|
1
by brian
clean slate |
1 |
/* Copyright (C) 2003 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
|
|
15 |
||
16 |
/* Key cache variable structures */
|
|
17 |
||
18 |
#ifndef _keycache_h
|
|
19 |
#define _keycache_h
|
|
20 |
C_MODE_START
|
|
21 |
||
22 |
/* declare structures that is used by st_key_cache */
|
|
23 |
||
24 |
struct st_block_link; |
|
25 |
typedef struct st_block_link BLOCK_LINK; |
|
26 |
struct st_keycache_page; |
|
27 |
typedef struct st_keycache_page KEYCACHE_PAGE; |
|
28 |
struct st_hash_link; |
|
29 |
typedef struct st_hash_link HASH_LINK; |
|
30 |
||
31 |
/* info about requests in a waiting queue */
|
|
32 |
typedef struct st_keycache_wqueue |
|
33 |
{
|
|
34 |
struct st_my_thread_var *last_thread; /* circular list of waiting threads */ |
|
35 |
} KEYCACHE_WQUEUE; |
|
36 |
||
37 |
#define CHANGED_BLOCKS_HASH 128 /* must be power of 2 */ |
|
38 |
||
39 |
/*
|
|
40 |
The key cache structure
|
|
41 |
It also contains read-only statistics parameters.
|
|
42 |
*/
|
|
43 |
||
44 |
typedef struct st_key_cache |
|
45 |
{
|
|
46 |
my_bool key_cache_inited; |
|
47 |
my_bool in_resize; /* true during resize operation */ |
|
48 |
my_bool resize_in_flush; /* true during flush of resize operation */ |
|
49 |
my_bool can_be_used; /* usage of cache for read/write is allowed */ |
|
50 |
size_t key_cache_mem_size; /* specified size of the cache memory */ |
|
51 |
uint key_cache_block_size; /* size of the page buffer of a cache block */ |
|
52 |
ulong min_warm_blocks; /* min number of warm blocks; */ |
|
53 |
ulong age_threshold; /* age threshold for hot blocks */ |
|
54 |
ulonglong keycache_time; /* total number of block link operations */ |
|
55 |
uint hash_entries; /* max number of entries in the hash table */ |
|
56 |
int hash_links; /* max number of hash links */ |
|
57 |
int hash_links_used; /* number of hash links currently used */ |
|
58 |
int disk_blocks; /* max number of blocks in the cache */ |
|
59 |
ulong blocks_used; /* maximum number of concurrently used blocks */ |
|
60 |
ulong blocks_unused; /* number of currently unused blocks */ |
|
61 |
ulong blocks_changed; /* number of currently dirty blocks */ |
|
62 |
ulong warm_blocks; /* number of blocks in warm sub-chain */ |
|
63 |
ulong cnt_for_resize_op; /* counter to block resize operation */ |
|
64 |
long blocks_available; /* number of blocks available in the LRU chain */ |
|
65 |
HASH_LINK **hash_root; /* arr. of entries into hash table buckets */ |
|
66 |
HASH_LINK *hash_link_root; /* memory for hash table links */ |
|
67 |
HASH_LINK *free_hash_list; /* list of free hash links */ |
|
68 |
BLOCK_LINK *free_block_list; /* list of free blocks */ |
|
69 |
BLOCK_LINK *block_root; /* memory for block links */ |
|
70 |
uchar *block_mem; /* memory for block buffers */ |
|
71 |
BLOCK_LINK *used_last; /* ptr to the last block of the LRU chain */ |
|
72 |
BLOCK_LINK *used_ins; /* ptr to the insertion block in LRU chain */ |
|
73 |
pthread_mutex_t cache_lock; /* to lock access to the cache structure */ |
|
74 |
KEYCACHE_WQUEUE resize_queue; /* threads waiting during resize operation */ |
|
75 |
/*
|
|
76 |
Waiting for a zero resize count. Using a queue for symmetry though
|
|
77 |
only one thread can wait here.
