** 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.
**
*************************************************************************
** $Id: btree.c,v 1.172 2004/06/22 14:40:11 drh Exp $
**
** This file implements a external (disk-based) database using BTrees.
** For a detailed discussion of BTrees, refer to
**
**     Donald E. Knuth, THE ART OF COMPUTER PROGRAMMING, Volume 3:
**     "Sorting And Searching", pages 473-480. Addison-Wesley
**     Publishing Company, Reading, Massachusetts.
................................................................................
**      sqlite3BtreeUpdateMeta()
**
** If wrflag is true, then nMaster specifies the maximum length of
** a master journal file name supplied later via sqlite3BtreeSync().
** This is so that appropriate space can be allocated in the journal file
** when it is created..
*/
int sqlite3BtreeBeginTrans(Btree *pBt, int wrflag, int nMaster){
  int rc = SQLITE_OK;

  /* If the btree is already in a write-transaction, or it
  ** is already in a read-transaction and a read-transaction
  ** is requested, this is a no-op.
  */
  if( pBt->inTrans==TRANS_WRITE || 
................................................................................
  }

  if( pBt->pPage1==0 ){
    rc = lockBtree(pBt);
  }

  if( rc==SQLITE_OK && wrflag ){
    rc = sqlite3pager_begin(pBt->pPage1->aData, nMaster);
    if( rc==SQLITE_OK ){
      rc = newDatabase(pBt);
    }
  }

  if( rc==SQLITE_OK ){
    pBt->inTrans = (wrflag?TRANS_WRITE:TRANS_READ);

** 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.
**
*************************************************************************
** $Id: btree.c,v 1.173 2004/06/26 08:38:25 danielk1977 Exp $
**
** This file implements a external (disk-based) database using BTrees.
** For a detailed discussion of BTrees, refer to
**
**     Donald E. Knuth, THE ART OF COMPUTER PROGRAMMING, Volume 3:
**     "Sorting And Searching", pages 473-480. Addison-Wesley
**     Publishing Company, Reading, Massachusetts.
................................................................................
**      sqlite3BtreeUpdateMeta()
**
** If wrflag is true, then nMaster specifies the maximum length of
** a master journal file name supplied later via sqlite3BtreeSync().
** This is so that appropriate space can be allocated in the journal file
** when it is created..
*/
int sqlite3BtreeBeginTrans(Btree *pBt, int wrflag){
  int rc = SQLITE_OK;

  /* If the btree is already in a write-transaction, or it
  ** is already in a read-transaction and a read-transaction
  ** is requested, this is a no-op.
  */
  if( pBt->inTrans==TRANS_WRITE || 
................................................................................
  }

  if( pBt->pPage1==0 ){
    rc = lockBtree(pBt);
  }

  if( rc==SQLITE_OK && wrflag ){
    rc = sqlite3pager_begin(pBt->pPage1->aData);
    if( rc==SQLITE_OK ){
      rc = newDatabase(pBt);
    }
  }

  if( rc==SQLITE_OK ){
    pBt->inTrans = (wrflag?TRANS_WRITE:TRANS_READ);

**    May you share freely, never taking more than you give.
**
*************************************************************************
** This header file defines the interface that the sqlite B-Tree file
** subsystem.  See comments in the source code for a detailed description
** of what each interface routine does.
**
** @(#) $Id: btree.h,v 1.54 2004/06/14 06:03:57 danielk1977 Exp $
*/
#ifndef _BTREE_H_
#define _BTREE_H_

/* TODO: This definition is just included so other modules compile. It
** needs to be revisited.
*/
................................................................................
*/
#define BTREE_OMIT_JOURNAL  1  /* Do not use journal.  No argument */
#define BTREE_MEMORY        2  /* In-memory DB.  No argument */

int sqlite3BtreeClose(Btree*);
int sqlite3BtreeSetCacheSize(Btree*,int);
int sqlite3BtreeSetSafetyLevel(Btree*,int);
int sqlite3BtreeBeginTrans(Btree*,int,int);
int sqlite3BtreeCommit(Btree*);
int sqlite3BtreeRollback(Btree*);
int sqlite3BtreeBeginStmt(Btree*);
int sqlite3BtreeCommitStmt(Btree*);
int sqlite3BtreeRollbackStmt(Btree*);
int sqlite3BtreeCreateTable(Btree*, int*, int flags);
int sqlite3BtreeIsInTrans(Btree*);

