1 /* Copyright (c) 2008, 2019, Oracle and/or its affiliates. All rights reserved. 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, version 2.0, 5 as published by the Free Software Foundation. 6 7 This program is also distributed with certain software (including 8 but not limited to OpenSSL) that is licensed under separate terms, 9 as designated in a particular file or component or in included license 10 documentation. The authors of MySQL hereby grant you an additional 11 permission to link the program and your derivative works with the 12 separately licensed software that they have included with MySQL. 13 14 This program is distributed in the hope that it will be useful, 15 but WITHOUT ANY WARRANTY; without even the implied warranty of 16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 17 GNU General Public License, version 2.0, for more details. 18 19 You should have received a copy of the GNU General Public License 20 along with this program; if not, write to the Free Software 21 Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */ 22 23 #ifndef LOCKED_TABLES_LIST_INCLUDED 24 #define LOCKED_TABLES_LIST_INCLUDED 25 26 #include <sys/types.h> 27 #include <vector> 28 #include "my_alloc.h" 29 30 struct MYSQL_LOCK; 31 class MDL_context; 32 class MDL_ticket; 33 struct TABLE; 34 struct TABLE_LIST; 35 class THD; 36 37 /** 38 Type of locked tables mode. 39 See comment for THD::locked_tables_mode for complete description. 40 While adding new enum values add them to the getter method for this enum 41 declared below and defined in binlog.cc as well. 42 */ 43 44 enum enum_locked_tables_mode { 45 LTM_NONE = 0, 46 LTM_LOCK_TABLES, 47 LTM_PRELOCKED, 48 LTM_PRELOCKED_UNDER_LOCK_TABLES 49 }; 50 51 #ifndef DBUG_OFF 52 /** 53 Getter for the enum enum_locked_tables_mode 54 @param locked_tables_mode enum for types of locked tables mode 55 56 @return The string represantation of that enum value 57 */ 58 const char *get_locked_tables_mode_name( 59 enum_locked_tables_mode locked_tables_mode); 60 #endif 61 62 /** 63 Tables that were locked with LOCK TABLES statement. 64 65 Encapsulates a list of TABLE_LIST instances for tables 66 locked by LOCK TABLES statement, memory root for metadata locks, 67 and, generally, the context of LOCK TABLES statement. 68 69 In LOCK TABLES mode, the locked tables are kept open between 70 statements. 71 Therefore, we can't allocate metadata locks on execution memory 72 root -- as well as tables, the locks need to stay around till 73 UNLOCK TABLES is called. 74 The locks are allocated in the memory root encapsulated in this 75 class. 76 77 Some SQL commands, like FLUSH TABLE or ALTER TABLE, demand that 78 the tables they operate on are closed, at least temporarily. 79 This class encapsulates a list of TABLE_LIST instances, one 80 for each base table from LOCK TABLES list, 81 which helps conveniently close the TABLEs when it's necessary 82 and later reopen them. 83 84 */ 85 86 class Locked_tables_list { 87 private: 88 MEM_ROOT m_locked_tables_root; 89 TABLE_LIST *m_locked_tables; 90 TABLE_LIST **m_locked_tables_last; 91 /** An auxiliary array used only in reopen_tables(). */ 92 TABLE **m_reopen_array; 93 /** 94 Count the number of tables in m_locked_tables list. We can't 95 rely on thd->lock->table_count because it excludes 96 non-transactional temporary tables. We need to know 97 an exact number of TABLE objects. 98 */ 99 size_t m_locked_tables_count; 100 101 struct MDL_ticket_pair { 102 MDL_ticket *m_src; 103 MDL_ticket *m_dst; 104 }; 105 using MDL_ticket_pairs = std::vector<MDL_ticket_pair>; 106 107 MDL_ticket_pairs m_rename_tablespace_mdls; 108 109 public: 110 Locked_tables_list(); 111 112 void unlock_locked_tables(THD *thd); ~Locked_tables_list()113 ~Locked_tables_list() { 114 unlock_locked_tables(nullptr); 115 DBUG_ASSERT(m_rename_tablespace_mdls.empty()); 116 } 117 bool init_locked_tables(THD *thd); locked_tables()118 TABLE_LIST *locked_tables() const { return m_locked_tables; } 119 void unlink_from_list(const THD *thd, TABLE_LIST *table_list, 120 bool remove_from_locked_tables); 121 void unlink_all_closed_tables(THD *thd, MYSQL_LOCK *lock, 122 size_t reopen_count); 123 bool reopen_tables(THD *thd); 124 void rename_locked_table(TABLE_LIST *old_table_list, const char *new_db, 125 const char *new_table_name, 126 MDL_ticket *target_mdl_ticket); 127 128 void add_rename_tablespace_mdls(MDL_ticket *src, MDL_ticket *dst); 129 void adjust_renamed_tablespace_mdls(MDL_context *mctx); discard_renamed_tablespace_mdls()130 void discard_renamed_tablespace_mdls() { m_rename_tablespace_mdls.clear(); } 131 }; 132 133 #endif /*not defined LOCK_TABLES_LIST_INCLUDED */ 134