db106a32c8
Previously the different states a reader can be in were all separate structs, and were joined together by a variant. When this was designed this made sense as states were numerous and quite different. By this point however the number of states has been reduced to 4, with 3 of them being almost the same. Thus it makes sense to merge these states into single struct and keep track of the current state with an enum field. This can theoretically increase the chances of mistakes, but in practice I expect the opposite, due to the simpler (and less) code. Also, all the important checks that verify that a reader is in the state expected by the code are all left in place. A byproduct of this change is that the amount of cross-shard writes is greatly reduced. Whereas previously the whole state object had to be rewritten on state change, now a single enum value has to be updated. Cross shard reads are reduced as well to the read of a few foreign pointers, all state-related data is now kept on the shard where the associated reader lives.
652 lines
28 KiB
C++
652 lines
28 KiB
C++
/*
|
|
* Copyright (C) 2018 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 "schema_registry.hh"
|
|
#include "service/priority_manager.hh"
|
|
#include "multishard_mutation_query.hh"
|
|
#include "database.hh"
|
|
|
|
#include <boost/range/adaptor/reversed.hpp>
|
|
|
|
#include <fmt/ostream.h>
|
|
|
|
logging::logger mmq_log("multishard_mutation_query");
|
|
|
|
template <typename T>
|
|
using foreign_unique_ptr = foreign_ptr<std::unique_ptr<T>>;
|
|
|
|
/// Context object for a multishard read.
|
|
///
|
|
/// Handles logic related to looking up, creating, saving and cleaning up remote
|
|
/// (shard) readers for the `multishard_mutation_reader`.
|
|
/// Has a state machine for each of the shard readers. See the state transition
|
|
/// diagram below, above the declaration of `reader state`.
|
|
/// The `read_context` is a short-lived object that is only kept around for the
|
|
/// duration of a single page. A new `read_context` is created on each page and
|
|
/// is discarded at the end of the page, after the readers are either saved
|
|
/// or the process of their safe disposal was started in the background.
|
|
/// Intended usage:
|
|
/// * Create the `read_context`.
|
|
/// * Call `read_context::lookup_readers()` to find any saved readers from the
|
|
/// previous page.
|
|
/// * Create the `multishard_mutation_reader`.
|
|
/// * Fill the page.
|
|
/// * Destroy the `multishard_mutation_reader` to trigger the disposal of the
|
|
/// shard readers.
|
|
/// * Call `read_context::save_readers()` if the read didn't finish yet, that is
|
|
/// more pages are expected.
|
|
/// * Call `read_context::stop()` to initiate the cleanup of any unsaved readers
|
|
/// and their dependencies.
|
|
/// * Destroy the `read_context`.
|
|
///
|
|
/// Note:
|
|
/// 1) Each step can only be started when the previous phase has finished.
|
|
/// 2) This usage is implemented in the `do_query_mutations()` function below.
|
|
/// 3) Both, `read_context::lookup_readers()` and `read_context::save_readers()`
|
|
/// knows to do nothing when the query is not stateful and just short
|
|
/// circuit.
