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
|
/* 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 */
/* Read record based on a key */
#include "myisamdef.h"
#include "rt_index.h"
/* Read a record using key */
/* Ordinary search_flag is 0 ; Give error if no record with key */
int mi_rkey(MI_INFO *info, byte *buf, int inx, const byte *key, uint key_len,
enum ha_rkey_function search_flag)
{
uchar *key_buff;
MYISAM_SHARE *share=info->s;
MI_KEYDEF *keyinfo;
HA_KEYSEG *last_used_keyseg;
uint pack_key_length, use_key_length, nextflag;
DBUG_ENTER("mi_rkey");
DBUG_PRINT("enter",("base: %lx inx: %d search_flag: %d",
info,inx,search_flag));
if ((inx = _mi_check_index(info,inx)) < 0)
DBUG_RETURN(my_errno);
info->update&= (HA_STATE_CHANGED | HA_STATE_ROW_CHANGED);
info->last_key_func= search_flag;
keyinfo= share->keyinfo + inx;
if (info->once_flags & USE_PACKED_KEYS)
{
info->once_flags&= ~USE_PACKED_KEYS; /* Reset flag */
/*
key is already packed!; This happens when we are using a MERGE TABLE
*/
key_buff=info->lastkey+info->s->base.max_key_length;
pack_key_length= key_len;
bmove(key_buff,key,key_len);
last_used_keyseg= 0;
}
else
{
if (key_len == 0)
key_len=USE_WHOLE_KEY;
key_buff=info->lastkey+info->s->base.max_key_length;
pack_key_length=_mi_pack_key(info,(uint) inx, key_buff, (uchar*) key,
key_len, &last_used_keyseg);
DBUG_EXECUTE("key",_mi_print_key(DBUG_FILE, keyinfo->seg,
key_buff, pack_key_length););
}
if (fast_mi_readinfo(info))
goto err;
if (share->concurrent_insert)
rw_rdlock(&share->key_root_lock[inx]);
nextflag=myisam_read_vec[search_flag];
use_key_length=pack_key_length;
if (!(nextflag & (SEARCH_FIND | SEARCH_NO_FIND | SEARCH_LAST)))
use_key_length=USE_WHOLE_KEY;
switch (info->s->keyinfo[inx].key_alg) {
#ifdef HAVE_RTREE_KEYS
case HA_KEY_ALG_RTREE:
if (rtree_find_first(info,inx,key_buff,use_key_length,nextflag) < 0)
{
my_errno=HA_ERR_CRASHED;
goto err;
}
break;
#endif
case HA_KEY_ALG_BTREE:
default:
if (!_mi_search(info, keyinfo, key_buff, use_key_length,
myisam_read_vec[search_flag], info->s->state.key_root[inx]))
{
while (info->lastpos >= info->state->data_file_length)
{
/*
Skip rows that are inserted by other threads since we got a lock
Note that this can only happen if we are not searching after an
exact key, because the keys are sorted according to position
*/
if (_mi_search_next(info, keyinfo, info->lastkey,
info->lastkey_length,
myisam_readnext_vec[search_flag],
info->s->state.key_root[inx]))
break;
}
}
}
if (share->concurrent_insert)
rw_unlock(&share->key_root_lock[inx]);
/* Calculate length of the found key; Used by mi_rnext_same */
if ((keyinfo->flag & HA_VAR_LENGTH_KEY) && last_used_keyseg &&
info->lastpos != HA_OFFSET_ERROR)
info->last_rkey_length= _mi_keylength_part(keyinfo, info->lastkey,
last_used_keyseg);
else
info->last_rkey_length= pack_key_length;
/* Check if we don't want to have record back, only error message */
if (!buf)
DBUG_RETURN(info->lastpos == HA_OFFSET_ERROR ? my_errno : 0);
if (!(*info->read_record)(info,info->lastpos,buf))
{
info->update|= HA_STATE_AKTIV; /* Record is read */
DBUG_RETURN(0);
}
info->lastpos = HA_OFFSET_ERROR; /* Didn't find key */
/* Store last used key as a base for read next */
memcpy(info->lastkey,key_buff,pack_key_length);
info->last_rkey_length= pack_key_length;
bzero((char*) info->lastkey+pack_key_length,info->s->base.rec_reflength);
info->lastkey_length=pack_key_length+info->s->base.rec_reflength;
if (search_flag == HA_READ_AFTER_KEY)
info->update|=HA_STATE_NEXT_FOUND; /* Previous gives last row */
err:
DBUG_RETURN(my_errno);
} /* _mi_rkey */
|
