Index: src/analyze.c ================================================================== --- src/analyze.c +++ src/analyze.c @@ -1852,13 +1852,13 @@ } /* Load the statistics from the sqlite_stat4 table. */ #ifdef SQLITE_ENABLE_STAT4 if( rc==SQLITE_OK ){ - db->lookaside.bDisable++; + DisableLookaside; rc = loadStat4(db, sInfo.zDatabase); - db->lookaside.bDisable--; + EnableLookaside; } for(i=sqliteHashFirst(&pSchema->idxHash); i; i=sqliteHashNext(i)){ Index *pIdx = sqliteHashData(i); sqlite3_free(pIdx->aiRowEst); pIdx->aiRowEst = 0; Index: src/build.c ================================================================== --- src/build.c +++ src/build.c @@ -2445,11 +2445,11 @@ pParse->eParseMode = PARSE_MODE_NORMAL; #endif n = pParse->nTab; sqlite3SrcListAssignCursors(pParse, pSel->pSrc); pTable->nCol = -1; - db->lookaside.bDisable++; + DisableLookaside; #ifndef SQLITE_OMIT_AUTHORIZATION xAuth = db->xAuth; db->xAuth = 0; pSelTab = sqlite3ResultSetOfSelect(pParse, pSel, SQLITE_AFF_NONE); db->xAuth = xAuth; @@ -2487,11 +2487,11 @@ pTable->nCol = 0; nErr++; } sqlite3DeleteTable(db, pSelTab); sqlite3SelectDelete(db, pSel); - db->lookaside.bDisable--; + EnableLookaside; #ifndef SQLITE_OMIT_ALTERTABLE pParse->eParseMode = eParseMode; #endif } else { nErr++; Index: src/fkey.c ================================================================== --- src/fkey.c +++ src/fkey.c @@ -1297,11 +1297,11 @@ ); pWhere = 0; } /* Disable lookaside memory allocation */ - db->lookaside.bDisable++; + DisableLookaside; pTrigger = (Trigger *)sqlite3DbMallocZero(db, sizeof(Trigger) + /* struct Trigger */ sizeof(TriggerStep) + /* Single step in trigger program */ nFrom + 1 /* Space for pStep->zTarget */ @@ -1319,11 +1319,11 @@ pTrigger->pWhen = sqlite3ExprDup(db, pWhen, EXPRDUP_REDUCE); } } /* Re-enable the lookaside buffer, if it was disabled earlier. */ - db->lookaside.bDisable--; + EnableLookaside; sqlite3ExprDelete(db, pWhere); sqlite3ExprDelete(db, pWhen); sqlite3ExprListDelete(db, pList); sqlite3SelectDelete(db, pSelect); Index: src/main.c ================================================================== --- src/main.c +++ src/main.c @@ -713,10 +713,11 @@ } db->lookaside.pStart = pStart; db->lookaside.pInit = 0; db->lookaside.pFree = 0; db->lookaside.sz = (u16)sz; + db->lookaside.szTrue = (u16)sz; if( pStart ){ int i; LookasideSlot *p; assert( sz > (int)sizeof(LookasideSlot*) ); db->lookaside.nSlot = cnt; @@ -731,10 +732,11 @@ db->lookaside.bMalloced = pBuf==0 ?1:0; }else{ db->lookaside.pStart = db; db->lookaside.pEnd = db; db->lookaside.bDisable = 1; + db->lookaside.sz = 0; db->lookaside.bMalloced = 0; db->lookaside.nSlot = 0; } #endif /* SQLITE_OMIT_LOOKASIDE */ return SQLITE_OK; @@ -3062,10 +3064,11 @@ db->errMask = 0xff; db->nDb = 2; db->magic = SQLITE_MAGIC_BUSY; db->aDb = db->aDbStatic; db->lookaside.bDisable = 1; + db->lookaside.sz = 0; assert( sizeof(db->aLimit)==sizeof(aHardLimit) ); memcpy(db->aLimit, aHardLimit, sizeof(db->aLimit)); db->aLimit[SQLITE_LIMIT_WORKER_THREADS] = SQLITE_DEFAULT_WORKER_THREADS; db->autoCommit = 1; Index: src/malloc.c ================================================================== --- src/malloc.c +++ src/malloc.c @@ -296,11 +296,11 @@ } #endif return sqlite3GlobalConfig.m.xSize(p); }else{ assert( sqlite3_mutex_held(db->mutex) ); - return db->lookaside.sz; + return db->lookaside.szTrue; } } sqlite3_uint64 sqlite3_msize(void *p){ assert( sqlite3MemdebugNoType(p, (u8)~MEMTYPE_HEAP) ); assert( sqlite3MemdebugHasType(p, MEMTYPE_HEAP) ); @@ -348,11 +348,11 @@ } if( isLookaside(db, p) ){ LookasideSlot *pBuf = (LookasideSlot*)p; #ifdef SQLITE_DEBUG /* Trash all content in the buffer being freed */ - memset(p, 0xaa, db->lookaside.sz); + memset(p, 0xaa, db->lookaside.szTrue); #endif pBuf->pNext = db->lookaside.pFree; db->lookaside.pFree = pBuf; return; } @@ -508,27 +508,25 @@ #ifndef SQLITE_OMIT_LOOKASIDE LookasideSlot *pBuf; assert( db!=0 ); assert( sqlite3_mutex_held(db->mutex) ); assert( db->pnBytesFreed==0 ); - if( db->lookaside.bDisable==0 ){ - assert( db->mallocFailed==0 ); - if( n>db->lookaside.sz ){ - db->lookaside.anStat[1]++; - }else if( (pBuf = db->lookaside.pFree)!=0 ){ - db->lookaside.pFree = pBuf->pNext; - db->lookaside.anStat[0]++; - return (void*)pBuf; - }else if( (pBuf = db->lookaside.pInit)!=0 ){ - db->lookaside.pInit = pBuf->pNext; - db->lookaside.anStat[0]++; - return (void*)pBuf; - }else{ - db->lookaside.anStat[2]++; - } - }else if( db->mallocFailed ){ - return 0; + if( n>db->lookaside.sz ){ + if( db->lookaside.bDisable ){ + return db->mallocFailed ? 0 : dbMallocRawFinish(db, n); + } + db->lookaside.anStat[1]++; + }else if( (pBuf = db->lookaside.pFree)!=0 ){ + db->lookaside.pFree = pBuf->pNext; + db->lookaside.anStat[0]++; + return (void*)pBuf; + }else if( (pBuf = db->lookaside.pInit)!=0 ){ + db->lookaside.pInit = pBuf->pNext; + db->lookaside.anStat[0]++; + return (void*)pBuf; + }else{ + db->lookaside.anStat[2]++; } #else assert( db!=0 ); assert( sqlite3_mutex_held(db->mutex) ); assert( db->pnBytesFreed==0 ); @@ -548,11 +546,11 @@ */ void *sqlite3DbRealloc(sqlite3 *db, void *p, u64 n){ assert( db!=0 ); if( p==0 ) return sqlite3DbMallocRawNN(db, n); assert( sqlite3_mutex_held(db->mutex) ); - if( isLookaside(db,p) && n<=db->lookaside.sz ) return p; + if( isLookaside(db,p) && n<=db->lookaside.szTrue ) return p; return dbReallocFinish(db, p, n); } static SQLITE_NOINLINE void *dbReallocFinish(sqlite3 *db, void *p, u64 n){ void *pNew = 0; assert( db!=0 ); @@ -559,11 +557,11 @@ assert( p!=0 ); if( db->mallocFailed==0 ){ if( isLookaside(db, p) ){ pNew = sqlite3DbMallocRawNN(db, n); if( pNew ){ - memcpy(pNew, p, db->lookaside.sz); + memcpy(pNew, p, db->lookaside.szTrue); sqlite3DbFree(db, p); } }else{ assert( sqlite3MemdebugHasType(p, (MEMTYPE_LOOKASIDE|MEMTYPE_HEAP)) ); assert( sqlite3MemdebugNoType(p, (u8)~(MEMTYPE_LOOKASIDE|MEMTYPE_HEAP)) ); @@ -658,11 +656,11 @@ if( db->mallocFailed==0 && db->bBenignMalloc==0 ){ db->mallocFailed = 1; if( db->nVdbeExec>0 ){ db->u1.isInterrupted = 1; } - db->lookaside.bDisable++; + DisableLookaside; if( db->pParse ){ db->pParse->rc = SQLITE_NOMEM_BKPT; } } } @@ -677,11 +675,11 @@ void sqlite3OomClear(sqlite3 *db){ if( db->mallocFailed && db->nVdbeExec==0 ){ db->mallocFailed = 0; db->u1.isInterrupted = 0; assert( db->lookaside.bDisable>0 ); - db->lookaside.bDisable--; + EnableLookaside; } } /* ** Take actions at the end of