|
|
class read_context : public reader_lifecycle_policy {
|
|
|
|
// ( ) (O)
|
|
// | ^
|
|
// | |
|
|
// +--- inexistent ---+
|
|
// | |
|
|
// (1) | (3) |
|
|
// | |
|
|
// successful_lookup |
|
|
// | | |
|
|
// | | |
|
|
// | | (3) |
|
|
// | +---------> used
|
|
// (2) | |
|
|
// | (4) |
|
|
// | |
|
|
// +---------------> saving_state
|
|
// |
|
|
// (O)
|
|
//
|
|
// 1) lookup_readers()
|
|
// 2) save_readers()
|
|
// 3) create_reader()
|
|
// 4) destroy_reader()
|
|
enum class reader_state {
|
|
inexistent,
|
|
successful_lookup,
|
|
used,
|
|
saving,
|
|
};
|
|
|
|
struct reader_meta {
|
|
struct remote_parts {
|
|
reader_concurrency_semaphore& semaphore;
|
|
std::unique_ptr<const dht::partition_range> range;
|
|
std::unique_ptr<const query::partition_slice> slice;
|
|
utils::phased_barrier::operation read_operation;
|
|
|
|
remote_parts(
|
|
reader_concurrency_semaphore& semaphore,
|
|
std::unique_ptr<const dht::partition_range> range = nullptr,
|
|
std::unique_ptr<const query::partition_slice> slice = nullptr,
|
|
utils::phased_barrier::operation read_operation = {})
|
|
: semaphore(semaphore)
|
|
, range(std::move(range))
|
|
, slice(std::move(slice))
|
|
, read_operation(std::move(read_operation)) {
|
|
}
|
|
};
|
|
|
|
reader_state state = reader_state::inexistent;
|
|
foreign_unique_ptr<remote_parts> rparts;
|
|
foreign_unique_ptr<reader_concurrency_semaphore::inactive_read_handle> handle;
|
|
bool has_pending_next_partition = false;
|
|
circular_buffer<mutation_fragment> buffer;
|
|
|
|
reader_meta() = default;
|
|
// Remote constructor.
|
|
reader_meta(reader_state s, remote_parts rp, reader_concurrency_semaphore::inactive_read_handle h = {})
|
|
: state(s)
|
|
, rparts(make_foreign(std::make_unique<remote_parts>(std::move(rp))))
|
|
, handle(make_foreign(std::make_unique<reader_concurrency_semaphore::inactive_read_handle>(std::move(h)))) {
|
|
}
|
|
};
|
|
|
|
struct dismantle_buffer_stats {
|
|
size_t partitions = 0;
|
|
size_t fragments = 0;
|
|
size_t bytes = 0;
|
|
size_t discarded_partitions = 0;
|
|
size_t discarded_fragments = 0;
|
|
size_t discarded_bytes = 0;
|
|
|
|
void add(const schema& s, const mutation_fragment& mf) {
|
|
partitions += unsigned(mf.is_partition_start());
|
|
++fragments;
|
|
bytes += mf.memory_usage(s);
|
|
}
|
|
void add(const schema& s, const range_tombstone& rt) {
|
|
++fragments;
|
|
bytes += rt.memory_usage(s);
|
|
}
|
|
void add(const schema& s, const static_row& sr) {
|
|
++fragments;
|
|
bytes += sr.memory_usage(s);
|
|
}
|
|
void add(const schema& s, const partition_start& ps) {
|
|
++partitions;
|
|
++fragments;
|
|
bytes += ps.memory_usage(s);
|
|
}
|
|
void add_discarded(const schema& s, const mutation_fragment& mf) {
|
|
discarded_partitions += unsigned(mf.is_partition_start());
|
|
++discarded_fragments;
|
|
discarded_bytes += mf.memory_usage(s);
|
|
}
|
|
void add_discarded(const schema& s, const range_tombstone& rt) {
|
|
++discarded_fragments;
|
|
discarded_bytes += rt.memory_usage(s);
|
|
}
|
|
void add_discarded(const schema& s, const static_row& sr) {
|
|
++discarded_fragments;
|
|
discarded_bytes += sr.memory_usage(s);
|
|
}
|
|
void add_discarded(const schema& s, const partition_start& ps) {
|
|
++discarded_partitions;
|
|
++discarded_fragments;
|
|
discarded_bytes += ps.memory_usage(s);
|
|
}
|
|
friend std::ostream& operator<<(std::ostream& os, const dismantle_buffer_stats& s) {
|
|
os << format(
|
|
"kept {} partitions/{} fragments/{} bytes, discarded {} partitions/{} fragments/{} bytes",
|
|
s.partitions,
|
|
s.fragments,
|
|
s.bytes,
|
|
s.discarded_partitions,
|
|
s.discarded_fragments,
|
|
s.discarded_bytes);
|
|
return os;
|
|
}
|
|
};
|
|
|
|
distributed<database>& _db;
|
|
schema_ptr _schema;
|
|
const query::read_command& _cmd;
|
|
const dht::partition_range_vector& _ranges;
|
|
tracing::trace_state_ptr _trace_state;
|
|
|
|
// One for each shard. Index is shard id.
