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
|
/* Copyright (c) 2000, 2002, 2005-2007 MySQL AB
Use is subject to license terms
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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1335 USA */
#include "heapdef.h"
/* Read next record with the same key */
int heap_rnext(HP_INFO *info, uchar *record)
{
uchar *pos;
HP_SHARE *share=info->s;
HP_KEYDEF *keyinfo;
DBUG_ENTER("heap_rnext");
if (info->lastinx < 0)
DBUG_RETURN(my_errno=HA_ERR_WRONG_INDEX);
keyinfo = share->keydef + info->lastinx;
if (keyinfo->algorithm == HA_KEY_ALG_BTREE)
{
heap_rb_param custom_arg;
/* If no active record and last was not deleted */
if (!(info->update & (HA_STATE_AKTIV | HA_STATE_NO_KEY |
HA_STATE_DELETED)))
{
if (info->update & HA_STATE_NEXT_FOUND)
pos= 0; /* Can't search after last row */
else
{
/* Last was 'prev' before first record; search after first record */
pos= tree_search_edge(&keyinfo->rb_tree, info->parents,
&info->last_pos, offsetof(TREE_ELEMENT, left));
}
}
else if (info->last_pos)
{
/*
We enter this branch for non-DELETE queries after heap_rkey()
or heap_rfirst(). As last key position (info->last_pos) is available,
we only need to climb the tree using tree_search_next().
*/
pos = tree_search_next(&keyinfo->rb_tree, &info->last_pos,
offsetof(TREE_ELEMENT, left),
offsetof(TREE_ELEMENT, right));
}
else if (!info->lastkey_len)
{
/*
We enter this branch only for DELETE queries after heap_rfirst(). E.g.
DELETE FROM t1 WHERE a<10. As last key position is not available
(last key is removed by heap_delete()), we must restart search as it
is done in heap_rfirst().
It should be safe to handle this situation without this branch. That is
branch below should find smallest element in a tree as lastkey_len is
zero. tree_search_edge() is a kind of optimisation here as it should be
faster than tree_search_key().
*/
pos= tree_search_edge(&keyinfo->rb_tree, info->parents,
&info->last_pos, offsetof(TREE_ELEMENT, left));
}
else
{
/*
We enter this branch only for DELETE queries after heap_rkey(). E.g.
DELETE FROM t1 WHERE a=10. As last key position is not available
(last key is removed by heap_delete()), we must restart search as it
is done in heap_rkey().
*/
custom_arg.keyseg = keyinfo->seg;
custom_arg.key_length = info->lastkey_len;
custom_arg.search_flag = SEARCH_SAME | SEARCH_FIND;
info->last_find_flag= HA_READ_KEY_OR_NEXT;
pos = tree_search_key(&keyinfo->rb_tree, info->lastkey, info->parents,
&info->last_pos, info->last_find_flag, &custom_arg);
}
if (pos)
{
memcpy(&pos, pos + (*keyinfo->get_key_length)(keyinfo, pos),
sizeof(uchar*));
info->current_ptr = pos;
}
else
{
my_errno = HA_ERR_KEY_NOT_FOUND;
}
}
else
{
if (info->current_hash_ptr)
pos= hp_search_next(info, keyinfo, info->lastkey,
info->current_hash_ptr);
else
{
if (!info->current_ptr && (info->update & HA_STATE_NEXT_FOUND))
{
pos=0; /* Read next after last */
my_errno=HA_ERR_KEY_NOT_FOUND;
}
else if (!info->current_ptr) /* Deleted or first call */
pos= hp_search(info, keyinfo, info->lastkey, 0);
else
pos= hp_search(info, keyinfo, info->lastkey, 1);
}
}
if (!pos)
{
info->update=HA_STATE_NEXT_FOUND; /* For heap_rprev */
if (my_errno == HA_ERR_KEY_NOT_FOUND)
my_errno=HA_ERR_END_OF_FILE;
DBUG_RETURN(my_errno);
}
memcpy(record,pos,(size_t) share->reclength);
info->update=HA_STATE_AKTIV | HA_STATE_NEXT_FOUND;
DBUG_RETURN(0);
}
|