**    May you share freely, never taking more than you give.
**
*************************************************************************
** This header file defines the interface that the sqlite B-Tree file
** subsystem.  See comments in the source code for a detailed description
** of what each interface routine does.
**
** @(#) $Id: btree.h,v 1.55 2004/06/26 08:38:25 danielk1977 Exp $
*/
#ifndef _BTREE_H_
#define _BTREE_H_

/* TODO: This definition is just included so other modules compile. It
** needs to be revisited.
*/
................................................................................
*/
#define BTREE_OMIT_JOURNAL  1  /* Do not use journal.  No argument */
#define BTREE_MEMORY        2  /* In-memory DB.  No argument */

int sqlite3BtreeClose(Btree*);
int sqlite3BtreeSetCacheSize(Btree*,int);
int sqlite3BtreeSetSafetyLevel(Btree*,int);
int sqlite3BtreeBeginTrans(Btree*,int);
int sqlite3BtreeCommit(Btree*);
int sqlite3BtreeRollback(Btree*);
int sqlite3BtreeBeginStmt(Btree*);
int sqlite3BtreeCommitStmt(Btree*);
int sqlite3BtreeRollbackStmt(Btree*);
int sqlite3BtreeCreateTable(Btree*, int*, int flags);
int sqlite3BtreeIsInTrans(Btree*);

**     DROP INDEX
**     creating ID lists
**     BEGIN TRANSACTION
**     COMMIT
**     ROLLBACK
**     PRAGMA
**
** $Id: build.c,v 1.232 2004/06/22 13:22:40 drh Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>

/*
** This routine is called when a new SQL statement is beginning to
** be parsed.  Check to see if the schema for the database needs
................................................................................
      sqlite3ErrorMsg(pParse, "unable to open a temporary database "
        "file for storing temporary tables");
      pParse->nErr++;
      sqliteFree(zName);
      return;
    }
    if( db->flags & !db->autoCommit ){
      rc = sqlite3BtreeBeginTrans(db->aDb[1].pBt, 1, 0);
      if( rc!=SQLITE_OK ){
        sqlite3ErrorMsg(pParse, "unable to get a write lock on "
          "the temporary database file");
        sqliteFree(zName);
        return;
      }
    }

**     DROP INDEX
**     creating ID lists
**     BEGIN TRANSACTION
**     COMMIT
**     ROLLBACK
**     PRAGMA
**
** $Id: build.c,v 1.233 2004/06/26 08:38:25 danielk1977 Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>

/*
** This routine is called when a new SQL statement is beginning to
** be parsed.  Check to see if the schema for the database needs
................................................................................
      sqlite3ErrorMsg(pParse, "unable to open a temporary database "
        "file for storing temporary tables");
      pParse->nErr++;
      sqliteFree(zName);
      return;
    }
    if( db->flags & !db->autoCommit ){
      rc = sqlite3BtreeBeginTrans(db->aDb[1].pBt, 1);
      if( rc!=SQLITE_OK ){
        sqlite3ErrorMsg(pParse, "unable to get a write lock on "
          "the temporary database file");
        sqliteFree(zName);
        return;
      }
    }

** The pager is used to access a database disk file.  It implements
** atomic commit and rollback through the use of a journal file that
** is separate from the database file.  The pager also implements file
** locking to prevent two processes from writing the same database
** file simultaneously, or one process from reading the database while
** another is writing.
**
** @(#) $Id: pager.c,v 1.143 2004/06/26 01:48:19 danielk1977 Exp $
*/
#include "os.h"         /* Must be first to enable large file support */
#include "sqliteInt.h"
#include "pager.h"
#include <assert.h>
#include <string.h>

