** either SQLITE_IOERR or SQLITE_FULL during rollback or while finalizing 
  ** a journal file. (although the in-memory journal implementation may 
  ** return SQLITE_IOERR_NOMEM while the journal file is being written). It 
  ** is therefore not possible for an in-memory pager to enter the ERROR 
  ** state.
  */
  if( MEMDB ){

    assert( p->noSync );
    assert( p->journalMode==PAGER_JOURNALMODE_OFF 
         || p->journalMode==PAGER_JOURNALMODE_MEMORY 
    );
    assert( p->eState!=PAGER_ERROR && p->eState!=PAGER_OPEN );
    assert( pagerUseWal(p)==0 );
  }
................................................................................

    case PAGER_ERROR:
      /* There must be at least one outstanding reference to the pager if
      ** in ERROR state. Otherwise the pager should have already dropped
      ** back to OPEN state.
      */
      assert( pPager->errCode!=SQLITE_OK );
      assert( sqlite3PcacheRefCount(pPager->pPCache)>0 );
      break;
  }

  return 1;
}
#endif /* ifndef NDEBUG */

................................................................................
    if( 0==(dc&(SQLITE_IOCAP_ATOMIC|(szPage>>8)) || nSector>szPage) ){
      return 0;
    }
  }

  return JOURNAL_HDR_SZ(pPager) + JOURNAL_PG_SZ(pPager);
}


#endif

/*
** If SQLITE_CHECK_PAGES is defined then we do some sanity checking
** on the cache using a hash function.  This is used for testing
** and debugging only.
*/
................................................................................
  }

  /* If Pager.errCode is set, the contents of the pager cache cannot be
  ** trusted. Now that there are no outstanding references to the pager,
  ** it can safely move back to PAGER_OPEN state. This happens in both
  ** normal and exclusive-locking mode.
  */

  if( pPager->errCode ){
    assert( !MEMDB );

    pager_reset(pPager);
    pPager->changeCountDone = pPager->tempFile;
    pPager->eState = PAGER_OPEN;
    pPager->errCode = SQLITE_OK;



    if( USEFETCH(pPager) ) sqlite3OsUnfetch(pPager->fd, 0, 0);

  }

  pPager->journalOff = 0;
  pPager->journalHdr = 0;
  pPager->setMaster = 0;
}

................................................................................
    pPager->errCode = rc;
    pPager->eState = PAGER_ERROR;
  }
  return rc;
}

static int pager_truncate(Pager *pPager, Pgno nPage);




















/*
** This routine ends a transaction. A transaction is usually ended by 
** either a COMMIT or a ROLLBACK operation. This routine may be called 
** after rollback of a hot-journal, or if an error occurs while opening
** the journal file or writing the very first journal-header of a
** database transaction.
................................................................................
    }
  }
#endif

  sqlite3BitvecDestroy(pPager->pInJournal);
  pPager->pInJournal = 0;
  pPager->nRec = 0;

  sqlite3PcacheCleanAll(pPager->pPCache);



  sqlite3PcacheTruncate(pPager->pPCache, pPager->dbSize);

  if( pagerUseWal(pPager) ){
    /* Drop the WAL write-lock, if any. Also, if the connection was in 
    ** locking_mode=exclusive mode but is no longer, drop the EXCLUSIVE 
    ** lock held on the database file.
    */
................................................................................
  */
  if( pagerUseWal(pPager) ){
    pPg = 0;
  }else{
    pPg = sqlite3PagerLookup(pPager, pgno);
  }
  assert( pPg || !MEMDB );
  assert( pPager->eState!=PAGER_OPEN || pPg==0 );
  PAGERTRACE(("PLAYBACK %d page %d hash(%08x) %s\n",
           PAGERID(pPager), pgno, pager_datahash(pPager->pageSize, (u8*)aData),
           (isMainJrnl?"main-journal":"sub-journal")
  ));
  if( isMainJrnl ){
    isSynced = pPager->noSync || (*pOffset <= pPager->journalHdr);
  }else{
................................................................................
      ** already in the journal file (recorded in Pager.pInJournal) and
      ** the PGHDR_NEED_SYNC flag is cleared, if the page is written to
      ** again within this transaction, it will be marked as dirty but
      ** the PGHDR_NEED_SYNC flag will not be set. It could then potentially
      ** be written out into the database file before its journal file
      ** segment is synced. If a crash occurs during or following this,
      ** database corruption may ensue.




      */
      assert( !pagerUseWal(pPager) );
      sqlite3PcacheMakeClean(pPg);
    }
    pager_set_pagehash(pPg);

    /* If this was page 1, then restore the value of Pager.dbFileVers.
    ** Do this before any decoding. */
    if( pgno==1 ){
      memcpy(&pPager->dbFileVers, &((u8*)pData)[24],sizeof(pPager->dbFileVers));
................................................................................
  ** function returns zero if the WAL is not open (i.e. Pager.pWal==0), or
  ** if the database size is not available. The database size is not
  ** available from the WAL sub-system if the log file is empty or
  ** contains no valid committed transactions.
  */
  assert( pPager->eState==PAGER_OPEN );
  assert( pPager->eLock>=SHARED_LOCK );


  nPage = sqlite3WalDbsize(pPager->pWal);

  /* If the number of pages in the database is not available from the
  ** WAL sub-system, determine the page counte based on the size of
  ** the database file.  If the size of the database file is not an
  ** integer multiple of the page-size, round up the result.
  */
  if( nPage==0 ){
    i64 n = 0;                    /* Size of db file in bytes */
    assert( isOpen(pPager->fd) || pPager->tempFile );
    if( isOpen(pPager->fd) ){
      int rc = sqlite3OsFileSize(pPager->fd, &n);
      if( rc!=SQLITE_OK ){
        return rc;
      }
    }
    nPage = (Pgno)((n+pPager->pageSize-1) / pPager->pageSize);
  }

