1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
|
/*****************************************************************************
Copyright (c) 1994, 2009, Innobase Oy. All Rights Reserved.
This program is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free Software
Foundation; version 2 of the License.
This program is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License along with
this program; if not, write to the Free Software Foundation, Inc., 59 Temple
Place, Suite 330, Boston, MA 02111-1307 USA
*****************************************************************************/
/******************************************************
The index tree cursor
Created 10/16/1994 Heikki Tuuri
*******************************************************/
#include "btr0btr.h"
#ifdef UNIV_DEBUG
/*************************************************************
Returns the page cursor component of a tree cursor. */
UNIV_INLINE
page_cur_t*
btr_cur_get_page_cur(
/*=================*/
/* out: pointer to page cursor
component */
const btr_cur_t* cursor) /* in: tree cursor */
{
return(&((btr_cur_t*) cursor)->page_cur);
}
#endif /* UNIV_DEBUG */
/*************************************************************
Returns the buffer block on which the tree cursor is positioned. */
UNIV_INLINE
buf_block_t*
btr_cur_get_block(
/*==============*/
/* out: pointer to buffer block */
btr_cur_t* cursor) /* in: tree cursor */
{
return(page_cur_get_block(btr_cur_get_page_cur(cursor)));
}
/*************************************************************
Returns the record pointer of a tree cursor. */
UNIV_INLINE
rec_t*
btr_cur_get_rec(
/*============*/
/* out: pointer to record */
btr_cur_t* cursor) /* in: tree cursor */
{
return(page_cur_get_rec(&(cursor->page_cur)));
}
/*************************************************************
Returns the compressed page on which the tree cursor is positioned. */
UNIV_INLINE
page_zip_des_t*
btr_cur_get_page_zip(
/*=================*/
/* out: pointer to compressed page,
or NULL if the page is not compressed */
btr_cur_t* cursor) /* in: tree cursor */
{
return(buf_block_get_page_zip(btr_cur_get_block(cursor)));
}
/*************************************************************
Invalidates a tree cursor by setting record pointer to NULL. */
UNIV_INLINE
void
btr_cur_invalidate(
/*===============*/
btr_cur_t* cursor) /* in: tree cursor */
{
page_cur_invalidate(&(cursor->page_cur));
}
/*************************************************************
Returns the page of a tree cursor. */
UNIV_INLINE
page_t*
btr_cur_get_page(
/*=============*/
/* out: pointer to page */
btr_cur_t* cursor) /* in: tree cursor */
{
return(page_align(page_cur_get_rec(&(cursor->page_cur))));
}
/*************************************************************
Returns the index of a cursor. */
UNIV_INLINE
dict_index_t*
btr_cur_get_index(
/*==============*/
/* out: index */
btr_cur_t* cursor) /* in: B-tree cursor */
{
return(cursor->index);
}
/*************************************************************
Positions a tree cursor at a given record. */
UNIV_INLINE
void
btr_cur_position(
/*=============*/
dict_index_t* index, /* in: index */
rec_t* rec, /* in: record in tree */
buf_block_t* block, /* in: buffer block of rec */
btr_cur_t* cursor) /* out: cursor */
{
ut_ad(page_align(rec) == block->frame);
page_cur_position(rec, block, btr_cur_get_page_cur(cursor));
cursor->index = index;
}
/*************************************************************************
Checks if compressing an index page where a btr cursor is placed makes
sense. */
UNIV_INLINE
ibool
btr_cur_compress_recommendation(
/*============================*/
/* out: TRUE if compression is recommended */
btr_cur_t* cursor, /* in: btr cursor */
mtr_t* mtr) /* in: mtr */
{
page_t* page;
ut_ad(mtr_memo_contains(mtr, btr_cur_get_block(cursor),
MTR_MEMO_PAGE_X_FIX));
page = btr_cur_get_page(cursor);
if ((page_get_data_size(page) < BTR_CUR_PAGE_COMPRESS_LIMIT)
|| ((btr_page_get_next(page, mtr) == FIL_NULL)
&& (btr_page_get_prev(page, mtr) == FIL_NULL))) {
/* The page fillfactor has dropped below a predefined
minimum value OR the level in the B-tree contains just
one page: we recommend compression if this is not the
root page. */
return(dict_index_get_page(cursor->index)
!= page_get_page_no(page));
}
return(FALSE);
}
/*************************************************************************
Checks if the record on which the cursor is placed can be deleted without
making tree compression necessary (or, recommended). */
UNIV_INLINE
ibool
btr_cur_can_delete_without_compress(
/*================================*/
/* out: TRUE if can be deleted without
recommended compression */
btr_cur_t* cursor, /* in: btr cursor */
ulint rec_size,/* in: rec_get_size(btr_cur_get_rec(cursor))*/
mtr_t* mtr) /* in: mtr */
{
page_t* page;
ut_ad(mtr_memo_contains(mtr, btr_cur_get_block(cursor),
MTR_MEMO_PAGE_X_FIX));
page = btr_cur_get_page(cursor);
if ((page_get_data_size(page) - rec_size < BTR_CUR_PAGE_COMPRESS_LIMIT)
|| ((btr_page_get_next(page, mtr) == FIL_NULL)
&& (btr_page_get_prev(page, mtr) == FIL_NULL))
|| (page_get_n_recs(page) < 2)) {
/* The page fillfactor will drop below a predefined
minimum value, OR the level in the B-tree contains just
one page, OR the page will become empty: we recommend
compression if this is not the root page. */
return(dict_index_get_page(cursor->index)
== page_get_page_no(page));
}
return(TRUE);
}
|
