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- /* Copyright (c) 2003, 2017, Oracle and/or its affiliates. All rights reserved.
- This program is free software; you can redistribute it and/or modify
- it under the terms of the GNU General Public License, version 2.0,
- as published by the Free Software Foundation.
- This program is also distributed with certain software (including
- but not limited to OpenSSL) that is licensed under separate terms,
- as designated in a particular file or component or in included license
- documentation. The authors of MySQL hereby grant you an additional
- permission to link the program and your derivative works with the
- separately licensed software that they have included with MySQL.
- 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, version 2.0, 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., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */
- /**
- @file include/keycache.h
- Key cache variable structures.
- */
- #ifndef _keycache_h
- #define _keycache_h
- #include <stddef.h>
- #include <sys/types.h>
- #include "my_inttypes.h"
- #include "my_io.h"
- #include "my_macros.h"
- #include "my_sys.h" /* flush_type */
- #include "mysql/psi/mysql_cond.h"
- #include "mysql/psi/mysql_mutex.h"
- /* declare structures that is used by KEY_CACHE */
- struct BLOCK_LINK;
- struct HASH_LINK;
- /* Thread specific variables */
- struct st_keycache_thread_var {
- mysql_cond_t suspend;
- struct st_keycache_thread_var *next, **prev;
- void *opt_info;
- };
- /* info about requests in a waiting queue */
- struct KEYCACHE_WQUEUE {
- st_keycache_thread_var *last_thread; /* circular list of waiting threads */
- };
- /* Typical key cash */
- #define KEY_CACHE_SIZE (uint)(8 * 1024 * 1024)
- /* Default size of a key cache block */
- #define KEY_CACHE_BLOCK_SIZE (uint)1024
- #define CHANGED_BLOCKS_HASH 128 /* must be power of 2 */
- /*
- The key cache structure
- It also contains read-only statistics parameters.
- */
- struct KEY_CACHE {
- bool key_cache_inited;
- bool in_resize; /* true during resize operation */
- bool resize_in_flush; /* true during flush of resize operation */
- 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 */
- ulonglong min_warm_blocks; /* min number of warm blocks; */
- ulonglong 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 *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 */
- mysql_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 */
- ulonglong param_block_size; /* size of the blocks in the key cache */
- ulonglong param_division_limit; /* min. percentage of warm blocks */
- ulonglong 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 */
- bool in_init; /* Set to 1 in MySQL during init/resize */
- };
- /* The default key cache */
- extern KEY_CACHE dflt_key_cache_var, *dflt_key_cache;
- extern int init_key_cache(KEY_CACHE *keycache, ulonglong key_cache_block_size,
- size_t use_mem, ulonglong division_limit,
- ulonglong age_threshold);
- extern int resize_key_cache(KEY_CACHE *keycache,
- st_keycache_thread_var *thread_var,
- ulonglong key_cache_block_size, size_t use_mem,
- ulonglong division_limit, ulonglong age_threshold);
- extern uchar *key_cache_read(KEY_CACHE *keycache,
- st_keycache_thread_var *thread_var, 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,
- st_keycache_thread_var *thread_var, File file,
- my_off_t filepos, int level, uchar *buff,
- uint length);
- extern int key_cache_write(KEY_CACHE *keycache,
- st_keycache_thread_var *thread_var, 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,
- st_keycache_thread_var *thread_var, int file,
- enum flush_type type);
- extern void end_key_cache(KEY_CACHE *keycache, bool cleanup);
- /* Functions to handle multiple key caches */
- extern bool multi_keycache_init(void);
- extern void multi_keycache_free(void);
- extern KEY_CACHE *multi_key_cache_search(uchar *key, uint length);
- extern 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);
- #endif /* _keycache_h */
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