  /* If the current number of pages in the file is greater than the
  ** configured maximum pager number, increase the allowed limit so
  ** that the file can be read.
................................................................................
** be obtained, SQLITE_BUSY is returned.
*/
static int pager_write_pagelist(Pager *pPager, PgHdr *pList){
  int rc = SQLITE_OK;                  /* Return code */

  /* This function is only called for rollback pagers in WRITER_DBMOD state. */
  assert( !pagerUseWal(pPager) );
  assert( pPager->eState==PAGER_WRITER_DBMOD );
  assert( pPager->eLock==EXCLUSIVE_LOCK );


  /* If the file is a temp-file has not yet been opened, open it now. It
  ** is not possible for rc to be other than SQLITE_OK if this branch
  ** is taken, as pager_wait_on_lock() is a no-op for temp-files.
  */
  if( !isOpen(pPager->fd) ){
    assert( pPager->tempFile && rc==SQLITE_OK );
................................................................................
    ** in fact there is none.  This results in a false-positive which will
    ** be dealt with by the playback routine.  Ticket #3883.
    */
    rc = sqlite3OsCheckReservedLock(pPager->fd, &locked);
    if( rc==SQLITE_OK && !locked ){
      Pgno nPage;                 /* Number of pages in database file */


      rc = pagerPagecount(pPager, &nPage);
      if( rc==SQLITE_OK ){
        /* If the database is zero pages in size, that means that either (1) the
        ** journal is a remnant from a prior database with the same name where
        ** the database file but not the journal was deleted, or (2) the initial
        ** transaction that populates a new database is being rolled back.
        ** In either case, the journal file can be deleted.  However, take care
................................................................................
*/
int sqlite3PagerSharedLock(Pager *pPager){
  int rc = SQLITE_OK;                /* Return code */

  /* This routine is only called from b-tree and only when there are no
  ** outstanding pages. This implies that the pager state should either
  ** be OPEN or READER. READER is only possible if the pager is or was in 
  ** exclusive access mode.
  */
  assert( sqlite3PcacheRefCount(pPager->pPCache)==0 );
  assert( assert_pager_state(pPager) );
  assert( pPager->eState==PAGER_OPEN || pPager->eState==PAGER_READER );
  if( NEVER(MEMDB && pPager->errCode) ){ return pPager->errCode; }

  if( !pagerUseWal(pPager) && pPager->eState==PAGER_OPEN ){
    int bHotJournal = 1;          /* True if there exists a hot journal-file */

    assert( !MEMDB );


    rc = pager_wait_on_lock(pPager, SHARED_LOCK);
    if( rc!=SQLITE_OK ){
      assert( pPager->eLock==NO_LOCK || pPager->eLock==UNKNOWN_LOCK );
      goto failed;
    }

................................................................................
      ** probably did not sync it and we are required to always sync
      ** the journal before playing it back.
      */
      if( isOpen(pPager->jfd) ){
        assert( rc==SQLITE_OK );
        rc = pagerSyncHotJournal(pPager);
        if( rc==SQLITE_OK ){
          rc = pager_playback(pPager, 1);
          pPager->eState = PAGER_OPEN;
        }
      }else if( !pPager->exclusiveMode ){
        pagerUnlockDb(pPager, SHARED_LOCK);
      }

      if( rc!=SQLITE_OK ){
................................................................................
  }

  if( pagerUseWal(pPager) ){
    assert( rc==SQLITE_OK );
    rc = pagerBeginReadTransaction(pPager);
  }

  if( pPager->eState==PAGER_OPEN && rc==SQLITE_OK ){
    rc = pagerPagecount(pPager, &pPager->dbSize);
  }

 failed:
  if( rc!=SQLITE_OK ){
    assert( !MEMDB );
    pager_unlock(pPager);
................................................................................
      void *pData = 0;

      rc = sqlite3OsFetch(pPager->fd, 
          (i64)(pgno-1) * pPager->pageSize, pPager->pageSize, &pData
      );

      if( rc==SQLITE_OK && pData ){
        if( pPager->eState>PAGER_READER ){
          pPg = sqlite3PagerLookup(pPager, pgno);
        }
        if( pPg==0 ){
          rc = pagerAcquireMapPage(pPager, pgno, pData, &pPg);
        }else{
          sqlite3OsUnfetch(pPager->fd, (i64)(pgno-1)*pPager->pageSize, pData);
        }
................................................................................
    /* The maximum page number is 2^31. Return SQLITE_CORRUPT if a page
    ** number greater than this, or the unused locking-page, is requested. */
    if( pgno>PAGER_MAX_PGNO || pgno==PAGER_MJ_PGNO(pPager) ){
      rc = SQLITE_CORRUPT_BKPT;
      goto pager_acquire_err;
    }


    if( MEMDB || pPager->dbSize<pgno || noContent || !isOpen(pPager->fd) ){
      if( pgno>pPager->mxPgno ){
        rc = SQLITE_FULL;
        goto pager_acquire_err;
      }
      if( noContent ){
        /* Failure to set the bits in the InJournal bit-vectors is benign.
        ** It merely means that we might do some extra work to journal a 
................................................................................
    }
  
    /* Open the journal file if it is not already open. */
    if( !isOpen(pPager->jfd) ){
      if( pPager->journalMode==PAGER_JOURNALMODE_MEMORY ){
        sqlite3MemJournalOpen(pPager->jfd);
      }else{
        const int flags =                   /* VFS flags to open journal file */
          SQLITE_OPEN_READWRITE|SQLITE_OPEN_CREATE|


          (pPager->tempFile ? 
            (SQLITE_OPEN_DELETEONCLOSE|SQLITE_OPEN_TEMP_JOURNAL):


            (SQLITE_OPEN_MAIN_JOURNAL)
          );



