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Changes In Branch mutex-free-pcache Excluding Merge-Ins
This is equivalent to a diff from 56417a33 to 2dc98d29
2011-01-18
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17:03 | Do not use mutexes in the pcache implementation unless SQLITE_ENABLE_MEMORY_MANAGMENT is defined. This is a performance enhancement. A side effect is that pcaches will not steal pages from one another unless ENABLE_MEMORY_MANAGEMENT is set, or unless SQLITE_THREADSAFE=0. (check-in: e5ca59e6 user: drh tags: trunk) | |
16:13 | Get all test cases working with the mutex-free-pcache implementation. (Closed-Leaf check-in: 2dc98d29 user: drh tags: mutex-free-pcache) | |
15:17 | Do not use SQLITE_MUTEX_STATIC_MEM2 since it has been reused as STATIC_OPEN. Instead, create a new static mutex STATIC_PMEM which is an alias for the unused STATIC_LRU2. (check-in: f1cf02ef user: drh tags: mutex-free-pcache) | |
2011-01-17
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21:32 | Here is a completely new implementation of the mutex-free-pcache. This one uses a common code base and automatically selects whether or not to use mutexes depending on compile-time and start-time options. (check-in: d094a1bf user: drh tags: mutex-free-pcache) | |
18:30 | Fix a typo in the documentation for sqlite3_stmt_readonly(). (check-in: 56417a33 user: drh tags: trunk) | |
17:42 | Add the SQLITE_OMIT_AUTORESET compile-time option which if enabled causes the sqlite3_step() routine to return SQLITE_MISUSE if it is called after it has previously returned anything other than SQLITE_ROW, SQLITE_BUSY, or SQLITE_LOCKED. (check-in: 053ce76d user: drh tags: trunk) | |
Changes to src/pcache1.c.
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18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 | */ #include "sqliteInt.h" typedef struct PCache1 PCache1; typedef struct PgHdr1 PgHdr1; typedef struct PgFreeslot PgFreeslot; /* Each page cache is an instance of the following object. Every ** open database file (including each in-memory database and each ** temporary or transient database) has a single page cache which ** is an instance of this object. ** ** Pointers to structures of this type are cast and returned as ** opaque sqlite3_pcache* handles. */ struct PCache1 { /* Cache configuration parameters. Page size (szPage) and the purgeable ** flag (bPurgeable) are set when the cache is created. nMax may be ** modified at any time by a call to the pcache1CacheSize() method. | > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > | > | < | 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 | */ #include "sqliteInt.h" typedef struct PCache1 PCache1; typedef struct PgHdr1 PgHdr1; typedef struct PgFreeslot PgFreeslot; typedef struct PGroup PGroup; /* Each page cache (or PCache) belongs to a PGroup. A PGroup is a set ** of one or more PCaches that are able to recycle each others unpinned ** pages when they are under memory pressure. A PGroup is an instance of ** the following object. ** ** This page cache implementation works in one of two modes: ** ** (1) Every PCache is the sole member of its own PGroup. There is ** one PGroup per PCache. ** ** (2) There is a single global PGroup that all PCaches are a member ** of. ** ** Mode 1 uses more memory (since PCache instances are not able to rob ** unused pages from other PCaches) but it also operates without a mutex, ** and is therefore often faster. Mode 2 requires a mutex in order to be ** threadsafe, but is able recycle pages more efficient. ** ** For mode (1), PGroup.mutex is NULL. For mode (2) there is only a single ** PGroup which is the pcache1.grp global variable and its mutex is ** SQLITE_MUTEX_STATIC_LRU. */ struct PGroup { sqlite3_mutex *mutex; /* MUTEX_STATIC_LRU or NULL */ int nMaxPage; /* Sum of nMax for purgeable caches */ int nMinPage; /* Sum of nMin for purgeable caches */ int nCurrentPage; /* Number of purgeable pages allocated */ PgHdr1 *pLruHead, *pLruTail; /* LRU list of unpinned pages */ }; /* Each page cache is an instance of the following object. Every ** open database file (including each in-memory database and each ** temporary or transient database) has a single page cache which ** is an instance of this object. ** ** Pointers to structures of this type are cast and returned as ** opaque sqlite3_pcache* handles. */ struct PCache1 { /* Cache configuration parameters. Page size (szPage) and the purgeable ** flag (bPurgeable) are set when the cache is created. nMax may be ** modified at any time by a call to the pcache1CacheSize() method. ** The PGroup mutex must be held when accessing nMax. */ PGroup *pGroup; /* PGroup this cache belongs to */ int szPage; /* Size of allocated pages in bytes */ int bPurgeable; /* True if cache is purgeable */ unsigned int nMin; /* Minimum number of pages reserved */ unsigned int nMax; /* Configured "cache_size" value */ /* Hash table of all pages. The following variables may only be accessed ** when the accessor is holding the PGroup mutex. */ unsigned int nRecyclable; /* Number of pages in the LRU list */ unsigned int nPage; /* Total number of pages in apHash */ unsigned int nHash; /* Number of slots in apHash[] */ PgHdr1 **apHash; /* Hash table for fast lookup by key */ unsigned int iMaxKey; /* Largest key seen since xTruncate() */ |
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76 77 78 79 80 81 82 | PgFreeslot *pNext; /* Next free slot */ }; /* ** Global data used by this cache. */ static SQLITE_WSD struct PCacheGlobal { | < | < < < < | > > > > > | | < | | > > > | > > > > | | 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 | PgFreeslot *pNext; /* Next free slot */ }; /* ** Global data used by this cache. */ static SQLITE_WSD struct PCacheGlobal { PGroup grp; /* The global PGroup for mode (2) */ /* Variables related to SQLITE_CONFIG_PAGECACHE settings. The ** szSlot, nSlot, pStart, pEnd, nReserve, and isInit values are all ** fixed at sqlite3_initialize() time and do not require mutex protection. ** The nFreeSlot and pFree values do require mutex protection. */ int isInit; /* True if initialized */ int szSlot; /* Size of each free slot */ int nSlot; /* The number of pcache slots */ int nReserve; /* Try to keep nFreeSlot above this */ void *pStart, *pEnd; /* Bounds of pagecache malloc range */ /* Above requires no mutex. Use mutex below for variable that follow. */ sqlite3_mutex *mutex; /* Mutex for accessing the following: */ int nFreeSlot; /* Number of unused pcache slots */ PgFreeslot *pFree; /* Free page blocks */ /* The following value requires a mutex to change. We skip the mutex on ** reading because (1) most platforms read a 32-bit integer atomically and ** (2) even if an incorrect value is read, no great harm is done since this ** is really just an optimization. */ int bUnderPressure; /* True if low on PAGECACHE memory */ } pcache1_g; /* ** All code in this file should access the global structure above via the ** alias "pcache1". This ensures that the WSD emulation is used when ** compiling for systems that do not support real WSD. */ |
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116 117 118 119 120 121 122 | ** ** assert( PGHDR1_TO_PAGE(PAGE_TO_PGHDR1(pCache, X))==X ); */ #define PGHDR1_TO_PAGE(p) (void*)(((char*)p) - p->pCache->szPage) #define PAGE_TO_PGHDR1(c, p) (PgHdr1*)(((char*)p) + c->szPage) /* | | | | > > > > > > > | | | | > | | > | | < | | < < < > > > | < < < > > > < | 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 | ** ** assert( PGHDR1_TO_PAGE(PAGE_TO_PGHDR1(pCache, X))==X ); */ #define PGHDR1_TO_PAGE(p) (void*)(((char*)p) - p->pCache->szPage) #define PAGE_TO_PGHDR1(c, p) (PgHdr1*)(((char*)p) + c->szPage) /* ** Macros to enter and leave the PCache LRU mutex. */ #define pcache1EnterMutex(X) sqlite3_mutex_enter((X)->mutex) #define pcache1LeaveMutex(X) sqlite3_mutex_leave((X)->mutex) /******************************************************************************/ /******** Page Allocation/SQLITE_CONFIG_PCACHE Related Functions **************/ /* ** This function is called during initialization if a static buffer is ** supplied to use for the page-cache by passing the SQLITE_CONFIG_PAGECACHE ** verb to sqlite3_config(). Parameter pBuf points to an allocation large ** enough to contain 'n' buffers of 'sz' bytes each. ** ** This routine is called from sqlite3_initialize() and so it is guaranteed ** to be serialized already. There is no need for further mutexing. */ void sqlite3PCacheBufferSetup(void *pBuf, int sz, int n){ if( pcache1.isInit ){ PgFreeslot *p; sz = ROUNDDOWN8(sz); pcache1.szSlot = sz; pcache1.nSlot = pcache1.nFreeSlot = n; pcache1.nReserve = n>90 ? 10 : (n/10 + 1); pcache1.pStart = pBuf; pcache1.pFree = 0; pcache1.bUnderPressure = 0; while( n-- ){ p = (PgFreeslot*)pBuf; p->pNext = pcache1.pFree; pcache1.pFree = p; pBuf = (void*)&((char*)pBuf)[sz]; } pcache1.pEnd = pBuf; } } /* ** Malloc function used within this file to allocate space from the buffer ** configured using sqlite3_config(SQLITE_CONFIG_PAGECACHE) option. If no ** such buffer exists or there is no space left in it, this function falls ** back to sqlite3Malloc(). ** ** Multiple threads can run this routine at the same time. Global variables ** in pcache1 need to be protected via mutex. */ static void *pcache1Alloc(int nByte){ void *p = 0; assert( sqlite3_mutex_notheld(pcache1.grp.mutex) ); sqlite3StatusSet(SQLITE_STATUS_PAGECACHE_SIZE, nByte); if( nByte<=pcache1.szSlot ){ sqlite3_mutex_enter(pcache1.mutex); p = (PgHdr1 *)pcache1.pFree; if( p ){ pcache1.pFree = pcache1.pFree->pNext; pcache1.nFreeSlot--; pcache1.bUnderPressure = pcache1.nFreeSlot<pcache1.nReserve; assert( pcache1.nFreeSlot>=0 ); sqlite3StatusAdd(SQLITE_STATUS_PAGECACHE_USED, 1); } sqlite3_mutex_leave(pcache1.mutex); } if( p==0 ){ /* Memory is not available in the SQLITE_CONFIG_PAGECACHE pool. Get ** it from sqlite3Malloc instead. */ p = sqlite3Malloc(nByte); if( p ){ int sz = sqlite3MallocSize(p); sqlite3StatusAdd(SQLITE_STATUS_PAGECACHE_OVERFLOW, sz); } sqlite3MemdebugSetType(p, MEMTYPE_PCACHE); } return p; } /* ** Free an allocated buffer obtained from pcache1Alloc(). */ static void pcache1Free(void *p){ if( p==0 ) return; if( p>=pcache1.pStart && p<pcache1.pEnd ){ PgFreeslot *pSlot; sqlite3_mutex_enter(pcache1.mutex); sqlite3StatusAdd(SQLITE_STATUS_PAGECACHE_USED, -1); pSlot = (PgFreeslot*)p; pSlot->pNext = pcache1.pFree; pcache1.pFree = pSlot; pcache1.nFreeSlot++; pcache1.bUnderPressure = pcache1.nFreeSlot<pcache1.nReserve; assert( pcache1.nFreeSlot<=pcache1.nSlot ); sqlite3_mutex_leave(pcache1.mutex); }else{ int iSize; assert( sqlite3MemdebugHasType(p, MEMTYPE_PCACHE) ); sqlite3MemdebugSetType(p, MEMTYPE_HEAP); iSize = sqlite3MallocSize(p); sqlite3StatusAdd(SQLITE_STATUS_PAGECACHE_OVERFLOW, -iSize); sqlite3_free(p); } } #ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT /* ** Return the size of a pcache allocation */ static int pcache1MemSize(void *p){ if( p>=pcache1.pStart && p<pcache1.pEnd ){ return pcache1.szSlot; }else{ int iSize; assert( sqlite3MemdebugHasType(p, MEMTYPE_PCACHE) ); sqlite3MemdebugSetType(p, MEMTYPE_HEAP); iSize = sqlite3MallocSize(p); |
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239 240 241 242 243 244 245 | static PgHdr1 *pcache1AllocPage(PCache1 *pCache){ int nByte = sizeof(PgHdr1) + pCache->szPage; void *pPg = pcache1Alloc(nByte); PgHdr1 *p; if( pPg ){ p = PAGE_TO_PGHDR1(pCache, pPg); if( pCache->bPurgeable ){ | | > | | < < | < < < < < | | | | | | 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 | static PgHdr1 *pcache1AllocPage(PCache1 *pCache){ int nByte = sizeof(PgHdr1) + pCache->szPage; void *pPg = pcache1Alloc(nByte); PgHdr1 *p; if( pPg ){ p = PAGE_TO_PGHDR1(pCache, pPg); if( pCache->bPurgeable ){ pCache->pGroup->nCurrentPage++; } }else{ p = 0; } return p; } /* ** Free a page object allocated by pcache1AllocPage(). ** ** The pointer is allowed to be NULL, which is prudent. But it turns out ** that the current implementation happens to never call this routine ** with a NULL pointer, so