1 /* Copyright (C) 2006 MySQL AB & MySQL Finland AB & TCX DataKonsult AB
2
3 This program is free software; you can redistribute it and/or modify
4 it under the terms of the GNU General Public License as published by
5 the Free Software Foundation; version 2 of the License.
6
7 This program is distributed in the hope that it will be useful,
8 but WITHOUT ANY WARRANTY; without even the implied warranty of
9 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
10 GNU General Public License for more details.
11
12 You should have received a copy of the GNU General Public License
13 along with this program; if not, write to the Free Software
14 Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1335 USA */
15
16 #include "maria_def.h"
17 #include "ma_rt_index.h"
18
19 /*
20 Read next row with the same key as previous read, but abort if
21 the key changes.
22 One may have done a write, update or delete of the previous row.
23
24 NOTE! Even if one changes the previous row, the next read is done
25 based on the position of the last used key!
26 */
27
maria_rnext_same(MARIA_HA * info,uchar * buf)28 int maria_rnext_same(MARIA_HA *info, uchar *buf)
29 {
30 int error;
31 uint inx,not_used[2];
32 MARIA_KEYDEF *keyinfo;
33 check_result_t check= CHECK_POS;
34 DBUG_ENTER("maria_rnext_same");
35
36 if ((int) (inx= info->lastinx) < 0 ||
37 info->cur_row.lastpos == HA_OFFSET_ERROR)
38 DBUG_RETURN(my_errno=HA_ERR_WRONG_INDEX);
39 if (fast_ma_readinfo(info))
40 DBUG_RETURN(my_errno);
41
42 keyinfo= info->s->keyinfo+inx;
43 if (info->s->lock_key_trees)
44 mysql_rwlock_rdlock(&keyinfo->root_lock);
45
46 switch (keyinfo->key_alg) {
47 #ifdef HAVE_RTREE_KEYS
48 case HA_KEY_ALG_RTREE:
49 if ((error=maria_rtree_find_next(info,inx,
50 maria_read_vec[info->last_key_func])))
51 {
52 error=1;
53 my_errno=HA_ERR_END_OF_FILE;
54 info->cur_row.lastpos= HA_OFFSET_ERROR;
55 break;
56 }
57 break;
58 #endif
59 case HA_KEY_ALG_BTREE:
60 default:
61 if (!(info->update & HA_STATE_RNEXT_SAME))
62 {
63 /* First rnext_same; Store old key */
64 memcpy(info->lastkey_buff2, info->last_key.data,
65 info->last_rkey_length);
66 }
67 for (;;)
68 {
69 if ((error= _ma_search_next(info, &info->last_key,
70 SEARCH_BIGGER,
71 info->s->state.key_root[inx])))
72 break;
73 if (ha_key_cmp(keyinfo->seg, info->last_key.data,
74 info->lastkey_buff2,
75 info->last_rkey_length, SEARCH_FIND,
76 not_used))
77 {
78 error=1;
79 my_errno=HA_ERR_END_OF_FILE;
80 info->cur_row.lastpos= HA_OFFSET_ERROR;
81 break;
82 }
83 /*
84 If we are at the last key on the key page, allow writers to
85 access the index.
86 */
87 if (info->int_keypos >= info->int_maxpos &&
88 ma_yield_and_check_if_killed(info, inx))
89 {
90 error= 1;
91 break;
92 }
93 /* Skip rows that are inserted by other threads since we got a lock */
94 if ((info->s->row_is_visible)(info) &&
95 ((check= ma_check_index_cond(info, inx, buf)) != CHECK_NEG))
96 break;
97 }
98 }
99 if (info->s->lock_key_trees)
100 mysql_rwlock_unlock(&keyinfo->root_lock);
101 /* Don't clear if database-changed */
102 info->update&= (HA_STATE_CHANGED | HA_STATE_ROW_CHANGED);
103 info->update|= HA_STATE_NEXT_FOUND | HA_STATE_RNEXT_SAME;
104
105 if (error || check != CHECK_POS)
106 {
107 fast_ma_writeinfo(info);
108 if (my_errno == HA_ERR_KEY_NOT_FOUND)
109 my_errno= HA_ERR_END_OF_FILE;
110 }
111 else if (!buf)
112 {
113 fast_ma_writeinfo(info);
114 DBUG_RETURN(info->cur_row.lastpos == HA_OFFSET_ERROR ? my_errno : 0);
115 }
116 else if (!(*info->read_record)(info, buf, info->cur_row.lastpos))
117 {
118 info->update|= HA_STATE_AKTIV; /* Record is read */
119 DBUG_RETURN(0);
120 }
121 DBUG_RETURN(my_errno);
122 } /* maria_rnext_same */
123