        /* Verify that the database still has the same name as it did when
        ** it was originally opened. */
        rc = databaseIsUnmoved(pPager);
        if( rc==SQLITE_OK ){
#ifdef SQLITE_ENABLE_ATOMIC_WRITE
          rc = sqlite3JournalOpen(
              pVfs, pPager->zJournal, pPager->jfd, flags, jrnlBufferSize(pPager)
          );
#else
          rc = sqlite3OsOpen(pVfs, pPager->zJournal, pPager->jfd, flags, 0);
#endif
        }
      }
      assert( rc!=SQLITE_OK || isOpen(pPager->jfd) );
    }
  
  
    /* Write the first journal header to the journal file and open 
................................................................................
  assert( assert_pager_state(pPager) );
  if( pPager->errCode ){
    return pPager->errCode;
  }else if( (pPg->flags & PGHDR_WRITEABLE)!=0 && pPager->dbSize>=pPg->pgno ){
    if( pPager->nSavepoint ) return subjournalPageIfRequired(pPg);
    return SQLITE_OK;
  }else if( pPager->sectorSize > (u32)pPager->pageSize ){

    return pagerWriteLargeSector(pPg);
  }else{
    return pager_write(pPg);
  }
}

/*
................................................................................
       || pPager->eState==PAGER_WRITER_DBMOD
       || pPager->eState==PAGER_ERROR
  );
  assert( assert_pager_state(pPager) );

  /* If a prior error occurred, report that error again. */
  if( NEVER(pPager->errCode) ) return pPager->errCode;




  PAGERTRACE(("DATABASE SYNC: File=%s zMaster=%s nSize=%d\n", 
      pPager->zFilename, zMaster, pPager->dbSize));

  /* If no database changes have been made, return early. */
  if( pPager->eState<PAGER_WRITER_CACHEMOD ) return SQLITE_OK;

  if( MEMDB ){


    /* If this is an in-memory db, or no pages have been written to, or this
    ** function has already been called, it is mostly a no-op.  However, any
    ** backup in progress needs to be restarted.
    */
    sqlite3BackupRestart(pPager->pBackup);
  }else{
    if( pagerUseWal(pPager) ){
      PgHdr *pList = sqlite3PcacheDirtyList(pPager->pPCache);
      PgHdr *pPageOne = 0;
      if( pList==0 ){
        /* Must have at least one page for the WAL commit flag.
................................................................................
  *pnVal += pPager->aStat[eStat - SQLITE_DBSTATUS_CACHE_HIT];
  if( reset ){
    pPager->aStat[eStat - SQLITE_DBSTATUS_CACHE_HIT] = 0;
  }
}

/*
** Return true if this is an in-memory pager.
*/
int sqlite3PagerIsMemdb(Pager *pPager){
  return MEMDB;
}

/*
** Check that there are at least nSavepoint savepoints open. If there are
** currently less than nSavepoints open, then open one or more savepoints
** to make up the difference. If the number of savepoints is already
** equal to nSavepoint, then this function is a no-op.
................................................................................
       || pPager->eState==PAGER_WRITER_DBMOD
  );
  assert( assert_pager_state(pPager) );

  /* In order to be able to rollback, an in-memory database must journal
  ** the page we are moving from.
  */
  if( MEMDB ){
    rc = sqlite3PagerWrite(pPg);
    if( rc ) return rc;
  }

  /* If the page being moved is dirty and has not been saved by the latest
  ** savepoint, then save the current contents of the page into the 
  ** sub-journal now. This is required to handle the following scenario:
................................................................................
  ** for the page moved there.
  */
  pPg->flags &= ~PGHDR_NEED_SYNC;
  pPgOld = sqlite3PagerLookup(pPager, pgno);
  assert( !pPgOld || pPgOld->nRef==1 );
  if( pPgOld ){
    pPg->flags |= (pPgOld->flags&PGHDR_NEED_SYNC);
    if( MEMDB ){
      /* Do not discard pages from an in-memory database since we might
      ** need to rollback later.  Just move the page out of the way. */
      sqlite3PcacheMove(pPgOld, pPager->dbSize+1);
    }else{
      sqlite3PcacheDrop(pPgOld);
    }
  }
................................................................................
  sqlite3PcacheMove(pPg, pgno);
  sqlite3PcacheMakeDirty(pPg);

  /* For an in-memory database, make sure the original page continues
  ** to exist, in case the transaction needs to roll back.  Use pPgOld
  ** as the original page since it has already been allocated.
  */
  if( MEMDB ){
    assert( pPgOld );
    sqlite3PcacheMove(pPgOld, origPgno);
    sqlite3PagerUnrefNotNull(pPgOld);
  }

  if( needSyncPgno ){
    /* If needSyncPgno is non-zero, then the journal file needs to be 
................................................................................
}

#ifndef SQLITE_OMIT_VACUUM
/*
** Unless this is an in-memory or temporary database, clear the pager cache.
*/
void sqlite3PagerClearCache(Pager *pPager){

  if( !MEMDB && pPager->tempFile==0 ) pager_reset(pPager);
}
#endif

#ifndef SQLITE_OMIT_WAL
/*
** This function is called when the user invokes "PRAGMA wal_checkpoint",
** "PRAGMA wal_blocking_checkpoint" or calls the sqlite3_wal_checkpoint()

  ** either SQLITE_IOERR or SQLITE_FULL during rollback or while finalizing 
  ** a journal file. (although the in-memory journal implementation may 
  ** return SQLITE_IOERR_NOMEM while the journal file is being written). It 
  ** is therefore not possible for an in-memory pager to enter the ERROR 
  ** state.
  */
  if( MEMDB ){
    assert( !isOpen(p->fd) );
    assert( p->noSync );
    assert( p->journalMode==PAGER_JOURNALMODE_OFF 
         || p->journalMode==PAGER_JOURNALMODE_MEMORY 
    );
    assert( p->eState!=PAGER_ERROR && p->eState!=PAGER_OPEN );
    assert( pagerUseWal(p)==0 );
  }
................................................................................