we mark the NULL test with ALWAYS(). */ static void pcache1FreePage(PgHdr1 *p){ if( ALWAYS(p) ){ PCache1 *pCache = p->pCache; if( pCache->bPurgeable ){ pCache->pGroup->nCurrentPage--; } pcache1Free(PGHDR1_TO_PAGE(p)); } } /* ** Malloc function used by SQLite to obtain space from the buffer configured ** using sqlite3_config(SQLITE_CONFIG_PAGECACHE) option. If no such buffer ** exists, this function falls back to sqlite3Malloc(). */ void *sqlite3PageMalloc(int sz){ return pcache1Alloc(sz); } /* ** Free an allocated buffer obtained from sqlite3PageMalloc(). */ void sqlite3PageFree(void *p){ pcache1Free(p); } /* ** Return true if it desirable to avoid allocating a new page cache ** entry. ** ** If memory was allocated specifically to the page cache using ** SQLITE_CONFIG_PAGECACHE but that memory has all been used, then ** it is desirable to avoid allocating a new page cache entry because ** presumably SQLITE_CONFIG_PAGECACHE was suppose to be sufficient ** for all page cache needs and we should not need to spill the ** allocation onto the heap. ** ** Or, the heap is used for all page cache memory put the heap is ** under memory pressure, then again it is desirable to avoid ** allocating a new page cache entry in order to avoid stressing ** the heap even further. */ static int pcache1UnderMemoryPressure(PCache1 *pCache){ if( pcache1.nSlot && pCache->szPage<=pcache1.szSlot ){ return pcache1.bUnderPressure; }else{ return sqlite3HeapNearlyFull(); } } /******************************************************************************/ /******** General Implementation Functions ************************************/ /* ** This function is used to resize the hash table used by the cache passed ** as the first argument. ** ** The PCache mutex must be held when this function is called. */ static int pcache1ResizeHash(PCache1 *p){ PgHdr1 **apNew; unsigned int nNew; unsigned int i; assert( sqlite3_mutex_held(p->pGroup->mutex) ); nNew = p->nHash*2; if( nNew<256 ){ nNew = 256; } pcache1LeaveMutex(p->pGroup); if( p->nHash ){ sqlite3BeginBenignMalloc(); } apNew = (PgHdr1 **)sqlite3_malloc(sizeof(PgHdr1 *)*nNew); if( p->nHash ){ sqlite3EndBenignMalloc(); } pcache1EnterMutex(p->pGroup); if( apNew ){ memset(apNew, 0, sizeof(PgHdr1 *)*nNew); for(i=0; i<p->nHash; i++){ PgHdr1 *pPage; PgHdr1 *pNext = p->apHash[i]; while( (pPage = pNext)!=0 ){ unsigned int h = pPage->iKey % nNew; |
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359 360 361 362 363 364 365 | } return (p->apHash ? SQLITE_OK : SQLITE_NOMEM); } /* ** This function is used internally to remove the page pPage from the | | | > > > > > > > > | | | | | | | > | | | | | | > | | | | | | 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 | } return (p->apHash ? SQLITE_OK : SQLITE_NOMEM); } /* ** This function is used internally to remove the page pPage from the ** PGroup LRU list, if is part of it. If pPage is not part of the PGroup ** LRU list, then this function is a no-op. ** ** The PGroup mutex must be held when this function is called. ** ** If pPage is NULL then this routine is a no-op. */ static void pcache1PinPage(PgHdr1 *pPage){ PCache1 *pCache; PGroup *pGroup; if( pPage==0 ) return; pCache = pPage->pCache; pGroup = pCache->pGroup; assert( sqlite3_mutex_held(pGroup->mutex) ); if( pPage->pLruNext || pPage==pGroup->pLruTail ){ if( pPage->pLruPrev ){ pPage->pLruPrev->pLruNext = pPage->pLruNext; } if( pPage->pLruNext ){ pPage->pLruNext->pLruPrev = pPage->pLruPrev; } if( pGroup->pLruHead==pPage ){ pGroup->pLruHead = pPage->pLruNext; } if( pGroup->pLruTail==pPage ){ pGroup->pLruTail = pPage->pLruPrev; } pPage->pLruNext = 0; pPage->pLruPrev = 0; pPage->pCache->nRecyclable--; } } /* ** Remove the page supplied as an argument from the hash table ** (PCache1.apHash structure) that it is currently stored in. ** ** The PGroup mutex must be held when this function is called. */ static void pcache1RemoveFromHash(PgHdr1 *pPage){ unsigned int h; PCache1 *pCache = pPage->pCache; PgHdr1 **pp; assert( sqlite3_mutex_held(pCache->pGroup->mutex) ); h = pPage->iKey % pCache->nHash; for(pp=&pCache->apHash[h]; (*pp)!