139 lines
6.6 KiB
C
139 lines
6.6 KiB
C
/* 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 */
|