7d71b42651
Add tracing for the following events: 1) Dismantling of the combined buffer. 2) Dismantling of the compaction state. 3) Cleaning up the readers. (1) and (2) can possibly have adverse effects on the performance of the query and hence it is important that details about the dismantled fragments is exposed in the tracing data. (3) is less critical but still good to know how much readers were created by the read (in case they aren't saved). Since normally (in strateful queries) this will always be 0 only trace this when it is non-zero (and is interesting).
725 lines
34 KiB
C++
725 lines
34 KiB
C++
/*
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* Copyright (C) 2018 ScyllaDB
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*/
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/*
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* This file is part of Scylla.
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*
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* Scylla is free software: you can redistribute it and/or modify
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* it under the terms of the GNU Affero General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* Scylla is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with Scylla. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include "schema_registry.hh"
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#include "service/priority_manager.hh"
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#include "multishard_mutation_query.hh"
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#include <boost/range/adaptor/reversed.hpp>
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logging::logger mmq_log("multishard_mutation_query");
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template <typename T>
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using foreign_unique_ptr = foreign_ptr<std::unique_ptr<T>>;
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/// Context object for a multishard read.
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///
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/// Handles logic related to looking up, creating, saving and cleaning up remote
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/// (shard) readers for the `multishard_mutation_reader`.
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/// Has a state machine for each of the shard readers. See the state transition
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/// diagram below, above the declaration of `reader state`.
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/// The `read_context` is a short-lived object that is only kept around for the
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/// duration of a single page. A new `read_context` is created on each page and
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/// is discarded at the end of the page, after the readers are either saved
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/// or the process of their safe disposal was started in the background.
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/// Intended usage:
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/// * Create the `read_context`.
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/// * Call `read_context::lookup_readers()` to find any saved readers from the
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/// previous page.
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/// * Create the `multishard_mutation_reader`.
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/// * Fill the page.
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/// * Destroy the `multishard_mutation_reader` to trigger the disposal of the
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/// shard readers.
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/// * Call `read_context::save_readers()` if the read didn't finish yet, that is
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/// more pages are expected.
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/// * Call `read_context::stop()` to initiate the cleanup of any unsaved readers
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/// and their dependencies.
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/// * Destroy the `read_context`.
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///
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/// Note:
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/// 1) Each step can only be started when the previous phase has finished.
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/// 2) This usage is implemented in the `do_query_mutations()` function below.
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/// 3) Both, `read_context::lookup_readers()` and `read_context::save_readers()`
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/// knows to do nothing when the query is not stateful and just short
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/// circuit.
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class read_context {
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struct reader_params {
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std::unique_ptr<const dht::partition_range> range;
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std::unique_ptr<const query::partition_slice> slice;
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reader_params(dht::partition_range range, query::partition_slice slice)
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: range(std::make_unique<const dht::partition_range>(std::move(range)))
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, slice(std::make_unique<const query::partition_slice>(std::move(slice))) {
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}
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reader_params(std::unique_ptr<const dht::partition_range> range, std::unique_ptr<const query::partition_slice> slice)
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: range(std::move(range))
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, slice(std::move(slice)) {
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}
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};
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struct bundled_remote_reader {
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foreign_unique_ptr<reader_params> params;
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foreign_unique_ptr<utils::phased_barrier::operation> read_operation;
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foreign_unique_ptr<flat_mutation_reader> reader;
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};
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using inexistent_state = std::monostate;
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struct successful_lookup_state {
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foreign_unique_ptr<reader_params> params;
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foreign_unique_ptr<utils::phased_barrier::operation> read_operation;
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foreign_unique_ptr<flat_mutation_reader> reader;
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};
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struct used_state {
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foreign_unique_ptr<reader_params> params;
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foreign_unique_ptr<utils::phased_barrier::operation> read_operation;
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};
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struct dismantling_state {
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foreign_unique_ptr<reader_params> params;
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foreign_unique_ptr<utils::phased_barrier::operation> read_operation;
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future<stopped_foreign_reader> reader_fut;
