/** * Copyright (C) 2017 MongoDB Inc. * * This program is free software: you can redistribute it and/or modify * it under the terms of the GNU Affero General Public License, version 3, * as published by the Free Software Foundation. * * This program 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 Affero General Public License for more details. * * You should have received a copy of the GNU Affero General Public License * along with this program. If not, see . * * As a special exception, the copyright holders give permission to link the * code of portions of this program with the OpenSSL library under certain * conditions as described in each individual source file and distribute * linked combinations including the program with the OpenSSL library. You * must comply with the GNU Affero General Public License in all respects for * all of the code used other than as permitted herein. If you modify file(s) * with this exception, you may extend this exception to your version of the * file(s), but you are not obligated to do so. If you do not wish to do so, * delete this exception statement from your version. If you delete this * exception statement from all source files in the program, then also delete * it in the license file. */ #pragma once #include "mongo/util/concurrency/thread_pool.h" namespace mongo { class NamespaceString; /** * Handles asynchronous auto-splitting of chunks. */ class ChunkSplitter { MONGO_DISALLOW_COPYING(ChunkSplitter); public: ChunkSplitter(); ~ChunkSplitter(); /** * Sets the mode of the ChunkSplitter to either primary or secondary. * The ChunkSplitter is only active when primary. */ void setReplicaSetMode(bool isPrimary); /** * Invoked when the shard server primary enters the 'PRIMARY' state to set up the ChunkSplitter * to begin accepting split requests. */ void initiateChunkSplitter(); /** * Invoked when this node which is currently serving as a 'PRIMARY' steps down. * * This method might be called multiple times in succession, which is what happens as a result * of incomplete transition to primary so it is resilient to that. */ void interruptChunkSplitter(); /** * Schedules an autosplit task. This function throws on scheduling failure. */ void trySplitting(const NamespaceString& nss, const BSONObj& min, const BSONObj& max); private: /** * Determines if the specified chunk should be split and then performs any necessary split. */ void _runAutosplit(const NamespaceString& nss, const BSONObj& min, const BSONObj& max); // Protects the state below. stdx::mutex _mutex; // The ChunkSplitter is only active on a primary node. bool _isPrimary; // Thread pool for parallelizing splits. ThreadPool _threadPool; }; } // namespace mongo