................................................................................
**
** A journal file is opened if this is not a temporary file.  For temporary
** files, the opening of the journal file is deferred until there is an
** actual need to write to the journal.
**
** If the database is already reserved for writing, this routine is a no-op.
*/
int sqlite3pager_begin(void *pData, int dummy_fixme){
  PgHdr *pPg = DATA_TO_PGHDR(pData);
  Pager *pPager = pPg->pPager;
  int rc = SQLITE_OK;
  assert( pPg->nRef>0 );
  assert( pPager->state!=PAGER_UNLOCK );
  if( pPager->state==PAGER_SHARED ){
    assert( pPager->aInJournal==0 );
................................................................................
  ** written to the transaction journal or the ckeckpoint journal
  ** or both.
  **
  ** First check to see that the transaction journal exists and
  ** create it if it does not.
  */
  assert( pPager->state!=PAGER_UNLOCK );
  rc = sqlite3pager_begin(pData, 0);
  if( rc!=SQLITE_OK ){
    return rc;
  }
  assert( pPager->state>=PAGER_RESERVED );
  if( !pPager->journalOpen && pPager->useJournal ){
    rc = pager_open_journal(pPager);
    if( rc!=SQLITE_OK ) return rc;

** The pager is used to access a database disk file.  It implements
** atomic commit and rollback through the use of a journal file that
** is separate from the database file.  The pager also implements file
** locking to prevent two processes from writing the same database
** file simultaneously, or one process from reading the database while
** another is writing.
**
** @(#) $Id: pager.c,v 1.144 2004/06/26 08:38:25 danielk1977 Exp $
*/
#include "os.h"         /* Must be first to enable large file support */
#include "sqliteInt.h"
#include "pager.h"
#include <assert.h>
#include <string.h>

................................................................................
**
** A journal file is opened if this is not a temporary file.  For temporary
** files, the opening of the journal file is deferred until there is an
** actual need to write to the journal.
**
** If the database is already reserved for writing, this routine is a no-op.
*/
int sqlite3pager_begin(void *pData){
  PgHdr *pPg = DATA_TO_PGHDR(pData);
  Pager *pPager = pPg->pPager;
  int rc = SQLITE_OK;
  assert( pPg->nRef>0 );
  assert( pPager->state!=PAGER_UNLOCK );
  if( pPager->state==PAGER_SHARED ){
    assert( pPager->aInJournal==0 );
................................................................................
  ** written to the transaction journal or the ckeckpoint journal
  ** or both.
  **
  ** First check to see that the transaction journal exists and
  ** create it if it does not.
  */
  assert( pPager->state!=PAGER_UNLOCK );
  rc = sqlite3pager_begin(pData);
  if( rc!=SQLITE_OK ){
    return rc;
  }
  assert( pPager->state>=PAGER_RESERVED );
  if( !pPager->journalOpen && pPager->useJournal ){
    rc = pager_open_journal(pPager);
    if( rc!=SQLITE_OK ) return rc;

**    May you share freely, never taking more than you give.
**
*************************************************************************
** This header file defines the interface that the sqlite page cache
** subsystem.  The page cache subsystem reads and writes a file a page
** at a time and provides a journal for rollback.
**
** @(#) $Id: pager.h,v 1.34 2004/06/14 06:03:57 danielk1977 Exp $
*/

/*
** The size of a page.
**
** You can change this value to another (reasonable) value you want.
** It need not be a power of two, though the interface to the disk
................................................................................
int sqlite3pager_unref(void*);
Pgno sqlite3pager_pagenumber(void*);
int sqlite3pager_write(void*);
int sqlite3pager_iswriteable(void*);
int sqlite3pager_overwrite(Pager *pPager, Pgno pgno, void*);
int sqlite3pager_pagecount(Pager*);
int sqlite3pager_truncate(Pager*,Pgno);
int sqlite3pager_begin(void*,int);
int sqlite3pager_commit(Pager*);
int sqlite3pager_sync(Pager*,const char *zMaster);
int sqlite3pager_rollback(Pager*);
int sqlite3pager_isreadonly(Pager*);
int sqlite3pager_stmt_begin(Pager*);
int sqlite3pager_stmt_commit(Pager*);
int sqlite3pager_stmt_rollback(Pager*);