|
|
std::vector<reader_meta> _readers;
|
|
|
|
gate _dismantling_gate;
|
|
|
|
static std::string_view reader_state_to_string(reader_state rs);
|
|
|
|
dismantle_buffer_stats dismantle_combined_buffer(circular_buffer<mutation_fragment> combined_buffer, const dht::decorated_key& pkey);
|
|
dismantle_buffer_stats dismantle_compaction_state(detached_compaction_state compaction_state);
|
|
future<> save_reader(shard_id shard, const dht::decorated_key& last_pkey, const std::optional<clustering_key_prefix>& last_ckey);
|
|
|
|
public:
|
|
read_context(distributed<database>& db, schema_ptr s, const query::read_command& cmd, const dht::partition_range_vector& ranges,
|
|
tracing::trace_state_ptr trace_state)
|
|
: _db(db)
|
|
, _schema(std::move(s))
|
|
, _cmd(cmd)
|
|
, _ranges(ranges)
|
|
, _trace_state(std::move(trace_state)) {
|
|
_readers.resize(smp::count);
|
|
}
|
|
|
|
read_context(read_context&&) = delete;
|
|
read_context(const read_context&) = delete;
|
|
|
|
read_context& operator=(read_context&&) = delete;
|
|
read_context& operator=(const read_context&) = delete;
|
|
|
|
virtual flat_mutation_reader create_reader(
|
|
schema_ptr schema,
|
|
const dht::partition_range& pr,
|
|
const query::partition_slice& ps,
|
|
const io_priority_class& pc,
|
|
tracing::trace_state_ptr trace_state,
|
|
mutation_reader::forwarding fwd_mr) override;
|
|
|
|
virtual void destroy_reader(shard_id shard, future<stopped_reader> reader_fut) noexcept override;
|
|
|
|
virtual reader_concurrency_semaphore& semaphore() override {
|
|
return _readers[engine().cpu_id()].rparts->semaphore;
|
|
}
|
|
|
|
future<> lookup_readers();
|
|
|
|
future<> save_readers(circular_buffer<mutation_fragment> unconsumed_buffer, detached_compaction_state compaction_state,
|
|
std::optional<clustering_key_prefix> last_ckey);
|
|
|
|
future<> stop();
|
|
};
|
|
|
|
std::string_view read_context::reader_state_to_string(reader_state rs) {
|
|
switch (rs) {
|
|
case reader_state::inexistent:
|
|
return "inexistent";
|
|
case reader_state::successful_lookup:
|
|
return "successful_lookup";
|
|
case reader_state::used:
|
|
return "used";
|
|
case reader_state::saving:
|
|
return "saving";
|
|
}
|
|
// If we got here, we are logging an error anyway, so the above layers
|
|
// (should) have detected the invalid state.
|
|
return "invalid";
|
|
}
|
|
|
|
flat_mutation_reader read_context::create_reader(
|
|
schema_ptr schema,
|
|
const dht::partition_range& pr,
|
|
const query::partition_slice& ps,
|
|
const io_priority_class&,
|
|
tracing::trace_state_ptr trace_state,
|
|
mutation_reader::forwarding) {
|
|
const auto shard = engine().cpu_id();
|
|
auto& rm = _readers[shard];
|
|
|
|
if (rm.state != reader_state::used && rm.state != reader_state::successful_lookup && rm.state != reader_state::inexistent) {
|
|
auto msg = format("Unexpected request to create reader for shard {}."
|
|
" The reader is expected to be in either `used`, `successful_lookup` or `inexistent` state,"
|
|
" but is in `{}` state instead.", shard, reader_state_to_string(rm.state));
|
|
mmq_log.warn(msg.c_str());
|
|
throw std::logic_error(msg.c_str());
|
|
}
|
|
|
|
// The reader is either in inexistent or successful lookup state.
