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