diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/sqliteInt.h | 1 | ||||
| -rw-r--r-- | src/where.c | 34 |
2 files changed, 25 insertions, 10 deletions
diff --git a/src/sqliteInt.h b/src/sqliteInt.h index 7fd999d9e..e56da4edd 100644 --- a/src/sqliteInt.h +++ b/src/sqliteInt.h @@ -1159,7 +1159,6 @@ struct sqlite3 { #define SQLITE_Transitive 0x0200 /* Transitive constraints */ #define SQLITE_OmitNoopJoin 0x0400 /* Omit unused tables in joins */ #define SQLITE_Stat3 0x0800 /* Use the SQLITE_STAT3 table */ -#define SQLITE_AdjustOutEst 0x1000 /* Adjust output estimates using WHERE */ #define SQLITE_AllOpts 0xffff /* All optimizations */ /* diff --git a/src/where.c b/src/where.c index e1e1e1d52..49b16b345 100644 --- a/src/where.c +++ b/src/where.c @@ -4221,14 +4221,16 @@ static int whereLoopInsert(WhereLoopBuilder *pBuilder, WhereLoop *pTemplate){ ** the number of output rows by a factor of 10 and each additional term ** reduces the number of output rows by sqrt(2). */ -static void whereLoopOutputAdjust(WhereClause *pWC, WhereLoop *pLoop){ +static void whereLoopOutputAdjust( + WhereClause *pWC, /* The WHERE clause */ + WhereLoop *pLoop, /* The loop to adjust downward */ + LogEst nRow /* Number of rows in the entire table */ +){ WhereTerm *pTerm, *pX; Bitmask notAllowed = ~(pLoop->prereq|pLoop->maskSelf); int i, j; + int nEq = 0; /* Number of = constraints not within likely()/unlike() */ - if( !OptimizationEnabled(pWC->pWInfo->pParse->db, SQLITE_AdjustOutEst) ){ - return; - } for(i=pWC->nTerm, pTerm=pWC->a; i>0; i--, pTerm++){ if( (pTerm->wtFlags & TERM_VIRTUAL)!=0 ) break; if( (pTerm->prereqAll & pLoop->maskSelf)==0 ) continue; @@ -4240,9 +4242,21 @@ static void whereLoopOutputAdjust(WhereClause *pWC, WhereLoop *pLoop){ if( pX->iParent>=0 && (&pWC->a[pX->iParent])==pTerm ) break; } if( j<0 ){ - pLoop->nOut += (pTerm->truthProb<=0 ? pTerm->truthProb : -1); + if( pTerm->truthProb<=0 ){ + pLoop->nOut += pTerm->truthProb; + }else{ + pLoop->nOut--; + if( pTerm->eOperator&WO_EQ ) nEq++; + } } } + /* TUNING: If there is at least one equality constraint in the WHERE + ** clause that does not have a likelihood() explicitly assigned to it + ** then do not let the estimated number of output rows exceed half + ** the number of rows in the table. */ + if( nEq && pLoop->nOut>nRow-10 ){ + pLoop->nOut = nRow - 10; + } } /* @@ -4288,6 +4302,7 @@ static int whereLoopAddBtreeIndex( LogEst saved_nOut; /* Original value of pNew->nOut */ int iCol; /* Index of the column in the table */ int rc = SQLITE_OK; /* Return code */ + LogEst rSize; /* Number of rows in the table */ LogEst rLogSize; /* Logarithm of table size */ WhereTerm *pTop = 0, *pBtm = 0; /* Top and bottom range constraints */ @@ -4317,7 +4332,8 @@ static int whereLoopAddBtreeIndex( saved_prereq = pNew->prereq; saved_nOut = pNew->nOut; pNew->rSetup = 0; - rLogSize = estLog(pProbe->aiRowLogEst[0]); + rSize = pProbe->aiRowLogEst[0]; + rLogSize = estLog(rSize); /* Consider using a skip-scan if there are no WHERE clause constraints ** available for the left-most terms of the index, and if the average @@ -4494,7 +4510,7 @@ static int whereLoopAddBtreeIndex( nOutUnadjusted = pNew->nOut; pNew->rRun += nInMul + nIn; pNew->nOut += nInMul + nIn; - whereLoopOutputAdjust(pBuilder->pWC, pNew); + whereLoopOutputAdjust(pBuilder->pWC, pNew, rSize); rc = whereLoopInsert(pBuilder, pNew); if( pNew->wsFlags & WHERE_COLUMN_RANGE ){ @@ -4748,7 +4764,7 @@ static int whereLoopAddBtree( /* TUNING: Cost of full table scan is (N*3.0). */ pNew->rRun = rSize + 16; ApplyCostMultiplier(pNew->rRun, pTab->costMult); - whereLoopOutputAdjust(pWC, pNew); + whereLoopOutputAdjust(pWC, pNew, rSize); rc = whereLoopInsert(pBuilder, pNew); pNew->nOut = rSize; if( rc ) break; @@ -4784,7 +4800,7 @@ static int whereLoopAddBtree( pNew->rRun = sqlite3LogEstAdd(pNew->rRun, rSize+16); } ApplyCostMultiplier(pNew->rRun, pTab->costMult); - whereLoopOutputAdjust(pWC, pNew); + whereLoopOutputAdjust(pWC, pNew, rSize); rc = whereLoopInsert(pBuilder, pNew); pNew->nOut = rSize; if( rc ) break; |