=pPage; pp=&(*pp)->pNext); *pp = (*pp)->pNext; pCache->nPage--; } /* ** If there are currently more than nMaxPage pages allocated, try ** to recycle pages to reduce the number allocated to nMaxPage. */ static void pcache1EnforceMaxPage(PGroup *pGroup){ assert( sqlite3_mutex_held(pGroup->mutex) ); while( pGroup->nCurrentPage>pGroup->nMaxPage && pGroup->pLruTail ){ PgHdr1 *p = pGroup->pLruTail; assert( p->pCache->pGroup==pGroup ); pcache1PinPage(p); pcache1RemoveFromHash(p); pcache1FreePage(p); } } /* ** Discard all pages from cache pCache with a page number (key value) ** greater than or equal to iLimit. Any pinned pages that meet this ** criteria are unpinned before they are discarded. ** ** The PCache mutex must be held when this function is called. */ static void pcache1TruncateUnsafe( PCache1 *pCache, /* The cache to truncate */ unsigned int iLimit /* Drop pages with this pgno or larger */ ){ TESTONLY( unsigned int nPage = 0; ) /* To assert pCache->nPage is correct */ unsigned int h; assert( sqlite3_mutex_held(pCache->pGroup->mutex) ); for(h=0; h<pCache->nHash; h++){ PgHdr1 **pp = &pCache->apHash[h]; PgHdr1 *pPage; while( (pPage = *pp)!=0 ){ if( pPage->iKey>=iLimit ){ pCache->nPage--; *pp = pPage->pNext; |
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461 462 463 464 465 466 467 | ** Implementation of the sqlite3_pcache.xInit method. */ static int pcache1Init(void *NotUsed){ UNUSED_PARAMETER(NotUsed); assert( pcache1.isInit==0 ); memset(&pcache1, 0, sizeof(pcache1)); if( sqlite3GlobalConfig.bCoreMutex ){ | > | | 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 | ** Implementation of the sqlite3_pcache.xInit method. */ static int pcache1Init(void *NotUsed){ UNUSED_PARAMETER(NotUsed); assert( pcache1.isInit==0 ); memset(&pcache1, 0, sizeof(pcache1)); if( sqlite3GlobalConfig.bCoreMutex ){ pcache1.grp.mutex = sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_LRU); pcache1.mutex = sqlite3_mutex_alloc(SQLITE_MUTEX_STATIC_PMEM); } pcache1.isInit = 1; return SQLITE_OK; } /* ** Implementation of the sqlite3_pcache.xShutdown method. |
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484 485 486 487 488 489 490 | /* ** Implementation of the sqlite3_pcache.xCreate method. ** ** Allocate a new cache. */ static sqlite3_pcache *pcache1Create(int szPage, int bPurgeable){ | | > > > > > > > > > > > > > > > > > > > > > | | > > > > > > | | | > | | | | > | | | | 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 | /* ** Implementation of the sqlite3_pcache.xCreate method. ** ** Allocate a new cache. */ static sqlite3_pcache *pcache1Create(int szPage, int bPurgeable){ PCache1 *pCache; /* The newly created page cache */ PGroup *pGroup; /* The group the new page cache will belong to */ int sz; /* Bytes of memory required to allocate the new cache */ /* ** The seperateCache variable is true if each PCache has its own private ** PGroup. In other words, separateCache is true for mode (1) where no ** mutexing is required. ** ** * Always use a unified cache (mode-2) if ENABLE_MEMORY_MANAGEMENT ** ** * Always use a unified cache in single-threaded applications ** ** * Otherwise (if multi-threaded and ENABLE_MEMORY_MANAGEMENT is off) ** use separate caches (mode-1) */ #if defined(SQLITE_ENABLE_MEMORY_MANAGEMENT) || SQLITE_THREADSAFE==0 const int separateCache = 0; #else int separateCache = sqlite3GlobalConfig.bCoreMutex>0; #endif sz = sizeof(PCache1) + sizeof(PGroup)*separateCache; pCache = (PCache1 *)sqlite3_malloc(sz); if( pCache ){ memset(pCache, 0, sz); if( separateCache ){ pGroup = (PGroup*)&pCache[1]; }else{ pGroup = &pcache1_g.grp; } pCache->pGroup = pGroup; pCache->szPage = szPage; pCache->bPurgeable = (bPurgeable ? 