1 /* Copyright (c) 2003, 2010, Oracle and/or its affiliates. All rights reserved.
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, version 2.0,
5 as published by the Free Software Foundation.
6
7 This program is also distributed with certain software (including
8 but not limited to OpenSSL) that is licensed under separate terms,
9 as designated in a particular file or component or in included license
10 documentation. The authors of MySQL hereby grant you an additional
11 permission to link the program and your derivative works with the
12 separately licensed software that they have included with MySQL.
13
14 This program is distributed in the hope that it will be useful,
15 but WITHOUT ANY WARRANTY; without even the implied warranty of
16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 GNU General Public License, version 2.0, for more details.
18
19 You should have received a copy of the GNU General Public License
20 along with this program; if not, write to the Free Software
21 Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */
22
23 /*
24 Preload indexes into key cache
25 */
26
27 #include "myisamdef.h"
28
29
30 /*
31 Preload pages of the index file for a table into the key cache
32
33 SYNOPSIS
34 mi_preload()
35 info open table
36 map map of indexes to preload into key cache
37 ignore_leaves only non-leaves pages are to be preloaded
38
39 RETURN VALUE
40 0 if a success. error code - otherwise.
41
42 NOTES.
43 At present pages for all indexes are preloaded.
44 In future only pages for indexes specified in the key_map parameter
45 of the table will be preloaded.
46 */
47
mi_preload(MI_INFO * info,ulonglong key_map,my_bool ignore_leaves)48 int mi_preload(MI_INFO *info, ulonglong key_map, my_bool ignore_leaves)
49 {
50 uint i;
51 ulong length, block_length= 0;
52 uchar *buff= NULL;
53 MYISAM_SHARE* share= info->s;
54 uint keys= share->state.header.keys;
55 MI_KEYDEF *keyinfo= share->keyinfo;
56 my_off_t key_file_length= share->state.state.key_file_length;
57 my_off_t pos= share->base.keystart;
58 DBUG_ENTER("mi_preload");
59
60 if (!keys || !mi_is_any_key_active(key_map) || key_file_length == pos)
61 DBUG_RETURN(0);
62
63 /* Preload into a non initialized key cache should never happen. */
64 DBUG_ASSERT(share->key_cache->key_cache_inited);
65
66 block_length= keyinfo[0].block_length;
67
68 if (ignore_leaves)
69 {
70 /* Check whether all indexes use the same block size */
71 for (i= 1 ; i < keys ; i++)
72 {
73 if (keyinfo[i].block_length != block_length)
74 DBUG_RETURN(my_errno= HA_ERR_NON_UNIQUE_BLOCK_SIZE);
75 }
76 }
77 else
78 block_length= share->key_cache->key_cache_block_size;
79
80 length= info->preload_buff_size/block_length * block_length;
81 set_if_bigger(length, block_length);
82
83 if (!(buff= (uchar *) my_malloc(length, MYF(MY_WME))))
84 DBUG_RETURN(my_errno= HA_ERR_OUT_OF_MEM);
85
86 if (flush_key_blocks(share->key_cache,share->kfile, FLUSH_RELEASE))
87 goto err;
88
89 do
90 {
91 /* Read the next block of index file into the preload buffer */
92 if ((my_off_t) length > (key_file_length-pos))
93 length= (ulong) (key_file_length-pos);
94 if (mysql_file_pread(share->kfile, (uchar*) buff, length, pos,
95 MYF(MY_FAE|MY_FNABP)))
96 goto err;
97
98 if (ignore_leaves)
99 {
100 uchar *end= buff+length;
101 do
102 {
103 if (mi_test_if_nod(buff))
104 {
105 if (key_cache_insert(share->key_cache,
106 share->kfile, pos, DFLT_INIT_HITS,
107 (uchar*) buff, block_length))
108 goto err;
109 }
110 pos+= block_length;
111 }
112 while ((buff+= block_length) != end);
113 buff= end-length;
114 }
115 else
116 {
117 if (key_cache_insert(share->key_cache,
118 share->kfile, pos, DFLT_INIT_HITS,
119 (uchar*) buff, length))
120 goto err;
121 pos+= length;
122 }
123 }
124 while (pos != key_file_length);
125
126 my_free(buff);
127 DBUG_RETURN(0);
128
129 err:
130 my_free(buff);
131 DBUG_RETURN(my_errno= errno);
132 }
133
134