    case PAGER_ERROR:
      /* There must be at least one outstanding reference to the pager if
      ** in ERROR state. Otherwise the pager should have already dropped
      ** back to OPEN state.
      */
      assert( pPager->errCode!=SQLITE_OK );
      assert( sqlite3PcacheRefCount(pPager->pPCache)>0 || pPager->tempFile );
      break;
  }

  return 1;
}
#endif /* ifndef NDEBUG */

................................................................................
    if( 0==(dc&(SQLITE_IOCAP_ATOMIC|(szPage>>8)) || nSector>szPage) ){
      return 0;
    }
  }

  return JOURNAL_HDR_SZ(pPager) + JOURNAL_PG_SZ(pPager);
}
#else
# define jrnlBufferSize(x) 0
#endif

/*
** If SQLITE_CHECK_PAGES is defined then we do some sanity checking
** on the cache using a hash function.  This is used for testing
** and debugging only.
*/
................................................................................
  }

  /* If Pager.errCode is set, the contents of the pager cache cannot be
  ** trusted. Now that there are no outstanding references to the pager,
  ** it can safely move back to PAGER_OPEN state. This happens in both
  ** normal and exclusive-locking mode.
  */
  assert( pPager->errCode==SQLITE_OK || !MEMDB );
  if( pPager->errCode ){

    if( pPager->tempFile==0 ){
      pager_reset(pPager);
      pPager->changeCountDone = 0;
      pPager->eState = PAGER_OPEN;

    }else{
      pPager->eState = (isOpen(pPager->jfd) ? PAGER_OPEN : PAGER_READER);
    }
    if( USEFETCH(pPager) ) sqlite3OsUnfetch(pPager->fd, 0, 0);
    pPager->errCode = SQLITE_OK;
  }

  pPager->journalOff = 0;
  pPager->journalHdr = 0;
  pPager->setMaster = 0;
}

................................................................................
    pPager->errCode = rc;
    pPager->eState = PAGER_ERROR;
  }
  return rc;
}

static int pager_truncate(Pager *pPager, Pgno nPage);

/*
** The write transaction open on the pager passed as the only argument is
** being committed. This function returns true if all dirty pages should
** be flushed to disk, or false otherwise. Pages should be flushed to disk
** unless one of the following is true:
**
**   * The db is an in-memory database.
**
**   * The db is a temporary database and the db file has not been opened.
**
**   * The db is a temporary database and the cache contains less than
**     C/4 dirty pages, where C is the configured cache-size.
*/
static int pagerFlushOnCommit(Pager *pPager){
  if( pPager->tempFile==0 ) return 1;
  if( !isOpen(pPager->fd) ) return 0;
  return (sqlite3PCachePercentDirty(pPager->pPCache)>=25);
}

/*
** This routine ends a transaction. A transaction is usually ended by 
** either a COMMIT or a ROLLBACK operation. This routine may be called 
** after rollback of a hot-journal, or if an error occurs while opening
** the journal file or writing the very first journal-header of a
** database transaction.
................................................................................
    }
  }
#endif

  sqlite3BitvecDestroy(pPager->pInJournal);
  pPager->pInJournal = 0;
  pPager->nRec = 0;
  if( MEMDB || pagerFlushOnCommit(pPager) ){
    sqlite3PcacheCleanAll(pPager->pPCache);
  }else{
    sqlite3PcacheClearWritable(pPager->pPCache);
  }
  sqlite3PcacheTruncate(pPager->pPCache, pPager->dbSize);

  if( pagerUseWal(pPager) ){
    /* Drop the WAL write-lock, if any. Also, if the connection was in 
    ** locking_mode=exclusive mode but is no longer, drop the EXCLUSIVE 
    ** lock held on the database file.
    */
................................................................................
  */
  if( pagerUseWal(pPager) ){
    pPg = 0;
  }else{
    pPg = sqlite3PagerLookup(pPager, pgno);
  }
  assert( pPg || !MEMDB );
  assert( pPager->eState!=PAGER_OPEN || pPg==0 || pPager->tempFile );
  PAGERTRACE(("PLAYBACK %d page %d hash(%08x) %s\n",
           PAGERID(pPager), pgno, pager_datahash(pPager->pageSize, (u8*)aData),
           (isMainJrnl?"main-journal":"sub-journal")
  ));
  if( isMainJrnl ){
    isSynced = pPager->noSync || (*pOffset <= pPager->journalHdr);
  }else{
................................................................................
      ** already in the journal file (recorded in Pager.pInJournal) and
      ** the PGHDR_NEED_SYNC flag is cleared, if the page is written to
      ** again within this transaction, it will be marked as dirty but
      ** the PGHDR_NEED_SYNC flag will not be set. It could then potentially
      ** be written out into the database file before its journal file
      ** segment is synced. If a crash occurs during or following this,
      ** database corruption may ensue.
      **
      ** Update: Another exception is for temp files that are not 
      ** in-memory databases. In this case the page may have been dirty
      ** at the start of the transaction.
      */
      assert( !pagerUseWal(pPager) );
      if( pPager->tempFile==0 ) sqlite3PcacheMakeClean(pPg);
    }
    pager_set_pagehash(pPg);

    /* If this was page 1, then restore the value of Pager.dbFileVers.
    ** Do this before any decoding. */
    if( pgno==1 ){
      memcpy(&pPager->dbFileVers, &((u8*)pData)[24],sizeof(pPager->dbFileVers));
................................................................................
  ** function returns zero if the WAL is not open (i.e. Pager.pWal==0), or
  ** if the database size is not available. The database size is not
  ** available from the WAL sub-system if the log file is empty or
  ** contains no valid committed transactions.
  */
  assert( pPager->eState==PAGER_OPEN );
  assert( pPager->eLock>=SHARED_LOCK );
  assert( isOpen(pPager->fd) );
  assert( pPager->tempFile==0 );
  nPage = sqlite3WalDbsize(pPager->pWal);