1 : 0); if( bPurgeable ){ pCache->nMin = 10; pcache1EnterMutex(pGroup); pGroup->nMinPage += pCache->nMin; pcache1LeaveMutex(pGroup); } } return (sqlite3_pcache *)pCache; } /* ** Implementation of the sqlite3_pcache.xCachesize method. ** ** Configure the cache_size limit for a cache. */ static void pcache1Cachesize(sqlite3_pcache *p, int nMax){ PCache1 *pCache = (PCache1 *)p; if( pCache->bPurgeable ){ PGroup *pGroup = pCache->pGroup; pcache1EnterMutex(pGroup); pGroup->nMaxPage += (nMax - pCache->nMax); pCache->nMax = nMax; pcache1EnforceMaxPage(pGroup); pcache1LeaveMutex(pGroup); } } /* ** Implementation of the sqlite3_pcache.xPagecount method. */ static int pcache1Pagecount(sqlite3_pcache *p){ int n; PCache1 *pCache = (PCache1*)p; pcache1EnterMutex(pCache->pGroup); n = pCache->nPage; pcache1LeaveMutex(pCache->pGroup); return n; } /* ** Implementation of the sqlite3_pcache.xFetch method. ** ** Fetch a page by key value. |
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585 586 587 588 589 590 591 592 593 594 | ** proceed to step 5. ** ** 5. Otherwise, allocate and return a new page buffer. */ static void *pcache1Fetch(sqlite3_pcache *p, unsigned int iKey, int createFlag){ unsigned int nPinned; PCache1 *pCache = (PCache1 *)p; PgHdr1 *pPage = 0; assert( pCache->bPurgeable || createFlag!=1 ); | > | | | | | > | > > | > | | | | | | | | | | | | | | | | > | | | | | | 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 | ** proceed to step 5. ** ** 5. Otherwise, allocate and return a new page buffer. */ static void *pcache1Fetch(sqlite3_pcache *p, unsigned int iKey, int createFlag){ unsigned int nPinned; PCache1 *pCache = (PCache1 *)p; PGroup *pGroup = pCache->pGroup; PgHdr1 *pPage = 0; assert( pCache->bPurgeable || createFlag!=1 ); pcache1EnterMutex(pGroup); if( createFlag==1 ) sqlite3BeginBenignMalloc(); /* Search the hash table for an existing entry. */ if( pCache->nHash>0 ){ unsigned int h = iKey % pCache->nHash; for(pPage=pCache->apHash[h]; pPage&&pPage->iKey!=iKey; pPage=pPage->pNext); } if( pPage || createFlag==0 ){ pcache1PinPage(pPage); goto fetch_out; } /* Step 3 of header comment. */ nPinned = pCache->nPage - pCache->nRecyclable; if( createFlag==1 && ( nPinned>=(pGroup->nMaxPage+pCache->nMin-pGroup->nMinPage) || nPinned>=(pCache->nMax * 9 / 10) || pcache1UnderMemoryPressure(pCache) )){ goto fetch_out; } if( pCache->nPage>=pCache->nHash && pcache1ResizeHash(pCache) ){ goto fetch_out; } /* Step 4. Try to recycle a page buffer if appropriate. */ if( pCache->bPurgeable && pGroup->pLruTail && ( (pCache->nPage+1>=pCache->nMax) || pGroup->nCurrentPage>=pGroup->nMaxPage || pcache1UnderMemoryPressure(pCache) )){ pPage = pGroup->pLruTail; pcache1RemoveFromHash(pPage); pcache1PinPage(pPage); if( pPage->pCache->szPage!=pCache->szPage ){ pcache1FreePage(pPage); pPage = 0; }else{ pGroup->nCurrentPage -= (pPage->pCache->bPurgeable - pCache->bPurgeable); } } /* Step 5. If a usable page buffer has still not been found, ** attempt to allocate a new one. */ if( !pPage ){ pcache1LeaveMutex(pGroup); pPage = pcache1AllocPage(pCache); pcache1EnterMutex(pGroup); } if( pPage ){ unsigned int h = iKey % pCache->nHash; pCache->nPage++; pPage->iKey = iKey; pPage->pNext = pCache->apHash[h]; pPage->pCache = pCache; pPage->pLruPrev = 0; pPage->pLruNext = 0; *(void **)(PGHDR1_TO_PAGE(pPage)) = 0; pCache->apHash[h] = pPage; } fetch_out: if( pPage && iKey>pCache->iMaxKey ){ pCache->iMaxKey = iKey; } if( createFlag==1 ) sqlite3EndBenignMalloc(); pcache1LeaveMutex(pGroup); return (pPage ? PGHDR1_TO_PAGE(pPage) : 0); } /* ** Implementation of the sqlite3_pcache.xUnpin method. ** ** Mark a page as unpinned (eligible for asynchronous recycling). */ static void pcache1Unpin(sqlite3_pcache *p, void *pPg, int reuseUnlikely){ PCache1 *pCache = (PCache1 *)p; PgHdr1 *pPage = PAGE_TO_PGHDR1(pCache, pPg); PGroup *pGroup = pCache->pGroup; assert( pPage->pCache==pCache ); pcache1EnterMutex(pGroup); /* It is an error to call this function if the page is already ** part of the PGroup LRU list. */ assert( pPage->pLruPrev==0 && pPage->pLruNext==0 ); assert( pGroup->pLruHead!=pPage && pGroup->pLruTail!