release/src/router/mysql/sql/scheduler.cc

   1 /* Copyright (C) 2007 MySQL AB
   2
   3    This program is free software; you can redistribute it and/or modify
   4    it under the terms of the GNU General Public License as published by
   5    the Free Software Foundation; version 2 of the License.
   6
   7    This program is distributed in the hope that it will be useful,
   8    but WITHOUT ANY WARRANTY; without even the implied warranty of
   9    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  10    GNU General Public License for more details.
  11
  12    You should have received a copy of the GNU General Public License
  13    along with this program; if not, write to the Free Software
  14    Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA */
  15
  16 /*
  17   Implementation for the thread scheduler
  18 */
  19
  20 #ifdef USE_PRAGMA_INTERFACE
  21 #pragma implementation
  22 #endif
  23
  24 #include <mysql_priv.h>
  25
  26 /*
  27   'Dummy' functions to be used when we don't need any handling for a scheduler
  28   event
  29  */
  30
  31 static bool init_dummy(void) {return 0;}
  32 static void post_kill_dummy(THD* thd) {}
  33 static void end_dummy(void) {}
  34 static bool end_thread_dummy(THD *thd, bool cache_thread) { return 0; }
  35
  36 /*
  37   Initialize default scheduler with dummy functions so that setup functions
  38   only need to declare those that are relvant for their usage
  39 */
  40
  41 scheduler_functions::scheduler_functions()
  42   :init(init_dummy),
  43    init_new_connection_thread(init_new_connection_handler_thread),
  44    add_connection(0),                           // Must be defined
  45    post_kill_notification(post_kill_dummy),
  46    end_thread(end_thread_dummy), end(end_dummy)
  47 {}
  48
  49
  50 /*
  51   End connection, in case when we are using 'no-threads'
  52 */
  53
  54 static bool no_threads_end(THD *thd, bool put_in_cache)
  55 {
  56   unlink_thd(thd);
  57   pthread_mutex_unlock(&LOCK_thread_count);
  58   return 1;                                     // Abort handle_one_connection
  59 }
  60
  61
  62 /*
  63   Initailize scheduler for --thread-handling=no-threads
  64 */
  65
  66 void one_thread_scheduler(scheduler_functions* func)
  67 {
  68   func->max_threads= 1;
  69 #ifndef EMBEDDED_LIBRARY
  70   func->add_connection= handle_connection_in_main_thread;
  71 #endif
  72   func->init_new_connection_thread= init_dummy;
  73   func->end_thread= no_threads_end;
  74 }
  75
  76
  77 /*
  78   Initialize scheduler for --thread-handling=one-thread-per-connection
  79 */
  80
  81 #ifndef EMBEDDED_LIBRARY
  82 void one_thread_per_connection_scheduler(scheduler_functions* func)
  83 {
  84   func->max_threads= max_connections;
  85   func->add_connection= create_thread_to_handle_connection;
  86   func->end_thread= one_thread_per_connection_end;
  87 }
  88 #endif /* EMBEDDED_LIBRARY */