Files
scylladb/mutation_reader.cc
Tomasz Grabiec 892d4a2165 db: Enable creating forwardable readers via mutation_source
Right now all mutation source implementations will use
make_forwardable() wrapper.
2017-02-23 18:50:44 +01:00

325 lines
12 KiB
C++

/*
* Copyright (C) 2015 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 <boost/range/algorithm/heap_algorithm.hpp>
#include <boost/range/algorithm/reverse.hpp>
#include <boost/move/iterator.hpp>
#include "mutation_reader.hh"
#include "core/future-util.hh"
#include "utils/move.hh"
namespace stdx = std::experimental;
template<typename T>
T move_and_clear(T& obj) {
T x = std::move(obj);
obj = T();
return x;
}
future<> combined_mutation_reader::prepare_next() {
return parallel_for_each(_next, [this] (mutation_reader* mr) {
return (*mr)().then([this, mr] (streamed_mutation_opt next) {
if (next) {
_ptables.emplace_back(mutation_and_reader { std::move(*next), mr });
boost::range::push_heap(_ptables, &heap_compare);
}
});
}).then([this] {
_next.clear();
});
}
future<streamed_mutation_opt> combined_mutation_reader::next() {
if (_current.empty() && !_next.empty()) {
return prepare_next().then([this] { return next(); });
}
if (_ptables.empty()) {
return make_ready_future<streamed_mutation_opt>();
};
while (!_ptables.empty()) {
boost::range::pop_heap(_ptables, &heap_compare);
auto& candidate = _ptables.back();
streamed_mutation& m = candidate.m;
if (!_current.empty() && !_current.back().decorated_key().equal(*m.schema(), m.decorated_key())) {
// key has changed, so emit accumulated mutation
boost::range::push_heap(_ptables, &heap_compare);
return make_ready_future<streamed_mutation_opt>(merge_mutations(move_and_clear(_current)));
}
_current.emplace_back(std::move(m));
_next.emplace_back(candidate.read);
_ptables.pop_back();
}
return make_ready_future<streamed_mutation_opt>(merge_mutations(move_and_clear(_current)));
}
void combined_mutation_reader::init_mutation_reader_set(std::vector<mutation_reader*> readers)
{
_all_readers = std::move(readers);
_next.assign(_all_readers.begin(), _all_readers.end());
_ptables.reserve(_all_readers.size());
}
future<> combined_mutation_reader::fast_forward_to(std::vector<mutation_reader*> to_add, std::vector<mutation_reader*> to_remove, const dht::partition_range& pr)
{
_ptables.clear();
std::vector<mutation_reader*> new_readers;
boost::range::sort(_all_readers);
boost::range::sort(to_remove);
boost::range::set_difference(_all_readers, to_remove, std::back_inserter(new_readers));
_all_readers = std::move(new_readers);
return parallel_for_each(_all_readers, [this, &pr] (mutation_reader* mr) {
return mr->fast_forward_to(pr);
}).then([this, to_add = std::move(to_add)] {
_all_readers.insert(_all_readers.end(), to_add.begin(), to_add.end());
_next.assign(_all_readers.begin(), _all_readers.end());
});
}
combined_mutation_reader::combined_mutation_reader(std::vector<mutation_reader> readers)
: _readers(std::move(readers))
{
_next.reserve(_readers.size());
_current.reserve(_readers.size());
_ptables.reserve(_readers.size());
for (auto&& r : _readers) {
_next.emplace_back(&r);
}
_all_readers.assign(_next.begin(), _next.end());
}
future<> combined_mutation_reader::fast_forward_to(const dht::partition_range& pr) {
_ptables.clear();
_next.assign(_all_readers.begin(), _all_readers.end());
return parallel_for_each(_next, [this, &pr] (mutation_reader* mr) {
return mr->fast_forward_to(pr);
});
}
future<streamed_mutation_opt> combined_mutation_reader::operator()() {
return next();
}
mutation_reader
make_combined_reader(std::vector<mutation_reader> readers) {
return make_mutation_reader<combined_mutation_reader>(std::move(readers));
}
mutation_reader
make_combined_reader(mutation_reader&& a, mutation_reader&& b) {
std::vector<mutation_reader> v;
v.reserve(2);
v.push_back(std::move(a));
v.push_back(std::move(b));
return make_combined_reader(std::move(v));
}
class reader_returning final : public mutation_reader::impl {
streamed_mutation _m;
bool _done = false;
public:
reader_returning(streamed_mutation m) : _m(std::move(m)) {
}
virtual future<streamed_mutation_opt> operator()() override {
if (_done) {
return make_ready_future<streamed_mutation_opt>();
} else {
_done = true;
return make_ready_future<streamed_mutation_opt>(std::move(_m));
}
}
};
mutation_reader make_reader_returning(mutation m) {
return make_mutation_reader<reader_returning>(streamed_mutation_from_mutation(std::move(m)));
}
mutation_reader make_reader_returning(streamed_mutation m) {
return make_mutation_reader<reader_returning>(std::move(m));
}
class reader_returning_many final : public mutation_reader::impl {
std::vector<streamed_mutation> _m;
dht::partition_range _pr;
public:
reader_returning_many(std::vector<streamed_mutation> m, const dht::partition_range& pr) : _m(std::move(m)), _pr(pr) {
boost::range::reverse(_m);
}
virtual future<streamed_mutation_opt> operator()() override {
while (!_m.empty()) {
auto& sm = _m.back();
dht::ring_position_comparator cmp(*sm.schema());
if (_pr.before(sm.decorated_key(), cmp)) {
_m.pop_back();
} else if (_pr.after(sm.decorated_key(), cmp)) {