**    May you share freely, never taking more than you give.
**
*************************************************************************
** This header file defines the interface that the sqlite page cache
** subsystem.  The page cache subsystem reads and writes a file a page
** at a time and provides a journal for rollback.
**
** @(#) $Id: pager.h,v 1.35 2004/06/26 08:38:25 danielk1977 Exp $
*/

/*
** The size of a page.
**
** You can change this value to another (reasonable) value you want.
** It need not be a power of two, though the interface to the disk
................................................................................
int sqlite3pager_unref(void*);
Pgno sqlite3pager_pagenumber(void*);
int sqlite3pager_write(void*);
int sqlite3pager_iswriteable(void*);
int sqlite3pager_overwrite(Pager *pPager, Pgno pgno, void*);
int sqlite3pager_pagecount(Pager*);
int sqlite3pager_truncate(Pager*,Pgno);
int sqlite3pager_begin(void*);
int sqlite3pager_commit(Pager*);
int sqlite3pager_sync(Pager*,const char *zMaster);
int sqlite3pager_rollback(Pager*);
int sqlite3pager_isreadonly(Pager*);
int sqlite3pager_stmt_begin(Pager*);
int sqlite3pager_stmt_commit(Pager*);
int sqlite3pager_stmt_rollback(Pager*);

**    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.
**
*************************************************************************
** Internal interface definitions for SQLite.
**
** @(#) $Id: sqliteInt.h,v 1.300 2004/06/26 06:37:07 danielk1977 Exp $
*/
#ifndef _SQLITEINT_H_
#define _SQLITEINT_H_

#include "config.h"
#include "sqlite3.h"
#include "hash.h"
................................................................................
  void *pProgressArg;           /* Argument to the progress callback */
  int nProgressOps;             /* Number of opcodes for progress callback */
#endif

  int errCode;                  /* Most recent error code (SQLITE_*) */
  u8 enc;                       /* Text encoding for this database. */
  u8 autoCommit;                /* The auto-commit flag. */
  int nMaster;                  /* Length of master journal name. -1=unknown */
  void(*xCollNeeded)(void*,sqlite3*,int eTextRep,const char*);
  void(*xCollNeeded16)(void*,sqlite3*,int eTextRep,const void*);
  void *pCollNeededArg;
  sqlite3_value *pValue;        /* Value used for transient conversions */
  sqlite3_value *pErr;          /* Most recent error message */

  char *zErrMsg;                /* Most recent error message (UTF-8 encoded) */

**    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.
**
*************************************************************************
** Internal interface definitions for SQLite.
**
** @(#) $Id: sqliteInt.h,v 1.301 2004/06/26 08:38:25 danielk1977 Exp $
*/
#ifndef _SQLITEINT_H_
#define _SQLITEINT_H_

#include "config.h"
#include "sqlite3.h"
#include "hash.h"
................................................................................
  void *pProgressArg;           /* Argument to the progress callback */
  int nProgressOps;             /* Number of opcodes for progress callback */
#endif

  int errCode;                  /* Most recent error code (SQLITE_*) */
  u8 enc;                       /* Text encoding for this database. */
  u8 autoCommit;                /* The auto-commit flag. */

  void(*xCollNeeded)(void*,sqlite3*,int eTextRep,const char*);
  void(*xCollNeeded16)(void*,sqlite3*,int eTextRep,const void*);
  void *pCollNeededArg;
  sqlite3_value *pValue;        /* Value used for transient conversions */
  sqlite3_value *pErr;          /* Most recent error message */

  char *zErrMsg;                /* Most recent error message (UTF-8 encoded) */

**    May you share freely, never taking more than you give.
**
*************************************************************************
** Code for testing the btree.c module in SQLite.  This code
** is not included in the SQLite library.  It is used for automated
** testing of the SQLite library.
**
** $Id: test3.c,v 1.44 2004/06/17 00:01:21 danielk1977 Exp $
*/
#include "sqliteInt.h"
#include "pager.h"
#include "btree.h"
#include "tcl.h"
#include <stdlib.h>
#include <string.h>
................................................................................
  int rc;
  if( argc!=2 ){
    Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0],
       " ID\"", 0);
    return TCL_ERROR;
  }
  if( Tcl_GetInt(interp, argv[1], (int*)&pBt) ) return TCL_ERROR;
  rc = sqlite3BtreeBeginTrans(pBt, 1, 0);
  if( rc!=SQLITE_OK ){
    Tcl_AppendResult(interp, errorName(rc), 0);
    return TCL_ERROR;
  }
  return TCL_OK;
}

