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/* Copyright (C) 2007 MySQL AB, 2008-2010 Sun Microsystems, Inc.
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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
/*
Implementation for the thread scheduler
*/
#ifdef USE_PRAGMA_INTERFACE
#pragma implementation
#endif
#include "sql_connect.h" // init_new_connection_handler_thread
#include "scheduler.h"
#include "mysqld.h"
#include "sql_class.h"
#include "sql_callback.h"
/*
End connection, in case when we are using 'no-threads'
*/
static bool no_threads_end(THD *thd, bool put_in_cache)
{
unlink_thd(thd);
mysql_mutex_unlock(&LOCK_thread_count);
return 1; // Abort handle_one_connection
}
/** @internal
Helper functions to allow mysys to call the thread scheduler when
waiting for locks.
*/
/**@{*/
extern "C"
{
static void scheduler_wait_lock_begin(void) {
THD *thd=current_thd;
scheduler_functions *func= thd->scheduler;
MYSQL_CALLBACK(func, thd_wait_begin, (thd, THD_WAIT_TABLE_LOCK));
}
static void scheduler_wait_lock_end(void) {
THD *thd=current_thd;
scheduler_functions *func= thd->scheduler;
MYSQL_CALLBACK(func, thd_wait_end, (thd));
}
static void scheduler_wait_sync_begin(void) {
THD *thd=current_thd;
scheduler_functions *func= thd->scheduler;
MYSQL_CALLBACK(func, thd_wait_begin, (thd, THD_WAIT_TABLE_LOCK));
}
static void scheduler_wait_sync_end(void) {
THD *thd=current_thd;
scheduler_functions *func= thd->scheduler;
MYSQL_CALLBACK(func, thd_wait_end, (thd));
}
};
/**@}*/
/**
Common scheduler init function.
The scheduler is either initialized by calling
one_thread_scheduler() or one_thread_per_connection_scheduler() in
mysqld.cc, so this init function will always be called.
*/
static void scheduler_init() {
thr_set_lock_wait_callback(scheduler_wait_lock_begin,
scheduler_wait_lock_end);
thr_set_sync_wait_callback(scheduler_wait_sync_begin,
scheduler_wait_sync_end);
}
/*
Initialize scheduler for --thread-handling=one-thread-per-connection
*/
#ifndef EMBEDDED_LIBRARY
void one_thread_per_connection_scheduler(scheduler_functions *func,
ulong *arg_max_connections,
uint *arg_connection_count)
{
scheduler_init();
func->max_threads= *arg_max_connections + 1;
func->max_connections= arg_max_connections;
func->connection_count= arg_connection_count;
func->init_new_connection_thread= init_new_connection_handler_thread;
func->add_connection= create_thread_to_handle_connection;
func->end_thread= one_thread_per_connection_end;
}
#endif
/*
Initailize scheduler for --thread-handling=no-threads
*/
void one_thread_scheduler(scheduler_functions *func)
{
scheduler_init();
func->max_threads= 1;
//max_connections= 1;
func->max_connections= &max_connections;
func->connection_count= &connection_count;
#ifndef EMBEDDED_LIBRARY
func->init_new_connection_thread= init_new_connection_handler_thread;
func->add_connection= handle_connection_in_main_thread;
#endif
func->end_thread= no_threads_end;
}
#ifdef HAVE_POOL_OF_THREADS
/*
thd_scheduler keeps the link between THD and events.
It's embedded in the THD class.
*/
thd_scheduler::thd_scheduler()
: m_psi(NULL), logged_in(FALSE), io_event(NULL), thread_attached(FALSE)
{
}
thd_scheduler::~thd_scheduler()
{
my_free(io_event);
}
#endif
/*
no pluggable schedulers in mariadb.
when we'll want it, we'll do it properly
*/
#if 0
static scheduler_functions *saved_thread_scheduler;
static uint saved_thread_handling;
extern "C"
int my_thread_scheduler_set(scheduler_functions *scheduler)
{
DBUG_ASSERT(scheduler != 0);
if (scheduler == NULL)
return 1;
saved_thread_scheduler= thread_scheduler;
saved_thread_handling= thread_handling;
thread_scheduler= scheduler;
// Scheduler loaded dynamically
thread_handling= SCHEDULER_TYPES_COUNT;
return 0;
}
extern "C"
int my_thread_scheduler_reset()
{
DBUG_ASSERT(saved_thread_scheduler != NULL);
if (saved_thread_scheduler == NULL)
return 1;
thread_scheduler= saved_thread_scheduler;
thread_handling= saved_thread_handling;
saved_thread_scheduler= 0;
return 0;
}
#else
extern "C" int my_thread_scheduler_set(scheduler_functions *scheduler)
{ return 1; }
extern "C" int my_thread_scheduler_reset()
{ return 1; }
#endif
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