break;
} else {
auto m = std::move(sm);
_m.pop_back();
return make_ready_future<streamed_mutation_opt>(std::move(m));
}
}
return make_ready_future<streamed_mutation_opt>();
}
virtual future<> fast_forward_to(const dht::partition_range& pr) override {
_pr = pr;
return make_ready_future<>();
}
};
mutation_reader make_reader_returning_many(std::vector<mutation> mutations, const query::partition_slice& slice, streamed_mutation::forwarding fwd) {
std::vector<streamed_mutation> streamed_mutations;
streamed_mutations.reserve(mutations.size());
for (auto& m : mutations) {
auto ck_ranges = query::clustering_key_filter_ranges::get_ranges(*m.schema(), slice, m.key());
auto mp = mutation_partition(std::move(m.partition()), *m.schema(), std::move(ck_ranges));
auto sm = streamed_mutation_from_mutation(mutation(m.schema(), m.decorated_key(), std::move(mp)), fwd);
streamed_mutations.emplace_back(std::move(sm));
}
return make_mutation_reader<reader_returning_many>(std::move(streamed_mutations), query::full_partition_range);
}
mutation_reader make_reader_returning_many(std::vector<mutation> mutations, const dht::partition_range& pr) {
std::vector<streamed_mutation> streamed_mutations;
boost::range::transform(mutations, std::back_inserter(streamed_mutations), [] (auto& m) {
return streamed_mutation_from_mutation(std::move(m));
});
return make_mutation_reader<reader_returning_many>(std::move(streamed_mutations), pr);
}
mutation_reader make_reader_returning_many(std::vector<streamed_mutation> mutations) {
return make_mutation_reader<reader_returning_many>(std::move(mutations), query::full_partition_range);
}
class empty_reader final : public mutation_reader::impl {
public:
virtual future<streamed_mutation_opt> operator()() override {
return make_ready_future<streamed_mutation_opt>();
}
virtual future<> fast_forward_to(const dht::partition_range&) override {
return make_ready_future<>();
}
};
mutation_reader make_empty_reader() {
return make_mutation_reader<empty_reader>();
}
class restricting_mutation_reader : public mutation_reader::impl {
const restricted_mutation_reader_config& _config;
unsigned _weight = 0;
bool _waited = false;
mutation_reader _base;
public:
restricting_mutation_reader(const restricted_mutation_reader_config& config, unsigned weight, mutation_reader&& base)
: _config(config), _weight(weight), _base(std::move(base)) {
if (_config.sem->waiters() >= _config.max_queue_length) {
_config.raise_queue_overloaded_exception();
}
}
~restricting_mutation_reader() {
if (_waited) {
_config.sem->signal(_weight);
}
}
future<streamed_mutation_opt> operator()() override {
// FIXME: we should defer freeing until the mutation is freed, perhaps,
// rather than just returned
if (_waited) {
return _base();
}
auto waited = _config.timeout.count() != 0
? _config.sem->wait(_config.timeout, _weight)
: _config.sem->wait(_weight);
return waited.then([this] {
_waited = true;
return _base();
});
}
virtual future<> fast_forward_to(const dht::partition_range& pr) override {
return _base.fast_forward_to(pr);
}
};
mutation_reader
make_restricted_reader(const restricted_mutation_reader_config& config, unsigned weight, mutation_reader&& base) {
return make_mutation_reader<restricting_mutation_reader>(config, weight, std::move(base));
}
class multi_range_mutation_reader : public mutation_reader::impl {
public:
using ranges_vector = dht::partition_range_vector;
private:
const ranges_vector& _ranges;
ranges_vector::const_iterator _current_range;
mutation_reader _reader;
public:
multi_range_mutation_reader(schema_ptr s, mutation_source source, const ranges_vector& ranges,
const query::partition_slice& slice, const io_priority_class& pc,
tracing::trace_state_ptr trace_state, streamed_mutation::forwarding fwd)
: _ranges(ranges)
, _current_range(_ranges.begin())
, _reader(source(s, *_current_range, slice, pc, trace_state, fwd))
{
}
virtual future<streamed_mutation_opt> operator()() override {
return repeat_until_value([this] {
return _reader().then([this] (streamed_mutation_opt smopt) {
if (smopt) {
return make_ready_future<stdx::optional<streamed_mutation_opt>>(std::move(smopt));
}
++_current_range;
if (_current_range == _ranges.end()) {
return make_ready_future<stdx::optional<streamed_mutation_opt>>(streamed_mutation_opt());
}
return _reader.fast_forward_to(*_current_range).then([] {
return make_ready_future<stdx::optional<streamed_mutation_opt>>();
});
});
});
}
virtual future<> fast_forward_to(const dht::partition_range& pr) override {
// When end of pr is reached, this reader will increment _current_range
// and notice that it now points to _ranges.end().
_current_range = std::prev(_ranges.end());
return _reader.fast_forward_to(pr);
}
};
mutation_reader
make_multi_range_reader(schema_ptr s, mutation_source source, const dht::partition_range_vector& ranges,
const query::partition_slice& slice, const io_priority_class& pc,
tracing::trace_state_ptr trace_state, streamed_mutation::forwarding fwd)
{
return make_mutation_reader<multi_range_mutation_reader>(std::move(s), std::move(source), ranges,
slice, pc, std::move(trace_state), fwd);
}