/* Copyright (C) 2000 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 */ /* These functions are to handle keyblock cacheing for NISAM, MISAM and PISAM databases. One cache can handle many files. It must contain buffers of the same blocksize. init_key_cache() should be used to init cache handler. */ #include "mysys_priv.h" #include "my_static.h" #include #include #include #include /* Some compilation flags have been added specifically for this module to control the following: - not to let a thread to yield the control when reading directly from key cache, which might improve performance in many cases; to enable this add: #define SERIALIZED_READ_FROM_CACHE - to set an upper bound for number of threads simultaneously using the key cache; this setting helps to determine an optimal size for hash table and improve performance when the number of blocks in the key cache much less than the number of threads accessing it; to set this number equal to add #define MAX_THREADS - to substitute calls of pthread_cond_wait for calls of pthread_cond_timedwait (wait with timeout set up); this setting should be used only when you want to trap a deadlock situation, which theoretically should not happen; to set timeout equal to seconds add #define KEYCACHE_TIMEOUT - to enable the module traps and to send debug information from key cache module to a special debug log add: #define KEYCACHE_DEBUG the name of this debug log file can be set through: #define KEYCACHE_DEBUG_LOG if the name is not defined, it's set by default; if the KEYCACHE_DEBUG flag is not set up and we are in a debug mode, i.e. when ! defined(DBUG_OFF), the debug information from the module is sent to the regular debug log. Example of the settings: #define SERIALIZED_READ_FROM_CACHE #define MAX_THREADS 100 #define KEYCACHE_TIMEOUT 1 #define KEYCACHE_DEBUG #define KEYCACHE_DEBUG_LOG "my_key_cache_debug.log" */ #if defined(MSDOS) && !defined(M_IC80386) /* we nead much memory */ #undef my_malloc_lock #undef my_free_lock #define my_malloc_lock(A,B) halloc((long) (A/IO_SIZE),IO_SIZE) #define my_free_lock(A,B) hfree(A) #endif /* defined(MSDOS) && !defined(M_IC80386) */ #define STRUCT_PTR(TYPE, MEMBER, a) \ (TYPE *) ((char *) (a) - offsetof(TYPE, MEMBER)) /* types of condition variables */ #define COND_FOR_REQUESTED 0 #define COND_FOR_SAVED 1 #define COND_FOR_READERS 2 typedef pthread_cond_t KEYCACHE_CONDVAR; /* 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; /* descriptor of the page in the key cache block buffer */ typedef struct st_keycache_page { int file; /* file to which the page belongs to */ my_off_t filepos; /* position of the page in the file */ } KEYCACHE_PAGE; /* element in the chain of a hash table bucket */ typedef struct st_hash_link { struct st_hash_link *next, **prev; /* to connect links in the same bucket */ struct st_block_link *block; /* reference to the block for the page: */ File file; /* from such a file */ my_off_t diskpos; /* with such an offset */ uint requests; /* number of requests for the page */ } HASH_LINK; /* offset is always alighed for key_cache_block_size */ /* simple states of a block */ #define BLOCK_ERROR 1 /* an error occured when performing disk i/o */ #define BLOCK_READ 2 /* the is page in the block buffer */ #define BLOCK_IN_SWITCH 4 /* block is preparing to read new page */ #define BLOCK_REASSIGNED 8 /* block does not accept requests for old page */ #define BLOCK_IN_FLUSH 16 /* block is in flush operation */ #define BLOCK_CHANGED 32 /* block buffer contains a dirty page */ /* page status, returned by find_key_block */ #define PAGE_READ 0 #define PAGE_TO_BE_READ 1 #define PAGE_WAIT_TO_BE_READ 2 /* key cache block */ typedef struct st_block_link { struct st_block_link *next_used, **prev_used; /* to connect links in the LRU chain (ring) */ struct st_block_link *next_changed, **prev_changed; /* for lists of file dirty/clean blocks */ struct st_hash_link *hash_link; /* backward ptr to referring hash_link */ KEYCACHE_WQUEUE wqueue[2]; /* queues on waiting requests for new/old pages */ uint requests; /* number of requests for the block */ byte *buffer; /* buffer for the block page */ uint offset; /* beginning of modified data in the buffer */ uint length; /* end of data in the buffer */ uint status; /* state of the block */ uint hits_left; /* number of hits left until promotion */ ulonglong last_hit_time; /* timestamp of the last hit */ KEYCACHE_CONDVAR *condvar; /* condition variable for 'no readers' event */ } BLOCK_LINK; KEY_CACHE_VAR dflt_key_cache_var= { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 }; KEY_CACHE_HANDLE *dflt_keycache= &dflt_key_cache_var.cache; #define CHANGED_BLOCKS_HASH 128 /* must be power of 2 */ #define FLUSH_CACHE 2000 /* sort this many blocks at once */ typedef struct st_key_cache { KEY_CACHE_VAR *env; /* pointer to key cache variables (if any) */ 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 */ #if defined(KEYCACHE_DEBUG) long blocks_available; /* number of blocks available in the LRU chain */ #endif 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.*/ } KEY_CACHE; static int flush_all_key_blocks(KEY_CACHE_HANDLE keycache); static void test_key_cache(KEY_CACHE *keycache, const char *where, my_bool lock); #define KEYCACHE_HASH(f, pos) \ (((ulong) ((pos) >> keycache->key_cache_shift)+ \ (ulong) (f)) & (keycache->hash_entries-1)) #define FILE_HASH(f) ((uint) (f) & (CHANGED_BLOCKS_HASH-1)) #define DEFAULT_KEYCACHE_DEBUG_LOG "keycache_debug.log" #if defined(KEYCACHE_DEBUG) && ! defined(KEYCACHE_DEBUG_LOG) #define KEYCACHE_DEBUG_LOG DEFAULT_KEYCACHE_DEBUG_LOG #endif #if defined(KEYCACHE_DEBUG_LOG) static FILE *keycache_debug_log=NULL; static void keycache_debug_print _VARARGS((const char *fmt,...)); #define KEYCACHE_DEBUG_OPEN \ keycache_debug_log=fopen(KEYCACHE_DEBUG_LOG, "w") #define KEYCACHE_DEBUG_CLOSE \ if (keycache_debug_log) fclose(keycache_debug_log) #else #define KEYCACHE_DEBUG_OPEN #define KEYCACHE_DEBUG_CLOSE #endif /* defined(KEYCACHE_DEBUG_LOG) */ #if defined(KEYCACHE_DEBUG_LOG) && defined(KEYCACHE_DEBUG) #define KEYCACHE_DBUG_PRINT(l, m) \ { if (keycache_debug_log) fprintf(keycache_debug_log, "%s: ", l); \ keycache_debug_print m; } #define KEYCACHE_DBUG_ASSERT(a) \ { if (! (a) && keycache_debug_log) fclose(keycache_debug_log); \ assert(a); } #else #define KEYCACHE_DBUG_PRINT(l, m) DBUG_PRINT(l, m) #define KEYCACHE_DBUG_ASSERT(a) DBUG_ASSERT(a) #endif /* defined(KEYCACHE_DEBUG_LOG) && defined(KEYCACHE_DEBUG) */ #if defined(KEYCACHE_DEBUG) || !defined(DBUG_OFF) static long keycache_thread_id; #define KEYCACHE_THREAD_TRACE(l) \ KEYCACHE_DBUG_PRINT(l,("|thread %ld",keycache_thread_id)) #define KEYCACHE_THREAD_TRACE_BEGIN(l) \ { struct st_my_thread_var *thread_var =my_thread_var; \ keycache_thread_id=my_thread_var->id; \ KEYCACHE_DBUG_PRINT(l,("[thread %ld",keycache_thread_id)) } #define KEYCACHE_THREAD_TRACE_END(l) \ KEYCACHE_DBUG_PRINT(l,("]thread %ld",keycache_thread_id)) #else #define KEYCACHE_THREAD_TRACE_BEGIN(l) #define KEYCACHE_THREAD_TRACE_END(l) #define KEYCACHE_THREAD_TRACE(l) #endif /* defined(KEYCACHE_DEBUG) || !defined(DBUG_OFF) */ #define BLOCK_NUMBER(b) \ ((uint) (((char*)(b)-(char *) keycache->block_root)/sizeof(BLOCK_LINK))) #define HASH_LINK_NUMBER(h) \ ((uint) (((char*)(h)-(char *) keycache->hash_link_root)/sizeof(HASH_LINK))) #if (defined(KEYCACHE_TIMEOUT) && !defined(__WIN__)) || defined(KEYCACHE_DEBUG) static int keycache_pthread_cond_wait(pthread_cond_t *cond, pthread_mutex_t *mutex); #else #define keycache_pthread_cond_wait pthread_cond_wait #endif #if defined(KEYCACHE_DEBUG) static int keycache_pthread_mutex_lock(pthread_mutex_t *mutex); static void keycache_pthread_mutex_unlock(pthread_mutex_t *mutex); static int keycache_pthread_cond_signal(pthread_cond_t *cond); static int keycache_pthread_cond_broadcast(pthread_cond_t *cond); #else #define keycache_pthread_mutex_lock pthread_mutex_lock #define keycache_pthread_mutex_unlock pthread_mutex_unlock #define keycache_pthread_cond_signal pthread_cond_signal #define keycache_pthread_cond_broadcast pthread_cond_broadcast #endif /* defined(KEYCACHE_DEBUG) */ static uint next_power(uint value) { uint old_value=1; while (value) { old_value=value; value&= value-1; } return (old_value << 1); } /* Initialize a key cache SYNOPSIS init_ky_cache() pkeycache in/out pointer to the key cache handle key_cache_block_size size of blocks to keep cached data use_mem total memory to use for the key cache env ref to other parameters of the key cache, if any RETURN VALUE number of blocks in the key cache, if successful, 0 - otherwise. NOTES. If pkeycache points to an undefined handle (NULL), a new KEY_CACHE data structure is created and a pointer to it is returned as a new key cache handle, otherwise *pkeycache is considered as a reused handle for a key cache with new blocks. It's assumed that no two threads call this function simultaneously referring to the same key cache handle. */ int init_key_cache(KEY_CACHE_HANDLE *pkeycache, uint key_cache_block_size, ulong use_mem, KEY_CACHE_VAR *env) { uint blocks, hash_links, length; int error; KEY_CACHE *keycache; DBUG_ENTER("init_key_cache"); DBUG_ASSERT(key_cache_block_size >= 512); if (!