  /* If the number of pages in the database is not available from the
  ** WAL sub-system, determine the page counte based on the size of
  ** the database file.  If the size of the database file is not an
  ** integer multiple of the page-size, round up the result.
  */
  if( nPage==0 && ALWAYS(isOpen(pPager->fd)) ){
    i64 n = 0;                    /* Size of db file in bytes */


    int rc = sqlite3OsFileSize(pPager->fd, &n);
    if( rc!=SQLITE_OK ){
      return rc;

    }
    nPage = (Pgno)((n+pPager->pageSize-1) / pPager->pageSize);
  }

  /* If the current number of pages in the file is greater than the
  ** configured maximum pager number, increase the allowed limit so
  ** that the file can be read.
................................................................................
** be obtained, SQLITE_BUSY is returned.
*/
static int pager_write_pagelist(Pager *pPager, PgHdr *pList){
  int rc = SQLITE_OK;                  /* Return code */

  /* This function is only called for rollback pagers in WRITER_DBMOD state. */
  assert( !pagerUseWal(pPager) );
  assert( pPager->tempFile || pPager->eState==PAGER_WRITER_DBMOD );
  assert( pPager->eLock==EXCLUSIVE_LOCK );
  assert( isOpen(pPager->fd) || pList->pDirty==0 );

  /* If the file is a temp-file has not yet been opened, open it now. It
  ** is not possible for rc to be other than SQLITE_OK if this branch
  ** is taken, as pager_wait_on_lock() is a no-op for temp-files.
  */
  if( !isOpen(pPager->fd) ){
    assert( pPager->tempFile && rc==SQLITE_OK );
................................................................................
    ** in fact there is none.  This results in a false-positive which will
    ** be dealt with by the playback routine.  Ticket #3883.
    */
    rc = sqlite3OsCheckReservedLock(pPager->fd, &locked);
    if( rc==SQLITE_OK && !locked ){
      Pgno nPage;                 /* Number of pages in database file */

      assert( pPager->tempFile==0 );
      rc = pagerPagecount(pPager, &nPage);
      if( rc==SQLITE_OK ){
        /* If the database is zero pages in size, that means that either (1) the
        ** journal is a remnant from a prior database with the same name where
        ** the database file but not the journal was deleted, or (2) the initial
        ** transaction that populates a new database is being rolled back.
        ** In either case, the journal file can be deleted.  However, take care
................................................................................
*/
int sqlite3PagerSharedLock(Pager *pPager){
  int rc = SQLITE_OK;                /* Return code */

  /* This routine is only called from b-tree and only when there are no
  ** outstanding pages. This implies that the pager state should either
  ** be OPEN or READER. READER is only possible if the pager is or was in 
  ** exclusive access mode.  */

  assert( sqlite3PcacheRefCount(pPager->pPCache)==0 );
  assert( assert_pager_state(pPager) );
  assert( pPager->eState==PAGER_OPEN || pPager->eState==PAGER_READER );
  assert( pPager->errCode==SQLITE_OK );

  if( !pagerUseWal(pPager) && pPager->eState==PAGER_OPEN ){
    int bHotJournal = 1;          /* True if there exists a hot journal-file */

    assert( !MEMDB );
    assert( pPager->tempFile==0 || pPager->eLock==EXCLUSIVE_LOCK );

    rc = pager_wait_on_lock(pPager, SHARED_LOCK);
    if( rc!=SQLITE_OK ){
      assert( pPager->eLock==NO_LOCK || pPager->eLock==UNKNOWN_LOCK );
      goto failed;
    }

................................................................................
      ** probably did not sync it and we are required to always sync
      ** the journal before playing it back.
      */
      if( isOpen(pPager->jfd) ){
        assert( rc==SQLITE_OK );
        rc = pagerSyncHotJournal(pPager);
        if( rc==SQLITE_OK ){
          rc = pager_playback(pPager, !pPager->tempFile);
          pPager->eState = PAGER_OPEN;
        }
      }else if( !pPager->exclusiveMode ){
        pagerUnlockDb(pPager, SHARED_LOCK);
      }

      if( rc!=SQLITE_OK ){
................................................................................
  }

  if( pagerUseWal(pPager) ){
    assert( rc==SQLITE_OK );
    rc = pagerBeginReadTransaction(pPager);
  }

  if( pPager->tempFile==0 && pPager->eState==PAGER_OPEN && rc==SQLITE_OK ){
    rc = pagerPagecount(pPager, &pPager->dbSize);
  }

 failed:
  if( rc!=SQLITE_OK ){
    assert( !MEMDB );
    pager_unlock(pPager);
................................................................................
      void *pData = 0;

      rc = sqlite3OsFetch(pPager->fd, 
          (i64)(pgno-1) * pPager->pageSize, pPager->pageSize, &pData
      );

      if( rc==SQLITE_OK && pData ){
        if( pPager->eState>PAGER_READER || pPager->tempFile ){
          pPg = sqlite3PagerLookup(pPager, pgno);
        }
        if( pPg==0 ){
          rc = pagerAcquireMapPage(pPager, pgno, pData, &pPg);
        }else{
          sqlite3OsUnfetch(pPager->fd, (i64)(pgno-1)*pPager->pageSize, pData);
        }
................................................................................
    /* The maximum page number is 2^31. Return SQLITE_CORRUPT if a page
    ** number greater than this, or the unused locking-page, is requested. */
    if( pgno>PAGER_MAX_PGNO || pgno==PAGER_MJ_PGNO(pPager) ){
      rc = SQLITE_CORRUPT_BKPT;
      goto pager_acquire_err;
    }

    assert( !isOpen(pPager->fd) || !MEMDB );
    if( !isOpen(pPager->fd) || pPager->dbSize<pgno || noContent ){
      if( pgno>pPager->mxPgno ){
        rc = SQLITE_FULL;
        goto pager_acquire_err;
      }
      if( noContent ){
        /* Failure to set the bits in the InJournal bit-vectors is benign.
        ** It merely means that we might do some extra work to journal a 
................................................................................
    }
  
