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Diffstat (limited to 'include/keycache.h')
| -rw-r--r-- | include/keycache.h | 134 |
1 files changed, 134 insertions, 0 deletions
diff --git a/include/keycache.h b/include/keycache.h new file mode 100644 index 00000000000..824c5874ffc --- /dev/null +++ b/include/keycache.h @@ -0,0 +1,134 @@ +/* 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; either version 2 of the License, or + (at your option) any later version. + + 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; + 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; /* number of currently used blocks */ + ulong blocks_changed; /* number of currently dirty blocks */ + ulong warm_blocks; /* number of blocks in warm sub-chain */ + 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 *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 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 */ + ulong global_blocks_used; /* number of currently used blocks */ + ulong global_blocks_changed; /* number of currently dirty blocks */ + ulong global_cache_w_requests;/* number of write requests (write hits) */ + ulong global_cache_write; /* number of writes from the cache to files */ + ulong global_cache_r_requests;/* number of read requests (read hits) */ + ulong global_cache_read; /* number of reads from files to the cache */ + int blocks; /* max number of blocks in the cache */ + my_bool in_init; /* Set to 1 in MySQL during init/resize */ + + /* optional call back function */ + void (*action)(struct st_key_cache *); +} 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); +C_MODE_END +#endif /* _keycache_h */ |