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circular_buffer<mutation_fragment> buffer;
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};
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struct ready_to_save_state {
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foreign_unique_ptr<reader_params> params;
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foreign_unique_ptr<utils::phased_barrier::operation> read_operation;
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foreign_unique_ptr<flat_mutation_reader> reader;
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circular_buffer<mutation_fragment> buffer;
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};
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struct future_used_state {
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future<used_state> fut;
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};
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struct future_dismantling_state {
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future<dismantling_state> fut;
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};
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// ( )
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// |
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// +------ inexistent_state -----+
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// | |
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// (1) | (6) |
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// | |
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// successful_lookup_state future_used_state
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// | | | |
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// (2) | (3) | (7) | (8) |
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// | | | |
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// | used_state <---------+ future_dismantling_state
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// | | |
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// | (4) | (9) |
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// | | |
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// | dismantling_state <-----------------+
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// | |
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// | (5) |
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// | |
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// +----> ready_to_save_state
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// |
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// (O)
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//
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// 1) lookup_readers()
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// 2) save_readers()
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// 3) make_remote_reader()
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// 4) dismantle_reader()
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// 5) prepare_reader_for_saving()
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// 6) do_make_remote_reader()
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// 7) reader is created
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// 8) dismantle_reader()
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// 9) reader is created
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using reader_state = std::variant<
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inexistent_state,
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successful_lookup_state,
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used_state,
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dismantling_state,
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ready_to_save_state,
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future_used_state,
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future_dismantling_state>;
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struct dismantle_buffer_stats {
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size_t partitions = 0;
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size_t fragments = 0;
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size_t bytes = 0;
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void add(const schema& s, const mutation_fragment& mf) {
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partitions += unsigned(mf.is_partition_start());
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++fragments;
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bytes += mf.memory_usage(s);
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}
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void add(const schema& s, const range_tombstone& rt) {
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++fragments;
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bytes += rt.memory_usage(s);
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}
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void add(const schema& s, const static_row& sr) {
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++fragments;
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bytes += sr.memory_usage(s);
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}
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void add(const schema& s, const partition_start& ps) {
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++partitions;
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++fragments;
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bytes += ps.memory_usage(s);
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}
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};
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distributed<database>& _db;
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schema_ptr _schema;
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const query::read_command& _cmd;
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const dht::partition_range_vector& _ranges;
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tracing::trace_state_ptr _trace_state;
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// One for each shard. Index is shard id.
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std::vector<reader_state> _readers;
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static future<bundled_remote_reader> do_make_remote_reader(
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distributed<database>& db,
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shard_id shard,
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schema_ptr schema,
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const dht::partition_range& pr,
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const query::partition_slice& ps,
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const io_priority_class& pc,
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tracing::trace_state_ptr trace_state);
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future<foreign_unique_ptr<flat_mutation_reader>> make_remote_reader(
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shard_id shard,
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schema_ptr schema,
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const dht::partition_range& pr,
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const query::partition_slice& ps,
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const io_priority_class& pc,
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tracing::trace_state_ptr trace_state,
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streamed_mutation::forwarding fwd_sm,
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mutation_reader::forwarding fwd_mr);
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void dismantle_reader(shard_id shard, future<stopped_foreign_reader>&& stopped_reader_fut);
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ready_to_save_state* prepare_reader_for_saving(dismantling_state& current_state, future<stopped_foreign_reader>&& stopped_reader_fut,