    /* Open the journal file if it is not already open. */
    if( !isOpen(pPager->jfd) ){
      if( pPager->journalMode==PAGER_JOURNALMODE_MEMORY ){
        sqlite3MemJournalOpen(pPager->jfd);
      }else{

        int flags = SQLITE_OPEN_READWRITE|SQLITE_OPEN_CREATE;
        int nSpill;

        if( pPager->tempFile ){
          flags |= (SQLITE_OPEN_DELETEONCLOSE|SQLITE_OPEN_TEMP_JOURNAL);
          nSpill = sqlite3Config.nStmtSpill;
        }else{
          flags |= SQLITE_OPEN_MAIN_JOURNAL;

          nSpill = jrnlBufferSize(pPager);
        }
          
        /* Verify that the database still has the same name as it did when
        ** it was originally opened. */
        rc = databaseIsUnmoved(pPager);
        if( rc==SQLITE_OK ){

          rc = sqlite3JournalOpen (
              pVfs, pPager->zJournal, pPager->jfd, flags, nSpill
          );



        }
      }
      assert( rc!=SQLITE_OK || isOpen(pPager->jfd) );
    }
  
  
    /* Write the first journal header to the journal file and open 
................................................................................
  assert( assert_pager_state(pPager) );
  if( pPager->errCode ){
    return pPager->errCode;
  }else if( (pPg->flags & PGHDR_WRITEABLE)!=0 && pPager->dbSize>=pPg->pgno ){
    if( pPager->nSavepoint ) return subjournalPageIfRequired(pPg);
    return SQLITE_OK;
  }else if( pPager->sectorSize > (u32)pPager->pageSize ){
    assert( pPager->tempFile==0 );
    return pagerWriteLargeSector(pPg);
  }else{
    return pager_write(pPg);
  }
}

/*
................................................................................
       || pPager->eState==PAGER_WRITER_DBMOD
       || pPager->eState==PAGER_ERROR
  );
  assert( assert_pager_state(pPager) );

  /* If a prior error occurred, report that error again. */
  if( NEVER(pPager->errCode) ) return pPager->errCode;

  /* Provide the ability to easily simulate an I/O error during testing */
  if( (rc = sqlite3FaultSim(400))!=SQLITE_OK ) return rc;

  PAGERTRACE(("DATABASE SYNC: File=%s zMaster=%s nSize=%d\n", 
      pPager->zFilename, zMaster, pPager->dbSize));

  /* If no database changes have been made, return early. */
  if( pPager->eState<PAGER_WRITER_CACHEMOD ) return SQLITE_OK;

  assert( MEMDB==0 || pPager->tempFile );
  assert( isOpen(pPager->fd) || pPager->tempFile );
  if( 0==pagerFlushOnCommit(pPager) ){
    /* If this is an in-memory db, or no pages have been written to, or this
    ** function has already been called, it is mostly a no-op.  However, any
    ** backup in progress needs to be restarted.  */

    sqlite3BackupRestart(pPager->pBackup);
  }else{
    if( pagerUseWal(pPager) ){
      PgHdr *pList = sqlite3PcacheDirtyList(pPager->pPCache);
      PgHdr *pPageOne = 0;
      if( pList==0 ){
        /* Must have at least one page for the WAL commit flag.
................................................................................
  *pnVal += pPager->aStat[eStat - SQLITE_DBSTATUS_CACHE_HIT];
  if( reset ){
    pPager->aStat[eStat - SQLITE_DBSTATUS_CACHE_HIT] = 0;
  }
}

/*
** Return true if this is an in-memory or temp-file backed pager.
*/
int sqlite3PagerIsMemdb(Pager *pPager){
  return pPager->tempFile;
}

/*
** Check that there are at least nSavepoint savepoints open. If there are
** currently less than nSavepoints open, then open one or more savepoints
** to make up the difference. If the number of savepoints is already
** equal to nSavepoint, then this function is a no-op.
................................................................................
       || pPager->eState==PAGER_WRITER_DBMOD
  );
  assert( assert_pager_state(pPager) );

  /* In order to be able to rollback, an in-memory database must journal
  ** the page we are moving from.
  */
  if( pPager->tempFile ){
    rc = sqlite3PagerWrite(pPg);
    if( rc ) return rc;
  }

  /* If the page being moved is dirty and has not been saved by the latest
  ** savepoint, then save the current contents of the page into the 
  ** sub-journal now. This is required to handle the following scenario:
................................................................................
  ** for the page moved there.
  */
  pPg->flags &= ~PGHDR_NEED_SYNC;
  pPgOld = sqlite3PagerLookup(pPager, pgno);
  assert( !pPgOld || pPgOld->nRef==1 );
  if( pPgOld ){
    pPg->flags |= (pPgOld->flags&PGHDR_NEED_SYNC);
    if( pPager->tempFile ){
      /* Do not discard pages from an in-memory database since we might
      ** need to rollback later.  Just move the page out of the way. */
      sqlite3PcacheMove(pPgOld, pPager->dbSize+1);
    }else{
      sqlite3PcacheDrop(pPgOld);
    }
  }
................................................................................
  sqlite3PcacheMove(pPg, pgno);
  sqlite3PcacheMakeDirty(pPg);

  /* For an in-memory database, make sure the original page continues
  ** to exist, in case the transaction needs to roll back.  Use pPgOld
  ** as the original page since it has already been allocated.
  */
  if( pPager->tempFile ){
    assert( pPgOld );
    sqlite3PcacheMove(pPgOld, origPgno);
    sqlite3PagerUnrefNotNull(pPgOld);
  }

  if( needSyncPgno ){
    /* If needSyncPgno is non-zero, then the journal file needs to be 
................................................................................
}

