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by brian
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/* Copyright (C) 2003 MySQL AB
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; version 2 of the License.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
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/* Key cache variable structures */
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#ifndef _keycache_h
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#define _keycache_h
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53.2.37
by Monty Taylor
Moved keycache code to MyISAM. |
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#include <my_global.h> |
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by brian
clean slate |
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C_MODE_START
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53.2.37
by Monty Taylor
Moved keycache code to MyISAM. |
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enum flush_type |
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{
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FLUSH_KEEP, /* flush block and keep it in the cache */ |
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FLUSH_RELEASE, /* flush block and remove it from the cache */ |
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FLUSH_IGNORE_CHANGED, /* remove block from the cache */ |
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/*
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* As my_disable_flush_pagecache_blocks is always 0, the following option
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* is strictly equivalent to FLUSH_KEEP
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* */
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FLUSH_FORCE_WRITE
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};
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by brian
clean slate |
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/* declare structures that is used by st_key_cache */
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struct st_block_link; |
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typedef struct st_block_link BLOCK_LINK; |
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struct st_keycache_page; |
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typedef struct st_keycache_page KEYCACHE_PAGE; |
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struct st_hash_link; |
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typedef struct st_hash_link HASH_LINK; |
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/* info about requests in a waiting queue */
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typedef struct st_keycache_wqueue |
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{
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struct st_my_thread_var *last_thread; /* circular list of waiting threads */ |
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} KEYCACHE_WQUEUE; |
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#define CHANGED_BLOCKS_HASH 128 /* must be power of 2 */ |
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/*
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The key cache structure
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It also contains read-only statistics parameters.
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*/
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typedef struct st_key_cache |
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{
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my_bool key_cache_inited; |
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my_bool in_resize; /* true during resize operation */ |
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my_bool resize_in_flush; /* true during flush of resize operation */ |
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my_bool can_be_used; /* usage of cache for read/write is allowed */ |
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size_t key_cache_mem_size; /* specified size of the cache memory */ |
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uint key_cache_block_size; /* size of the page buffer of a cache block */ |
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ulong min_warm_blocks; /* min number of warm blocks; */ |
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ulong age_threshold; /* age threshold for hot blocks */ |
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ulonglong keycache_time; /* total number of block link operations */ |
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uint hash_entries; /* max number of entries in the hash table */ |
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int hash_links; /* max number of hash links */ |
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int hash_links_used; /* number of hash links currently used */ |
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int disk_blocks; /* max number of blocks in the cache */ |
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ulong blocks_used; /* maximum number of concurrently used blocks */ |
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ulong blocks_unused; /* number of currently unused blocks */ |
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ulong blocks_changed; /* number of currently dirty blocks */ |
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ulong warm_blocks; /* number of blocks in warm sub-chain */ |
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ulong cnt_for_resize_op; /* counter to block resize operation */ |
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long blocks_available; /* number of blocks available in the LRU chain */ |
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HASH_LINK **hash_root; /* arr. of entries into hash table buckets */ |
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HASH_LINK *hash_link_root; /* memory for hash table links */ |
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HASH_LINK *free_hash_list; /* list of free hash links */ |
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BLOCK_LINK *free_block_list; /* list of free blocks */ |
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BLOCK_LINK *block_root; /* memory for block links */ |
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uchar *block_mem; /* memory for block buffers */ |
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BLOCK_LINK *used_last; /* ptr to the last block of the LRU chain */ |
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BLOCK_LINK *used_ins; /* ptr to the insertion block in LRU chain */ |
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pthread_mutex_t cache_lock; /* to lock access to the cache structure */ |
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KEYCACHE_WQUEUE resize_queue; /* threads waiting during resize operation */ |
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/*
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Waiting for a zero resize count. Using a queue for symmetry though
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only one thread can wait here.
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*/
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KEYCACHE_WQUEUE waiting_for_resize_cnt; |
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KEYCACHE_WQUEUE waiting_for_hash_link; /* waiting for a free hash link */ |
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KEYCACHE_WQUEUE waiting_for_block; /* requests waiting for a free block */ |
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BLOCK_LINK *changed_blocks[CHANGED_BLOCKS_HASH]; /* hash for dirty file bl.*/ |
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BLOCK_LINK *file_blocks[CHANGED_BLOCKS_HASH]; /* hash for other file bl.*/ |
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/*
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The following variables are and variables used to hold parameters for
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initializing the key cache.
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*/
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ulonglong param_buff_size; /* size the memory allocated for the cache */ |
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ulong param_block_size; /* size of the blocks in the key cache */ |
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ulong param_division_limit; /* min. percentage of warm blocks */ |
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ulong param_age_threshold; /* determines when hot block is downgraded */ |
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/* Statistics variables. These are reset in reset_key_cache_counters(). */
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ulong global_blocks_changed; /* number of currently dirty blocks */ |
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ulonglong global_cache_w_requests;/* number of write requests (write hits) */ |
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ulonglong global_cache_write; /* number of writes from cache to files */ |
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ulonglong global_cache_r_requests;/* number of read requests (read hits) */ |
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ulonglong global_cache_read; /* number of reads from files to cache */ |
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int blocks; /* max number of blocks in the cache */ |
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my_bool in_init; /* Set to 1 in MySQL during init/resize */ |
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} KEY_CACHE; |
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/* The default key cache */
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extern KEY_CACHE dflt_key_cache_var, *dflt_key_cache; |
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extern int init_key_cache(KEY_CACHE *keycache, uint key_cache_block_size, |
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size_t use_mem, uint division_limit, |
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uint age_threshold); |
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extern int resize_key_cache(KEY_CACHE *keycache, uint key_cache_block_size, |
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size_t use_mem, uint division_limit, |
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uint age_threshold); |
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extern void change_key_cache_param(KEY_CACHE *keycache, uint division_limit, |
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uint age_threshold); |
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extern uchar *key_cache_read(KEY_CACHE *keycache, |
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File file, my_off_t filepos, int level, |
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uchar *buff, uint length, |
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uint block_length,int return_buffer); |
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extern int key_cache_insert(KEY_CACHE *keycache, |
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File file, my_off_t filepos, int level, |
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uchar *buff, uint length); |
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extern int key_cache_write(KEY_CACHE *keycache, |
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File file, my_off_t filepos, int level, |
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uchar *buff, uint length, |
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uint block_length,int force_write); |
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extern int flush_key_blocks(KEY_CACHE *keycache, |
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int file, enum flush_type type); |
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extern void end_key_cache(KEY_CACHE *keycache, my_bool cleanup); |
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/* Functions to handle multiple key caches */
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extern my_bool multi_keycache_init(void); |
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extern void multi_keycache_free(void); |
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extern KEY_CACHE *multi_key_cache_search(uchar *key, uint length); |
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extern my_bool multi_key_cache_set(const uchar *key, uint length, |
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KEY_CACHE *key_cache); |
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extern void multi_key_cache_change(KEY_CACHE *old_data, |
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KEY_CACHE *new_data); |
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extern int reset_key_cache_counters(const char *name, |
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KEY_CACHE *key_cache); |
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C_MODE_END
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#endif /* _keycache_h */ |