an API call to indicate an OOM error Index: src/parse.y ================================================================== --- src/parse.y +++ src/parse.y @@ -104,12 +104,13 @@ /* ** Disable lookaside memory allocation for objects that might be ** shared across database connections. */ static void disableLookaside(Parse *pParse){ + sqlite3 *db = pParse->db; pParse->disableLookaside++; - pParse->db->lookaside.bDisable++; + DisableLookaside; } } // end %include // Input is a single SQL command Index: src/prepare.c ================================================================== --- src/prepare.c +++ src/prepare.c @@ -525,10 +525,11 @@ sqlite3DbFree(db, pParse->aLabel); sqlite3ExprListDelete(db, pParse->pConstExpr); if( db ){ assert( db->lookaside.bDisable >= pParse->disableLookaside ); db->lookaside.bDisable -= pParse->disableLookaside; + db->lookaside.sz = db->lookaside.bDisable ? 0 : db->lookaside.szTrue; } pParse->disableLookaside = 0; } /* @@ -558,11 +559,11 @@ /* For a long-term use prepared statement avoid the use of ** lookaside memory. */ if( prepFlags & SQLITE_PREPARE_PERSISTENT ){ sParse.disableLookaside++; - db->lookaside.bDisable++; + DisableLookaside; } sParse.disableVtab = (prepFlags & SQLITE_PREPARE_NO_VTAB)!=0; /* Check to verify that it is possible to get a read lock on all ** database schemas. The inability to get a read lock indicates that Index: src/sqliteInt.h ================================================================== --- src/sqliteInt.h +++ src/sqliteInt.h @@ -1269,14 +1269,21 @@ ** with a particular database connection. Hence, schema information cannot ** be stored in lookaside because in shared cache mode the schema information ** is shared by multiple database connections. Therefore, while parsing ** schema information, the Lookaside.bEnabled flag is cleared so that ** lookaside allocations are not used to construct the schema objects. +** +** New lookaside allocations are only allowed if bDisable==0. When +** bDisable is greater than zero, sz is set to zero which effectively +** disables lookaside without adding a new test for the bDisable flag +** in a performance-critical path. sz should be set by to szTrue whenever +** bDisable changes back to zero. */ struct Lookaside { u32 bDisable; /* Only operate the lookaside when zero */ u16 sz; /* Size of each buffer in bytes */ + u16 szTrue; /* True value of sz, even if disabled */ u8 bMalloced; /* True if pStart obtained from sqlite3_malloc() */ u32 nSlot; /* Number of lookaside slots allocated */ u32 anStat[3]; /* 0: hits. 1: size misses. 2: full misses */ LookasideSlot *pInit; /* List of buffers not previously used */ LookasideSlot *pFree; /* List of available buffers */ @@ -1284,10 +1291,14 @@ void *pEnd; /* First byte past end of available space */ }; struct LookasideSlot { LookasideSlot *pNext; /* Next buffer in the list of free buffers */ }; + +#define DisableLookaside db->lookaside.bDisable++;db->lookaside.sz=0 +#define EnableLookaside db->lookaside.bDisable--;\ + db->lookaside.sz=db->lookaside.bDisable?0:db->lookaside.szTrue /* ** A hash table for built-in function definitions. (Application-defined ** functions use a regular table table from hash.h.) **