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const dht::decorated_key& last_pkey, const std::optional<clustering_key_prefix>& last_ckey);
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dismantle_buffer_stats dismantle_combined_buffer(circular_buffer<mutation_fragment> combined_buffer, const dht::decorated_key& pkey);
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dismantle_buffer_stats dismantle_compaction_state(detached_compaction_state compaction_state);
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future<> save_reader(ready_to_save_state& current_state, const dht::decorated_key& last_pkey,
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const std::optional<clustering_key_prefix>& last_ckey);
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public:
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read_context(distributed<database>& db, schema_ptr s, const query::read_command& cmd, const dht::partition_range_vector& ranges,
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tracing::trace_state_ptr trace_state)
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: _db(db)
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, _schema(std::move(s))
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, _cmd(cmd)
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, _ranges(ranges)
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, _trace_state(std::move(trace_state)) {
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_readers.resize(smp::count);
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}
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read_context(read_context&&) = delete;
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read_context(const read_context&) = delete;
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read_context& operator=(read_context&&) = delete;
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read_context& operator=(const read_context&) = delete;
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remote_reader_factory factory() {
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return [this] (
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shard_id shard,
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schema_ptr schema,
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const dht::partition_range& pr,
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const query::partition_slice& ps,
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const io_priority_class& pc,
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tracing::trace_state_ptr trace_state,
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streamed_mutation::forwarding fwd_sm,
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mutation_reader::forwarding fwd_mr) {
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return make_remote_reader(shard, std::move(schema), pr, ps, pc, std::move(trace_state), fwd_sm, fwd_mr);
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};
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}
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foreign_reader_dismantler dismantler() {
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return [this] (shard_id shard, future<stopped_foreign_reader>&& stopped_reader_fut) {
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dismantle_reader(shard, std::move(stopped_reader_fut));
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};
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}
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future<> lookup_readers();
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future<> save_readers(circular_buffer<mutation_fragment> unconsumed_buffer, detached_compaction_state compaction_state,
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std::optional<clustering_key_prefix> last_ckey);
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future<> stop();
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};
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future<read_context::bundled_remote_reader> read_context::do_make_remote_reader(
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distributed<database>& db,
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shard_id shard,
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schema_ptr schema,
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const dht::partition_range& pr,
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const query::partition_slice& ps,
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const io_priority_class&,
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tracing::trace_state_ptr trace_state) {
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return db.invoke_on(shard, [gs = global_schema_ptr(schema), &pr, &ps, gts = tracing::global_trace_state_ptr(std::move(trace_state))] (
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database& db) {
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auto s = gs.get();
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auto& table = db.find_column_family(s);
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//TODO need a way to transport io_priority_calls across shards
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auto& pc = service::get_local_sstable_query_read_priority();
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auto params = reader_params(pr, ps);
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auto read_operation = table.read_in_progress();
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auto reader = table.as_mutation_source().make_reader(std::move(s), *params.range, *params.slice, pc, gts.get());
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return make_ready_future<bundled_remote_reader>(bundled_remote_reader{
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make_foreign(std::make_unique<reader_params>(std::move(params))),
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make_foreign(std::make_unique<utils::phased_barrier::operation>(std::move(read_operation))),
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make_foreign(std::make_unique<flat_mutation_reader>(std::move(reader)))});
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});
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}
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future<foreign_unique_ptr<flat_mutation_reader>> read_context::make_remote_reader(
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shard_id shard,
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schema_ptr schema,
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const dht::partition_range& pr,
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const query::partition_slice& ps,
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const io_priority_class& pc,
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tracing::trace_state_ptr trace_state,
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streamed_mutation::forwarding,
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mutation_reader::forwarding) {
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auto& rs = _readers[shard];
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if (!std::holds_alternative<successful_lookup_state>(rs) && !std::holds_alternative<inexistent_state>(rs)) {
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mmq_log.warn("Unexpected request to create reader for shard {}. A reader for this shard was already created.", shard);
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throw std::logic_error(sprint("Unexpected request to create reader for shard {}."
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" A reader for this shard was already created in the context of this read.", shard));
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}
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// The reader is either in inexistent or successful lookup state.