**    May you share freely, never taking more than you give.
**
*************************************************************************
** Code for testing the btree.c module in SQLite.  This code
** is not included in the SQLite library.  It is used for automated
** testing of the SQLite library.
**
** $Id: test3.c,v 1.45 2004/06/26 08:38:25 danielk1977 Exp $
*/
#include "sqliteInt.h"
#include "pager.h"
#include "btree.h"
#include "tcl.h"
#include <stdlib.h>
#include <string.h>
................................................................................
  int rc;
  if( argc!=2 ){
    Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0],
       " ID\"", 0);
    return TCL_ERROR;
  }
  if( Tcl_GetInt(interp, argv[1], (int*)&pBt) ) return TCL_ERROR;
  rc = sqlite3BtreeBeginTrans(pBt, 1);
  if( rc!=SQLITE_OK ){
    Tcl_AppendResult(interp, errorName(rc), 0);
    return TCL_ERROR;
  }
  return TCL_OK;
}

**
*************************************************************************
** This file contains code used to implement the VACUUM command.
**
** Most of the code in this file may be omitted by defining the
** SQLITE_OMIT_VACUUM macro.
**
** $Id: vacuum.c,v 1.23 2004/06/19 09:08:16 danielk1977 Exp $
*/
#include "sqliteInt.h"
#include "os.h"

#if !defined(SQLITE_OMIT_VACUUM) || SQLITE_OMIT_VACUUM
/*
** Generate a random name of 20 character in length.
................................................................................
  */
  pTemp = db->aDb[db->nDb-1].pBt;
  if( sqlite3BtreeIsInTrans(pTemp) ){
    Btree *pMain = db->aDb[0].pBt;
    u32 meta;

    assert( 0==sqlite3BtreeIsInTrans(pMain) );
    rc = sqlite3BtreeBeginTrans(pMain, 1, 0);
    if( rc!=SQLITE_OK ) goto end_of_vacuum;

    /* Copy Btree meta values 3 and 4. These correspond to SQL layer meta 
    ** values 2 and 3, the default values of a couple of pragmas.
    */
    rc = sqlite3BtreeGetMeta(pMain, 3, &meta);
    if( rc!=SQLITE_OK ) goto end_of_vacuum;

**
*************************************************************************
** This file contains code used to implement the VACUUM command.
**
** Most of the code in this file may be omitted by defining the
** SQLITE_OMIT_VACUUM macro.
**
** $Id: vacuum.c,v 1.24 2004/06/26 08:38:25 danielk1977 Exp $
*/
#include "sqliteInt.h"
#include "os.h"

#if !defined(SQLITE_OMIT_VACUUM) || SQLITE_OMIT_VACUUM
/*
** Generate a random name of 20 character in length.
................................................................................
  */
  pTemp = db->aDb[db->nDb-1].pBt;
  if( sqlite3BtreeIsInTrans(pTemp) ){
    Btree *pMain = db->aDb[0].pBt;
    u32 meta;

    assert( 0==sqlite3BtreeIsInTrans(pMain) );
    rc = sqlite3BtreeBeginTrans(pMain, 1);
    if( rc!=SQLITE_OK ) goto end_of_vacuum;

    /* Copy Btree meta values 3 and 4. These correspond to SQL layer meta 
    ** values 2 and 3, the default values of a couple of pragmas.
    */
    rc = sqlite3BtreeGetMeta(pMain, 3, &meta);
    if( rc!=SQLITE_OK ) goto end_of_vacuum;

