morningman commented on a change in pull request #1798: Optimize the load performance for large file URL: https://github.com/apache/incubator-doris/pull/1798#discussion_r327114794
########## File path: be/src/olap/memtable_flush_executor.h ########## @@ -0,0 +1,158 @@ +// Licensed to the Apache Software Foundation (ASF) under one +// or more contributor license agreements. See the NOTICE file +// distributed with this work for additional information +// regarding copyright ownership. The ASF licenses this file +// to you under the Apache License, Version 2.0 (the +// "License"); you may not use this file except in compliance +// with the License. You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, +// software distributed under the License is distributed on an +// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY +// KIND, either express or implied. See the License for the +// specific language governing permissions and limitations +// under the License. + +#pragma once + +#include <atomic> +#include <cstdint> +#include <future> +#include <memory> +#include <queue> +#include <vector> +#include <unordered_map> +#include <utility> + +#include "olap/olap_define.h" +#include "util/blocking_queue.hpp" +#include "util/spinlock.h" +#include "util/thread_pool.hpp" + +namespace doris { + +class DataDir; +class DeltaWriter; +class ExecEnv; +class MemTable; + +// The context for a memtable to be flushed. +class FlushHandler; +struct MemTableFlushContext { + // generated by memtable flush executor + // denote a certain memtable flush execution. + int64_t flush_id; + // memtable to be flushed + std::shared_ptr<MemTable> memtable; + // flush handler from a delta writer. + // use shared ptr because flush_handler may be deleted before this + // memtable being flushed. so we need to make sure the flush_handler + // is alive until this memtable being flushed. + std::shared_ptr<FlushHandler> flush_handler; +}; + +// the flush result of a single memtable flush +struct FlushResult { + OLAPStatus flush_status; + int64_t flush_time_ns; +}; + +// the statistic of a certain flush handler. +// use atomic because it may be updated by multi threads +struct FlushStatistic { + std::atomic_int64_t flush_time_ns = {0}; + std::atomic_int64_t flush_count= {0}; +}; +std::ostream& operator<<(std::ostream& os, const FlushStatistic& stat); + +// flush handler is for flushing memtables in a delta writer +// This class must be wrapped by std::shared_ptr, or you will get bad_weak_ptr exception +// when calling submit(); +class MemTableFlushExecutor; +class FlushHandler : public std::enable_shared_from_this<FlushHandler> { +public: + FlushHandler(int32_t flush_queue_idx, MemTableFlushExecutor* flush_executor): + _flush_queue_idx(flush_queue_idx), + _last_flush_status(OLAP_SUCCESS), + _flush_executor(flush_executor) { + } + + // submit a memtable to flush. return error if some previous submitted MemTable has failed + OLAPStatus submit(std::shared_ptr<MemTable> memtable); + // wait for all submitted memtable finished. + OLAPStatus wait(); + // get flush operations' statistics + const FlushStatistic& get_stats(); + // called when a memtable is finished by executor. + void on_flush_finished(const FlushResult& res); + + OLAPStatus last_flush_status() { return _last_flush_status.load(); } +private: + // flush queue idx in memtable flush executor + int32_t _flush_queue_idx; + // the flush status of last memtable + std::atomic<OLAPStatus> _last_flush_status; + // save all futures of memtable flush execution. + std::queue<std::future<OLAPStatus>> _flush_futures; + FlushStatistic _stats; + MemTableFlushExecutor* _flush_executor; +}; + +// MemTableFlushExecutor is for flushing memtables to disk. +// Each data directory has a specified number of worker threads and a corresponding number of flush queues. +// Each worker thread only takes memtable from the corresponding flush queue and writes it to disk. +// User SHOULD NOT call method of this class directly, use pattern should be: +// +// ... +// FlushHandler* flush_handler; +// memTableFlushExecutor.create_flush_handler(path_hash, &flush_handler); +// std::shared_ptr<FlushHandler> shared_handler(flush_handler); Review comment: OK ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: us...@infra.apache.org With regards, Apache Git Services --------------------------------------------------------------------- To unsubscribe, e-mail: commits-unsubscr...@doris.apache.org For additional commands, e-mail: commits-h...@doris.apache.org