|
|
if (rm.state == reader_state::successful_lookup) {
|
|
if (auto reader_opt = try_resume(std::move(*rm.handle))) {
|
|
rm.state = reader_state::used;
|
|
return std::move(*reader_opt);
|
|
}
|
|
}
|
|
|
|
auto& table = _db.local().find_column_family(schema);
|
|
|
|
if (!rm.rparts) {
|
|
rm.rparts = make_foreign(std::make_unique<reader_meta::remote_parts>(table.read_concurrency_semaphore()));
|
|
}
|
|
|
|
//TODO need a way to transport io_priority_calls across shards
|
|
auto& pc = service::get_local_sstable_query_read_priority();
|
|
rm.rparts->range = std::make_unique<const dht::partition_range>(pr);
|
|
rm.rparts->slice = std::make_unique<const query::partition_slice>(ps);
|
|
rm.rparts->read_operation = table.read_in_progress();
|
|
rm.state = reader_state::used;
|
|
|
|
return table.as_mutation_source().make_reader(std::move(schema), *rm.rparts->range, *rm.rparts->slice, pc, std::move(trace_state));
|
|
}
|
|
|
|
void read_context::destroy_reader(shard_id shard, future<stopped_reader> reader_fut) noexcept {
|
|
with_gate(_dismantling_gate, [this, shard, reader_fut = std::move(reader_fut)] () mutable {
|
|
return reader_fut.then_wrapped([this, shard] (future<stopped_reader>&& reader_fut) {
|
|
auto& rm = _readers[shard];
|
|
|
|
if (reader_fut.failed()) {
|
|
mmq_log.debug("Failed to stop reader on shard {}: {}", shard, reader_fut.get_exception());
|
|
++_db.local().get_stats().multishard_query_failed_reader_stops;
|
|
rm.state = reader_state::inexistent;
|
|
return;
|
|
}
|
|
|
|
auto reader = reader_fut.get0();
|
|
if (rm.state == reader_state::used) {
|
|
rm.state = reader_state::saving;
|
|
rm.handle = std::move(reader.handle);
|
|
rm.has_pending_next_partition = reader.has_pending_next_partition;
|
|
rm.buffer = std::move(reader.unconsumed_fragments);
|
|
} else {
|
|
mmq_log.warn(
|
|
"Unexpected request to dismantle reader in state `{}` for shard {}."
|
|
" Reader was not created nor is in the process of being created.",
|
|
reader_state_to_string(rm.state),
|
|
shard);
|
|
}
|
|
});
|
|
});
|
|
}
|
|
|
|
future<> read_context::stop() {
|
|
auto pr = promise<>();
|
|
auto fut = pr.get_future();
|
|
auto gate_fut = _dismantling_gate.is_closed() ? make_ready_future<>() : _dismantling_gate.close();
|
|
gate_fut.then([this] {
|
|
for (shard_id shard = 0; shard != smp::count; ++shard) {
|
|
if (_readers[shard].state == reader_state::saving) {
|
|
_db.invoke_on(shard, [schema = global_schema_ptr(_schema), rm = std::move(_readers[shard])] (database& db) mutable {
|
|
// We cannot use semaphore() here, as this can be already destroyed.