=pPage ); if( reuseUnlikely || pGroup->nCurrentPage>pGroup->nMaxPage ){ pcache1RemoveFromHash(pPage); pcache1FreePage(pPage); }else{ /* Add the page to the PGroup LRU list. */ if( pGroup->pLruHead ){ pGroup->pLruHead->pLruPrev = pPage; pPage->pLruNext = pGroup->pLruHead; pGroup->pLruHead = pPage; }else{ pGroup->pLruTail = pPage; pGroup->pLruHead = pPage; } pCache->nRecyclable++; } pcache1LeaveMutex(pCache->pGroup); } /* ** Implementation of the sqlite3_pcache.xRekey method. */ static void pcache1Rekey( sqlite3_pcache *p, void *pPg, unsigned int iOld, unsigned int iNew ){ PCache1 *pCache = (PCache1 *)p; PgHdr1 *pPage = PAGE_TO_PGHDR1(pCache, pPg); PgHdr1 **pp; unsigned int h; assert( pPage->iKey==iOld ); assert( pPage->pCache==pCache ); pcache1EnterMutex(pCache->pGroup); h = iOld%pCache->nHash; pp = &pCache->apHash[h]; while( (*pp)!=pPage ){ pp = &(*pp)->pNext; } *pp = pPage->pNext; h = iNew%pCache->nHash; pPage->iKey = iNew; pPage->pNext = pCache->apHash[h]; pCache->apHash[h] = pPage; if( iNew>pCache->iMaxKey ){ pCache->iMaxKey = iNew; } pcache1LeaveMutex(pCache->pGroup); } /* ** Implementation of the sqlite3_pcache.xTruncate method. ** ** Discard all unpinned pages in the cache with a page number equal to ** or greater than parameter iLimit. Any pinned pages with a page number ** equal to or greater than iLimit are implicitly unpinned. */ static void pcache1Truncate(sqlite3_pcache *p, unsigned int iLimit){ PCache1 *pCache = (PCache1 *)p; pcache1EnterMutex(pCache->pGroup); if( iLimit<=pCache->iMaxKey ){ pcache1TruncateUnsafe(pCache, iLimit); pCache->iMaxKey = iLimit-1; } pcache1LeaveMutex(pCache->pGroup); } /* ** Implementation of the sqlite3_pcache.xDestroy method. ** ** Destroy a cache allocated using pcache1Create(). */ static void pcache1Destroy(sqlite3_pcache *p){ PCache1 *pCache = (PCache1 *)p; PGroup *pGroup = pCache->pGroup; assert( pCache->bPurgeable || (pCache->nMax==0 && pCache->nMin==0) ); pcache1EnterMutex(pGroup); pcache1TruncateUnsafe(pCache, 0); pGroup->nMaxPage -= pCache->nMax; pGroup->nMinPage -= pCache->nMin; pcache1EnforceMaxPage(pGroup); pcache1LeaveMutex(pGroup); sqlite3_free(pCache->apHash); sqlite3_free(pCache); } /* ** This function is called during initialization (sqlite3_initialize()) to ** install the default pluggable cache module, assuming the user has not |
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804 805 806 807 808 809 810 811 812 | ** ** nReq is the number of bytes of memory required. Once this much has ** been released, the function returns. The return value is the total number ** of bytes of memory released. */ int sqlite3PcacheReleaseMemory(int nReq){ int nFree = 0; if( pcache1.pStart==0 ){ PgHdr1 *p; | > > | | | | | | | | 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 | ** ** nReq is the number of bytes of memory required. Once this much has ** been released, the function returns. The return value is the total number ** of bytes of memory released. */ int sqlite3PcacheReleaseMemory(int nReq){ int nFree = 0; assert( sqlite3_mutex_notheld(pcache1.grp.mutex) ); assert( sqlite3_mutex_notheld(pcache1.mutex) ); if( pcache1.pStart==0 ){ PgHdr1 *p; pcache1EnterMutex(&pcache1.grp); while( (nReq<0 || nFree<nReq) && ((p=pcache1.grp.pLruTail)!=0) ){ nFree += pcache1MemSize(PGHDR1_TO_PAGE(p)); pcache1PinPage(p); pcache1RemoveFromHash(p); pcache1FreePage(p); } pcache1LeaveMutex(&pcache1.grp); } return nFree; } #endif /* SQLITE_ENABLE_MEMORY_MANAGEMENT */ #ifdef SQLITE_TEST /* ** This function is used by test procedures to inspect the internal state ** of the global cache. */ void sqlite3PcacheStats( int *pnCurrent, /* OUT: Total number of pages cached */ int *pnMax, /* OUT: Global maximum cache size */ int *pnMin, /* OUT: Sum of PCache1.nMin for purgeable caches */ int *pnRecyclable /* OUT: Total number of pages available for recycling */ ){ PgHdr1 *p; int nRecyclable = 0; for(p=pcache1.grp.pLruHead; p; p=p->pLruNext){ nRecyclable++; } *pnCurrent = pcache1.grp.nCurrentPage; *pnMax = pcache1.grp.nMaxPage; *pnMin = pcache1.grp.nMinPage; *pnRecyclable = nRecyclable; } #endif |
Changes to src/sqlite.h.in.
