1/* Copyright (c) 2000-2003, 2005-2008 MySQL AB, 2009 Sun Microsystems, Inc.
2 Use is subject to license terms.
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/* Read record based on a key */
18
19/*
20 * HA_READ_KEY_EXACT => SEARCH_BIGGER
21 * HA_READ_KEY_OR_NEXT => SEARCH_BIGGER
22 * HA_READ_AFTER_KEY => SEARCH_BIGGER
23 * HA_READ_PREFIX => SEARCH_BIGGER
24 * HA_READ_KEY_OR_PREV => SEARCH_SMALLER
25 * HA_READ_BEFORE_KEY => SEARCH_SMALLER
26 * HA_READ_PREFIX_LAST => SEARCH_SMALLER
27 */
28
29
30#include "myrg_def.h"
31
32/* todo: we could store some additional info to speedup lookups:
33 column (key, keyseg) can be constant per table
34 it can also be increasing (table1.val > table2.val > ...),
35 or decreasing, <=, >=, etc.
36 SerG
37*/
38
39int myrg_rkey(MYRG_INFO *info,uchar *buf,int inx, const uchar *key,
40 key_part_map keypart_map, enum ha_rkey_function search_flag)
41{
42 uchar *UNINIT_VAR(key_buff);
43 uint UNINIT_VAR(pack_key_length);
44 uint16 UNINIT_VAR(last_used_keyseg);
45 MYRG_TABLE *table;
46 MI_INFO *mi;
47 int err;
48 DBUG_ENTER("myrg_rkey");
49
50 if (_myrg_init_queue(info,inx,search_flag))
51 DBUG_RETURN(my_errno);
52
53 for (table=info->open_tables ; table != info->end_table ; table++)
54 {
55 mi=table->table;
56
57 if (table == info->open_tables)
58 {
59 err=mi_rkey(mi, 0, inx, key, keypart_map, search_flag);
60 /* Get the saved packed key and packed key length. */
61 key_buff=(uchar*) mi->lastkey+mi->s->base.max_key_length;
62 pack_key_length=mi->pack_key_length;
63 last_used_keyseg= mi->last_used_keyseg;
64 }
65 else
66 {
67 mi->once_flags|= USE_PACKED_KEYS;
68 mi->last_used_keyseg= last_used_keyseg;
69 err=mi_rkey(mi, 0, inx, key_buff, pack_key_length, search_flag);
70 }
71 info->last_used_table=table+1;
72
73 if (err)
74 {
75 if (err == HA_ERR_KEY_NOT_FOUND)
76 continue;
77 DBUG_PRINT("exit", ("err: %d", err));
78 DBUG_RETURN(err);
79 }
80 /* adding to queue */
81 queue_insert(&(info->by_key),(uchar *)table);
82
83 }
84
85 DBUG_PRINT("info", ("tables with matches: %u", info->by_key.elements));
86 if (!info->by_key.elements)
87 DBUG_RETURN(HA_ERR_KEY_NOT_FOUND);
88
89 mi=(info->current_table=(MYRG_TABLE *)queue_top(&(info->by_key)))->table;
90 mi->once_flags|= RRND_PRESERVE_LASTINX;
91 DBUG_PRINT("info", ("using table no: %d",
92 (int) (info->current_table - info->open_tables + 1)));
93 DBUG_DUMP("result key", (uchar*) mi->lastkey, mi->lastkey_length);
94 DBUG_RETURN(_myrg_mi_read_record(mi,buf));
95}
96