#ifndef SQLITE_OMIT_VACUUM
/*
** Unless this is an in-memory or temporary database, clear the pager cache.
*/
void sqlite3PagerClearCache(Pager *pPager){
  assert( MEMDB==0 || pPager->tempFile );
  if( pPager->tempFile==0 ) pager_reset(pPager);
}
#endif

#ifndef SQLITE_OMIT_WAL
/*
** This function is called when the user invokes "PRAGMA wal_checkpoint",
** "PRAGMA wal_blocking_checkpoint" or calls the sqlite3_wal_checkpoint()

  assert( createFlag==0 || pCache->eCreate==eCreate );
  assert( createFlag==0 || eCreate==1+(!pCache->bPurgeable||!pCache->pDirty) );
  return sqlite3GlobalConfig.pcache2.xFetch(pCache->pCache, pgno, eCreate);
}

/*
** If the sqlite3PcacheFetch() routine is unable to allocate a new
** page because new clean pages are available for reuse and the cache
** size limit has been reached, then this routine can be invoked to 
** try harder to allocate a page.  This routine might invoke the stress
** callback to spill dirty pages to the journal.  It will then try to
** allocate the new page and will only fail to allocate a new page on
** an OOM error.
**
** This routine should be invoked only after sqlite3PcacheFetch() fails.
................................................................................
*/
void sqlite3PcacheCleanAll(PCache *pCache){
  PgHdr *p;
  while( (p = pCache->pDirty)!=0 ){
    sqlite3PcacheMakeClean(p);
  }
}












/*
** Clear the PGHDR_NEED_SYNC flag from all dirty pages.
*/
void sqlite3PcacheClearSyncFlags(PCache *pCache){
  PgHdr *p;
  for(p=pCache->pDirty; p; p=p->pDirtyNext){
................................................................................
    for(p=pCache->pDirty; p; p=pNext){
      pNext = p->pDirtyNext;
      /* This routine never gets call with a positive pgno except right
      ** after sqlite3PcacheCleanAll().  So if there are dirty pages,
      ** it must be that pgno==0.
      */
      assert( p->pgno>0 );
      if( ALWAYS(p->pgno>pgno) ){
        assert( p->flags&PGHDR_DIRTY );
        sqlite3PcacheMakeClean(p);
      }
    }
    if( pgno==0 && pCache->nRefSum ){
      sqlite3_pcache_page *pPage1;
      pPage1 = sqlite3GlobalConfig.pcache2.xFetch(pCache->pCache,1,0);
................................................................................

/*
** Return the size of the header added by this middleware layer
** in the page-cache hierarchy.
*/
int sqlite3HeaderSizePcache(void){ return ROUND8(sizeof(PgHdr)); }













#if defined(SQLITE_CHECK_PAGES) || defined(SQLITE_DEBUG)
/*
** For all dirty pages currently in the cache, invoke the specified
** callback. This is only used if the SQLITE_CHECK_PAGES macro is
** defined.
*/

  assert( createFlag==0 || pCache->eCreate==eCreate );
  assert( createFlag==0 || eCreate==1+(!pCache->bPurgeable||!pCache->pDirty) );
  return sqlite3GlobalConfig.pcache2.xFetch(pCache->pCache, pgno, eCreate);
}

/*
** If the sqlite3PcacheFetch() routine is unable to allocate a new
** page because no clean pages are available for reuse and the cache
** size limit has been reached, then this routine can be invoked to 
** try harder to allocate a page.  This routine might invoke the stress
** callback to spill dirty pages to the journal.  It will then try to
** allocate the new page and will only fail to allocate a new page on
** an OOM error.
**
** This routine should be invoked only after sqlite3PcacheFetch() fails.
................................................................................
*/
void sqlite3PcacheCleanAll(PCache *pCache){
  PgHdr *p;
  while( (p = pCache->pDirty)!=0 ){
    sqlite3PcacheMakeClean(p);
  }
}

/*
** Clear the PGHDR_NEED_SYNC and PGHDR_WRITEABLE flag from all dirty pages.
*/
void sqlite3PcacheClearWritable(PCache *pCache){
  PgHdr *p;
  for(p=pCache->pDirty; p; p=p->pDirtyNext){
    p->flags &= ~(PGHDR_NEED_SYNC|PGHDR_WRITEABLE);
  }
  pCache->pSynced = pCache->pDirtyTail;
}

/*
** Clear the PGHDR_NEED_SYNC flag from all dirty pages.
*/
void sqlite3PcacheClearSyncFlags(PCache *pCache){
  PgHdr *p;
  for(p=pCache->pDirty; p; p=p->pDirtyNext){
................................................................................
    for(p=pCache->pDirty; p; p=pNext){
      pNext = p->pDirtyNext;
      /* This routine never gets call with a positive pgno except right
      ** after sqlite3PcacheCleanAll().  So if there are dirty pages,
      ** it must be that pgno==0.
      */
      assert( p->pgno>0 );
      if( p->pgno>pgno ){
        assert( p->flags&PGHDR_DIRTY );
        sqlite3PcacheMakeClean(p);
      }
    }
    if( pgno==0 && pCache->nRefSum ){
      sqlite3_pcache_page *pPage1;
      pPage1 = sqlite3GlobalConfig.pcache2.xFetch(pCache->pCache,1,0);
................................................................................