**
** Various scripts scan this source file in order to generate HTML
** documentation, headers files, or other derived files.  The formatting
** of the code in this file is, therefore, important.  See other comments
** in this file for details.  If in doubt, do not deviate from existing
** commenting and indentation practices when changing or adding code.
**
** $Id: vdbe.c,v 1.388 2004/06/22 22:54:23 drh Exp $
*/
#include "sqliteInt.h"
#include "os.h"
#include <ctype.h>
#include "vdbeInt.h"

/*
................................................................................
  int i = pOp->p1;
  Btree *pBt;

  assert( i>=0 && i<db->nDb );
  pBt = db->aDb[i].pBt;

  if( pBt ){
    if( db->nMaster<0 ){
      db->nMaster = strlen(sqlite3BtreeGetFilename(db->aDb[0].pBt))+20;
    }
    rc = sqlite3BtreeBeginTrans(pBt, pOp->p2, db->nMaster);
    if( rc==SQLITE_BUSY ){
      p->pc = pc;
      p->rc = SQLITE_BUSY;
      p->pTos = pTos;
      return SQLITE_BUSY;
    }
    if( rc!=SQLITE_OK && rc!=SQLITE_READONLY /* && rc!=SQLITE_BUSY */ ){
................................................................................
  int i = pOp->p1;
  Cursor *pCx;
  assert( i>=0 );
  pCx = allocateCursor(p, i);
  if( pCx==0 ) goto no_mem;
  pCx->nullRow = 1;
  rc = sqlite3BtreeFactory(db, 0, 1, TEMP_PAGES, &pCx->pBt);

  if( rc==SQLITE_OK ){
    rc = sqlite3BtreeBeginTrans(pCx->pBt, 1, 0);
  }
  if( rc==SQLITE_OK ){
    /* If a transient index is required, create it by calling
    ** sqlite3BtreeCreateTable() with the BTREE_ZERODATA flag before
    ** opening it. If a transient table is required, just use the
    ** automatically created table with root-page 1 (an INTKEY table).
    */

**
** Various scripts scan this source file in order to generate HTML
** documentation, headers files, or other derived files.  The formatting
** of the code in this file is, therefore, important.  See other comments
** in this file for details.  If in doubt, do not deviate from existing
** commenting and indentation practices when changing or adding code.
**
** $Id: vdbe.c,v 1.389 2004/06/26 08:38:25 danielk1977 Exp $
*/
#include "sqliteInt.h"
#include "os.h"
#include <ctype.h>
#include "vdbeInt.h"

/*
................................................................................
  int i = pOp->p1;
  Btree *pBt;

  assert( i>=0 && i<db->nDb );
  pBt = db->aDb[i].pBt;

  if( pBt ){



    rc = sqlite3BtreeBeginTrans(pBt, pOp->p2);
    if( rc==SQLITE_BUSY ){
      p->pc = pc;
      p->rc = SQLITE_BUSY;
      p->pTos = pTos;
      return SQLITE_BUSY;
    }
    if( rc!=SQLITE_OK && rc!=SQLITE_READONLY /* && rc!=SQLITE_BUSY */ ){
................................................................................
  int i = pOp->p1;
  Cursor *pCx;
  assert( i>=0 );
  pCx = allocateCursor(p, i);
  if( pCx==0 ) goto no_mem;
  pCx->nullRow = 1;
  rc = sqlite3BtreeFactory(db, 0, 1, TEMP_PAGES, &pCx->pBt);

  if( rc==SQLITE_OK ){
    rc = sqlite3BtreeBeginTrans(pCx->pBt, 1);
  }
  if( rc==SQLITE_OK ){
    /* If a transient index is required, create it by calling
    ** sqlite3BtreeCreateTable() with the BTREE_ZERODATA flag before
    ** opening it. If a transient table is required, just use the
    ** automatically created table with root-page 1 (an INTKEY table).
    */

