SQLite

  p->wsFlags = 0;
}

/*
** Clear the WhereLoop.u union.  Leave WhereLoop.pLTerm intact.
*/
static void whereLoopClearUnion(sqlite3 *db, WhereLoop *p){

  if( (p->wsFlags & WHERE_VIRTUALTABLE)!=0 ){
    if( p->u.vtab.needFree ) sqlite3_free(p->u.vtab.idxStr);
    p->u.vtab.needFree = 0;
    p->u.vtab.idxStr = 0;
  }else if( (p->wsFlags & WHERE_TEMP_INDEX)!=0 && p->u.btree.pIndex!=0 ){
    sqlite3DbFree(db, p->u.btree.pIndex->zColAff);
    sqlite3DbFree(db, p->u.btree.pIndex);
    p->u.btree.pIndex = 0;
  }
}


/*
** Deallocate internal memory used by a WhereLoop object
*/
static void whereLoopClear(sqlite3 *db, WhereLoop *p){
  if( p->aLTerm!=p->aLTermSpace ) sqlite3DbFree(db, p->aLTerm);
  whereLoopClearUnion(db, p);

  if( pTo->nLTerm ){
    memcpy(pTo->aLTerm, pFrom->aLTerm, pTo->nLTerm*sizeof(pTo->aLTerm[0]));
  }
  pTo->wsFlags = pFrom->wsFlags;
  pTo->u = pFrom->u;
  if( pFrom->wsFlags & WHERE_VIRTUALTABLE ){
    pFrom->u.vtab.needFree = 0;
  }else if( (pFrom->wsFlags & WHERE_TEMP_INDEX)!=0 && pFrom->u.btree.pIndex!=0 ){
    sqlite3DbFree(db, pFrom->u.btree.pIndex->zColAff);
    sqlite3DbFree(db, pFrom->u.btree.pIndex);
    pFrom->u.btree.pIndex = 0;
  }
  return SQLITE_OK;
}

/*
** Delete a WhereLoop object

       && (pTemplate->wsFlags & WHERE_INDEXED)!=0
       && p->u.btree.pIndex==pTemplate->u.btree.pIndex
       && p->prereq==pTemplate->prereq
      ){
        /* Overwrite an existing WhereLoop with an similar one that uses
        ** more terms of the index */
        pNext = p->pNextLoop;
        whereLoopClear(db, p);
        break;
      }else{
        /* pTemplate is not helpful.
        ** Return without changing or adding anything */
        goto whereLoopInsert_noop;
      }
    }
    if( (p->prereq & pTemplate->prereq)==pTemplate->prereq
     && p->rSetup>=pTemplate->rSetup
     && p->rRun>=pTemplate->rRun
    ){
      /* Overwrite an existing WhereLoop with a better one */
      pNext = p->pNextLoop;
      whereLoopClear(db, p);
      break;
    }
  }

  /* If we reach this point it means that either p[] should be overwritten
  ** with pTemplate[] if p[] exists, or if p==NULL then allocate a new
  ** WhereLoop and insert it.

  WhereLoop sBest;
  struct SrcList_item *pItem;
  
  pWC = pBuilder->pWC;
  if( pWInfo->wctrlFlags & WHERE_AND_ONLY ) return SQLITE_OK;
  pWCEnd = pWC->a + pWC->nTerm;
  pNew = pBuilder->pNew;
  whereLoopInit(&sBest);

  for(pTerm=pWC->a; pTerm<pWCEnd && rc==SQLITE_OK; pTerm++){
    if( (pTerm->eOperator & WO_OR)!=0
     && (pTerm->u.pOrInfo->indexable & pNew->maskSelf)!=0 
    ){
      WhereClause * const pOrWC = &pTerm->u.pOrInfo->wc;
      WhereTerm * const pOrWCEnd = &pOrWC->a[pOrWC->nTerm];
      WhereTerm *pOrTerm;
      WhereCost rTotal = 0;
      WhereCost nRow = 0;
      Bitmask prereq = mExtra;
    

      pItem = pWInfo->pTabList->a + pNew->iTab;
      iCur = pItem->iCursor;
      sSubBuild = *pBuilder;
      sSubBuild.pOrderBy = 0;
      sSubBuild.pBest = &sBest;

      for(pOrTerm=pOrWC->a; pOrTerm<pOrWCEnd; pOrTerm++){

      pNew->wsFlags = WHERE_MULTI_OR;
      pNew->rSetup = (WhereCost)0;
      pNew->rRun = rTotal;
      pNew->nOut = nRow;
      pNew->prereq = prereq;
      memset(&pNew->u, 0, sizeof(pNew->u));
      rc = whereLoopInsert(pBuilder, pNew);

    }
  }
  whereLoopClear(pWInfo->pParse->db, &sBest);
  return rc;
}

/*
** Add all WhereLoop objects for all tables 
*/
static int whereLoopAddAll(WhereLoopBuilder *pBuilder){