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if (auto current_state = std::get_if<successful_lookup_state>(&rs)) {
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auto reader = std::move(current_state->reader);
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rs = used_state{std::move(current_state->params), std::move(current_state->read_operation)};
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return make_ready_future<foreign_unique_ptr<flat_mutation_reader>>(std::move(reader));
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}
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auto created = promise<used_state>();
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rs = future_used_state{created.get_future()};
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return do_make_remote_reader(_db, shard, std::move(schema), pr, ps, pc, std::move(trace_state)).then_wrapped([this, &rs,
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created = std::move(created)] (future<bundled_remote_reader>&& bundled_reader_fut) mutable {
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if (bundled_reader_fut.failed()) {
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auto ex = bundled_reader_fut.get_exception();
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if (!std::holds_alternative<future_used_state>(rs)) {
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created.set_exception(ex);
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}
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return make_exception_future<foreign_unique_ptr<flat_mutation_reader>>(std::move(ex));
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}
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auto bundled_reader = bundled_reader_fut.get0();
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auto new_state = used_state{std::move(bundled_reader.params), std::move(bundled_reader.read_operation)};
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if (std::holds_alternative<future_used_state>(rs)) {
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rs = std::move(new_state);
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} else {
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created.set_value(std::move(new_state));
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}
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return make_ready_future<foreign_unique_ptr<flat_mutation_reader>>(std::move(bundled_reader.reader));
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});
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}
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void read_context::dismantle_reader(shard_id shard, future<stopped_foreign_reader>&& stopped_reader_fut) {
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auto& rs = _readers[shard];
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if (auto* maybe_used_state = std::get_if<used_state>(&rs)) {
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auto read_operation = std::move(maybe_used_state->read_operation);
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auto params = std::move(maybe_used_state->params);
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rs = dismantling_state{std::move(params), std::move(read_operation), std::move(stopped_reader_fut), circular_buffer<mutation_fragment>{}};
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} else if (auto* maybe_future_used_state = std::get_if<future_used_state>(&rs)) {
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auto f = maybe_future_used_state->fut.then([stopped_reader_fut = std::move(stopped_reader_fut)] (used_state&& current_state) mutable {
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auto read_operation = std::move(current_state.read_operation);
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auto params = std::move(current_state.params);
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return dismantling_state{std::move(params), std::move(read_operation), std::move(stopped_reader_fut),
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circular_buffer<mutation_fragment>{}};
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});
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rs = future_dismantling_state{std::move(f)};
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} else {
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mmq_log.warn("Unexpected request to dismantle reader for shard {}. Reader was not created nor is in the process of being created.", shard);
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}
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}
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future<> read_context::stop() {
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auto cleanup = [db = &_db.local()] (shard_id shard, dismantling_state state) {
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return state.reader_fut.then_wrapped([db, shard, params = std::move(state.params),
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read_operation = std::move(state.read_operation)] (future<stopped_foreign_reader>&& fut) mutable {
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if (fut.failed()) {
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mmq_log.debug("Failed to stop reader on shard {}: {}", shard, fut.get_exception());
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++db->get_stats().multishard_query_failed_reader_stops;
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} else {
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smp::submit_to(shard, [reader = fut.get0().remote_reader, params = std::move(params),
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read_operation = std::move(read_operation)] () mutable {
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reader.release();
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params.release();
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read_operation.release();
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});
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}
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});
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};
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std::vector<future<>> futures;
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auto immediate_cleanup = size_t(0);
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auto future_cleanup = size_t(0);
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// Wait for pending read-aheads in the background.