|
|
auto& table = db.find_column_family(schema);
|
|
table.read_concurrency_semaphore().unregister_inactive_read(std::move(*rm.handle));
|
|
});
|
|
}
|
|
}
|
|
}).finally([pr = std::move(pr)] () mutable {
|
|
pr.set_value();
|
|
});
|
|
return fut;
|
|
}
|
|
|
|
read_context::dismantle_buffer_stats read_context::dismantle_combined_buffer(circular_buffer<mutation_fragment> combined_buffer,
|
|
const dht::decorated_key& pkey) {
|
|
auto& partitioner = dht::global_partitioner();
|
|
|
|
std::vector<mutation_fragment> tmp_buffer;
|
|
dismantle_buffer_stats stats;
|
|
|
|
auto rit = std::reverse_iterator(combined_buffer.end());
|
|
const auto rend = std::reverse_iterator(combined_buffer.begin());
|
|
for (;rit != rend; ++rit) {
|
|
if (rit->is_partition_start()) {
|
|
const auto shard = partitioner.shard_of(rit->as_partition_start().key().token());
|
|
|
|
// It is possible that the reader this partition originates from
|
|
// does not exist anymore. Either because we failed stopping it or
|
|
// because it was evicted.
|
|
if (_readers[shard].state != reader_state::saving) {
|
|
for (auto& smf : tmp_buffer) {
|
|
stats.add_discarded(*_schema, smf);
|
|
}
|
|
stats.add_discarded(*_schema, *rit);
|
|
tmp_buffer.clear();
|
|
continue;
|
|
}
|
|
|
|
auto& shard_buffer = _readers[shard].buffer;
|
|
for (auto& smf : tmp_buffer) {
|
|
stats.add(*_schema, smf);
|
|
shard_buffer.emplace_front(std::move(smf));
|
|
}
|
|
stats.add(*_schema, *rit);
|
|
shard_buffer.emplace_front(std::move(*rit));
|
|
tmp_buffer.clear();
|
|
} else {
|
|
tmp_buffer.emplace_back(std::move(*rit));
|
|
}
|
|
}
|
|
|
|
const auto shard = partitioner.shard_of(pkey.token());
|
|
auto& shard_buffer = _readers[shard].buffer;
|
|
for (auto& smf : tmp_buffer) {
|
|
stats.add(*_schema, smf);
|
|
shard_buffer.emplace_front(std::move(smf));
|
|
}
|
|
|
|
return stats;
|
|
}
|
|
|
|
read_context::dismantle_buffer_stats read_context::dismantle_compaction_state(detached_compaction_state compaction_state) {
|
|
auto stats = dismantle_buffer_stats();
|
|
auto& partitioner = dht::global_partitioner();
|
|
const auto shard = partitioner.shard_of(compaction_state.partition_start.key().token());
|
|
|
|
// It is possible that the reader this partition originates from does not
|
|
// exist anymore. Either because we failed stopping it or because it was
|
|
// evicted.
|
|
if (_readers[shard].state != reader_state::saving) {
|
|
for (auto& rt : compaction_state.range_tombstones) {
|
|
stats.add_discarded(*_schema, rt);
|
|
}
|
|
if (compaction_state.static_row) {
|
|
stats.add_discarded(*_schema, *compaction_state.static_row);
|
|
}
|
|
stats.add_discarded(*_schema, compaction_state.partition_start);
|
|
return stats;
|
|
}
|
|
|
|
auto& shard_buffer = _readers[shard].buffer;
|
|
|
|
for (auto& rt : compaction_state.range_tombstones | boost::adaptors::reversed) {
|
|
stats.add(*_schema, rt);
|
|
shard_buffer.emplace_front(std::move(rt));
|
|
}
|
|
|
|
if (compaction_state.static_row) {
|
|
stats.add(*_schema, *compaction_state.static_row);
|
|
shard_buffer.emplace_front(std::move(*compaction_state.static_row));
|
|
}
|
|
|
|
stats.add(*_schema, compaction_state.partition_start);
|
|
shard_buffer.emplace_front(std::move(compaction_state.partition_start));
|
|
|
|
return stats;
|
|
}
|
|
|
|
future<> read_context::save_reader(shard_id shard, const dht::decorated_key& last_pkey, const std::optional<clustering_key_prefix>& last_ckey) {
|
|
return _db.invoke_on(shard, [this, shard, query_uuid = _cmd.query_uuid, query_ranges = _ranges, rm = std::exchange(_readers[shard], {}),
|
|
&last_pkey, &last_ckey, gts = tracing::global_trace_state_ptr(_trace_state)] (database& db) mutable {
|
|
try {
|
|
flat_mutation_reader_opt reader = try_resume(rm.rparts->semaphore, std::move(*rm.handle));
|
|
|
|
if (!reader) {
|
|
return;
|
|
}
|
|
|
|
if (rm.has_pending_next_partition) {
|
|
reader->next_partition();
|
|
}
|
|
|
|
auto& buffer = rm.buffer;
|
|
const auto fragments = buffer.size();
|
|
const auto size_before = reader->buffer_size();
|
|
|
|
auto rit = std::reverse_iterator(buffer.cend());
|
|
auto rend = std::reverse_iterator(buffer.cbegin());
|
|
auto& schema = *reader->schema();
|
|
for (;rit != rend; ++rit) {
|
|
// Copy the fragment, the buffer is on another shard.