(keycache= (KEY_CACHE *) *pkeycache) && !(keycache= (KEY_CACHE *) my_malloc(sizeof(KEY_CACHE), MYF(MY_ZEROFILL)))) DBUG_RETURN(0); keycache->env= env; KEYCACHE_DEBUG_OPEN; if (keycache->key_cache_inited && keycache->disk_blocks > 0) { DBUG_PRINT("warning",("key cache already in use")); DBUG_RETURN(0); } if (env && ! keycache->key_cache_inited) { env->cache_w_requests= env->cache_r_requests= 0; env->cache_read= env->cache_write=0; } if (! keycache->key_cache_inited) { keycache->key_cache_inited= 1; keycache->disk_blocks= -1; pthread_mutex_init(&keycache->cache_lock, MY_MUTEX_INIT_FAST); keycache->key_cache_shift= my_bit_log2(key_cache_block_size); keycache->key_cache_mem_size= use_mem; keycache->key_cache_block_size= key_cache_block_size; DBUG_PRINT("info", ("key_cache_block_size: %u", key_cache_block_size)); } /* These are safety deallocations: actually we always call the function after having called end_key_cache that deallocates these memory itself. */ if (keycache->block_mem) my_free_lock((gptr) keycache->block_mem, MYF(0)); keycache->block_mem= NULL; if (keycache->block_root) my_free((gptr) keycache->block_root, MYF(0)); keycache->block_root= NULL; blocks= (uint) (use_mem / (sizeof(BLOCK_LINK) + 2 * sizeof(HASH_LINK) + sizeof(HASH_LINK*) * 5/4 + key_cache_block_size)); /* It doesn't make sense to have too few blocks (less than 8) */ if (blocks >= 8 && keycache->disk_blocks < 0) { for ( ; ; ) { /* Set my_hash_entries to the next bigger 2 power */ if ((keycache->hash_entries= next_power(blocks)) < blocks * 5/4) keycache->hash_entries<<= 1; hash_links= 2 * blocks; #if defined(MAX_THREADS) if (hash_links < MAX_THREADS + blocks - 1) hash_links= MAX_THREADS + blocks - 1; #endif while ((length= (ALIGN_SIZE(blocks * sizeof(BLOCK_LINK)) + ALIGN_SIZE(hash_links * sizeof(HASH_LINK)) + ALIGN_SIZE(sizeof(HASH_LINK*) * keycache->hash_entries))) + ((ulong) blocks << keycache->key_cache_shift) > use_mem) blocks--; /* Allocate memory for cache page buffers */ if ((keycache->block_mem= my_malloc_lock((ulong) blocks * keycache->key_cache_block_size, MYF(0)))) { /* Allocate memory for blocks, hash_links and hash entries; For each block 2 hash links are allocated */ if ((keycache->block_root= (BLOCK_LINK*) my_malloc((uint) length, MYF(0)))) break; my_free_lock(keycache->block_mem, MYF(0)); } if (blocks < 8) { my_errno= ENOMEM; goto err; } blocks= blocks / 4*3; } keycache->disk_blocks= (int) blocks; keycache->hash_links= hash_links; keycache->hash_root= (HASH_LINK**) ((char*) keycache->block_root + ALIGN_SIZE(blocks*sizeof(BLOCK_LINK))); keycache->hash_link_root= (HASH_LINK*) ((char*) keycache->hash_root + ALIGN_SIZE((sizeof(HASH_LINK*) * keycache->hash_entries))); bzero((byte*) keycache->block_root, keycache->disk_blocks * sizeof(BLOCK_LINK)); bzero((byte*) keycache->hash_root, keycache->hash_entries * sizeof(HASH_LINK*)); bzero((byte*) keycache->hash_link_root, keycache->hash_links * sizeof(HASH_LINK)); keycache->hash_links_used= 0; keycache->free_hash_list= NULL; keycache->blocks_used= keycache->blocks_changed= 0; if (env) env->blocks_used= env->blocks_changed= 0; #if defined(KEYCACHE_DEBUG) keycache->blocks_available=0; #endif /* The LRU chain is empty after initialization */ keycache->used_last= NULL; keycache->used_ins= NULL; keycache->keycache_time= 0; keycache->warm_blocks= 0; keycache->min_warm_blocks= (env && env->division_limit ? blocks * env->division_limit / 100 + 1 : blocks); keycache->age_threshold= (env && env->age_threshold ? blocks * env->age_threshold / 100 : blocks); keycache->waiting_for_hash_link.last_thread= NULL; keycache->waiting_for_block.last_thread= NULL; DBUG_PRINT("exit", ("disk_blocks: %d block_root: %lx hash_entries: %d hash_root: %lx \ hash_links: %d hash_link_root %lx", keycache->disk_blocks, keycache->block_root, keycache->hash_entries, keycache->hash_root, keycache->hash_links, keycache->hash_link_root)); } bzero((gptr) keycache->changed_blocks, sizeof(keycache->changed_blocks[0]) * CHANGED_BLOCKS_HASH); bzero((gptr) keycache->file_blocks, sizeof(keycache->file_blocks[0]) * CHANGED_BLOCKS_HASH); if (env) env->blocks= keycache->disk_blocks > 0 ? keycache->disk_blocks : 0; *pkeycache= keycache; DBUG_PRINT("exit", ("key_cache: %lx", keycache)); DBUG_RETURN((int) blocks); err: error= my_errno; keycache->disk_blocks= 0; if (env) env->blocks= 0; if (keycache->block_mem) { my_free_lock((gptr) keycache->block_mem, MYF(0)); keycache->block_mem= NULL; } if (keycache->block_root) { my_free((gptr) keycache->block_root, MYF(0)); keycache->block_root= NULL; } my_errno= error; DBUG_RETURN(0); } /* Resize a key cache SYNOPSIS resize_key_cache() pkeycache in/out pointer to the key cache handle key_cache_block_size size of blocks to keep cached data use_mem total memory to use for the new key cache RETURN VALUE number of blocks in the key cache, if successful, 0 - otherwise. NOTES. The function first compares the memory size and the block size parameters with the corresponding parameters of the key cache referred by *pkeycache. If they differ the function free the the memory allocated for the old key cache blocks by calling the end_key_cache function and then rebuilds the key cache with new blocks by calling init_key_cache. */ int resize_key_cache(KEY_CACHE_HANDLE *pkeycache, uint key_cache_block_size, ulong use_mem) { int blocks; KEY_CACHE *keycache= *pkeycache; DBUG_ENTER("resize_key_cache"); if (key_cache_block_size == keycache->key_cache_block_size && use_mem == keycache->key_cache_mem_size) return keycache->disk_blocks; keycache_pthread_mutex_lock(&keycache->cache_lock); if (flush_all_key_blocks(keycache)) { /* TODO: if this happens, we should write a warning in the log file ! */ keycache_pthread_mutex_unlock(&keycache->cache_lock); return 0; } keycache_pthread_mutex_unlock(&keycache->cache_lock); end_key_cache(keycache, 0); /* the following will work even if memory is 0 */ blocks= init_key_cache(pkeycache, key_cache_block_size, use_mem, keycache->env); return blocks; } /* Change the key cache parameters SYNOPSIS change_key_cache_param() keycache the key cache handle RETURN VALUE none NOTES. Presently the function resets the key cache parameters concerning midpoint insertion strategy - division_limit and age_threshold. It corresponding values are passed through the keycache->env structure. */ void change_key_cache_param(KEY_CACHE_HANDLE keycache) { KEY_CACHE_VAR *env= keycache->env; DBUG_ENTER("change_key_cache_param"); if (env) { if (env->division_limit) keycache->min_warm_blocks= (keycache->disk_blocks * env->division_limit / 100 + 1); if (env->age_threshold) keycache->age_threshold= (keycache->disk_blocks * env->age_threshold / 100); } DBUG_VOID_RETURN; } /* Remove key_cache from memory SYNOPSIS end_key_cache() pkeycache in/out pointer to the key cache handle cleanup <-> the key cache data structure is freed as well RETURN VALUE none NOTES. If the cleanup parameter is TRUE the data structure with all associated elements are freed completely Otherwise only memory used by the key cache blocks is freed. */ void end_key_cache(KEY_CACHE_HANDLE keycache, my_bool cleanup) { KEY_CACHE_VAR *env;; DBUG_ENTER("end_key_cache"); DBUG_PRINT("enter", ("key_cache: %lx", keycache)); if (!keycache) DBUG_VOID_RETURN; if (keycache->disk_blocks > 0) { if (keycache->block_mem) { my_free_lock((gptr) keycache->block_mem, MYF(0)); keycache->block_mem= NULL; my_free((gptr) keycache->block_root, MYF(0)); keycache->block_root= NULL; } keycache->disk_blocks= -1; } KEYCACHE_DEBUG_CLOSE; keycache->key_cache_inited= 0; if ((env= keycache->env)) { DBUG_PRINT("status", ("used: %d changed: %d w_requests: %ld \ writes: %ld r_requests: %ld reads: %ld", env->blocks_used, env->blocks_changed, env->cache_w_requests, env->cache_write, env->cache_r_requests, env->cache_read)); } if (cleanup) { pthread_mutex_destroy(&keycache->cache_lock); my_free((gptr) keycache, MYF(0)); } DBUG_VOID_RETURN; } /* end_key_cache */ /* Link a thread into double-linked queue of waiting threads. SYNOPSIS link_into_queue() wqueue pointer to the queue structure thread pointer to the thread to be added to the queue RETURN VALUE none NOTES. Queue is represented by a circular list of the thread structures The list is double-linked of the type (**prev,*next), accessed by a pointer to the last element. */ static inline void link_into_queue(KEYCACHE_WQUEUE *wqueue, struct st_my_thread_var *thread) { struct st_my_thread_var *last; if (! (last= wqueue->last_thread)) { /* Queue is empty */ thread->next= thread; thread->prev= &thread->next; } else { thread->prev= last->next->prev; last->next->prev= &thread->next; thread->next= last->next; last->next= thread; } wqueue->last_thread= thread; } /* Unlink a thread from double-linked queue of waiting threads SYNOPSIS unlink_from_queue() wqueue pointer to the queue structure thread pointer to the thread to be removed from the queue RETURN VALUE none NOTES. See NOTES for link_into_queue */ static inline void unlink_from_queue(KEYCACHE_WQUEUE *wqueue, struct st_my_thread_var *thread) { KEYCACHE_DBUG_PRINT("unlink_from_queue", ("thread %ld", thread->id)); if (thread->next == thread) /* The queue contains only one member */ wqueue->last_thread= NULL; else { thread->next->prev= thread->prev; *thread->prev=thread->next; if (wqueue->last_thread == thread) wqueue->last_thread= STRUCT_PTR(struct st_my_thread_var, next, thread->prev); } thread->next= NULL; } /* Add a thread to single-linked queue of waiting threads SYNOPSIS add_to_queue() wqueue pointer to the queue structure thread pointer to the thread to be added to the queue RETURN VALUE none NOTES. Queue is represented by a circular list of the thread structures The list is single-linked of the type (*next), accessed by a pointer to the last element. */ static inline void add_to_queue(KEYCACHE_WQUEUE *wqueue, struct st_my_thread_var *thread) { struct st_my_thread_var *last; if (! (last= wqueue->last_thread)) thread->next= thread; else { thread->next= last->next; last->next= thread; } wqueue->last_thread= thread; } /* Remove all threads from queue signaling them to proceed SYNOPSIS realease_queue() wqueue pointer to the queue structure thread pointer to the thread to be added to the queue RETURN VALUE none NOTES. See notes for add_to_queue When removed from the queue each thread is signaled via condition variable thread->suspend. */ static void release_queue(KEYCACHE_WQUEUE *wqueue) { struct st_my_thread_var *last=wqueue->last_thread; struct st_my_thread_var *next=last->next; struct st_my_thread_var *thread; do { thread=next; keycache_pthread_cond_signal(&thread->suspend); KEYCACHE_DBUG_PRINT("release_queue: signal", ("thread %ld", thread->id)); next=thread->next; thread->next= NULL; } while (thread != last); wqueue->last_thread= NULL; } /* Unlink a block from the chain of dirty/clean blocks */ static inline void unlink_changed(BLOCK_LINK *block) { if (block->next_changed) block->next_changed->prev_changed= block->prev_changed; *block->prev_changed= block->next_changed; } /* Link a block into the chain of dirty/clean blocks */ static inline void link_changed(BLOCK_LINK *block, BLOCK_LINK **phead) { block->prev_changed= phead; if ((block->next_changed= *phead)) (*phead)->prev_changed= &block->next_changed; *phead= block; } /* Unlink a block from the chain of dirty/clean blocks, if it's asked for, and link it to the chain of clean blocks for the specified file */ static void link_to_file_list(KEY_CACHE *keycache, BLOCK_LINK *block, int file, my_bool unlink) { if (unlink) unlink_changed(block); link_changed(block, &keycache->file_blocks[FILE_HASH(file)]); if (block->status & BLOCK_CHANGED) { block->status&= ~BLOCK_CHANGED; keycache->blocks_changed--; if (keycache->env) keycache->env->blocks_changed--; } } /* Unlink a block from the chain of clean blocks for the specified file and link it to the chain of dirty blocks for this file */ static inline void link_to_changed_list(KEY_CACHE *keycache, BLOCK_LINK *block) { unlink_changed(block); link_changed(block, &keycache->changed_blocks[FILE_HASH(block->hash_link->file)]); block->status|=BLOCK_CHANGED; keycache->blocks_changed++; if (keycache->env) keycache->env->blocks_changed++; } /* Link a block to the LRU chain at the beginning or at the end of one of two parts. SYNOPSIS link_block() keycache pointer to a key cache data structure block pointer to the block to link to the LRU chain hot <-> to link the block into the hot subchain at_end <-> to link the block at the end of the subchain RETURN VALUE none NOTES. The LRU chain is represented by a curcular list of block structures. The list is double-linked of the type (**prev,*next) type. The LRU chain is divided into two parts - hot and warm. There are two pointers to access the last blocks of these two parts. The beginning of the warm part follows right after the end of the hot part. Only blocks of the warm part can be used for replacement. The first block from the beginning of this subchain is always taken for eviction (keycache->last_used->next) LRU chain: +------+ H O T +------+ +----| end |----...<----| beg |----+ | +------+last +------+ | v<-link in latest hot (new end) | | link in latest warm (new end)->^ | +------+ W A R M +------+ | +----| beg |---->...----| end |----+ +------+ +------+ins first for eviction */ static void link_block(KEY_CACHE *keycache, BLOCK_LINK *block, my_bool hot, my_bool at_end) { BLOCK_LINK *ins; BLOCK_LINK **pins; KEYCACHE_DBUG_ASSERT(! (block->hash_link && block->hash_link->requests)); if (!hot && keycache->waiting_for_block.last_thread) { /* Signal that in the LRU warm sub-chain an available block has appeared */ struct st_my_thread_var *last_thread= keycache->waiting_for_block.last_thread; struct st_my_thread_var *first_thread= last_thread->next; struct st_my_thread_var *next_thread= first_thread; HASH_LINK *hash_link= (HASH_LINK *) first_thread->opt_info; struct st_my_thread_var *thread; do { thread= next_thread; next_thread= thread->next; /* We notify about the event all threads that ask for the same page as the first thread in the queue */ if ((HASH_LINK *) thread->opt_info == hash_link) { keycache_pthread_cond_signal(&thread->suspend); unlink_from_queue(&keycache->waiting_for_block, thread); block->requests++; } } while (thread != last_thread); hash_link->block= block; KEYCACHE_THREAD_TRACE("link_block: after signaling"); #if defined(KEYCACHE_DEBUG) KEYCACHE_DBUG_PRINT("link_block", ("linked,unlinked block %u status=%x #requests=%u #available=%u", BLOCK_NUMBER(block), block->status, block->requests, keycache->blocks_available)); #endif return; } pins= hot ? &keycache->used_ins : &keycache->used_last; ins= *pins; if (ins) { ins->next_used->prev_used= &block->next_used; block->next_used= ins->next_used; block->prev_used= &ins->next_used; ins->next_used= block; if (at_end) *pins= block; } else { /* The LRU chain is empty */ keycache->used_last= keycache->used_ins= block->next_used= block; block->prev_used= &block->next_used; } KEYCACHE_THREAD_TRACE("link_block"); #if defined(KEYCACHE_DEBUG) keycache->blocks_available++; KEYCACHE_DBUG_PRINT("link_block", ("linked block %u:%1u status=%x #requests=%u #available=%u", BLOCK_NUMBER(block), at_end, block->status, block->requests, keycache->blocks_available)); KEYCACHE_DBUG_ASSERT((ulong) keycache->blocks_available <= keycache->blocks_used); #endif } /* Unlink a block from the LRU chain SYNOPSIS unlink_block() keycache pointer to a key cache data structure block pointer to the block to unlink from the LRU chain RETURN VALUE none NOTES. See NOTES for link_block */ static void unlink_block(KEY_CACHE *keycache, BLOCK_LINK *block) { if (block->next_used == block) /* The list contains only one member */ keycache->used_last= keycache->used_ins= NULL; else { block->next_used->prev_used= block->prev_used; *block->prev_used= block->next_used; if (keycache->used_last == block) keycache->used_last= STRUCT_PTR(BLOCK_LINK, next_used, block->prev_used); if (keycache->used_ins == block) keycache->used_ins=STRUCT_PTR(BLOCK_LINK, next_used, block->prev_used); } block->next_used= NULL; KEYCACHE_THREAD_TRACE("unlink_block"); #if defined(KEYCACHE_DEBUG) keycache->blocks_available--; KEYCACHE_DBUG_PRINT("unlink_block", ("unlinked block %u status=%x #requests=%u #available=%u", BLOCK_NUMBER(block), block->status, block->requests, keycache->blocks_available)); KEYCACHE_DBUG_ASSERT(keycache->blocks_available >= 0); #endif } /* Register requests for a block */ static void reg_requests(KEY_CACHE *keycache, BLOCK_LINK *block, int count) { if (! block->requests) /* First request for the block unlinks it */ unlink_block(keycache, block); block->requests+=count; } /* Unregister request for a block linking it to the LRU chain if it's the last request SYNOPSIS unreg_block() keycache pointer to a key cache data structure block pointer to the block to link to the LRU chain at_end <-> to link the block at the end of the LRU chain RETURN VALUE none NOTES. Every linking to the LRU chain decrements by one a special block counter (if it's positive). If the at_end parameter is TRUE the block is added either at the end of warm sub-chain or at the end of hot sub-chain. It is added to the hot subchain if its counter is zero and number of blocks in warm sub-chain is not less than some low limit (determined by the division_limit parameter). Otherwise the block is added to the warm sub-chain. If the at_end parameter is FALSE the block is always added at beginning of the warm sub-chain. Thus a warm block can be promoted to the hot sub-chain when its counter becomes zero for the first time. At the same time the block at the very beginning of the hot subchain might be moved to the beginning of the warm subchain if it stays untouched for a too long time (this time is determined by parameter age_threshold). */ static inline void unreg_request(KEY_CACHE *keycache, BLOCK_LINK *block, int at_end) { if (! --block->requests) { my_bool hot; if (block->hits_left) block->hits_left--; hot= !block->hits_left && at_end && keycache->warm_blocks > keycache->min_warm_blocks; if (hot) { keycache->warm_blocks--; KEYCACHE_DBUG_PRINT("unreg_request", ("#warm_blocks=%u", keycache->warm_blocks)); } link_block(keycache, block, hot, (my_bool)at_end); block->last_hit_time= keycache->keycache_time; if (++keycache->keycache_time - keycache->used_ins->last_hit_time > keycache->age_threshold) { block= keycache->used_ins; unlink_block(keycache, block); link_block(keycache, block, 0, 0); keycache->warm_blocks++; KEYCACHE_DBUG_PRINT("unreg_request", ("#warm_blocks=%u", keycache->warm_blocks)); } } } /* Remove a reader of the page in block */ static inline void remove_reader(BLOCK_LINK *block) { if (! --block->hash_link->requests && block->condvar) keycache_pthread_cond_signal(block->condvar); } /* Wait until the last reader of the page in block signals on its termination */ static inline void wait_for_readers(KEY_CACHE *keycache, BLOCK_LINK *block) { struct st_my_thread_var *thread=my_thread_var; while (block->hash_link->requests) { block->condvar= &thread->suspend; keycache_pthread_cond_wait(&thread->suspend, &keycache->cache_lock); block->condvar= NULL; } } /* Add a hash link to a bucket in the hash_table */ static inline void link_hash(HASH_LINK **start, HASH_LINK *hash_link) { if (*start) (*start)->prev= &hash_link->next; hash_link->next= *start; hash_link->prev= start; *start= hash_link; } /* Remove a hash link from the hash table */ static void unlink_hash(KEY_CACHE *keycache, HASH_LINK *hash_link) { KEYCACHE_DBUG_PRINT("unlink_hash", ("file %u, filepos %lu #requests=%u", (uint) hash_link->file,(ulong) hash_link->diskpos, hash_link->requests)); KEYCACHE_DBUG_ASSERT(hash_link->requests == 0); if ((*hash_link->prev= hash_link->next)) hash_link->next->prev= hash_link->prev; hash_link->block= NULL; if (keycache->waiting_for_hash_link.last_thread) { /* Signal that A free hash link appeared */ struct st_my_thread_var *last_thread= keycache->waiting_for_hash_link.last_thread; struct st_my_thread_var *first_thread= last_thread->next; struct st_my_thread_var *next_thread= first_thread; KEYCACHE_PAGE *first_page= (KEYCACHE_PAGE *) (first_thread->opt_info); struct st_my_thread_var *thread; hash_link->file= first_page->file; hash_link->diskpos= first_page->filepos; do { KEYCACHE_PAGE *page; thread= next_thread; page= (KEYCACHE_PAGE *) thread->opt_info; next_thread= thread->next; /* We notify about the event all threads that ask for the same page as the first thread in the queue */ if (page->file == hash_link->file && page->filepos == hash_link->diskpos) { keycache_pthread_cond_signal(&thread->suspend); unlink_from_queue(&keycache->waiting_for_hash_link, thread); } } while (thread != last_thread); link_hash(&keycache->hash_root[KEYCACHE_HASH(hash_link->file, hash_link->diskpos)], hash_link); return; } hash_link->next= keycache->free_hash_list; keycache->free_hash_list= hash_link; } /* Get the hash link for a page */ static HASH_LINK *get_hash_link(KEY_CACHE *keycache, int file, my_off_t filepos) { reg1 HASH_LINK *hash_link, **start; KEYCACHE_PAGE page; #if defined(KEYCACHE_DEBUG) int cnt; #endif KEYCACHE_DBUG_PRINT("get_hash_link", ("file %u, filepos %lu", (uint) file,(ulong) filepos)); restart: /* Find the bucket in the hash table for the pair (file, filepos); start contains the head of the bucket list, hash_link points to the first member of the list */ hash_link= *(start= &keycache->hash_root[KEYCACHE_HASH(file, filepos)]); #if defined(KEYCACHE_DEBUG) cnt= 0; #endif /* Look for an element for the pair (file, filepos) in the bucket chain */ while (hash_link && (hash_link->diskpos != filepos || hash_link->file != file)) { hash_link= hash_link->next; #if defined(KEYCACHE_DEBUG) cnt++; if (! (cnt <= keycache->hash_links_used)) { int i; for (i=0, hash_link= *start ; i < cnt ; i++, hash_link= hash_link->next) { KEYCACHE_DBUG_PRINT("get_hash_link", ("file %u, filepos %lu", (uint) hash_link->file,(ulong) hash_link->diskpos)); } } KEYCACHE_DBUG_ASSERT(cnt <= keycache->hash_links_used); #endif } if (! hash_link) { /* There is no hash link in the hash table for the pair (file, filepos) */ if (keycache->free_hash_list) { hash_link= keycache->free_hash_list; keycache->free_hash_list= hash_link->next; } else if (keycache->hash_links_used < keycache->hash_links) { hash_link= &keycache->hash_link_root[keycache->hash_links_used++]; } else { /* Wait for a free hash link */ struct st_my_thread_var *thread= my_thread_var; KEYCACHE_DBUG_PRINT("get_hash_link", ("waiting")); page.file= file; page.filepos= filepos; thread->opt_info= (void *) &page; link_into_queue(&keycache->waiting_for_hash_link, thread); keycache_pthread_cond_wait(&thread->suspend, &keycache->cache_lock); thread->opt_info= NULL; goto restart; } hash_link->file= file; hash_link->diskpos= filepos; link_hash(start, hash_link); } /* Register the request for the page */ hash_link->requests++; return hash_link; } /* Get a block for the file page requested by a keycache read/write operation; If the page is not in the cache return a free block, if there is none return the lru block after saving its buffer if the page is dirty. SYNOPSIS find_key_block() keycache pointer to a key cache data structure file handler for the file to read page from filepos position of the page in the file init_hits_left how initialize the block counter for the page wrmode <-> get for writing page_st out {PAGE_READ,PAGE_TO_BE_READ,PAGE_WAIT_TO_BE_READ} RETURN VALUE