1 /***************************************************************************** 2 3 Copyright (c) 1997, 2019, Oracle and/or its affiliates. All Rights Reserved. 4 5 This program is free software; you can redistribute it and/or modify it under 6 the terms of the GNU General Public License, version 2.0, as published by the 7 Free Software Foundation. 8 9 This program is also distributed with certain software (including but not 10 limited to OpenSSL) that is licensed under separate terms, as designated in a 11 particular file or component or in included license documentation. The authors 12 of MySQL hereby grant you an additional permission to link the program and 13 your derivative works with the separately licensed software that they have 14 included with MySQL. 15 16 This program is distributed in the hope that it will be useful, but WITHOUT 17 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS 18 FOR A PARTICULAR PURPOSE. See the GNU General Public License, version 2.0, 19 for more details. 20 21 You should have received a copy of the GNU General Public License along with 22 this program; if not, write to the Free Software Foundation, Inc., 23 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA 24 25 *****************************************************************************/ 26 27 /** @file include/row0purge.h 28 Purge obsolete records 29 30 Created 3/14/1997 Heikki Tuuri 31 *******************************************************/ 32 33 #ifndef row0purge_h 34 #define row0purge_h 35 36 #include "univ.i" 37 38 #include "btr0pcur.h" 39 #include "btr0types.h" 40 #include "data0data.h" 41 #include "dict0types.h" 42 #include "que0types.h" 43 #include "row0types.h" 44 #include "trx0types.h" 45 #include "ut0vec.h" 46 47 /** Create a purge node to a query graph. 48 @param[in] parent parent node, i.e., a thr node 49 @param[in] heap memory heap where created 50 @return own: purge node */ 51 purge_node_t *row_purge_node_create(que_thr_t *parent, mem_heap_t *heap) 52 MY_ATTRIBUTE((warn_unused_result)); 53 54 /** Determines if it is possible to remove a secondary index entry. 55 Removal is possible if the secondary index entry does not refer to any 56 not delete marked version of a clustered index record where DB_TRX_ID 57 is newer than the purge view. 58 59 NOTE: This function should only be called by the purge thread, only 60 while holding a latch on the leaf page of the secondary index entry 61 (or keeping the buffer pool watch on the page). It is possible that 62 this function first returns true and then false, if a user transaction 63 inserts a record that the secondary index entry would refer to. 64 However, in that case, the user transaction would also re-insert the 65 secondary index entry after purge has removed it and released the leaf 66 page latch. 67 @return true if the secondary index record can be purged */ 68 bool row_purge_poss_sec(purge_node_t *node, /*!< in/out: row purge node */ 69 dict_index_t *index, /*!< in: secondary index */ 70 const dtuple_t *entry) /*!< in: secondary index entry */ 71 MY_ATTRIBUTE((warn_unused_result)); 72 /*************************************************************** 73 Does the purge operation for a single undo log record. This is a high-level 74 function used in an SQL execution graph. 75 @return query thread to run next or NULL */ 76 que_thr_t *row_purge_step(que_thr_t *thr) /*!< in: query thread */ 77 MY_ATTRIBUTE((warn_unused_result)); 78 79 /* Purge node structure */ 80 81 struct purge_node_t { 82 /** Info required to purge a record */ 83 struct rec_t { 84 /** Record to purge */ 85 trx_undo_rec_t *undo_rec; 86 87 /** File pointer to UNDO record */ 88 roll_ptr_t roll_ptr; 89 90 /** Trx that created this undo record */ 91 trx_id_t modifier_trx_id; 92 }; 93 94 using Recs = std::list<rec_t, mem_heap_allocator<rec_t>>; 95 96 /** node type: QUE_NODE_PURGE */ 97 que_common_t common; 98 99 /* Local storage for this graph node */ 100 101 /** roll pointer to undo log record */ 102 roll_ptr_t roll_ptr; 103 104 /** undo number of the record */ 105 undo_no_t undo_no; 106 107 /** undo log record type: TRX_UNDO_INSERT_REC, ... */ 108 ulint rec_type; 109 110 /** table where purge is done */ 111 dict_table_t *table; 112 113 /** MDL ticket for the table name */ 114 MDL_ticket *mdl; 115 116 /** parent table for an FTS AUX TABLE */ 117 dict_table_t *parent; 118 119 /** MDL ticket for the parent table of an FTS AUX TABLE */ 120 MDL_ticket *parent_mdl; 121 122 /** MySQL table instance */ 123 TABLE *mysql_table; 124 125 /** compiler analysis info of an update */ 126 ulint cmpl_info; 127 128 /** update vector for a clustered index record */ 129 upd_t *update; 130 131 /** NULL, or row reference to the next row to handle */ 132 dtuple_t *ref; 133 134 /** NULL, or a copy (also fields copied to heap) of the indexed 135 fields of the row to handle */ 136 dtuple_t *row; 137 138 /** NULL, or the next index whose record should be handled */ 139 dict_index_t *index; 140 141 /** The heap is owned by purge_sys and is reset after a purge 142 batch has completed. */ 143 mem_heap_t *heap; 144 145 /** true if the clustered index record determined by ref was 146 found in the clustered index, and we were able to position pcur on it */ 147 bool found_clust; 148 149 /** persistent cursor used in searching the clustered index record */ 150 btr_pcur_t pcur; 151 152 /** Debug flag */ 153 bool done; 154 155 /** trx id for this purging record */ 156 trx_id_t trx_id; 157 158 /** trx id for this purging record */ 159 trx_id_t modifier_trx_id; 160 161 /** Undo recs to purge */ 162 Recs *recs; 163 164 /** Check if undo records of given table_id is there in this purge node. 165 @param[in] table_id look for undo records of this table id. 166 @return true if undo records of table id exists, false otherwise. */ 167 bool is_table_id_exists(table_id_t table_id) const; 168 169 #ifdef UNIV_DEBUG 170 /** Check if there are more than one undo record with same (trx_id, undo_no) 171 combination. 172 @return true when no duplicates are found, false otherwise. */ 173 bool check_duplicate_undo_no() const; 174 #endif /* UNIV_DEBUG */ 175 176 trx_rseg_t *rseg; 177 #ifdef UNIV_DEBUG 178 /** Validate the persisent cursor. The purge node has two references 179 to the clustered index record - one via the ref member, and the 180 other via the persistent cursor. These two references must match 181 each other if the found_clust flag is set. 182 @return true if the persistent cursor is consistent with 183 the ref member.*/ 184 bool validate_pcur(); 185 #endif 186 }; 187 188 #endif 189