forked from twitter-forks/mysql
/
keycache.h
138 lines (120 loc) · 6.57 KB
/
keycache.h
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
/* Copyright (C) 2003 MySQL AB
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; version 2 of the License.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
/* Key cache variable structures */
#ifndef _keycache_h
#define _keycache_h
C_MODE_START
/* declare structures that is used by st_key_cache */
struct st_block_link;
typedef struct st_block_link BLOCK_LINK;
struct st_keycache_page;
typedef struct st_keycache_page KEYCACHE_PAGE;
struct st_hash_link;
typedef struct st_hash_link HASH_LINK;
/* info about requests in a waiting queue */
typedef struct st_keycache_wqueue
{
struct st_my_thread_var *last_thread; /* circular list of waiting threads */
} KEYCACHE_WQUEUE;
#define CHANGED_BLOCKS_HASH 128 /* must be power of 2 */
/*
The key cache structure
It also contains read-only statistics parameters.
*/
typedef struct st_key_cache
{
my_bool key_cache_inited;
my_bool resize_in_flush; /* true during flush of resize operation */
my_bool can_be_used; /* usage of cache for read/write is allowed */
uint key_cache_shift;
ulong key_cache_mem_size; /* specified size of the cache memory */
uint key_cache_block_size; /* size of the page buffer of a cache block */
ulong min_warm_blocks; /* min number of warm blocks; */
ulong age_threshold; /* age threshold for hot blocks */
ulonglong keycache_time; /* total number of block link operations */
uint hash_entries; /* max number of entries in the hash table */
int hash_links; /* max number of hash links */
int hash_links_used; /* number of hash links currently used */
int disk_blocks; /* max number of blocks in the cache */
ulong blocks_used; /* maximum number of concurrently used blocks */
ulong blocks_unused; /* number of currently unused blocks */
ulong blocks_changed; /* number of currently dirty blocks */
ulong warm_blocks; /* number of blocks in warm sub-chain */
ulong cnt_for_resize_op; /* counter to block resize operation */
long blocks_available; /* number of blocks available in the LRU chain */
HASH_LINK **hash_root; /* arr. of entries into hash table buckets */
HASH_LINK *hash_link_root; /* memory for hash table links */
HASH_LINK *free_hash_list; /* list of free hash links */
BLOCK_LINK *free_block_list; /* list of free blocks */
BLOCK_LINK *block_root; /* memory for block links */
byte HUGE_PTR *block_mem; /* memory for block buffers */
BLOCK_LINK *used_last; /* ptr to the last block of the LRU chain */
BLOCK_LINK *used_ins; /* ptr to the insertion block in LRU chain */
pthread_mutex_t cache_lock; /* to lock access to the cache structure */
KEYCACHE_WQUEUE resize_queue; /* threads waiting during resize operation */
KEYCACHE_WQUEUE waiting_for_hash_link; /* waiting for a free hash link */
KEYCACHE_WQUEUE waiting_for_block; /* requests waiting for a free block */
BLOCK_LINK *changed_blocks[CHANGED_BLOCKS_HASH]; /* hash for dirty file bl.*/
BLOCK_LINK *file_blocks[CHANGED_BLOCKS_HASH]; /* hash for other file bl.*/
/*
The following variables are and variables used to hold parameters for
initializing the key cache.
*/
ulonglong param_buff_size; /* size the memory allocated for the cache */
ulong param_block_size; /* size of the blocks in the key cache */
ulong param_division_limit; /* min. percentage of warm blocks */
ulong param_age_threshold; /* determines when hot block is downgraded */
/* Statistics variables. These are reset in reset_key_cache_counters(). */
ulong global_blocks_changed; /* number of currently dirty blocks */
ulonglong global_cache_w_requests;/* number of write requests (write hits) */
ulonglong global_cache_write; /* number of writes from cache to files */
ulonglong global_cache_r_requests;/* number of read requests (read hits) */
ulonglong global_cache_read; /* number of reads from files to cache */
int blocks; /* max number of blocks in the cache */
my_bool in_init; /* Set to 1 in MySQL during init/resize */
} KEY_CACHE;
/* The default key cache */
extern KEY_CACHE dflt_key_cache_var, *dflt_key_cache;
extern int init_key_cache(KEY_CACHE *keycache, uint key_cache_block_size,
ulong use_mem, uint division_limit,
uint age_threshold);
extern int resize_key_cache(KEY_CACHE *keycache, uint key_cache_block_size,
ulong use_mem, uint division_limit,
uint age_threshold);
extern void change_key_cache_param(KEY_CACHE *keycache, uint division_limit,
uint age_threshold);
extern byte *key_cache_read(KEY_CACHE *keycache,
File file, my_off_t filepos, int level,
byte *buff, uint length,
uint block_length,int return_buffer);
extern int key_cache_insert(KEY_CACHE *keycache,
File file, my_off_t filepos, int level,
byte *buff, uint length);
extern int key_cache_write(KEY_CACHE *keycache,
File file, my_off_t filepos, int level,
byte *buff, uint length,
uint block_length,int force_write);
extern int flush_key_blocks(KEY_CACHE *keycache,
int file, enum flush_type type);
extern void end_key_cache(KEY_CACHE *keycache, my_bool cleanup);
/* Functions to handle multiple key caches */
extern my_bool multi_keycache_init(void);
extern void multi_keycache_free(void);
extern KEY_CACHE *multi_key_cache_search(byte *key, uint length);
extern my_bool multi_key_cache_set(const byte *key, uint length,
KEY_CACHE *key_cache);
extern void multi_key_cache_change(KEY_CACHE *old_data,
KEY_CACHE *new_data);
extern int reset_key_cache_counters(const char *name,
KEY_CACHE *key_cache);
C_MODE_END
#endif /* _keycache_h */