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for (shard_id shard = 0; shard != smp::count; ++shard) {
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auto& rs = _readers[shard];
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if (auto maybe_dismantling_state = std::get_if<dismantling_state>(&rs)) {
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++immediate_cleanup;
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cleanup(shard, std::move(*maybe_dismantling_state));
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} else if (auto maybe_future_dismantling_state = std::get_if<future_dismantling_state>(&rs)) {
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++future_cleanup;
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futures.emplace_back(maybe_future_dismantling_state->fut.then_wrapped([=] (future<dismantling_state>&& current_state_fut) {
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if (current_state_fut.failed()) {
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mmq_log.debug("Failed to stop reader on shard {}: {}", shard, current_state_fut.get_exception());
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++_db.local().get_stats().multishard_query_failed_reader_stops;
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} else {
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cleanup(shard, current_state_fut.get0());
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}
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}));
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}
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}
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if (const auto total = immediate_cleanup + future_cleanup) {
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tracing::trace(_trace_state,
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"Stopping {} shard readers, {} ready for immediate cleanup, {} will be cleaned up after finishes read-ahead",
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total,
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immediate_cleanup,
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future_cleanup);
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}
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return when_all(futures.begin(), futures.end()).discard_result();
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}
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read_context::dismantle_buffer_stats read_context::dismantle_combined_buffer(circular_buffer<mutation_fragment> combined_buffer,
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const dht::decorated_key& pkey) {
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auto& partitioner = dht::global_partitioner();
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std::vector<mutation_fragment> tmp_buffer;
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dismantle_buffer_stats stats;
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auto rit = std::reverse_iterator(combined_buffer.end());
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const auto rend = std::reverse_iterator(combined_buffer.begin());
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for (;rit != rend; ++rit) {
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if (rit->is_partition_start()) {
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const auto shard = partitioner.shard_of(rit->as_partition_start().key().token());
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auto& shard_buffer = std::get<dismantling_state>(_readers[shard]).buffer;
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for (auto& smf : tmp_buffer) {
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stats.add(*_schema, smf);
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shard_buffer.emplace_front(std::move(smf));
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}
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stats.add(*_schema, *rit);
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shard_buffer.emplace_front(std::move(*rit));
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tmp_buffer.clear();
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} else {
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tmp_buffer.emplace_back(std::move(*rit));
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|
}
|
|
}
|
|
|
|
const auto shard = partitioner.shard_of(pkey.token());
|
|
auto& shard_buffer = std::get<dismantling_state>(_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& partitioner = dht::global_partitioner();
|
|
const auto shard = partitioner.shard_of(compaction_state.partition_start.key().token());
|
|
auto& shard_buffer = std::get<dismantling_state>(_readers[shard]).buffer;
|
|
auto stats = dismantle_buffer_stats();
|
|
|
|
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;
|
|
}
|
|
|
|
read_context::ready_to_save_state* read_context::prepare_reader_for_saving(
|
|
dismantling_state& current_state,
|
|
future<stopped_foreign_reader>&& stopped_reader_fut,
|
|
const dht::decorated_key& last_pkey,
|
|
const std::optional<clustering_key_prefix>& last_ckey) {
|
|
const auto shard = current_state.params.get_owner_shard();
|
|
auto& rs = _readers[shard];
|
|
|
|
if (stopped_reader_fut.failed()) {
|
|
