1 /* Copyright (C) 2003-2007 MySQL 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 /*
17 Handling of multiple key caches
18
19 The idea is to have a thread safe hash on the table name,
20 with a default key cache value that is returned if the table name is not in
21 the cache.
22 */
23
24 #include "maria_def.h"
25 #include "ma_pagecache.h"
26 #include <hash.h>
27 #include <m_string.h>
28 #include "../../mysys/my_safehash.h"
29
30 /*****************************************************************************
31 Functions to handle the pagecache objects
32 *****************************************************************************/
33
34 /* Variable to store all key cache objects */
35 static SAFE_HASH pagecache_hash;
36
37
multi_pagecache_init(void)38 my_bool multi_pagecache_init(void)
39 {
40 return safe_hash_init(&pagecache_hash, 16, (uchar*) maria_pagecache);
41 }
42
43
multi_pagecache_free(void)44 void multi_pagecache_free(void)
45 {
46 safe_hash_free(&pagecache_hash);
47 }
48
49 /*
50 Get a key cache to be used for a specific table.
51
52 SYNOPSIS
53 multi_pagecache_search()
54 key key to find (usually table path)
55 uint length Length of key.
56 def Default value if no key cache
57
58 NOTES
59 This function is coded in such a way that we will return the
60 default key cache even if one never called multi_pagecache_init.
61 This will ensure that it works with old MyISAM clients.
62
63 RETURN
64 key cache to use
65 */
66
multi_pagecache_search(uchar * key,uint length,PAGECACHE * def)67 PAGECACHE *multi_pagecache_search(uchar *key, uint length,
68 PAGECACHE *def)
69 {
70 if (!pagecache_hash.hash.records)
71 return def;
72 return (PAGECACHE*) safe_hash_search(&pagecache_hash, key, length,
73 (void*) def);
74 }
75
76
77 /*
78 Assosiate a key cache with a key
79
80
81 SYONOPSIS
82 multi_pagecache_set()
83 key key (path to table etc..)
84 length Length of key
85 pagecache cache to assococite with the table
86
87 NOTES
88 This can be used both to insert a new entry and change an existing
89 entry
90 */
91
92
multi_pagecache_set(const uchar * key,uint length,PAGECACHE * pagecache)93 my_bool multi_pagecache_set(const uchar *key, uint length,
94 PAGECACHE *pagecache)
95 {
96 return safe_hash_set(&pagecache_hash, key, length, (uchar*) pagecache);
97 }
98
99
multi_pagecache_change(PAGECACHE * old_data,PAGECACHE * new_data)100 void multi_pagecache_change(PAGECACHE *old_data,
101 PAGECACHE *new_data)
102 {
103 safe_hash_change(&pagecache_hash, (uchar*) old_data, (uchar*) new_data);
104 }
105