  ** If db is NULL, then close the temporary btree if it is open.
  */
  if( db ){
    if( !pAgg->pBtree ){
      assert( pAgg->nTab==0 );
      rc = sqlite3BtreeFactory(db, ":memory:", 0, TEMP_PAGES, &pAgg->pBtree);
      if( rc!=SQLITE_OK ) return rc;
      sqlite3BtreeBeginTrans(pAgg->pBtree, 1, 0);
      rc = sqlite3BtreeCreateTable(pAgg->pBtree, &pAgg->nTab, 0);
      if( rc!=SQLITE_OK ) return rc;
    }
    assert( pAgg->nTab!=0 );

    rc = sqlite3BtreeCursor(pAgg->pBtree, pAgg->nTab, 1,
        sqlite3VdbeRecordCompare, pKeyInfo, &pAgg->pCsr);
................................................................................
  /* If there are any write-transactions at all, invoke the commit hook */
  if( needXcommit && db->xCommitCallback ){
    if( db->xCommitCallback(db->pCommitArg) ){
      return SQLITE_CONSTRAINT;
    }
  }

  /* The simple case - no more than one database file (not counting the TEMP
  ** database) has a transaction active.   There is no need for the
  ** master-journal.
  **

  ** if db->nMaster==0, it means the main database is :memory:.  In that case
  ** we do not support atomic multi-file commits, so use the simple case then
  ** too.
  */
  if( db->nMaster<=0 || nTrans<=1 ){

    for(i=0; rc==SQLITE_OK && i<db->nDb; i++){ 
      Btree *pBt = db->aDb[i].pBt;
      if( pBt ){
        rc = sqlite3BtreeSync(pBt, 0);
      }
    }

................................................................................
      zMaster = sqlite3MPrintf("%s-mj%08X", zMainFile, random&0x7fffffff);
      if( !zMaster ){
        return SQLITE_NOMEM;
      }
    }while( sqlite3OsFileExists(zMaster) );

    /* Open the master journal. */
    assert( strlen(zMaster)<db->nMaster );
    memset(&master, 0, sizeof(master));
    rc = sqlite3OsOpenExclusive(zMaster, &master, 0);
    if( rc!=SQLITE_OK ){
      sqliteFree(zMaster);
      return rc;
    }
 

  ** If db is NULL, then close the temporary btree if it is open.
  */
  if( db ){
    if( !pAgg->pBtree ){
      assert( pAgg->nTab==0 );
      rc = sqlite3BtreeFactory(db, ":memory:", 0, TEMP_PAGES, &pAgg->pBtree);
      if( rc!=SQLITE_OK ) return rc;
      sqlite3BtreeBeginTrans(pAgg->pBtree, 1);
      rc = sqlite3BtreeCreateTable(pAgg->pBtree, &pAgg->nTab, 0);
      if( rc!=SQLITE_OK ) return rc;
    }
    assert( pAgg->nTab!=0 );

    rc = sqlite3BtreeCursor(pAgg->pBtree, pAgg->nTab, 1,
        sqlite3VdbeRecordCompare, pKeyInfo, &pAgg->pCsr);
................................................................................
  /* If there are any write-transactions at all, invoke the commit hook */
  if( needXcommit && db->xCommitCallback ){
    if( db->xCommitCallback(db->pCommitArg) ){
      return SQLITE_CONSTRAINT;
    }
  }

  /* The simple case - no more than one database file (not counting the
  ** TEMP database) has a transaction active.   There is no need for the
  ** master-journal.
  **
  ** If the return value of sqlite3BtreeGetFilename() is a zero length
  ** string, it means the main database is :memory:.  In that case we do
  ** not support atomic multi-file commits, so use the simple case then
  ** too.
  */

  if( 0==strlen(sqlite3BtreeGetFilename(db->aDb[0].pBt)) || nTrans<=1 ){
    for(i=0; rc==SQLITE_OK && i<db->nDb; i++){ 
      Btree *pBt = db->aDb[i].pBt;
      if( pBt ){
        rc = sqlite3BtreeSync(pBt, 0);
      }
    }

................................................................................
      zMaster = sqlite3MPrintf("%s-mj%08X", zMainFile, random&0x7fffffff);
      if( !zMaster ){
        return SQLITE_NOMEM;
      }
    }while( sqlite3OsFileExists(zMaster) );

    /* Open the master journal. */

    memset(&master, 0, sizeof(master));
    rc = sqlite3OsOpenExclusive(zMaster, &master, 0);
    if( rc!=SQLITE_OK ){
      sqliteFree(zMaster);
      return rc;
    }