|
|
78 |
*/
|
|
79 |
KEYCACHE_WQUEUE waiting_for_resize_cnt; |
|
80 |
KEYCACHE_WQUEUE waiting_for_hash_link; /* waiting for a free hash link */ |
|
81 |
KEYCACHE_WQUEUE waiting_for_block; /* requests waiting for a free block */ |
|
82 |
BLOCK_LINK *changed_blocks[CHANGED_BLOCKS_HASH]; /* hash for dirty file bl.*/ |
|
83 |
BLOCK_LINK *file_blocks[CHANGED_BLOCKS_HASH]; /* hash for other file bl.*/ |
|
84 |
||
85 |
/*
|
|
86 |
The following variables are and variables used to hold parameters for
|
|
87 |
initializing the key cache.
|
|
88 |
*/
|
|
89 |
||
90 |
ulonglong param_buff_size; /* size the memory allocated for the cache */ |
|
91 |
ulong param_block_size; /* size of the blocks in the key cache */ |
|
92 |
ulong param_division_limit; /* min. percentage of warm blocks */ |
|
93 |
ulong param_age_threshold; /* determines when hot block is downgraded */ |
|
94 |
||
95 |
/* Statistics variables. These are reset in reset_key_cache_counters(). */
|
|
96 |
ulong global_blocks_changed; /* number of currently dirty blocks */ |
|
97 |
ulonglong global_cache_w_requests;/* number of write requests (write hits) */ |
|
98 |
ulonglong global_cache_write; /* number of writes from cache to files */ |
|
99 |
ulonglong global_cache_r_requests;/* number of read requests (read hits) */ |
|
100 |
ulonglong global_cache_read; /* number of reads from files to cache */ |
|
101 |
||
102 |
int blocks; /* max number of blocks in the cache */ |
|
103 |
my_bool in_init; /* Set to 1 in MySQL during init/resize */ |
|
104 |
} KEY_CACHE; |
|
105 |
||
106 |
/* The default key cache */
|
|
107 |
extern KEY_CACHE dflt_key_cache_var, *dflt_key_cache; |
|
108 |
||
109 |
extern int init_key_cache(KEY_CACHE *keycache, uint key_cache_block_size, |
|
110 |
size_t use_mem, uint division_limit, |
|
111 |
uint age_threshold); |
|
112 |
extern int resize_key_cache(KEY_CACHE *keycache, uint key_cache_block_size, |
|
113 |
size_t use_mem, uint division_limit, |
|
114 |
uint age_threshold); |
|
115 |
extern void change_key_cache_param(KEY_CACHE *keycache, uint division_limit, |
|
116 |
uint age_threshold); |
|
117 |
extern uchar *key_cache_read(KEY_CACHE *keycache, |
|
118 |
File file, my_off_t filepos, int level, |
|
119 |
uchar *buff, uint length, |
|
120 |
uint block_length,int return_buffer); |
|
121 |
extern int key_cache_insert(KEY_CACHE *keycache, |
|
122 |
File file, my_off_t filepos, int level, |
|
123 |
uchar *buff, uint length); |
|
124 |
extern int key_cache_write(KEY_CACHE *keycache, |
|
125 |
File file, my_off_t filepos, int level, |
|
126 |
uchar *buff, uint length, |
|
127 |
uint block_length,int force_write); |
|
128 |
extern int flush_key_blocks(KEY_CACHE *keycache, |
|
129 |
int file, enum flush_type type); |
|
130 |
extern void end_key_cache(KEY_CACHE *keycache, my_bool cleanup); |
|
131 |
||
132 |
/* Functions to handle multiple key caches */
|
|
133 |
extern my_bool multi_keycache_init(void); |
|
134 |
extern void multi_keycache_free(void); |
|
135 |
extern KEY_CACHE *multi_key_cache_search(uchar *key, uint length); |
|
136 |
extern my_bool multi_key_cache_set(const uchar *key, uint length, |
|
137 |
KEY_CACHE *key_cache); |
|
138 |
extern void multi_key_cache_change(KEY_CACHE *old_data, |
|
139 |
KEY_CACHE *new_data); |
|
140 |
extern int reset_key_cache_counters(const char *name, |
|
141 |
KEY_CACHE *key_cache); |
|
142 |
C_MODE_END
|
|
143 |
#endif /* _keycache_h */ |