SQLite

  }else{
    while( x>255 ){ y += 40; x >>= 4; }
    while( x>15 ){  y += 10; x >>= 1; }
  }
  return a[x&7] + y - 10;
}

#ifndef SQLITE_OMIT_VIRTUALTABLE
/*
** Convert a double (as received from xBestIndex of a virtual table)
** into a WhereCost
*/
static WhereCost whereCostFromDouble(double x){
  u64 a;
  WhereCost e;
  assert( sizeof(x)==8 && sizeof(a)==8 );
  if( x<=1 ) return 0;
  if( x<=2000000000 ) return whereCostFromInt((tRowcnt)x);
  memcpy(&a, &x, 8);
  e = (a>>52) - 1022;
  return e*10;
}
#endif /* SQLITE_OMIT_VIRTUALTABLE */

/*
** Prepare a crude estimate of the logarithm of the input value.
** The results need not be exact.  This is only used for estimating
** the total cost of performing operations with O(logN) or O(NlogN)
** complexity.  Because N is just a guess, it is no great tragedy if
** logN is a little off.
*/

       && 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;
        break;
      }else if( p->nOut>pTemplate->nOut
       && p->rSetup==pTemplate->rSetup
       && p->rRun==pTemplate->rRun
      ){
        /* Overwrite an existing WhereLoop with the same cost but more
        ** outputs */
        pNext = p->pNextLoop;
        break;
      }else{
        /* pTemplate is not helpful.
        ** Return without changing or adding anything */
        goto whereLoopInsert_noop;
      }
    }
    if( (p->prereq & pTemplate->prereq)==pTemplate->prereq

                     pNew->aLTerm[pNew->nLTerm-2] : 0;
    }
    if( pNew->wsFlags & WHERE_COLUMN_RANGE ){
      /* Adjust nOut and rRun for STAT3 range values */
      WhereCost rDiv;
      whereRangeScanEst(pParse, pProbe, pNew->u.btree.nEq,
                        pBtm, pTop, &rDiv);
      pNew->nOut = saved_nOut>rDiv+10 ? saved_nOut - rDiv : 10;
    }
#ifdef SQLITE_ENABLE_STAT3
    if( pNew->u.btree.nEq==1 && pProbe->nSample ){
      tRowcnt nOut = 0;
      if( (pTerm->eOperator & (WO_EQ|WO_ISNULL))!=0 ){
        rc = whereEqualScanEst(pParse, pProbe, pTerm->pExpr->pRight, &nOut);
      }else if( (pTerm->eOperator & WO_IN)

    /* If there was an INDEXED BY clause, then only that one index is
    ** considered. */
    if( pSrc->pIndex ) break;
  }
  return rc;
}

#ifndef SQLITE_OMIT_VIRTUALTABLE
/*
** Add all WhereLoop objects for a table of the join identified by
** pBuilder->pNew->iTab.  That table is guaranteed to be a virtual table.
*/
static int whereLoopAddVirtual(
  WhereLoopBuilder *pBuilder,  /* WHERE clause information */
  Bitmask mExtra               /* Extra prerequesites for using this table */

    }
    memset(pUsage, 0, sizeof(pUsage[0])*pIdxInfo->nConstraint);
    if( pIdxInfo->needToFreeIdxStr ) sqlite3_free(pIdxInfo->idxStr);
    pIdxInfo->idxStr = 0;
    pIdxInfo->idxNum = 0;
    pIdxInfo->needToFreeIdxStr = 0;
    pIdxInfo->orderByConsumed = 0;

    pIdxInfo->estimatedCost = SQLITE_BIG_DBL / (double)2;
    rc = vtabBestIndex(pParse, pTab, pIdxInfo);
    if( rc ) goto whereLoopAddVtab_exit;
    pIdxCons = *(struct sqlite3_index_constraint**)&pIdxInfo->aConstraint;
    pNew->prereq = 0;
    mxTerm = -1;
    assert( pNew->nLSlot>=nConstraint );
    for(i=0; i<nConstraint; i++) pNew->aLTerm[i] = 0;

      pNew->u.vtab.idxNum = pIdxInfo->idxNum;
      pNew->u.vtab.needFree = pIdxInfo->needToFreeIdxStr;
      pIdxInfo->needToFreeIdxStr = 0;
      pNew->u.vtab.idxStr = pIdxInfo->idxStr;
      pNew->u.vtab.isOrdered = (u8)((pIdxInfo->nOrderBy!=0)
                                     && pIdxInfo->orderByConsumed);
      pNew->rSetup = 0;
      pNew->rRun = whereCostFromDouble(pIdxInfo->estimatedCost);
      pNew->nOut = 46;  assert( 46 == whereCostFromInt(25) );
      whereLoopInsert(pBuilder, pNew);
      if( pNew->u.vtab.needFree ){
        sqlite3_free(pNew->u.vtab.idxStr);
        pNew->u.vtab.needFree = 0;
      }
    }
  }  

whereLoopAddVtab_exit:
  if( pIdxInfo->needToFreeIdxStr ) sqlite3_free(pIdxInfo->idxStr);
  sqlite3DbFree(db, pIdxInfo);
  return rc;
}
#endif /* SQLITE_OMIT_VIRTUALTABLE */

