1 /***************************************************************************** 2 3 Copyright (c) 2011, 2012, Oracle and/or its affiliates. All Rights Reserved. 4 5 Portions of this file contain modifications contributed and copyrighted by 6 Google, Inc. Those modifications are gratefully acknowledged and are described 7 briefly in the InnoDB documentation. The contributions by Google are 8 incorporated with their permission, and subject to the conditions contained in 9 the file COPYING.Google. 10 11 Portions of this file contain modifications contributed and copyrighted 12 by Percona Inc.. Those modifications are 13 gratefully acknowledged and are described briefly in the InnoDB 14 documentation. The contributions by Percona Inc. are incorporated with 15 their permission, and subject to the conditions contained in the file 16 COPYING.Percona. 17 18 This program is free software; you can redistribute it and/or modify 19 it under the terms of the GNU General Public License, version 2.0, 20 as published by the Free Software Foundation. 21 22 This program is also distributed with certain software (including 23 but not limited to OpenSSL) that is licensed under separate terms, 24 as designated in a particular file or component or in included license 25 documentation. The authors of MySQL hereby grant you an additional 26 permission to link the program and your derivative works with the 27 separately licensed software that they have included with MySQL. 28 29 This program is distributed in the hope that it will be useful, 30 but WITHOUT ANY WARRANTY; without even the implied warranty of 31 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 32 GNU General Public License, version 2.0, for more details. 33 34 You should have received a copy of the GNU General Public License along with 35 this program; if not, write to the Free Software Foundation, Inc., 36 51 Franklin Street, Suite 500, Boston, MA 02110-1335 USA 37 38 *****************************************************************************/ 39 40 /**************************************************//** 41 @file srv/srv0conc.h 42 43 InnoDB concurrency manager header file 44 45 Created 2011/04/18 Sunny Bains 46 *******************************************************/ 47 48 #ifndef srv_conc_h 49 #define srv_conc_h 50 51 /** We are prepared for a situation that we have this many threads waiting for 52 a semaphore inside InnoDB. innobase_start_or_create_for_mysql() sets the 53 value. */ 54 55 extern ulint srv_max_n_threads; 56 57 /** The following controls how many threads we let inside InnoDB concurrently: 58 threads waiting for locks are not counted into the number because otherwise 59 we could get a deadlock. Value of 0 will disable the concurrency check. */ 60 61 extern ulong srv_thread_concurrency; 62 63 /*********************************************************************//** 64 Initialise the concurrency management data structures */ 65 void 66 srv_conc_init(void); 67 /*===============*/ 68 69 /*********************************************************************//** 70 Free the concurrency management data structures */ 71 void 72 srv_conc_free(void); 73 /*===============*/ 74 75 /*********************************************************************//** 76 Puts an OS thread to wait if there are too many concurrent threads 77 (>= srv_thread_concurrency) inside InnoDB. The threads wait in a FIFO queue. */ 78 UNIV_INTERN 79 void 80 srv_conc_enter_innodb( 81 /*==================*/ 82 trx_t* trx); /*!< in: transaction object associated 83 with the thread */ 84 85 /*********************************************************************//** 86 This lets a thread enter InnoDB regardless of the number of threads inside 87 InnoDB. This must be called when a thread ends a lock wait. */ 88 UNIV_INTERN 89 void 90 srv_conc_force_enter_innodb( 91 /*========================*/ 92 trx_t* trx); /*!< in: transaction object associated with 93 the thread */ 94 95 /*********************************************************************//** 96 This must be called when a thread exits InnoDB in a lock wait or at the 97 end of an SQL statement. */ 98 UNIV_INTERN 99 void 100 srv_conc_force_exit_innodb( 101 /*=======================*/ 102 trx_t* trx); /*!< in: transaction object associated with 103 the thread */ 104 105 /*********************************************************************//** 106 Get the count of threads waiting inside InnoDB. */ 107 UNIV_INTERN 108 ulint 109 srv_conc_get_waiting_threads(void); 110 /*==============================*/ 111 112 /*********************************************************************//** 113 Get the count of threads active inside InnoDB. */ 114 UNIV_INTERN 115 ulint 116 srv_conc_get_active_threads(void); 117 /*==============================*/ 118 119 #endif /* srv_conc_h */ 120