Pointer to the found block if successful, 0 - otherwise NOTES. For the page from file positioned at filepos the function checks whether the page is in the key cache specified by the first parameter. If this is the case it immediately returns the block. If not, the function first chooses a block for this page. If there is no not used blocks in the key cache yet, the function takes the block at the very beginning of the warm sub-chain. It saves the page in that block if it's dirty before returning the pointer to it. The function returns in the page_st parameter the following values: PAGE_READ - if page already in the block, PAGE_TO_BE_READ - if it is to be read yet by the current thread WAIT_TO_BE_READ - if it is to be read by another thread If an error occurs THE BLOCK_ERROR bit is set in the block status. It might happen that there are no blocks in LRU chain (in warm part) - all blocks are unlinked for some read/write operations. Then the function waits until first of this operations links any block back. */ static BLOCK_LINK *find_key_block(KEY_CACHE *keycache, File file, my_off_t filepos, int init_hits_left, int wrmode, int *page_st) { HASH_LINK *hash_link; BLOCK_LINK *block; int error= 0; int page_status; DBUG_ENTER("find_key_block"); KEYCACHE_THREAD_TRACE("find_key_block:begin"); DBUG_PRINT("enter", ("file %u, filepos %lu, wrmode %lu", (uint) file, (ulong) filepos, (uint) wrmode)); KEYCACHE_DBUG_PRINT("find_key_block", ("file %u, filepos %lu, wrmode %lu", (uint) file, (ulong) filepos, (uint) wrmode)); #if !defined(DBUG_OFF) && defined(EXTRA_DEBUG) DBUG_EXECUTE("check_keycache2", test_key_cache(keycache, "start of find_key_block", 0);); #endif restart: /* Find the hash link for the requested page (file, filepos) */ hash_link= get_hash_link(keycache, file, filepos); page_status= -1; if ((block= hash_link->block) && block->hash_link == hash_link && (block->status & BLOCK_READ)) page_status= PAGE_READ; if (page_status == PAGE_READ && (block->status & BLOCK_IN_SWITCH)) { /* This is a request for a page to be removed from cache */ KEYCACHE_DBUG_PRINT("find_key_block", ("request for old page in block %u",BLOCK_NUMBER(block))); /* Only reading requests can proceed until the old dirty page is flushed, all others are to be suspended, then resubmitted */ if (!wrmode && !(block->status & BLOCK_REASSIGNED)) reg_requests(keycache, block, 1); else { hash_link->requests--; KEYCACHE_DBUG_PRINT("find_key_block", ("request waiting for old page to be saved")); { struct st_my_thread_var *thread= my_thread_var; /* Put the request into the queue of those waiting for the old page */ add_to_queue(&block->wqueue[COND_FOR_SAVED], thread); /* Wait until the request can be resubmitted */ do { keycache_pthread_cond_wait(&thread->suspend, &keycache->cache_lock); } while(thread->next); } KEYCACHE_DBUG_PRINT("find_key_block", ("request for old page resubmitted")); /* Resubmit the request */ goto restart; } } else { /* This is a request for a new page or for a page not to be removed */ if (! block) { /* No block is assigned for the page yet */ if (keycache->blocks_used < (uint) keycache->disk_blocks) { /* There are some never used blocks, take first of them */ hash_link->block= block= &keycache->block_root[keycache->blocks_used]; block->buffer= ADD_TO_PTR(keycache->block_mem, ((ulong) keycache->blocks_used* keycache->key_cache_block_size), byte*); block->status= 0; block->length= 0; block->offset= keycache->key_cache_block_size; block->requests= 1; keycache->blocks_used++; if (keycache->env) keycache->env->blocks_used++; keycache->warm_blocks++; block->hits_left= init_hits_left; block->last_hit_time= 0; link_to_file_list(keycache, block, file, 0); block->hash_link= hash_link; page_status= PAGE_TO_BE_READ; KEYCACHE_DBUG_PRINT("find_key_block", ("got never used block %u", BLOCK_NUMBER(block))); } else { /* There are no never used blocks, use a block from the LRU chain */ /* Wait until a new block is added to the LRU chain; several threads might wait here for the same page, all of them must get the same block */ if (! keycache->used_last) { struct st_my_thread_var *thread= my_thread_var; thread->opt_info= (void *) hash_link; link_into_queue(&keycache->waiting_for_block, thread); do { keycache_pthread_cond_wait(&thread->suspend, &keycache->cache_lock); } while (thread->next); thread->opt_info= NULL; } block= hash_link->block; if (! block) { /* Take the first block from the LRU chain unlinking it from the chain */ block= keycache->used_last->next_used; block->hits_left= init_hits_left; block->last_hit_time= 0; reg_requests(keycache, block,1); hash_link->block= block; } if (block->hash_link != hash_link && ! (block->status & BLOCK_IN_SWITCH) ) { /* this is a primary request for a new page */ block->status|= BLOCK_IN_SWITCH; KEYCACHE_DBUG_PRINT("find_key_block", ("got block %u for new page", BLOCK_NUMBER(block))); if (block->status & BLOCK_CHANGED) { /* The block contains a dirty page - push it out of the cache */ KEYCACHE_DBUG_PRINT("find_key_block", ("block is dirty")); keycache_pthread_mutex_unlock(&keycache->cache_lock); /* The call is thread safe because only the current thread might change the block->hash_link value */ error= my_pwrite(block->hash_link->file, block->buffer+block->offset, block->length - block->offset, block->hash_link->diskpos+ block->offset, MYF(MY_NABP | MY_WAIT_IF_FULL)); keycache_pthread_mutex_lock(&keycache->cache_lock); if (keycache->env) keycache->env->cache_write++; } block->status|= BLOCK_REASSIGNED; if (block->hash_link) { /* Wait until all pending read requests for this page are executed (we could have avoided this waiting, if we had read a page in the cache in a sweep, without yielding control) */ wait_for_readers(keycache, block); /* Remove the hash link for this page from the hash table */ unlink_hash(keycache, block->hash_link); /* All pending requests for this page must be resubmitted */ if (block->wqueue[COND_FOR_SAVED].last_thread) release_queue(&block->wqueue[COND_FOR_SAVED]); } link_to_file_list(keycache, block, file, (my_bool)(block->hash_link ? 1 : 0)); block->status= error? BLOCK_ERROR : 0; block->length= 0; block->offset= keycache->key_cache_block_size; block->hash_link= hash_link; page_status= PAGE_TO_BE_READ; KEYCACHE_DBUG_ASSERT(block->hash_link->block == block); KEYCACHE_DBUG_ASSERT(hash_link->block->hash_link == hash_link); } else { /* This is for secondary requests for a new page only */ page_status= block->hash_link == hash_link && (block->status & BLOCK_READ) ? PAGE_READ : PAGE_WAIT_TO_BE_READ; } } if (keycache->env) keycache->env->cache_read++; } else { reg_requests(keycache, block, 1); page_status = block->hash_link == hash_link && (block->status & BLOCK_READ) ? PAGE_READ : PAGE_WAIT_TO_BE_READ; } } KEYCACHE_DBUG_ASSERT(page_status != -1); *page_st=page_status; KEYCACHE_DBUG_PRINT("find_key_block", ("file %u, filepos %lu, page_status %lu", (uint) file,(ulong) filepos,(uint) page_status)); #if !defined(DBUG_OFF) && defined(EXTRA_DEBUG) DBUG_EXECUTE("check_keycache2", test_key_cache(keycache, "end of find_key_block",0);); #endif KEYCACHE_THREAD_TRACE("find_key_block:end"); DBUG_RETURN(block); } /* Read into a key cache block buffer from disk. SYNOPSIS read_block() keycache pointer to a key cache data structure block block to which buffer the data is to be read read_length size of data to be read min_length at least so much data must be read primary <-> the current thread will read the data RETURN VALUE None NOTES. The function either reads a page data from file to the block buffer, or waits until another thread reads it. What page to read is determined by a block parameter - reference to a hash link for this page. If an error occurs THE BLOCK_ERROR bit is set in the block status. We do not report error when the size of successfully read portion is less than read_length, but not less than min_length. */ static void read_block(KEY_CACHE *keycache, BLOCK_LINK *block, uint read_length, uint min_length, my_bool primary) { uint got_length; /* On entry cache_lock is locked */ KEYCACHE_THREAD_TRACE("read_block"); if (primary) { /* This code is executed only by threads that submitted primary