/*
** Add WhereLoop entries to handle OR terms.  This works for either
** btrees or virtual tables.
*/
static int whereLoopAddOr(WhereLoopBuilder *pBuilder, Bitmask mExtra){
  WhereInfo *pWInfo = pBuilder->pWInfo;

          sSubBuild.pWC = &tempWC;
        }else{
          continue;
        }
        sBest.maskSelf = 0;
        sBest.rSetup = 0;
        sBest.rRun = 0;
#ifndef SQLITE_OMIT_VIRTUALTABLE
        if( IsVirtual(pItem->pTab) ){
          rc = whereLoopAddVirtual(&sSubBuild, mExtra);
        }else
#endif
        {
          rc = whereLoopAddBtree(&sSubBuild, mExtra);
        }
        if( sBest.maskSelf==0 ) break;
        assert( sBest.rSetup==0 );
        rTotal = whereCostAdd(rTotal, sBest.rRun);
        nRow = whereCostAdd(nRow, sBest.nOut);
        prereq |= sBest.prereq;

  301  {y=1}                 t1y   26
  302  {y=0.1}               t1y    1

  400  {x IS NULL}           t1x  400

} {
  # Verify that the expected index is used with the expected row count
  # No longer valid due to an EXPLAIN QUERY PLAN output format change
  # do_test analyze5-1.${testid}a {
  #   set x [lindex [eqp "SELECT * FROM t1 WHERE $where"] 3]
  #   set idx {}
  #   regexp {INDEX (t1.) } $x all idx
  #   regexp {~([0-9]+) rows} $x all nrow
  #   list $idx $nrow
  # } [list $index $rows]

  # Verify that the same result is achieved regardless of whether or not
  # the index is used
  do_test analyze5-1.${testid}b {
    set w2 [string map {y +y z +z} $where]
    set a1 [db eval "SELECT rowid FROM t1 NOT INDEXED WHERE $w2\
                     ORDER BY +rowid"]

  503  {x=1}                               t1x   1
  504  {x IS NOT NULL}                     t1x   2
  505  {+x IS NOT NULL}                     {} 500
  506  {upper(x) IS NOT NULL}               {} 500

} {
  # Verify that the expected index is used with the expected row count
  # No longer valid due to an EXPLAIN QUERY PLAN format change
  # do_test analyze5-1.${testid}a {
  #   set x [lindex [eqp "SELECT * FROM t1 WHERE $where"] 3]
  #   set idx {}
  #   regexp {INDEX (t1.) } $x all idx
  #   regexp {~([0-9]+) rows} $x all nrow
  #   list $idx $nrow
  # } [list $index $rows]


  # Verify that the same result is achieved regardless of whether or not
  # the index is used
  do_test analyze5-1.${testid}b {
    set w2 [string map {y +y z +z} $where]
    set a1 [db eval "SELECT rowid FROM t1 NOT INDEXED WHERE $w2\
                     ORDER BY +rowid"]

  set ::sqlite_sort_count 0
  set data [execsql $sql]
  if {$::sqlite_sort_count} {set x sort} {set x nosort}
  lappend data $x
  set eqp [execsql "EXPLAIN QUERY PLAN $sql"]
  # puts eqp=$eqp
  foreach {a b c x} $eqp {
    if {[regexp { TABLE (\w+ AS )?(\w+) USING.* INDEX (\w+)\y} \
        $x all as tab idx]} {
      lappend data $tab $idx
    } elseif {[regexp { TABLE (\w+ AS )?(\w+)\y} $x all as tab]} {
      lappend data $tab *
    }
  }
  return $data   
}

do_test between-1.1.1 {

}

det 7.1 "SELECT count(*) FROM t1" {
  0 0 0 {SCAN TABLE t1}
}

det 7.2 "SELECT count(*) FROM t2" {
  0 0 0 {SCAN TABLE t2 USING COVERING INDEX i1}
}

do_execsql_test 7.3 {
  INSERT INTO t1 VALUES(1, 2);
  INSERT INTO t1 VALUES(3, 4);

  INSERT INTO t2 VALUES(1, 2);

sqlite3 db test.db

det 7.4 "SELECT count(*) FROM t1" {
  0 0 0 {SCAN TABLE t1}
}

det 7.5 "SELECT count(*) FROM t2" {
  0 0 0 {SCAN TABLE t2 USING COVERING INDEX i1}
}


finish_test