|
|
reader->unpop_mutation_fragment(mutation_fragment(schema, *rit));
|
|
}
|
|
|
|
const auto size_after = reader->buffer_size();
|
|
|
|
auto querier = query::shard_mutation_querier(
|
|
std::move(query_ranges),
|
|
std::move(rm.rparts->range),
|
|
std::move(rm.rparts->slice),
|
|
std::move(*reader),
|
|
last_pkey,
|
|
last_ckey);
|
|
|
|
db.get_querier_cache().insert(query_uuid, std::move(querier), gts.get());
|
|
|
|
db.get_stats().multishard_query_unpopped_fragments += fragments;
|
|
db.get_stats().multishard_query_unpopped_bytes += (size_after - size_before);
|
|
} catch (...) {
|
|
// We don't want to fail a read just because of a failure to
|
|
// save any of the readers.
|
|
mmq_log.debug("Failed to save reader: {}", std::current_exception());
|
|
++db.get_stats().multishard_query_failed_reader_saves;
|
|
}
|
|
}).handle_exception([this, shard] (std::exception_ptr e) {
|
|
// We don't want to fail a read just because of a failure to
|
|
// save any of the readers.
|
|
mmq_log.debug("Failed to save reader on shard {}: {}", shard, e);
|
|
// This will account the failure on the local shard but we don't
|
|
// know where exactly the failure happened anyway.
|
|
++_db.local().get_stats().multishard_query_failed_reader_saves;
|
|
});
|
|
}
|
|
|
|
future<> read_context::lookup_readers() {
|
|
if (_cmd.query_uuid == utils::UUID{} || _cmd.is_first_page) {
|
|
return make_ready_future<>();
|
|
}
|
|
|
|
return parallel_for_each(boost::irange(0u, smp::count), [this] (shard_id shard) {
|
|
return _db.invoke_on(shard, [shard, cmd = &_cmd, ranges = &_ranges, gs = global_schema_ptr(_schema),
|
|
gts = tracing::global_trace_state_ptr(_trace_state)] (database& db) mutable {
|
|
auto schema = gs.get();
|
|
auto querier_opt = db.get_querier_cache().lookup_shard_mutation_querier(cmd->query_uuid, *schema, *ranges, cmd->slice, gts.get());
|
|
auto& table = db.find_column_family(schema);
|
|
auto& semaphore = table.read_concurrency_semaphore();
|
|
|
|
if (!querier_opt) {
|
|
return reader_meta(reader_state::inexistent, reader_meta::remote_parts(semaphore));
|
|
}
|
|
|
|
auto& q = *querier_opt;
|
|
auto handle = pause(semaphore, std::move(q).reader());
|
|
return reader_meta(
|
|
reader_state::successful_lookup,
|
|
reader_meta::remote_parts(semaphore, std::move(q).reader_range(), std::move(q).reader_slice(), table.read_in_progress()),
|
|
std::move(handle));
|
|
}).then([this, shard] (reader_meta rm) {
|
|
_readers[shard] = std::move(rm);
|
|
});
|
|
});
|
|
}
|
|
|
|
future<> read_context::save_readers(circular_buffer<mutation_fragment> unconsumed_buffer, detached_compaction_state compaction_state,
|
|
std::optional<clustering_key_prefix> last_ckey) {
|
|
if (_cmd.query_uuid == utils::UUID{}) {
|
|
return make_ready_future<>();
|
|
}
|
|
|
|
return _dismantling_gate.close().then([this, unconsumed_buffer = std::move(unconsumed_buffer), compaction_state = std::move(compaction_state),
|
|
last_ckey = std::move(last_ckey)] () mutable {
