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
|
/* Copyright (C) 2000 MySQL AB & MySQL Finland AB & TCX DataKonsult AB
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; either version 2 of the License, or
(at your option) any later version.
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 */
#include "myisamdef.h"
#include "rt_index.h"
/*
Read next row with the same key as previous read, but abort if
the key changes.
One may have done a write, update or delete of the previous row.
NOTE! Even if one changes the previous row, the next read is done
based on the position of the last used key!
*/
int mi_rnext_same(MI_INFO *info, byte *buf)
{
int error;
uint inx,not_used[2];
MI_KEYDEF *keyinfo;
DBUG_ENTER("mi_rnext_same");
if ((int) (inx=info->lastinx) < 0 || info->lastpos == HA_OFFSET_ERROR)
DBUG_RETURN(my_errno=HA_ERR_WRONG_INDEX);
keyinfo=info->s->keyinfo+inx;
if (fast_mi_readinfo(info))
DBUG_RETURN(my_errno);
if (info->s->concurrent_insert)
rw_rdlock(&info->s->key_root_lock[inx]);
switch (keyinfo->key_alg)
{
#ifdef HAVE_RTREE_KEYS
case HA_KEY_ALG_RTREE:
if ((error=rtree_find_next(info,inx,
myisam_read_vec[info->last_key_func])))
{
error=1;
my_errno=HA_ERR_END_OF_FILE;
info->lastpos= HA_OFFSET_ERROR;
break;
}
break;
#endif
case HA_KEY_ALG_BTREE:
default:
if (!(info->update & HA_STATE_RNEXT_SAME))
{
/* First rnext_same; Store old key */
memcpy(info->lastkey2,info->lastkey,info->last_rkey_length);
}
for (;;)
{
if ((error=_mi_search_next(info,keyinfo,info->lastkey,
info->lastkey_length,SEARCH_BIGGER,
info->s->state.key_root[inx])))
break;
if (ha_key_cmp(keyinfo->seg, info->lastkey, info->lastkey2,
info->last_rkey_length, SEARCH_FIND, not_used))
{
error=1;
my_errno=HA_ERR_END_OF_FILE;
info->lastpos= HA_OFFSET_ERROR;
break;
}
/* Skip rows that are inserted by other threads since we got a lock */
if (info->lastpos < info->state->data_file_length)
break;
}
}
if (info->s->concurrent_insert)
rw_unlock(&info->s->key_root_lock[inx]);
/* Don't clear if database-changed */
info->update&= (HA_STATE_CHANGED | HA_STATE_ROW_CHANGED);
info->update|= HA_STATE_NEXT_FOUND | HA_STATE_RNEXT_SAME;
if (error)
{
if (my_errno == HA_ERR_KEY_NOT_FOUND)
my_errno=HA_ERR_END_OF_FILE;
}
else if (!buf)
{
DBUG_RETURN(info->lastpos==HA_OFFSET_ERROR ? my_errno : 0);
}
else if (!(*info->read_record)(info,info->lastpos,buf))
{
info->update|= HA_STATE_AKTIV; /* Record is read */
DBUG_RETURN(0);
}
DBUG_RETURN(my_errno);
} /* mi_rnext_same */
|