requests */ KEYCACHE_DBUG_PRINT("read_block", ("page to be read by primary request")); /* Page is not in buffer yet, is to be read from disk */ keycache_pthread_mutex_unlock(&keycache->cache_lock); got_length= my_pread(block->hash_link->file, block->buffer, read_length, block->hash_link->diskpos, MYF(0)); keycache_pthread_mutex_lock(&keycache->cache_lock); if (got_length < min_length) block->status|= BLOCK_ERROR; else { block->status= BLOCK_READ; block->length= got_length; } KEYCACHE_DBUG_PRINT("read_block", ("primary request: new page in cache")); /* Signal that all pending requests for this page now can be processed */ if (block->wqueue[COND_FOR_REQUESTED].last_thread) release_queue(&block->wqueue[COND_FOR_REQUESTED]); } else { /* This code is executed only by threads that submitted secondary requests */ KEYCACHE_DBUG_PRINT("read_block", ("secondary request waiting for new page to be read")); { struct st_my_thread_var *thread= my_thread_var; /* Put the request into a queue and wait until it can be processed */ add_to_queue(&block->wqueue[COND_FOR_REQUESTED], thread); do { keycache_pthread_cond_wait(&thread->suspend, &keycache->cache_lock); } while (thread->next); } KEYCACHE_DBUG_PRINT("read_block", ("secondary request: new page in cache")); } } /* Read a block of data from a cached file into a buffer; SYNOPSIS key_cache_read() keycache pointer to a key cache data structure file handler for the file for the block of data to be read filepos position of the block of data in the file level determines the weight of the data buff buffer to where the data must be placed length length of the buffer block_length length of the block in the key cache buffer return_buffer return pointer to the key cache buffer with the data RETURN VALUE Returns address from where the data is placed if sucessful, 0 - otherwise. NOTES. The function ensures that a block of data of size length from file positioned at filepos is in the buffers for some key cache blocks. Then the function either copies the data into the buffer buff, or, if return_buffer is TRUE, it just returns the pointer to the key cache buffer with the data. Filepos must be a multiple of 'block_length', but it doesn't have to be a multiple of key_cache_block_size; */ byte *key_cache_read(KEY_CACHE_HANDLE keycache, File file, my_off_t filepos, int level, byte *buff, uint length, uint block_length __attribute__((unused)), int return_buffer __attribute__((unused))) { int error=0; DBUG_ENTER("key_cache_read"); DBUG_PRINT("enter", ("file %u, filepos %lu, length %u", (uint) file, (ulong) filepos, length)); if (keycache && keycache->disk_blocks > 0) { /* Key cache is used */ reg1 BLOCK_LINK *block; uint offset= (uint) (filepos & (keycache->key_cache_block_size-1)); byte *start= buff; uint read_length; uint status; int page_st; #ifndef THREAD if (block_length > keycache->key_cache_block_size || offset) return_buffer=0; #endif /* Read data in key_cache_block_size increments */ filepos-= offset; do { read_length= length > keycache->key_cache_block_size ? keycache->key_cache_block_size : length; KEYCACHE_DBUG_ASSERT(read_length > 0); keycache_pthread_mutex_lock(&keycache->cache_lock); if (keycache->env) keycache->env->cache_r_requests++; block=find_key_block(keycache, file, filepos, level, 0, &page_st); if (block->status != BLOCK_ERROR && page_st != PAGE_READ) { /* The requested page is to be read into the block buffer */ read_block(keycache, block, keycache->key_cache_block_size, read_length+offset, (my_bool)(page_st == PAGE_TO_BE_READ)); } else if (! (block->status & BLOCK_ERROR) && block->length < read_length + offset) { /* Impossible if nothing goes wrong: this could only happen if we are using a file with small key blocks and are trying to read outside the file */ my_errno= -1; block->status|= BLOCK_ERROR; } if (! ((status= block->status) & BLOCK_ERROR)) { #ifndef THREAD if (! return_buffer) #endif { #if !defined(SERIALIZED_READ_FROM_CACHE) keycache_pthread_mutex_unlock(&keycache->cache_lock); #endif /* Copy data from the cache buffer */ if (!(read_length & 511)) bmove512(buff, block->buffer+offset, read_length); else memcpy(buff, block->buffer+offset, (size_t) read_length); #if !defined(SERIALIZED_READ_FROM_CACHE) keycache_pthread_mutex_lock(&keycache->cache_lock); #endif } } remove_reader(block); /* Link the block into the LRU chain if it's the last submitted request for the block */ unreg_request(keycache, block, 1); keycache_pthread_mutex_unlock(&keycache->cache_lock); if (status & BLOCK_ERROR) DBUG_RETURN((byte *) 0); #ifndef THREAD if (return_buffer) return (block->buffer); #endif buff+= read_length; filepos+= read_length; offset= 0; } while ((length-= read_length)); DBUG_RETURN(start); } /* Key cache is not used */ if (keycache && keycache->env) { statistic_increment(keycache->env->cache_r_requests, &keycache->cache_lock); statistic_increment(keycache->env->cache_read, &keycache->cache_lock); } if (my_pread(file, (byte*) buff, length, filepos, MYF(MY_NABP))) error= 1; DBUG_RETURN(error? (byte*) 0 : buff); } /* Insert a block of file data from a buffer into key cache SYNOPSIS key_cache_insert() keycache pointer to a key cache data structure file handler for the file to insert data from filepos position of the block of data in the file to insert level determines the weight of the data buff buffer to read data from length length of the data in the buffer RETURN VALUE 0 if a success, 1 - otherwise. */ int key_cache_insert(KEY_CACHE_HANDLE keycache, File file, my_off_t filepos, int level, byte *buff, uint length) { DBUG_ENTER("key_cache_insert"); DBUG_PRINT("enter", ("file %u, filepos %lu, length %u", (uint) file,(ulong) filepos, length)); if (keycache->disk_blocks > 0) { /* Key cache is used */ reg1 BLOCK_LINK *block; uint offset= (uint) (filepos & (keycache->key_cache_block_size-1)); uint read_length; int page_st; /* Read data into key cache from buff in key_cache_block_size increments */ filepos-= offset; do { read_length= length > keycache->key_cache_block_size ? keycache->key_cache_block_size : length; KEYCACHE_DBUG_ASSERT(read_length > 0); keycache_pthread_mutex_lock(&keycache->cache_lock); if (keycache->env) keycache->env->cache_r_requests++; block= find_key_block(keycache, file, filepos, level, 0, &page_st); if (block->status != BLOCK_ERROR && page_st != PAGE_READ) { /* The requested page is to be read into the block buffer */ #if !defined(SERIALIZED_READ_FROM_CACHE) keycache_pthread_mutex_unlock(&keycache->cache_lock); #endif /* Copy data from buff */ if (!(read_length & 511)) bmove512(block->buffer+offset, buff, read_length); else memcpy(block->buffer+offset, buff, (size_t) read_length); #if !defined(SERIALIZED_READ_FROM_CACHE) keycache_pthread_mutex_lock(&keycache->cache_lock); #endif block->status= BLOCK_READ; block->length= read_length+offset; } remove_reader(block); /* Link the block into the LRU chain if it's the last submitted request for the block */ unreg_request(keycache, block, 1); keycache_pthread_mutex_unlock(&keycache->cache_lock); if (block->status & BLOCK_ERROR) DBUG_RETURN(1); buff+= read_length; filepos+= read_length; offset=0; } while ((length-= read_length)); } DBUG_RETURN(0); } /* Write a buffer into a cached file. SYNOPSIS key_cache_write() keycache pointer to a key cache data structure file handler for the file to write data to filepos position in the file to write data to level determines the weight of the data buff buffer with the data length length of the buffer dont_write if is 0 then all dirty pages involved in writing should have been flushed from key cache RETURN VALUE 0 if a success, 1 - otherwise. NOTES. The function copies the data of size length from buff into buffers for key cache blocks that are assigned to contain the portion of the file starting with position filepos. It ensures that this data is flushed to the file if dont_write is FALSE. Filepos must be a multiple of 'block_length', but it doesn't have to be a multiple of key_cache_block_size; */ int key_cache_write(KEY_CACHE_HANDLE keycache, File file, my_off_t filepos, int level, byte *buff, uint length, uint block_length __attribute__((unused)), int dont_write) { reg1 