|
|
auto last_pkey = compaction_state.partition_start.key();
|
|
|
|
const auto cb_stats = dismantle_combined_buffer(std::move(unconsumed_buffer), last_pkey);
|
|
tracing::trace(_trace_state, "Dismantled combined buffer: {}", cb_stats);
|
|
|
|
const auto cs_stats = dismantle_compaction_state(std::move(compaction_state));
|
|
tracing::trace(_trace_state, "Dismantled compaction state: {}", cs_stats);
|
|
|
|
return do_with(std::move(last_pkey), std::move(last_ckey), [this] (const dht::decorated_key& last_pkey,
|
|
const std::optional<clustering_key_prefix>& last_ckey) {
|
|
return parallel_for_each(boost::irange(0u, smp::count), [this, &last_pkey, &last_ckey] (shard_id shard) {
|
|
auto& rm = _readers[shard];
|
|
if (rm.state == reader_state::successful_lookup || rm.state == reader_state::saving) {
|
|
return save_reader(shard, last_pkey, last_ckey);
|
|
}
|
|
|
|
return make_ready_future<>();
|
|
});
|
|
});
|
|
});
|
|
}
|
|
|
|
static future<reconcilable_result> do_query_mutations(
|
|
distributed<database>& db,
|
|
schema_ptr s,
|
|
const query::read_command& cmd,
|
|
const dht::partition_range_vector& ranges,
|
|
tracing::trace_state_ptr trace_state,
|
|
db::timeout_clock::time_point timeout,
|
|
query::result_memory_accounter&& accounter) {
|
|
return do_with(seastar::make_shared<read_context>(db, s, cmd, ranges, trace_state), [s, &cmd, &ranges, trace_state, timeout,
|
|
accounter = std::move(accounter)] (shared_ptr<read_context>& ctx) mutable {
|
|
return ctx->lookup_readers().then([&ctx, s = std::move(s), &cmd, &ranges, trace_state, timeout,
|
|
accounter = std::move(accounter)] () mutable {
|
|
auto ms = mutation_source([&] (schema_ptr s,
|
|
const dht::partition_range& pr,
|
|
const query::partition_slice& ps,
|
|
const io_priority_class& pc,
|
|
tracing::trace_state_ptr trace_state,
|
|
streamed_mutation::forwarding,
|
|
mutation_reader::forwarding fwd_mr) {
|
|
return make_multishard_combining_reader(ctx, dht::global_partitioner(), std::move(s), pr, ps, pc, std::move(trace_state), fwd_mr);
|
|
});
|
|
auto reader = make_flat_multi_range_reader(s, std::move(ms), ranges, cmd.slice, service::get_local_sstable_query_read_priority(),
|
|
trace_state, mutation_reader::forwarding::no);
|
|
|
|
auto compaction_state = make_lw_shared<compact_for_mutation_query_state>(*s, cmd.timestamp, cmd.slice, cmd.row_limit,
|
|
cmd.partition_limit);
|
|
|
|
return do_with(std::move(reader), std::move(compaction_state), [&, accounter = std::move(accounter), timeout] (
|
|
flat_mutation_reader& reader, lw_shared_ptr<compact_for_mutation_query_state>& compaction_state) mutable {
|
|
auto rrb = reconcilable_result_builder(*reader.schema(), cmd.slice, std::move(accounter));
|
|
return query::consume_page(reader,
|
|
compaction_state,
|
|
cmd.slice,
|
|
std::move(rrb),
|
|
cmd.row_limit,
|
|
cmd.partition_limit,
|
|
cmd.timestamp,
|
|
timeout).then([&] (std::optional<clustering_key_prefix>&& last_ckey, reconcilable_result&& result) mutable {
