| /* 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 in_resize; /* true during resize operation */ |
| my_bool resize_in_flush; /* true during flush of resize operation */ |
| my_bool can_be_used; /* usage of cache for read/write is allowed */ |
| size_t 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 */ |
| uchar 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 */ |
| /* |
| Waiting for a zero resize count. Using a queue for symmetry though |
| only one thread can wait here. |
| */ |
| KEYCACHE_WQUEUE waiting_for_resize_cnt; |
| 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, |
| size_t use_mem, uint division_limit, |
| uint age_threshold); |
| extern int resize_key_cache(KEY_CACHE *keycache, uint key_cache_block_size, |
| size_t use_mem, uint division_limit, |
| uint age_threshold); |
| extern void change_key_cache_param(KEY_CACHE *keycache, uint division_limit, |
| uint age_threshold); |
| extern uchar *key_cache_read(KEY_CACHE *keycache, |
| File file, my_off_t filepos, int level, |
| uchar *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, |
| uchar *buff, uint length); |
| extern int key_cache_write(KEY_CACHE *keycache, |
| File file, my_off_t filepos, int level, |
| uchar *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(uchar *key, uint length); |
| extern my_bool multi_key_cache_set(const uchar *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 */ |
