79 lines
3.3 KiB
C++
79 lines
3.3 KiB
C++
/*
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Copyright (c) 2015, 2019, Oracle and/or its affiliates. All rights reserved.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License, version 2.0,
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as published by the Free Software Foundation.
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This program is also distributed with certain software (including
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but not limited to OpenSSL) that is licensed under separate terms,
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as designated in a particular file or component or in included license
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documentation. The authors of MySQL hereby grant you an additional
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permission to link the program and your derivative works with the
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separately licensed software that they have included with MySQL.
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This program 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, version 2.0, for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include "client/dump/single_transaction_connection_provider.h"
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#include <stddef.h>
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#include <functional>
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using namespace Mysql::Tools::Dump;
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Mysql::Tools::Base::Mysql_query_runner *
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Single_transaction_connection_provider::create_new_runner(
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std::function<bool(const Mysql::Tools::Base::Message_data &)> *) {
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Mysql::Tools::Base::Mysql_query_runner *runner = NULL;
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std::lock_guard<std::mutex> lock(m_pool_mutex);
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if (m_runner_pool.size() > 0) {
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runner = m_runner_pool.back();
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m_runner_pool.pop_back();
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}
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return runner;
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}
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Single_transaction_connection_provider::Single_transaction_connection_provider(
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Mysql::Tools::Base::I_connection_factory *connection_factory,
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unsigned int connections,
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std::function<bool(const Mysql::Tools::Base::Message_data &)>
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*message_handler)
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: Thread_specific_connection_provider(connection_factory),
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m_connections(connections) {
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/* create a pool of connections */
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for (unsigned int conn_count = 1; conn_count <= m_connections; conn_count++) {
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Mysql::Tools::Base::Mysql_query_runner *runner =
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Abstract_connection_provider::create_new_runner(message_handler);
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if (runner) {
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/*
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To get a consistent backup we lock the server and flush all the tables.
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This is done with FLUSH TABLES WITH READ LOCK (FTWRL).
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FTWRL does following:
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1. Acquire a global read lock so that other clients can still query the
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database.
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2. Close all open tables.
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3. No further commits is allowed.
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This will ensure that any further connections will view the same state
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of all the databases which is ideal state to take backup.
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However flush tables is needed only if the database we backup has non
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innodb tables.
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*/
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if (conn_count == 1) runner->run_query("FLUSH TABLES WITH READ LOCK");
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runner->run_query(
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"SET SESSION TRANSACTION ISOLATION LEVEL REPEATABLE READ");
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runner->run_query("START TRANSACTION WITH CONSISTENT SNAPSHOT");
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if (conn_count == m_connections)
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m_runner_pool[0]->run_query("UNLOCK TABLES");
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m_runner_pool.push_back(runner);
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}
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}
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}
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