
while (b_it != b_end && (*b_it).id() < (*a_it).id()) {
++b_it;
}
if (b_it == b_end || (*a_it).id() != (*b_it).id() || (*a_it).logical_clock() > (*b_it).logical_clock()) {
result.add_shard(counter_shard(*a_it));
}
++a_it;
}
stdx::optional<atomic_cell> diff;
if (!result.empty()) {
diff = result.build(std::max(a.timestamp(), b.timestamp()));
} else if (a.timestamp() > b.timestamp()) {
diff = atomic_cell::make_live(a.timestamp(), bytes_view());
}
return diff;
}
void transform_counter_updates_to_shards(mutation& m, const mutation* current_state, uint64_t clock_offset) {
// FIXME: allow current_state to be frozen_mutation
auto transform_new_row_to_shards = [clock_offset] (auto& cells) {
cells.for_each_cell([clock_offset] (auto, atomic_cell_or_collection& ac_o_c) {
auto acv = ac_o_c.as_atomic_cell();
if (!acv.is_live()) {
return; // continue -- we are in lambda
}
auto delta = acv.counter_update_value();
auto cs = counter_shard(counter_id::local(), delta, clock_offset + 1);
ac_o_c = counter_cell_builder::from_single_shard(acv.timestamp(), cs);
});
};
if (!current_state) {
transform_new_row_to_shards(m.partition().static_row());
for (auto& cr : m.partition().clustered_rows()) {
transform_new_row_to_shards(cr.row().cells());
}
return;
}
clustering_key::less_compare cmp(*m.schema());
auto transform_row_to_shards = [clock_offset] (auto& transformee, auto& state) {
std::deque<std::pair<column_id, counter_shard>> shards;
state.for_each_cell([&] (column_id id, const atomic_cell_or_collection& ac_o_c) {
auto acv = ac_o_c.as_atomic_cell();
if (!acv.is_live()) {
return; // continue -- we are in lambda
}
counter_cell_view ccv(acv);
auto cs = ccv.local_shard();
if (!cs) {
return; // continue
}
shards.emplace_back(std::make_pair(id, counter_shard(*cs)));
});
transformee.for_each_cell([&] (column_id id, atomic_cell_or_collection& ac_o_c) {
auto acv = ac_o_c.as_atomic_cell();
if (!acv.is_live()) {
return; // continue -- we are in lambda
}
while (!shards.empty() && shards.front().first < id) {
shards.pop_front();
}
auto delta = acv.counter_update_value();
if (shards.empty() || shards.front().first > id) {
auto cs = counter_shard(counter_id::local(), delta, clock_offset + 1);
ac_o_c = counter_cell_builder::from_single_shard(acv.timestamp(), cs);
} else {
auto& cs = shards.front().second;
cs.update(delta, clock_offset + 1);
ac_o_c = counter_cell_builder::from_single_shard(acv.timestamp(), cs);
shards.pop_front();
}
});
};
transform_row_to_shards(m.partition().static_row(), current_state->partition().static_row());
auto& cstate = current_state->partition();
auto it = cstate.clustered_rows().begin();
auto end = cstate.clustered_rows().end();
for (auto& cr : m.partition().clustered_rows()) {
while (it != end && cmp(it->key(), cr.key())) {
++it;
}
if (it == end || cmp(cr.key(), it->key())) {
transform_new_row_to_shards(cr.row().cells());
continue;
}
transform_row_to_shards(cr.row().cells(), it->row().cells());
}
}