64
64
typedef struct st_key_cache
66
66
bool key_cache_inited;
67
bool in_resize; /* true during resize operation */
68
bool resize_in_flush; /* true during flush of resize operation */
69
67
bool can_be_used; /* usage of cache for read/write is allowed */
70
uint32_t hash_entries; /* max number of entries in the hash table */
71
uint32_t key_cache_mem_size; /* specified size of the cache memory */
72
69
uint32_t key_cache_block_size; /* size of the page buffer of a cache block */
73
int disk_blocks; /* max number of blocks in the cache */
74
ulong min_warm_blocks; /* min number of warm blocks; */
75
ulong age_threshold; /* age threshold for hot blocks */
76
uint64_t keycache_time; /* total number of block link operations */
77
int hash_links; /* max number of hash links */
78
int hash_links_used; /* number of hash links currently used */
79
ulong blocks_used; /* maximum number of concurrently used blocks */
80
ulong blocks_unused; /* number of currently unused blocks */
81
ulong blocks_changed; /* number of currently dirty blocks */
82
ulong warm_blocks; /* number of blocks in warm sub-chain */
83
ulong cnt_for_resize_op; /* counter to block resize operation */
84
long blocks_available; /* number of blocks available in the LRU chain */
85
HASH_LINK **hash_root; /* arr. of entries into hash table buckets */
86
HASH_LINK *hash_link_root; /* memory for hash table links */
87
HASH_LINK *free_hash_list; /* list of free hash links */
88
BLOCK_LINK *free_block_list; /* list of free blocks */
89
BLOCK_LINK *block_root; /* memory for block links */
90
unsigned char *block_mem; /* memory for block buffers */
91
BLOCK_LINK *used_last; /* ptr to the last block of the LRU chain */
92
BLOCK_LINK *used_ins; /* ptr to the insertion block in LRU chain */
93
pthread_mutex_t cache_lock; /* to lock access to the cache structure */
94
KEYCACHE_WQUEUE resize_queue; /* threads waiting during resize operation */
96
Waiting for a zero resize count. Using a queue for symmetry though
97
only one thread can wait here.
99
KEYCACHE_WQUEUE waiting_for_resize_cnt;
100
KEYCACHE_WQUEUE waiting_for_hash_link; /* waiting for a free hash link */
101
KEYCACHE_WQUEUE waiting_for_block; /* requests waiting for a free block */
102
BLOCK_LINK *changed_blocks[CHANGED_BLOCKS_HASH]; /* hash for dirty file bl.*/
103
BLOCK_LINK *file_blocks[CHANGED_BLOCKS_HASH]; /* hash for other file bl.*/
106
The following variables are and variables used to hold parameters for
107
initializing the key cache.
110
uint32_t param_buff_size; /* size the memory allocated for the cache */
111
uint32_t param_block_size; /* size of the blocks in the key cache */
112
uint32_t param_division_limit; /* min. percentage of warm blocks */
113
uint32_t param_age_threshold; /* determines when hot block is downgraded */
115
71
int blocks; /* max number of blocks in the cache */
116
/* Statistics variables. These are reset in reset_key_cache_counters(). */
117
ulong global_blocks_changed; /* number of currently dirty blocks */
118
uint64_t global_cache_w_requests;/* number of write requests (write hits) */
119
uint64_t global_cache_write; /* number of writes from cache to files */
120
uint64_t global_cache_r_requests;/* number of read requests (read hits) */
121
uint64_t global_cache_read; /* number of reads from files to cache */
123
73
bool in_init; /* Set to 1 in MySQL during init/resize */
76
key_cache_inited(false),
78
key_cache_block_size(0),
126
85
} /* namespace drizzled */
added
removed
plugin/myisam/keycache.h
