SQLite

    Table *pTab;
    pNewItem->zDatabase = sqlite3DbStrDup(db, pOldItem->zDatabase);
    pNewItem->zName = sqlite3DbStrDup(db, pOldItem->zName);
    pNewItem->zAlias = sqlite3DbStrDup(db, pOldItem->zAlias);
    pNewItem->jointype = pOldItem->jointype;
    pNewItem->iCursor = pOldItem->iCursor;
    pNewItem->isPopulated = pOldItem->isPopulated;
    pNewItem->isCorrelated = pOldItem->isCorrelated;
    pNewItem->zIndex = sqlite3DbStrDup(db, pOldItem->zIndex);
    pNewItem->notIndexed = pOldItem->notIndexed;
    pNewItem->pIndex = pOldItem->pIndex;
    pTab = pNewItem->pTab = pOldItem->pTab;
    if( pTab ){
      pTab->nRef++;
    }

    }
  
    /* Recursively resolve names in all subqueries
    */
    for(i=0; i<p->pSrc->nSrc; i++){
      struct SrcList_item *pItem = &p->pSrc->a[i];
      if( pItem->pSelect ){
        NameContext *pNC;         /* Used to iterate name contexts */
        int nRef = 0;             /* Refcount for pOuterNC and outer contexts */
        const char *zSavedContext = pParse->zAuthContext;

        /* Count the total number of references to pOuterNC and all of its
        ** parent contexts. After resolving references to expressions in
        ** pItem->pSelect, check if this value has changed. If so, then
        ** SELECT statement pItem->pSelect must be correlated. Set the
        ** pItem->isCorrelated flag if this is the case. */
        for(pNC=pOuterNC; pNC; pNC=pNC->pNext) nRef += pNC->nRef;

        if( pItem->zName ) pParse->zAuthContext = pItem->zName;
        sqlite3ResolveSelectNames(pParse, pItem->pSelect, pOuterNC);
        pParse->zAuthContext = zSavedContext;
        if( pParse->nErr || db->mallocFailed ) return WRC_Abort;

        for(pNC=pOuterNC; pNC; pNC=pNC->pNext) nRef -= pNC->nRef;
        assert( pItem->isCorrelated==0 && nRef<=0 );
        pItem->isCorrelated = (nRef!=0);
      }
    }
  
    /* If there are no aggregate functions in the result-set, and no GROUP BY 
    ** expression, do not allow aggregates in any of the other expressions.
    */
    assert( (p->selFlags & SF_Aggregate)==0 );

    char *zName;      /* Name of the table */
    char *zAlias;     /* The "B" part of a "A AS B" phrase.  zName is the "A" */
    Table *pTab;      /* An SQL table corresponding to zName */
    Select *pSelect;  /* A SELECT statement used in place of a table name */
    u8 isPopulated;   /* Temporary table associated with SELECT is populated */
    u8 jointype;      /* Type of join between this able and the previous */
    u8 notIndexed;    /* True if there is a NOT INDEXED clause */
    u8 isCorrelated;  /* True if sub-query is correlated */
#ifndef SQLITE_OMIT_EXPLAIN
    u8 iSelectId;     /* If pSelect!=0, the id of the sub-select in EQP */
#endif
    int iCursor;      /* The VDBE cursor number used to access this table */
    Expr *pOn;        /* The ON clause of a join */
    IdList *pUsing;   /* The USING clause of a join */
    Bitmask colUsed;  /* Bit N (1<<N) set if column N of pTab is used */

  if( (pCost->plan.wsFlags & WHERE_NOT_FULLSCAN)!=0 ){
    /* We already have some kind of index in use for this query. */
    return;
  }
  if( pSrc->notIndexed ){
    /* The NOT INDEXED clause appears in the SQL. */
    return;
  }
  if( pSrc->isCorrelated ){
    /* The source is a correlated sub-query. No point in indexing it. */
    return;
  }

  assert( pParse->nQueryLoop >= (double)1 );
  pTable = pSrc->pTab;
  nTableRow = pTable->nRowEst;
  logN = estLog(nTableRow);
  costTempIdx = 2*logN*(nTableRow/pParse->nQueryLoop + 1);

# 2011 July 8
#
# The author disclaims copyright to this source code.  In place of
# a legal notice, here is a blessing:
#
#    May you do good and not evil.
#    May you find forgiveness for yourself and forgive others.
#    May you share freely, never taking more than you give.
#
#***********************************************************************
# This file implements regression tests for SQLite library.  The
# focus of this file is testing that bug [54844eea3f] has been fixed.
#

set testdir [file dirname $argv0]
source $testdir/tester.tcl

set ::testprefix tkt-54844eea3f

do_test 1.0 {
  execsql {
    CREATE TABLE t1(a INTEGER PRIMARY KEY);
    INSERT INTO t1 VALUES(1);
    INSERT INTO t1 VALUES(4);

    CREATE TABLE t2(b INTEGER PRIMARY KEY);
    INSERT INTO t2 VALUES(1);
    INSERT INTO t2 VALUES(2);
    INSERT INTO t2 SELECT b+2 FROM t2;
    INSERT INTO t2 SELECT b+4 FROM t2;
    INSERT INTO t2 SELECT b+8 FROM t2;
    INSERT INTO t2 SELECT b+16 FROM t2;

    CREATE TABLE t3(c INTEGER PRIMARY KEY);
    INSERT INTO t3 VALUES(1);
    INSERT INTO t3 VALUES(2);
    INSERT INTO t3 VALUES(3);
  }
} {}

do_test 1.1 {
  execsql {
    SELECT 'test-2', t3.c, (
          SELECT count(*) 
          FROM t1 JOIN (SELECT DISTINCT t3.c AS p FROM t2) AS x ON t1.a=x.p
    )
    FROM t3;
  }
} {test-2 1 1 test-2 2 0 test-2 3 0}

do_test 1.2 {
  execsql {
    CREATE TABLE t4(a, b, c);
    INSERT INTO t4 VALUES('a', 1, 'one');
    INSERT INTO t4 VALUES('a', 2, 'two');
    INSERT INTO t4 VALUES('b', 1, 'three');
    INSERT INTO t4 VALUES('b', 2, 'four');
    SELECT ( 
      SELECT c FROM (
        SELECT * FROM t4 WHERE a=out.a ORDER BY b LIMIT 10 OFFSET 1
      ) WHERE b=out.b
    ) FROM t4 AS out;
  }
} {{} two {} four}


finish_test