diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/where.c | 21 | ||||
| -rw-r--r-- | src/whereInt.h | 2 |
2 files changed, 11 insertions, 12 deletions
diff --git a/src/where.c b/src/where.c index 01ae180ae..3a865d3f1 100644 --- a/src/where.c +++ b/src/where.c @@ -3700,9 +3700,6 @@ static int whereLoopAddBtree( #else pNew->rRun = rSize + 16; #endif - if( IsView(pTab) || (pTab->tabFlags & TF_Ephemeral)!=0 ){ - pNew->wsFlags |= WHERE_VIEWSCAN; - } ApplyCostMultiplier(pNew->rRun, pTab->costMult); whereLoopOutputAdjust(pWC, pNew, rSize); rc = whereLoopInsert(pBuilder, pNew); @@ -5121,14 +5118,6 @@ static int wherePathSolver(WhereInfo *pWInfo, LogEst nRowEst){ rUnsorted -= 2; /* TUNING: Slight bias in favor of no-sort plans */ } - /* TUNING: A full-scan of a VIEW or subquery in the outer loop - ** is not so bad. */ - if( iLoop==0 && (pWLoop->wsFlags & WHERE_VIEWSCAN)!=0 && nLoop>1 ){ - rCost += -10; - nOut += -30; - WHERETRACE(0x80,("VIEWSCAN cost reduction for %c\n",pWLoop->cId)); - } - /* Check to see if pWLoop should be added to the set of ** mxChoice best-so-far paths. ** @@ -6143,6 +6132,16 @@ WhereInfo *sqlite3WhereBegin( wherePathSolver(pWInfo, pWInfo->nRowOut+1); if( db->mallocFailed ) goto whereBeginError; } + + /* TUNING: Assume that a DISTINCT clause on a subquery reduces + ** the output size by a factor of 8 (LogEst -30). + */ + if( (pWInfo->wctrlFlags & WHERE_WANT_DISTINCT)!=0 ){ + WHERETRACE(0x0080,("nRowOut reduced from %d to %d due to DISTINCT\n", + pWInfo->nRowOut, pWInfo->nRowOut-30)); + pWInfo->nRowOut -= 30; + } + } assert( pWInfo->pTabList!=0 ); if( pWInfo->pOrderBy==0 && (db->flags & SQLITE_ReverseOrder)!=0 ){ diff --git a/src/whereInt.h b/src/whereInt.h index 759e774e3..343aca9f3 100644 --- a/src/whereInt.h +++ b/src/whereInt.h @@ -633,7 +633,7 @@ void sqlite3WhereTabFuncArgs(Parse*, SrcItem*, WhereClause*); #define WHERE_BLOOMFILTER 0x00400000 /* Consider using a Bloom-filter */ #define WHERE_SELFCULL 0x00800000 /* nOut reduced by extra WHERE terms */ #define WHERE_OMIT_OFFSET 0x01000000 /* Set offset counter to zero */ -#define WHERE_VIEWSCAN 0x02000000 /* A full-scan of a VIEW or subquery */ + /* 0x02000000 -- available for reuse */ #define WHERE_EXPRIDX 0x04000000 /* Uses an index-on-expressions */ #endif /* !defined(SQLITE_WHEREINT_H) */ |