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Overview
Comment:Simplification and performance tweak to the high-speed NGQP bypass.
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Timelines: family | ancestors | descendants | both | nextgen-query-plan-exp
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SHA1: 0f8a38ee54208d6a477aa2482cd277b4808450f0
User & Date: drh 2013-06-10 14:56:25.426
Context
2013-06-11
02:36
Use a logarithmic rather than linear cost and row-count measures. Do not report row count estimates in EQP output. (check-in: b777b1097d user: drh tags: nextgen-query-plan-exp)
2013-06-10
19:12
First attempt to store costs and row counts as a logarithm. (check-in: 9e8109673c user: drh tags: nextgen-query-plan-logcost)
14:56
Simplification and performance tweak to the high-speed NGQP bypass. (check-in: 0f8a38ee54 user: drh tags: nextgen-query-plan-exp)
12:34
Performance improvements for whereScan methods. (check-in: aae14350a3 user: drh tags: nextgen-query-plan-exp)
Changes
Unified Diff Ignore Whitespace Patch
Changes to src/where.c.
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  WhereInfo *pWInfo;
  struct SrcList_item *pItem;
  WhereClause *pWC;
  WhereTerm *pTerm;
  WhereLoop *pLoop;
  int iCur;
  int j;
  int nOrderBy;
  Table *pTab;
  Index *pIdx;
  
  pWInfo = pBuilder->pWInfo;
  assert( pWInfo->pTabList->nSrc>=1 );
  pItem = pWInfo->pTabList->a;
  pTab = pItem->pTab;
  if( IsVirtual(pTab) ) return 0;
  if( pItem->zIndex ) return 0;
  iCur = pItem->iCursor;
  pWC = &pWInfo->sWC;
  pLoop = pBuilder->pNew;
  pWInfo->a[0].pWLoop = pLoop;
  pLoop->wsFlags = 0;
  pLoop->maskSelf = getMask(&pWInfo->sMaskSet, iCur);
  pWInfo->a[0].iTabCur = iCur;
#ifdef SQLITE_DEBUG
  pLoop->cId = '0';
#endif
  nOrderBy = pWInfo->pOrderBy ? pWInfo->pOrderBy->nExpr : 0;
  pTerm = findTerm(pWC, iCur, -1, 1, WO_EQ, 0);
  if( pTerm ){
    pLoop->wsFlags = WHERE_COLUMN_EQ|WHERE_IPK|WHERE_ONEROW;
    pLoop->aLTerm[0] = pTerm;
    pLoop->nLTerm = 1;
    pLoop->u.btree.nEq = 1;
    pLoop->rRun = (WhereCost)10;
    pLoop->nOut = (WhereCost)1;
    pWInfo->nRowOut = 1;
    pWInfo->nOBSat = nOrderBy;
  }else{
    for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
      if( pIdx->onError==OE_None ) continue;
      for(j=0; j<pIdx->nColumn; j++){
        pTerm = findTerm(pWC, iCur, pIdx->aiColumn[j], 1, WO_EQ, pIdx);
        if( pTerm==0 ) break;
        whereLoopResize(pWInfo->pParse->db, pLoop, j);
        pLoop->aLTerm[j] = pTerm;
      }
      if( j!=pIdx->nColumn ) continue;
      pLoop->wsFlags = WHERE_COLUMN_EQ|WHERE_ONEROW|WHERE_INDEXED;
      if( (pItem->colUsed & ~columnsUsedByIndex(pIdx))==0 ){
        pLoop->wsFlags |= WHERE_IDX_ONLY;
      }
      pLoop->nLTerm = j;
      pLoop->u.btree.nEq = j;
      pLoop->u.btree.pIndex = pIdx;
      pLoop->rRun = (WhereCost)15;
      pLoop->nOut = (WhereCost)1;
      pWInfo->nRowOut = 1;
      pWInfo->nOBSat = nOrderBy;
      break;
    }
  }
  return pLoop->wsFlags!=0;












}

/*
** Generate the beginning of the loop used for WHERE clause processing.
** The return value is a pointer to an opaque structure that contains
** information needed to terminate the loop.  Later, the calling routine
** should invoke sqlite3WhereEnd() with the return value of this function








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  WhereInfo *pWInfo;
  struct SrcList_item *pItem;
  WhereClause *pWC;
  WhereTerm *pTerm;
  WhereLoop *pLoop;
  int iCur;
  int j;

  Table *pTab;
  Index *pIdx;
  
  pWInfo = pBuilder->pWInfo;
  assert( pWInfo->pTabList->nSrc>=1 );
  pItem = pWInfo->pTabList->a;
  pTab = pItem->pTab;
  if( IsVirtual(pTab) ) return 0;
  if( pItem->zIndex ) return 0;
  iCur = pItem->iCursor;
  pWC = &pWInfo->sWC;
  pLoop = pBuilder->pNew;

  pLoop->wsFlags = 0;






  pTerm = findTerm(pWC, iCur, -1, 0, WO_EQ, 0);
  if( pTerm ){
    pLoop->wsFlags = WHERE_COLUMN_EQ|WHERE_IPK|WHERE_ONEROW;
    pLoop->aLTerm[0] = pTerm;
    pLoop->nLTerm = 1;
    pLoop->u.btree.nEq = 1;
    pLoop->rRun = (WhereCost)10;



  }else{
    for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
      if( pIdx->onError==OE_None ) continue;
      for(j=0; j<pIdx->nColumn; j++){
        pTerm = findTerm(pWC, iCur, pIdx->aiColumn[j], 0, WO_EQ, pIdx);
        if( pTerm==0 ) break;
        whereLoopResize(pWInfo->pParse->db, pLoop, j);
        pLoop->aLTerm[j] = pTerm;
      }
      if( j!=pIdx->nColumn ) continue;
      pLoop->wsFlags = WHERE_COLUMN_EQ|WHERE_ONEROW|WHERE_INDEXED;
      if( (pItem->colUsed & ~columnsUsedByIndex(pIdx))==0 ){
        pLoop->wsFlags |= WHERE_IDX_ONLY;
      }
      pLoop->nLTerm = j;
      pLoop->u.btree.nEq = j;
      pLoop->u.btree.pIndex = pIdx;
      pLoop->rRun = (WhereCost)15;



      break;
    }
  }
  if( pLoop->wsFlags ){
    pLoop->nOut = (WhereCost)1;
    pWInfo->a[0].pWLoop = pLoop;
    pLoop->maskSelf = getMask(&pWInfo->sMaskSet, iCur);
    pWInfo->a[0].iTabCur = iCur;
    pWInfo->nRowOut = 1;
    pWInfo->nOBSat =  pWInfo->pOrderBy ? pWInfo->pOrderBy->nExpr : 0;
#ifdef SQLITE_DEBUG
    pLoop->cId = '0';
#endif
    return 1;
  }
  return 0;
}

/*
** Generate the beginning of the loop used for WHERE clause processing.
** The return value is a pointer to an opaque structure that contains
** information needed to terminate the loop.  Later, the calling routine
** should invoke sqlite3WhereEnd() with the return value of this function
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