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5262 5263 5264 5265 5266 5267 5268 | #define SQLITE_MUTEX_RECURSIVE 1 #define SQLITE_MUTEX_STATIC_MASTER 2 #define SQLITE_MUTEX_STATIC_MEM 3 /* sqlite3_malloc() */ #define SQLITE_MUTEX_STATIC_MEM2 4 /* NOT USED */ #define SQLITE_MUTEX_STATIC_OPEN 4 /* sqlite3BtreeOpen() */ #define SQLITE_MUTEX_STATIC_PRNG 5 /* sqlite3_random() */ #define SQLITE_MUTEX_STATIC_LRU 6 /* lru page list */ | | > | 5262 5263 5264 5265 5266 5267 5268 5269 5270 5271 5272 5273 5274 5275 5276 5277 | #define SQLITE_MUTEX_RECURSIVE 1 #define SQLITE_MUTEX_STATIC_MASTER 2 #define SQLITE_MUTEX_STATIC_MEM 3 /* sqlite3_malloc() */ #define SQLITE_MUTEX_STATIC_MEM2 4 /* NOT USED */ #define SQLITE_MUTEX_STATIC_OPEN 4 /* sqlite3BtreeOpen() */ #define SQLITE_MUTEX_STATIC_PRNG 5 /* sqlite3_random() */ #define SQLITE_MUTEX_STATIC_LRU 6 /* lru page list */ #define SQLITE_MUTEX_STATIC_LRU2 7 /* NOT USED */ #define SQLITE_MUTEX_STATIC_PMEM 7 /* sqlite3PageMalloc() */ /* ** CAPI3REF: Retrieve the mutex for a database connection ** ** ^This interface returns a pointer the [sqlite3_mutex] object that ** serializes access to the [database connection] given in the argument ** when the [threading mode] is Serialized. |
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Changes to test/memsubsys1.test.
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92 93 94 95 96 97 98 99 100 | db close sqlite3_shutdown sqlite3_config_pagecache [expr 1024+$xtra_size] 20 sqlite3_initialize reset_highwater_marks build_test_db memsubsys1-2 {PRAGMA page_size=1024} #show_memstats do_test memsubsys1-2.3 { set pg_ovfl [lindex [sqlite3_status SQLITE_STATUS_PAGECACHE_OVERFLOW 0] 2] | > | | 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 | db close sqlite3_shutdown sqlite3_config_pagecache [expr 1024+$xtra_size] 20 sqlite3_initialize reset_highwater_marks build_test_db memsubsys1-2 {PRAGMA page_size=1024} #show_memstats set MEMORY_MANAGEMENT $sqlite_options(memorymanage) do_test memsubsys1-2.3 { set pg_ovfl [lindex [sqlite3_status SQLITE_STATUS_PAGECACHE_OVERFLOW 0] 2] } [expr ($AUTOVACUUM+$TEMP_STORE+$MEMORY_MANAGEMENT>=3)*1024] do_test memsubsys1-2.4 { set pg_used [lindex [sqlite3_status SQLITE_STATUS_PAGECACHE_USED 0] 2] } 20 do_test memsubsys1-2.5 { set s_used [lindex [sqlite3_status SQLITE_STATUS_SCRATCH_USED 0] 2] } 0 |
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Changes to test/mutex1.test.
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116 117 118 119 120 121 122 | clear_mutex_counters sqlite3 db test.db -nomutex 0 -fullmutex 0 catchsql { CREATE TABLE abc(a, b, c) } db eval { INSERT INTO abc VALUES(1, 2, 3); } } {} | > > | | 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 | clear_mutex_counters sqlite3 db test.db -nomutex 0 -fullmutex 0 catchsql { CREATE TABLE abc(a, b, c) } db eval { INSERT INTO abc VALUES(1, 2, 3); } } {} ifcapable !memorymanage { regsub { static_lru} $mutexes {} mutexes } do_test mutex1.2.$mode.3 { mutex_counters counters set res [list] foreach {key value} [array get counters] { if {$key ne "total" && $value > 0} { lappend res $key |
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Changes to test/pcache.test.
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16 17 18 19 20 21 22 23 24 25 26 27 28 29 | set testdir [file dirname $argv0] source $testdir/tester.tcl # Do not use a codec for tests in this file, as the database file is # manipulated directly using tcl scripts (using the [hexio_write] command). # do_not_use_codec # The pcache module limits the number of pages available to purgeable # caches to the sum of the 'cache_size' values for the set of open # caches. This block of tests, pcache-1.*, test that the library behaves # corrctly when it is forced to exceed this limit. # do_test pcache-1.1 { | > > > > > > > > | 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 | set testdir [file dirname $argv0] source $testdir/tester.tcl # Do not use a codec for tests in this file, as the database file is # manipulated directly using tcl scripts (using the [hexio_write] command). # do_not_use_codec # Only works with a mode-2 pcache where all pcaches share a single set # of pages. # ifcapable {!memorymanage && threadsafe} { finish_test return } # The pcache module limits the number of pages available to purgeable # caches to the sum of the 'cache_size' values for the set of open # caches. This block of tests, pcache-1.*, test that the library behaves # corrctly when it is forced to exceed this limit. # do_test pcache-1.1 { |
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