1/*
2 Copyright (c) 2000, 2010, Oracle and/or its affiliates
3
4 This program is free software; you can redistribute it and/or modify
5 it under the terms of the GNU General Public License as published by
6 the Free Software Foundation; version 2 of the License.
7
8 This program is distributed in the hope that it will be useful,
9 but WITHOUT ANY WARRANTY; without even the implied warranty of
10 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 GNU General Public License for more details.
12
13 You should have received a copy of the GNU General Public License
14 along with this program; if not, write to the Free Software
15 Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */
16
17#include "myisamdef.h"
18#include "rt_index.h"
19
20 /*
21 Read next row with the same key as previous read
22 One may have done a write, update or delete of the previous row.
23 NOTE! Even if one changes the previous row, the next read is done
24 based on the position of the last used key!
25 */
26
27int mi_rnext(MI_INFO *info, uchar *buf, int inx)
28{
29 int error,changed;
30 uint flag;
31 ICP_RESULT icp_res= ICP_MATCH;
32 uint update_mask= HA_STATE_NEXT_FOUND;
33 DBUG_ENTER("mi_rnext");
34
35 if ((inx = _mi_check_index(info,inx)) < 0)
36 DBUG_RETURN(my_errno);
37 flag=SEARCH_BIGGER; /* Read next */
38 if (info->lastpos == HA_OFFSET_ERROR && info->update & HA_STATE_PREV_FOUND)
39 flag=0; /* Read first */
40
41 if (fast_mi_readinfo(info))
42 DBUG_RETURN(my_errno);
43 if (info->s->concurrent_insert)
44 mysql_rwlock_rdlock(&info->s->key_root_lock[inx]);
45 changed=_mi_test_if_changed(info);
46 if (!flag)
47 {
48 switch(info->s->keyinfo[inx].key_alg){
49#ifdef HAVE_RTREE_KEYS
50 case HA_KEY_ALG_RTREE:
51 error=rtree_get_first(info,inx,info->lastkey_length);
52 break;
53#endif
54 case HA_KEY_ALG_BTREE:
55 default:
56 error=_mi_search_first(info,info->s->keyinfo+inx,
57 info->s->state.key_root[inx]);
58 break;
59 }
60 /*
61 "search first" failed. This means we have no pivot for
62 "search next", or in other words MI_INFO::lastkey is
63 likely uninitialized.
64
65 Normally SQL layer would never request "search next" if
66 "search first" failed. But HANDLER may do anything.
67
68 As mi_rnext() without preceding mi_rkey()/mi_rfirst()
69 equals to mi_rfirst(), we must restore original state
70 as if failing mi_rfirst() was not called.
71 */
72 if (error)
73 update_mask|= HA_STATE_PREV_FOUND;
74 }
75 else
76 {
77 switch (info->s->keyinfo[inx].key_alg) {
78#ifdef HAVE_RTREE_KEYS
79 case HA_KEY_ALG_RTREE:
80 /*
81 Note that rtree doesn't support that the table
82 may be changed since last call, so we do need
83 to skip rows inserted by other threads like in btree
84 */
85 error= rtree_get_next(info,inx,info->lastkey_length);
86 break;
87#endif
88 case HA_KEY_ALG_BTREE:
89 default:
90 if (!changed)
91 error= _mi_search_next(info,info->s->keyinfo+inx,info->lastkey,
92 info->lastkey_length,flag,
93 info->s->state.key_root[inx]);
94 else
95 error= _mi_search(info,info->s->keyinfo+inx,info->lastkey,
96 USE_WHOLE_KEY,flag, info->s->state.key_root[inx]);
97 }
98 }
99
100 if (!error)
101 {
102 while ((info->s->concurrent_insert &&
103 info->lastpos >= info->state->data_file_length) ||
104 (info->index_cond_func &&
105 (icp_res= mi_check_index_cond(info, inx, buf)) == ICP_NO_MATCH))
106 {
107 /*
108 If we are at the last key on the key page, allow writers to
109 access the index.
110 */
111 if (info->int_keypos >= info->int_maxpos &&
112 mi_yield_and_check_if_killed(info, inx))
113 {
114 error= 1;
115 break;
116 }
117
118 /*
119 Skip rows that are either inserted by other threads since
120 we got a lock or do not match pushed index conditions
121 */
122 if ((error=_mi_search_next(info,info->s->keyinfo+inx,
123 info->lastkey,
124 info->lastkey_length,
125 SEARCH_BIGGER,
126 info->s->state.key_root[inx])))
127 break;
128 }
129 }
130
131 if (info->s->concurrent_insert)
132 mysql_rwlock_unlock(&info->s->key_root_lock[inx]);
133
134 /* Don't clear if database-changed */
135 info->update&= (HA_STATE_CHANGED | HA_STATE_ROW_CHANGED);
136 info->update|= update_mask;
137
138 if (error || icp_res != ICP_MATCH)
139 {
140 fast_mi_writeinfo(info);
141 if (my_errno == HA_ERR_KEY_NOT_FOUND)
142 my_errno=HA_ERR_END_OF_FILE;
143 }
144 else if (!buf)
145 {
146 fast_mi_writeinfo(info);
147 DBUG_RETURN(info->lastpos==HA_OFFSET_ERROR ? my_errno : 0);
148 }
149 else if (!(*info->read_record)(info,info->lastpos,buf))
150 {
151 info->update|= HA_STATE_AKTIV; /* Record is read */
152 DBUG_RETURN(0);
153 }
154 DBUG_PRINT("error",("Got error: %d, errno: %d",error, my_errno));
155 DBUG_RETURN(my_errno);
156} /* mi_rnext */
157