|
|
return make_ready_future<std::optional<clustering_key_prefix>,
|
|
reconcilable_result,
|
|
circular_buffer<mutation_fragment>,
|
|
lw_shared_ptr<compact_for_mutation_query_state>>(std::move(last_ckey), std::move(result), reader.detach_buffer(),
|
|
std::move(compaction_state));
|
|
});
|
|
}).then_wrapped([&ctx] (future<std::optional<clustering_key_prefix>, reconcilable_result, circular_buffer<mutation_fragment>,
|
|
lw_shared_ptr<compact_for_mutation_query_state>>&& result_fut) {
|
|
if (result_fut.failed()) {
|
|
return make_exception_future<reconcilable_result>(std::move(result_fut.get_exception()));
|
|
}
|
|
|
|
auto [last_ckey, result, unconsumed_buffer, compaction_state] = result_fut.get();
|
|
if (!compaction_state->are_limits_reached() && !result.is_short_read()) {
|
|
return make_ready_future<reconcilable_result>(std::move(result));
|
|
}
|
|
|
|
return ctx->save_readers(std::move(unconsumed_buffer), std::move(*compaction_state).detach_state(),
|
|
std::move(last_ckey)).then_wrapped([result = std::move(result)] (future<>&&) mutable {
|
|
return make_ready_future<reconcilable_result>(std::move(result));
|
|
});
|
|
}).finally([&ctx] {
|
|
return ctx->stop();
|
|
});
|
|
});
|
|
});
|
|
}
|
|
|
|
future<foreign_ptr<lw_shared_ptr<reconcilable_result>>, cache_temperature> query_mutations_on_all_shards(
|
|
distributed<database>& db,
|
|
schema_ptr s,
|
|
const query::read_command& cmd,
|
|
const dht::partition_range_vector& ranges,
|
|
tracing::trace_state_ptr trace_state,
|
|
uint64_t max_size,
|
|
db::timeout_clock::time_point timeout) {
|
|
if (cmd.row_limit == 0 || cmd.slice.partition_row_limit() == 0 || cmd.partition_limit == 0) {
|
|
return make_ready_future<foreign_ptr<lw_shared_ptr<reconcilable_result>>, cache_temperature>(
|
|
make_foreign(make_lw_shared<reconcilable_result>()),
|
|
db.local().find_column_family(s).get_global_cache_hit_rate());
|
|
}
|
|
|
|
return db.local().get_result_memory_limiter().new_mutation_read(max_size).then([&, s = std::move(s), trace_state = std::move(trace_state),
|
|
timeout] (query::result_memory_accounter accounter) mutable {
|
|
return do_query_mutations(db, s, cmd, ranges, std::move(trace_state), timeout, std::move(accounter)).then_wrapped(
|
|
[&db, s = std::move(s)] (future<reconcilable_result>&& f) {
|
|
auto& local_db = db.local();
|
|
auto& stats = local_db.get_stats();
|
|
if (f.failed()) {
|
|
++stats.total_reads_failed;
|
|
return make_exception_future<foreign_ptr<lw_shared_ptr<reconcilable_result>>, cache_temperature>(f.get_exception());
|
|
} else {
|
|
++stats.total_reads;
|
|
auto result = f.get0();
|
|
stats.short_mutation_queries += bool(result.is_short_read());
|
|
auto hit_rate = local_db.find_column_family(s).get_global_cache_hit_rate();
|
|
return make_ready_future<foreign_ptr<lw_shared_ptr<reconcilable_result>>, cache_temperature>(
|
|
make_foreign(make_lw_shared<reconcilable_result>(std::move(result))), hit_rate);
|
|
}
|
|
});
|
|
});
|
|
}
|