SQLite

** on how SQLite interfaces are suppose to operate.
**
** The name of this file under configuration management is "sqlite.h.in".
** The makefile makes some minor changes to this file (such as inserting
** the version number) and changes its name to "sqlite3.h" as
** part of the build process.
**
** @(#) $Id: sqlite.h.in,v 1.315 2008/05/20 18:43:38 drh Exp $
** @(#) $Id: sqlite.h.in,v 1.316 2008/05/21 13:44:14 drh Exp $
*/
#ifndef _SQLITE3_H_
#define _SQLITE3_H_
#include <stdarg.h>     /* Needed for the definition of va_list */

/*
** Make sure we can call this stuff from C++.

** "DELETE FROM table" are not row changes and will not be counted
** by the sqlite3_changes() or [sqlite3_total_changes()] functions.
** To get an accurate count of the number of rows deleted, use
** "DELETE FROM table WHERE 1" instead.
**
** INVARIANTS:
**
** {F12241} The [sqlite3_changes()] function returns the number of
** {F12241} The [sqlite3_changes()] function shall return the number of
**          row changes caused by the most recent INSERT, UPDATE,
**          or DELETE statement on the same database connection and
**          within the same trigger context, or zero if there have
**          within the same or higher trigger context, or zero if there have
**          not been any qualifying row changes.
**
** {F12243} Statements of the form "DELETE FROM tablename" with no
**          WHERE clause shall cause subsequent calls to 
**          [sqlite3_changes()] to return zero, regardless of the
**          number of rows originally in the table.
**
** LIMITATIONS:
**
** {U12252} If a separate thread makes changes on the same database connection
**          while [sqlite3_changes()] is running then the value returned
**          is unpredictable and unmeaningful.
*/

** INVARIANTS:
** 
** {F12261} The [sqlite3_total_changes()] returns the total number
**          of row changes caused by INSERT, UPDATE, and/or DELETE
**          statements on the same [database connection], in any
**          trigger context, since the database connection was
**          created.
**
** {F12263} Statements of the form "DELETE FROM tablename" with no
**          WHERE clause shall not change the value returned
**          by [sqlite3_total_changes()]
**
** LIMITATIONS:
**
** {U12264} If a separate thread makes changes on the same database connection
**          while [sqlite3_total_changes()] is running then the value 
**          returned is unpredictable and unmeaningful.
*/

**
*************************************************************************
** 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 1.78 2008/04/30 16:38:23 drh Exp $
** $Id: vacuum.c,v 1.79 2008/05/21 13:44:14 drh Exp $
*/
#include "sqliteInt.h"
#include "vdbeInt.h"

#if !defined(SQLITE_OMIT_VACUUM) && !defined(SQLITE_OMIT_ATTACH)
/*
** Execute zSql on database db. Return an error code.

*/
int sqlite3RunVacuum(char **pzErrMsg, sqlite3 *db){
  int rc = SQLITE_OK;     /* Return code from service routines */
  Btree *pMain;           /* The database being vacuumed */
  Btree *pTemp;           /* The temporary database we vacuum into */
  char *zSql = 0;         /* SQL statements */
  int saved_flags;        /* Saved value of the db->flags */
  int saved_nChange;      /* Saved value of db->nChange */
  int saved_nTotalChange; /* Saved value of db->nTotalChange */
  Db *pDb = 0;            /* Database to detach at end of vacuum */
  int nRes;

  /* Save the current value of the write-schema flag before setting it. */
  saved_flags = db->flags;
  saved_nChange = db->nChange;
  saved_nTotalChange = db->nTotalChange;
  db->flags |= SQLITE_WriteSchema | SQLITE_IgnoreChecks;

  if( !db->autoCommit ){
    sqlite3SetString(pzErrMsg, "cannot VACUUM from within a transaction", 
       (char*)0);
    rc = SQLITE_ERROR;
    goto end_of_vacuum;

  if( rc==SQLITE_OK ){
    rc = sqlite3BtreeSetPageSize(pMain, sqlite3BtreeGetPageSize(pTemp), nRes);
  }

end_of_vacuum:
  /* Restore the original value of db->flags */
  db->flags = saved_flags;
  db->nChange = saved_nChange;
  db->nTotalChange = saved_nTotalChange;

  /* Currently there is an SQL level transaction open on the vacuum
  ** database. No locks are held on any other files (since the main file
  ** was committed at the btree level). So it safe to end the transaction
  ** by manually setting the autoCommit flag to true and detaching the
  ** vacuum database. The vacuum_db journal file is deleted when the pager
  ** is closed by the DETACH.