1/*****************************************************************************
2
3Copyright (c) 1997, 2016, Oracle and/or its affiliates. All Rights Reserved.
4Copyright (c) 2017, MariaDB Corporation.
5
6This program is free software; you can redistribute it and/or modify it under
7the terms of the GNU General Public License as published by the Free Software
8Foundation; version 2 of the License.
9
10This program is distributed in the hope that it will be useful, but WITHOUT
11ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
12FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
13
14You should have received a copy of the GNU General Public License along with
15this program; if not, write to the Free Software Foundation, Inc.,
1651 Franklin Street, Suite 500, Boston, MA 02110-1335 USA
17
18*****************************************************************************/
19
20/**************************************************//**
21@file include/row0purge.h
22Purge obsolete records
23
24Created 3/14/1997 Heikki Tuuri
25*******************************************************/
26
27#ifndef row0purge_h
28#define row0purge_h
29
30#include "univ.i"
31#include "data0data.h"
32#include "btr0types.h"
33#include "btr0pcur.h"
34#include "dict0types.h"
35#include "trx0types.h"
36#include "que0types.h"
37#include "row0types.h"
38#include "ut0vec.h"
39
40/** Create a purge node to a query graph.
41@param[in] parent parent node, i.e., a thr node
42@param[in] heap memory heap where created
43@return own: purge node */
44purge_node_t*
45row_purge_node_create(
46 que_thr_t* parent,
47 mem_heap_t* heap)
48 MY_ATTRIBUTE((warn_unused_result));
49
50/***********************************************************//**
51Determines if it is possible to remove a secondary index entry.
52Removal is possible if the secondary index entry does not refer to any
53not delete marked version of a clustered index record where DB_TRX_ID
54is newer than the purge view.
55
56NOTE: This function should only be called by the purge thread, only
57while holding a latch on the leaf page of the secondary index entry
58(or keeping the buffer pool watch on the page). It is possible that
59this function first returns true and then false, if a user transaction
60inserts a record that the secondary index entry would refer to.
61However, in that case, the user transaction would also re-insert the
62secondary index entry after purge has removed it and released the leaf
63page latch.
64@return true if the secondary index record can be purged */
65bool
66row_purge_poss_sec(
67/*===============*/
68 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((nonnull, warn_unused_result));
72/***************************************************************
73Does the purge operation for a single undo log record. This is a high-level
74function used in an SQL execution graph.
75@return query thread to run next or NULL */
76que_thr_t*
77row_purge_step(
78/*===========*/
79 que_thr_t* thr) /*!< in: query thread */
80 MY_ATTRIBUTE((nonnull, warn_unused_result));
81
82/* Purge node structure */
83
84struct purge_node_t{
85 que_common_t common; /*!< node type: QUE_NODE_PURGE */
86 /*----------------------*/
87 /* Local storage for this graph node */
88 roll_ptr_t roll_ptr;/* roll pointer to undo log record */
89 ib_vector_t* undo_recs;/*!< Undo recs to purge */
90
91 undo_no_t undo_no;/*!< undo number of the record */
92
93 ulint rec_type;/*!< undo log record type: TRX_UNDO_INSERT_REC,
94 ... */
95 dict_table_t* table; /*!< table where purge is done */
96
97 ulint cmpl_info;/* compiler analysis info of an update */
98
99 upd_t* update; /*!< update vector for a clustered index
100 record */
101 const dtuple_t* ref; /*!< NULL, or row reference to the next row to
102 handle */
103 dtuple_t* row; /*!< NULL, or a copy (also fields copied to
104 heap) of the indexed fields of the row to
105 handle */
106 dict_index_t* index; /*!< NULL, or the next index whose record should
107 be handled */
108 mem_heap_t* heap; /*!< memory heap used as auxiliary storage for
109 row; this must be emptied after a successful
110 purge of a row */
111 ibool found_clust;/* TRUE if the clustered index record
112 determined by ref was found in the clustered
113 index, and we were able to position pcur on
114 it */
115 btr_pcur_t pcur; /*!< persistent cursor used in searching the
116 clustered index record */
117 ibool done; /* Debug flag */
118 trx_id_t trx_id; /*!< trx id for this purging record */
119
120#ifdef UNIV_DEBUG
121 /***********************************************************//**
122 Validate the persisent cursor. The purge node has two references
123 to the clustered index record - one via the ref member, and the
124 other via the persistent cursor. These two references must match
125 each other if the found_clust flag is set.
126 @return true if the persistent cursor is consistent with
127 the ref member.*/
128 bool validate_pcur();
129#endif
130};
131
132#endif
133