mysql5/mysql-5.7.27/sql/conn_handler/connection_handler_impl.h

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3.2 KiB
C++

/*
Copyright (c) 2013, 2015, Oracle and/or its affiliates. All rights reserved.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; version 2 of the License.
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 General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#ifndef CONNECTION_HANDLER_IMPL_INCLUDED
#define CONNECTION_HANDLER_IMPL_INCLUDED
#include "my_global.h"
#include "mysql/psi/mysql_thread.h" // mysql_mutex_t
#include "connection_handler.h" // Connection_handler
#include <list>
class Channel_info;
class THD;
/**
This class represents the connection handling functionality
that each connection is being handled in a single thread
*/
class Per_thread_connection_handler : public Connection_handler
{
Per_thread_connection_handler(const Per_thread_connection_handler&);
Per_thread_connection_handler&
operator=(const Per_thread_connection_handler&);
/**
Check if idle threads to handle connection in
thread cache. If so enqueue the new connection
to be picked by the idle thread in thread cache.
@retval false if idle pthread was found, else true.
*/
bool check_idle_thread_and_enqueue_connection(Channel_info* channel_info);
/**
List of pending channel info objects to be picked by idle
threads. Protected by LOCK_thread_cache.
*/
static std::list<Channel_info*> *waiting_channel_info_list;
static mysql_mutex_t LOCK_thread_cache;
static mysql_cond_t COND_thread_cache;
static mysql_cond_t COND_flush_thread_cache;
public:
// Status variables related to Per_thread_connection_handler
static ulong blocked_pthread_count; // Protected by LOCK_thread_cache.
static ulong slow_launch_threads;
// System variable
static ulong max_blocked_pthreads;
static void init();
static void destroy();
/**
Wake blocked pthreads and wait until they have terminated.
*/
static void kill_blocked_pthreads();
/**
Block until a new connection arrives.
*/
static Channel_info* block_until_new_connection();
Per_thread_connection_handler() {}
virtual ~Per_thread_connection_handler() { }
protected:
virtual bool add_connection(Channel_info* channel_info);
virtual uint get_max_threads() const;
};
/**
This class represents the connection handling functionality
of all connections being handled in a single worker thread.
*/
class One_thread_connection_handler : public Connection_handler
{
One_thread_connection_handler(const One_thread_connection_handler&);
One_thread_connection_handler&
operator=(const One_thread_connection_handler&);
public:
One_thread_connection_handler() {}
virtual ~One_thread_connection_handler() {}
protected:
virtual bool add_connection(Channel_info* channel_info);
virtual uint get_max_threads() const { return 1; }
};
#endif // CONNECTION_HANDLER_IMPL_INCLUDED