BLOCK_LINK *block; int error=0; DBUG_ENTER("key_cache_write"); DBUG_PRINT("enter", ("file %u filepos %lu length %u block_length %u key_block_length: %u", (uint) file, (ulong) filepos, length, block_length, keycache ? keycache->key_cache_block_size : 0)); if (!dont_write) { /* Force writing from buff into disk */ if (keycache && keycache->env) statistic_increment(keycache->env->cache_write, &keycache->cache_lock); if (my_pwrite(file, buff, length, filepos, MYF(MY_NABP | MY_WAIT_IF_FULL))) DBUG_RETURN(1); } #if !defined(DBUG_OFF) && defined(EXTRA_DEBUG) DBUG_EXECUTE("check_keycache", test_key_cache(keycache, "start of key_cache_write", 1);); #endif if (keycache && keycache->disk_blocks > 0) { /* Key cache is used */ uint read_length; uint offset= (uint) (filepos & (keycache->key_cache_block_size-1)); int page_st; /* Write data in key_cache_block_size increments */ filepos-= offset; do { read_length= length > keycache->key_cache_block_size ? keycache->key_cache_block_size : length; KEYCACHE_DBUG_ASSERT(read_length > 0); keycache_pthread_mutex_lock(&keycache->cache_lock); if (keycache->env) keycache->env->cache_w_requests++; block= find_key_block(keycache, file, filepos, level, 1, &page_st); if (block->status != BLOCK_ERROR && page_st != PAGE_READ && (offset || read_length < keycache->key_cache_block_size)) read_block(keycache, block, offset + read_length >= keycache->key_cache_block_size? offset : keycache->key_cache_block_size, offset,(my_bool)(page_st == PAGE_TO_BE_READ)); if (!dont_write) { /* buff has been written to disk at start */ if ((block->status & BLOCK_CHANGED) && (!offset && read_length >= keycache->key_cache_block_size)) link_to_file_list(keycache, block, block->hash_link->file, 1); } else if (! (block->status & BLOCK_CHANGED)) link_to_changed_list(keycache, block); set_if_smaller(block->offset, offset) set_if_bigger(block->length, read_length+offset); if (! (block->status & BLOCK_ERROR)) { if (!(read_length & 511)) bmove512(block->buffer+offset, buff, read_length); else memcpy(block->buffer+offset, buff, (size_t) read_length); } block->status|=BLOCK_READ; /* Unregister the request */ block->hash_link->requests--; unreg_request(keycache, block, 1); if (block->status & BLOCK_ERROR) { keycache_pthread_mutex_unlock(&keycache->cache_lock); error= 1; break; } keycache_pthread_mutex_unlock(&keycache->cache_lock); buff+= read_length; filepos+= read_length; offset= 0; } while ((length-= read_length)); } else { /* Key cache is not used */ if (dont_write) { if (keycache && keycache->env) { statistic_increment(keycache->env->cache_w_requests, &keycache->cache_lock); statistic_increment(keycache->env->cache_write, &keycache->cache_lock); } if (my_pwrite(file, (byte*) buff, length, filepos, MYF(MY_NABP | MY_WAIT_IF_FULL))) error=1; } } #if !defined(DBUG_OFF) && defined(EXTRA_DEBUG) DBUG_EXECUTE("exec", test_key_cache(keycache, "end of key_cache_write", 1);); #endif DBUG_RETURN(error); } /* Free block: remove reference to it from hash table, remove it from the chain file of dirty/clean blocks and add it at the beginning of the LRU chain */ static void free_block(KEY_CACHE *keycache, BLOCK_LINK *block) { KEYCACHE_THREAD_TRACE("free block"); KEYCACHE_DBUG_PRINT("free_block", ("block %u to be freed",BLOCK_NUMBER(block))); if (block->hash_link) { block->status|= BLOCK_REASSIGNED; wait_for_readers(keycache, block); unlink_hash(keycache, block->hash_link); } unlink_changed(block); block->status= 0; block->length= 0; block->offset= keycache->key_cache_block_size; KEYCACHE_THREAD_TRACE("free block"); KEYCACHE_DBUG_PRINT("free_block", ("block is freed")); unreg_request(keycache, block, 0); block->hash_link= NULL; } static int cmp_sec_link(BLOCK_LINK **a, BLOCK_LINK **b) { return (((*a)->hash_link->diskpos < (*b)->hash_link->diskpos) ? -1 : ((*a)->hash_link->diskpos > (*b)->hash_link->diskpos) ? 1 : 0); } /* Flush a portion of changed blocks to disk, free used blocks if requested */ static int flush_cached_blocks(KEY_CACHE *keycache, File file, BLOCK_LINK **cache, BLOCK_LINK **end, enum flush_type type) { int error; int last_errno= 0; uint count= end-cache; /* Don't lock the cache during the flush */ keycache_pthread_mutex_unlock(&keycache->cache_lock); /* As all blocks referred in 'cache' are marked by BLOCK_IN_FLUSH we are guarunteed no thread will change them */ qsort((byte*) cache, count, sizeof(*cache), (qsort_cmp) cmp_sec_link); keycache_pthread_mutex_lock(&keycache->cache_lock); for ( ; cache != end ; cache++) { BLOCK_LINK *block= *cache; KEYCACHE_DBUG_PRINT("flush_cached_blocks", ("block %u to be flushed", BLOCK_NUMBER(block))); keycache_pthread_mutex_unlock(&keycache->cache_lock); error= my_pwrite(file, block->buffer+block->offset, block->length - block->offset, block->hash_link->diskpos+ block->offset, MYF(MY_NABP | MY_WAIT_IF_FULL)); keycache_pthread_mutex_lock(&keycache->cache_lock); if (keycache->env) keycache->env->cache_write++; if (error) { block->status|= BLOCK_ERROR; if (!last_errno) last_errno= errno ? errno : -1; } /* type will never be FLUSH_IGNORE_CHANGED here */ if (! (type == FLUSH_KEEP || type == FLUSH_FORCE_WRITE)) { keycache->blocks_changed--; if (keycache->env) keycache->env->blocks_changed--; free_block(keycache, block); } else { block->status&= ~BLOCK_IN_FLUSH; link_to_file_list(keycache, block, file, 1); unreg_request(keycache, block, 1); } } return last_errno; } /* flush all key blocks for a file to disk, but don't do any mutex locks flush_key_blocks_int() keycache pointer to a key cache data structure file handler for the file to flush to flush_type type of the flush NOTES This function doesn't do any mutex locks because it needs to be called both from flush_key_blocks and flush_all_key_blocks (the later one does the mutex lock in the resize_key_cache() function). RETURN 0 ok 1 error */ static int flush_key_blocks_int(KEY_CACHE_HANDLE keycache, File file, enum flush_type type) { KEY_CACHE_VAR *env; BLOCK_LINK *cache_buff[FLUSH_CACHE],**cache; int last_errno= 0; DBUG_ENTER("flush_key_blocks_int"); DBUG_PRINT("enter",("file: %d blocks_used: %d blocks_changed: %d", file, keycache->blocks_used, keycache->blocks_changed)); #if !defined(DBUG_OFF) && defined(EXTRA_DEBUG) DBUG_EXECUTE("check_keycache", test_key_cache(keycache, "start of flush_key_blocks", 0);); #endif cache= cache_buff; if (keycache->disk_blocks > 0 && (!my_disable_flush_key_blocks || type != FLUSH_KEEP)) { /* Key cache exists and flush is not disabled */ int error= 0; uint count= 0; BLOCK_LINK **pos,**end; BLOCK_LINK *first_in_switch= NULL; BLOCK_LINK *block, *next; #if defined(KEYCACHE_DEBUG) uint cnt=0; #endif if (type != FLUSH_IGNORE_CHANGED) { /* Count how many key blocks we have to cache to be able to flush all dirty pages with minimum seek moves */ for (block= keycache->changed_blocks[FILE_HASH(file)] ; block ; block= block->next_changed) { if (block->hash_link->file == file) { count++; KEYCACHE_DBUG_ASSERT(count<= keycache->blocks_used); } } /* Allocate a new buffer only if its bigger than the one we have */ if (count > FLUSH_CACHE && !