mmq_log.debug("Failed to stop reader on shard {}: {}", shard, stopped_reader_fut.get_exception());
|
|
++_db.local().get_stats().multishard_query_failed_reader_stops;
|
|
return nullptr;
|
|
}
|
|
|
|
auto stopped_reader = stopped_reader_fut.get0();
|
|
|
|
// If the buffer is empty just overwrite it.
|
|
// If it has some data in it append the fragments to the back.
|
|
// The unconsumed fragments appended here come from the
|
|
// foreign_reader which is at the lowest layer, hence its
|
|
// fragments need to be at the back of the buffer.
|
|
if (current_state.buffer.empty()) {
|
|
current_state.buffer = std::move(stopped_reader.unconsumed_fragments);
|
|
} else {
|
|
std::move(stopped_reader.unconsumed_fragments.begin(), stopped_reader.unconsumed_fragments.end(), std::back_inserter(current_state.buffer));
|
|
}
|
|
rs = ready_to_save_state{std::move(current_state.params), std::move(current_state.read_operation), std::move(stopped_reader.remote_reader),
|
|
std::move(current_state.buffer)};
|
|
return &std::get<ready_to_save_state>(rs);
|
|
}
|
|
|
|
future<> read_context::save_reader(ready_to_save_state& current_state, const dht::decorated_key& last_pkey,
|
|
const std::optional<clustering_key_prefix>& last_ckey) {
|
|
const auto shard = current_state.reader.get_owner_shard();
|
|
return _db.invoke_on(shard, [shard, query_uuid = _cmd.query_uuid, query_ranges = _ranges, ¤t_state, &last_pkey, &last_ckey,
|
|
gts = tracing::global_trace_state_ptr(_trace_state)] (database& db) mutable {
|
|
try {
|
|
auto params = current_state.params.release();
|
|
auto read_operation = current_state.read_operation.release();
|
|
auto reader = current_state.reader.release();
|
|
auto& buffer = current_state.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(params->range),
|
|
std::move(params->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 -> reader_state {
|
|
auto schema = gs.get();
|
|
auto querier_opt = db.get_querier_cache().lookup_shard_mutation_querier(cmd->query_uuid, *schema, *ranges, cmd->slice, gts.get());
|
|
if (!querier_opt) {
|
|
return inexistent_state{};
|
|
}
|
|
|
|
auto& q = *querier_opt;
|
|
auto& table = db.find_column_family(schema);
|
|
auto params = make_foreign(std::make_unique<reader_params>(std::move(q).reader_range(), std::move(q).reader_slice()));
|
|
auto read_operation = make_foreign(std::make_unique<utils::phased_barrier::operation>(table.read_in_progress()));
|
|
auto reader = make_foreign(std::make_unique<flat_mutation_reader>(std::move(q).reader()));
|
|
return successful_lookup_state{std::move(params), std::move(read_operation), std::move(reader)};
|
|
}).then([this, shard] (reader_state&& state) {
|
|
_readers[shard] = std::move(state);
|
|
});
|
|
});
|
|
}
|
|
|
|
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<>();
|
|
}
|
|
|
|
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: {} partitions/{} fragments/{} bytes", cb_stats.partitions, cb_stats.fragments,
|
|
cb_stats.bytes);
|
|
|
|
const auto cs_stats = dismantle_compaction_state(std::move(compaction_state));
|
|
tracing::trace(_trace_state, "Dismantled compaction state: {} partitions/{} fragments/{} bytes", cs_stats.partitions, cs_stats.fragments,
|
|
cs_stats.bytes);
|
|
|
|
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(_readers, [this, &last_pkey, &last_ckey] (reader_state& rs) {
|
|
if (auto* maybe_successful_lookup_state = std::get_if<successful_lookup_state>(&rs)) {
|
|
auto& current_state = *maybe_successful_lookup_state;
|
|
rs = ready_to_save_state{std::move(current_state.params), std::move(current_state.read_operation),
|
|
std::move(current_state.reader), circular_buffer<mutation_fragment>{}};
|
|
return save_reader(std::get<ready_to_save_state>(rs), last_pkey, last_ckey);
|
|
}
|
|
|
|
auto finish_saving = [this, &last_pkey, &last_ckey] (dismantling_state& current_state) {
|
|
return current_state.reader_fut.then_wrapped([this, ¤t_state, &last_pkey, &last_ckey] (
|
|
future<stopped_foreign_reader>&& stopped_reader_fut) mutable {
|
|
if (auto* ready_state = prepare_reader_for_saving(current_state, std::move(stopped_reader_fut), last_pkey, last_ckey)) {
|
|
return save_reader(*ready_state, last_pkey, last_ckey);
|
|
}
|
|
return make_ready_future<>();
|
|
});
|
|
};
|
|
|
|
if (auto* maybe_dismantling_state = std::get_if<dismantling_state>(&rs)) {
|
|
return finish_saving(*maybe_dismantling_state);
|
|
}
|
|
|
|
if (auto* maybe_future_dismantling_state = std::get_if<future_dismantling_state>(&rs)) {
|
|
return maybe_future_dismantling_state->fut.then([this, &rs,
|
|
finish_saving = std::move(finish_saving)] (dismantling_state&& next_state) mutable {
|
|
rs = std::move(next_state);
|
|
return finish_saving(std::get<dismantling_state>(rs));
|
|
});
|
|
}
|
|
|
|
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(std::make_unique<read_context>(db, s, cmd, ranges, trace_state), [s, &cmd, &ranges, trace_state, timeout,
|
|
accounter = std::move(accounter)] (std::unique_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 fwd_sm,
|
|
mutation_reader::forwarding fwd_mr) {
|
|
return make_multishard_combining_reader(std::move(s), pr, ps, pc, dht::global_partitioner(), ctx->factory(), std::move(trace_state),
|
|
fwd_sm, fwd_mr, ctx->dismantler());
|
|
});
|
|
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);
|
|
}
|
|
});
|
|
});
|
|
}
|