(cache= (BLOCK_LINK**) my_malloc(sizeof(BLOCK_LINK*)*count, MYF(0)))) { cache= cache_buff; count= FLUSH_CACHE; } } /* Retrieve the blocks and write them to a buffer to be flushed */ restart: end= (pos= cache)+count; for (block= keycache->changed_blocks[FILE_HASH(file)] ; block ; block= next) { #if defined(KEYCACHE_DEBUG) cnt++; KEYCACHE_DBUG_ASSERT(cnt <= keycache->blocks_used); #endif next= block->next_changed; if (block->hash_link->file == file) { /* Mark the block with BLOCK_IN_FLUSH in order not to let other threads to use it for new pages and interfere with our sequence ot flushing dirty file pages */ block->status|= BLOCK_IN_FLUSH; if (! (block->status & BLOCK_IN_SWITCH)) { /* We care only for the blocks for which flushing was not initiated by other threads as a result of page swapping */ reg_requests(keycache, block, 1); if (type != FLUSH_IGNORE_CHANGED) { /* It's not a temporary file */ if (pos == end) { /* This happens only if there is not enough memory for the big block */ if ((error= flush_cached_blocks(keycache, file, cache, end,type))) last_errno=error; /* Restart the scan as some other thread might have changed the changed blocks chain: the blocks that were in switch state before the flush started have to be excluded */ goto restart; } *pos++= block; } else { /* It's a temporary file */ keycache->blocks_changed--; if (keycache->env) keycache->env->blocks_changed--; free_block(keycache, block); } } else { /* Link the block into a list of blocks 'in switch' */ unlink_changed(block); link_changed(block, &first_in_switch); } } } if (pos != cache) { if ((error= flush_cached_blocks(keycache, file, cache, pos, type))) last_errno= error; } /* Wait until list of blocks in switch is empty */ while (first_in_switch) { #if defined(KEYCACHE_DEBUG) cnt= 0; #endif block= first_in_switch; { struct st_my_thread_var *thread= my_thread_var; add_to_queue(&block->wqueue[COND_FOR_SAVED], thread); do { keycache_pthread_cond_wait(&thread->suspend, &keycache->cache_lock); } while (thread->next); } #if defined(KEYCACHE_DEBUG) cnt++; KEYCACHE_DBUG_ASSERT(cnt <= keycache->blocks_used); #endif } /* The following happens very seldom */ if (! (type == FLUSH_KEEP || type == FLUSH_FORCE_WRITE)) { #if defined(KEYCACHE_DEBUG) cnt=0; #endif for (block= keycache->file_blocks[FILE_HASH(file)] ; block ; block= next) { #if defined(KEYCACHE_DEBUG) cnt++; KEYCACHE_DBUG_ASSERT(cnt <= keycache->blocks_used); #endif next= block->next_changed; if (block->hash_link->file == file && (! (block->status & BLOCK_CHANGED) || type == FLUSH_IGNORE_CHANGED)) { reg_requests(keycache, block, 1); free_block(keycache, block); } } } } if (type == FLUSH_REMOVE && (env= keycache->env) && (env->action)) (*env->action)((void *) env); #ifndef DBUG_OFF DBUG_EXECUTE("check_keycache", test_key_cache(keycache, "end of flush_key_blocks", 0);); #endif if (cache != cache_buff) my_free((gptr) cache, MYF(0)); if (last_errno) errno=last_errno; /* Return first error */ DBUG_RETURN(last_errno != 0); } /* Flush all blocks for a file to disk SYNOPSIS flush_key_blocks() keycache pointer to a key cache data structure file handler for the file to flush to flush_type type of the flush RETURN 0 ok 1 error */ int flush_key_blocks(KEY_CACHE_HANDLE key_cache, File file, enum flush_type type) { int res; DBUG_ENTER("flush_key_blocks"); DBUG_PRINT("enter", ("key_cache: %lx", key_cache)); if (!key_cache || !key_cache->disk_blocks) DBUG_RETURN(0); keycache_pthread_mutex_lock(&key_cache->cache_lock); res= flush_key_blocks_int(key_cache, file, type); keycache_pthread_mutex_unlock(&key_cache->cache_lock); DBUG_RETURN(res); } /* Flush all blocks in the key cache to disk */ static int flush_all_key_blocks(KEY_CACHE *keycache) { #if defined(KEYCACHE_DEBUG) uint cnt=0; #endif while (keycache->blocks_changed > 0) { BLOCK_LINK *block; for (block= keycache->used_last->next_used ; ; block=block->next_used) { if (block->hash_link) { #if defined(KEYCACHE_DEBUG) cnt++; KEYCACHE_DBUG_ASSERT(cnt <= keycache->blocks_used); #endif if (flush_key_blocks_int(keycache, block->hash_link->file, FLUSH_RELEASE)) return 1; break; } if (block == keycache->used_last) break; } } return 0; } #ifndef DBUG_OFF /* Test if disk-cache is ok */ static void test_key_cache(KEY_CACHE *keycache __attribute__((unused)), const char *where __attribute__((unused)), my_bool lock __attribute__((unused))) { /* TODO */ } #endif #if defined(KEYCACHE_TIMEOUT) #define KEYCACHE_DUMP_FILE "keycache_dump.txt" #define MAX_QUEUE_LEN 100 static void keycache_dump(KEY_CACHE *keycache) { FILE *keycache_dump_file=fopen(KEYCACHE_DUMP_FILE, "w"); struct st_my_thread_var *thread_var= my_thread_var; struct st_my_thread_var *last; struct st_my_thread_var *thread; BLOCK_LINK *block; HASH_LINK *hash_link; KEYCACHE_PAGE *page; uint i; fprintf(keycache_dump_file, "thread:%u\n", thread->id); i=0; thread=last=waiting_for_hash_link.last_thread; fprintf(keycache_dump_file, "queue of threads waiting for hash link\n"); if (thread) do { thread=thread->next; page= (KEYCACHE_PAGE *) thread->opt_info; fprintf(keycache_dump_file, "thread:%u, (file,filepos)=(%u,%lu)\n", thread->id,(uint) page->file,(ulong) page->filepos); if (++i == MAX_QUEUE_LEN) break; } while (thread != last); i=0; thread=last=waiting_for_block.last_thread; fprintf(keycache_dump_file, "queue of threads waiting for block\n"); if (thread) do { thread=thread->next; hash_link= (HASH_LINK *) thread->opt_info; fprintf(keycache_dump_file, "thread:%u hash_link:%u (file,filepos)=(%u,%lu)\n", thread->id, (uint) HASH_LINK_NUMBER(hash_link), (uint) hash_link->file,(ulong) hash_link->diskpos); if (++i == MAX_QUEUE_LEN) break; } while (thread != last); for (i=0 ; i< keycache->blocks_used ; i++) { int j; block= &keycache->block_root[i]; hash_link= block->hash_link; fprintf(keycache_dump_file, "block:%u hash_link:%d status:%x #requests=%u waiting_for_readers:%d\n", i, (int) (hash_link ? HASH_LINK_NUMBER(hash_link) : -1), block->status, block->requests, block->condvar ? 1 : 0); for (j=0 ; j < 2; j++) { KEYCACHE_WQUEUE *wqueue=&block->wqueue[j]; thread= last= wqueue->last_thread; fprintf(keycache_dump_file, "queue #%d\n", j); if (thread) { do { thread=thread->next; fprintf(keycache_dump_file, "thread:%u\n", thread->id); if (++i == MAX_QUEUE_LEN) break; } while (thread != last); } } } fprintf(keycache_dump_file, "LRU chain:"); block= keycache= used_last; if (block) { do { block= block->next_used; fprintf(keycache_dump_file, "block:%u, ", BLOCK_NUMBER(block)); } while (block != keycache->used_last); } fprintf(keycache_dump_file, "\n"); fclose(keycache_dump_file); } #endif /* defined(KEYCACHE_TIMEOUT) */ #if defined(KEYCACHE_TIMEOUT) && !defined(__WIN__) static int keycache_pthread_cond_wait(pthread_cond_t *cond, pthread_mutex_t *mutex) { int rc; struct timeval now; /* time when we started waiting */ struct timespec timeout; /* timeout value for the wait function */ struct timezone tz; #if defined(KEYCACHE_DEBUG) int cnt=0; #endif /* Get current time */ gettimeofday(&now, &tz); /* Prepare timeout value */ timeout.tv_sec= now.tv_sec + KEYCACHE_TIMEOUT; timeout.tv_nsec= now.tv_usec * 1000; /* timeval uses microseconds. */ /* timespec uses nanoseconds. */ /* 1 nanosecond = 1000 micro seconds. */ KEYCACHE_THREAD_TRACE_END("started waiting"); #if defined(KEYCACHE_DEBUG) cnt++; if (cnt % 100 == 0) fprintf(keycache_debug_log, "waiting...\n"); fflush(keycache_debug_log); #endif rc= pthread_cond_timedwait(cond, mutex, &timeout); KEYCACHE_THREAD_TRACE_BEGIN("finished waiting"); #if defined(KEYCACHE_DEBUG) if (rc == ETIMEDOUT) { fprintf(keycache_debug_log,"aborted by keycache timeout\n"); fclose(keycache_debug_log); abort(); } #endif if (rc == ETIMEDOUT) keycache_dump(); #if defined(KEYCACHE_DEBUG) KEYCACHE_DBUG_ASSERT(rc != ETIMEDOUT); #else assert(rc != ETIMEDOUT); #endif return rc; } #else #if defined(KEYCACHE_DEBUG) static int keycache_pthread_cond_wait(pthread_cond_t *cond, pthread_mutex_t *mutex) { int rc; KEYCACHE_THREAD_TRACE_END("started waiting"); rc= pthread_cond_wait(cond, mutex); KEYCACHE_THREAD_TRACE_BEGIN("finished waiting"); return rc; } #endif #endif /* defined(KEYCACHE_TIMEOUT) && !defined(__WIN__) */ #if defined(KEYCACHE_DEBUG) static int keycache_pthread_mutex_lock(pthread_mutex_t *mutex) { int rc; rc= pthread_mutex_lock(mutex); KEYCACHE_THREAD_TRACE_BEGIN(""); return rc; } static void keycache_pthread_mutex_unlock(pthread_mutex_t *mutex) { KEYCACHE_THREAD_TRACE_END(""); pthread_mutex_unlock(mutex); } static int keycache_pthread_cond_signal(pthread_cond_t *cond) { int rc; KEYCACHE_THREAD_TRACE("signal"); rc= pthread_cond_signal(cond); return rc; } static int keycache_pthread_cond_broadcast(pthread_cond_t *cond) { int rc; KEYCACHE_THREAD_TRACE("signal"); rc= pthread_cond_broadcast(cond); return rc; } #if defined(KEYCACHE_DEBUG_LOG) static void keycache_debug_print(const char * fmt,...) { va_list args; va_start(args,fmt); if (keycache_debug_log) { VOID(vfprintf(keycache_debug_log, fmt, args)); VOID(fputc('\n',keycache_debug_log)); } va_end(args); } #endif /* defined(KEYCACHE_DEBUG_LOG) */ #if defined(KEYCACHE_DEBUG_LOG) void keycache_debug_log_close(void) { if (keycache_debug_log) fclose(keycache_debug_log); } #endif /* defined(KEYCACHE_DEBUG_LOG) */ #endif /* defined(KEYCACHE_DEBUG) */