/*
** Return the size of the header added by this middleware layer
** in the page-cache hierarchy.
*/
int sqlite3HeaderSizePcache(void){ return ROUND8(sizeof(PgHdr)); }

/*
** Return the number of dirty pages currently in the cache, as a percentage
** of the configured cache size.
*/
int sqlite3PCachePercentDirty(PCache *pCache){
  PgHdr *pDirty;
  int nDirty = 0;
  int nCache = numberOfCachePages(pCache);
  for(pDirty=pCache->pDirty; pDirty; pDirty=pDirty->pDirtyNext) nDirty++;
  return nCache ? (int)(((i64)nDirty * 100) / nCache) : 0;
}

#if defined(SQLITE_CHECK_PAGES) || defined(SQLITE_DEBUG)
/*
** For all dirty pages currently in the cache, invoke the specified
** callback. This is only used if the SQLITE_CHECK_PAGES macro is
** defined.
*/

PgHdr *sqlite3PcacheFetchFinish(PCache*, Pgno, sqlite3_pcache_page *pPage);
void sqlite3PcacheRelease(PgHdr*);

void sqlite3PcacheDrop(PgHdr*);         /* Remove page from cache */
void sqlite3PcacheMakeDirty(PgHdr*);    /* Make sure page is marked dirty */
void sqlite3PcacheMakeClean(PgHdr*);    /* Mark a single page as clean */
void sqlite3PcacheCleanAll(PCache*);    /* Mark all dirty list pages as clean */


/* Change a page number.  Used by incr-vacuum. */
void sqlite3PcacheMove(PgHdr*, Pgno);

/* Remove all pages with pgno>x.  Reset the cache if x==0 */
void sqlite3PcacheTruncate(PCache*, Pgno x);

................................................................................
#endif

void sqlite3PCacheSetDefault(void);

/* Return the header size */
int sqlite3HeaderSizePcache(void);
int sqlite3HeaderSizePcache1(void);




#endif /* _PCACHE_H_ */

PgHdr *sqlite3PcacheFetchFinish(PCache*, Pgno, sqlite3_pcache_page *pPage);
void sqlite3PcacheRelease(PgHdr*);

void sqlite3PcacheDrop(PgHdr*);         /* Remove page from cache */
void sqlite3PcacheMakeDirty(PgHdr*);    /* Make sure page is marked dirty */
void sqlite3PcacheMakeClean(PgHdr*);    /* Mark a single page as clean */
void sqlite3PcacheCleanAll(PCache*);    /* Mark all dirty list pages as clean */
void sqlite3PcacheClearWritable(PCache*);

/* Change a page number.  Used by incr-vacuum. */
void sqlite3PcacheMove(PgHdr*, Pgno);

/* Remove all pages with pgno>x.  Reset the cache if x==0 */
void sqlite3PcacheTruncate(PCache*, Pgno x);

................................................................................
#endif

void sqlite3PCacheSetDefault(void);

/* Return the header size */
int sqlite3HeaderSizePcache(void);
int sqlite3HeaderSizePcache1(void);

/* Number of dirty pages as a percentage of the configured cache size */
int sqlite3PCachePercentDirty(PCache*);

#endif /* _PCACHE_H_ */

  Tcl_SetResult(interp, zBuf, TCL_VOLATILE);
  return TCL_OK;
}

/*
** Usage:   btree_ismemdb ID
**
** Return true if the B-Tree is in-memory.
*/
static int btree_ismemdb(
  void *NotUsed,
  Tcl_Interp *interp,    /* The TCL interpreter that invoked this command */
  int argc,              /* Number of arguments */
  const char **argv      /* Text of each argument */
){
  Btree *pBt;
  int res;


  if( argc!=2 ){
    Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0],
       " ID\"", 0);
    return TCL_ERROR;
  }
  pBt = sqlite3TestTextToPtr(argv[1]);
  sqlite3_mutex_enter(pBt->db->mutex);
  sqlite3BtreeEnter(pBt);
  res = sqlite3PagerIsMemdb(sqlite3BtreePager(pBt));

  sqlite3BtreeLeave(pBt);
  sqlite3_mutex_leave(pBt->db->mutex);
  Tcl_SetObjResult(interp, Tcl_NewBooleanObj(res));
  return SQLITE_OK;
}

/*

  Tcl_SetResult(interp, zBuf, TCL_VOLATILE);
  return TCL_OK;
}

/*
** Usage:   btree_ismemdb ID
**
** Return true if the B-Tree is currently stored entirely in memory.
*/
static int btree_ismemdb(
  void *NotUsed,
  Tcl_Interp *interp,    /* The TCL interpreter that invoked this command */
  int argc,              /* Number of arguments */
  const char **argv      /* Text of each argument */
){
  Btree *pBt;
  int res;
  sqlite3_file *pFile;

  if( argc!=2 ){
    Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0],
       " ID\"", 0);
    return TCL_ERROR;
  }
  pBt = sqlite3TestTextToPtr(argv[1]);
  sqlite3_mutex_enter(pBt->db->mutex);
  sqlite3BtreeEnter(pBt);
  pFile = sqlite3PagerFile(sqlite3BtreePager(pBt));
  res = (pFile->pMethods==0);
  sqlite3BtreeLeave(pBt);
  sqlite3_mutex_leave(pBt->db->mutex);
  Tcl_SetObjResult(interp, Tcl_NewBooleanObj(res));
  return SQLITE_OK;
}

/*

} {
  sqlite3 db $zSrcFile
  sqlite3 db2 $zDestFile
  set db_dest db2
  set file_dest temp
}] {
foreach rows_dest {0 3 10} {
foreach pgsz_dest {512 1024 2048} {
foreach nPagePerStep {1 200} {

  # Open the databases.
  catch { delete_file test.db }
  catch { delete_file test2.db }
  eval $zOpenScript

  # Set to true if copying to an in-memory destination. Copying to an 
  # in-memory destination is only possible if the initial destination
  # page size is the same as the source page size (in this case 1024 bytes).
  #
  set isMemDest [expr {
    $zDestFile eq ":memory:" || $file_dest eq "temp" && $TEMP_STORE>=2
  }]

  if { $isMemDest==0 || $pgsz_dest == 1024 } {
    if 0 {
      puts -nonewline "Test $iTest: src=$zSrcFile dest=$zDestFile"
      puts -nonewline " (as $db_dest.$file_dest)"
      puts -nonewline " rows_dest=$rows_dest pgsz_dest=$pgsz_dest"
      puts ""
    }



    # Set up the content of the source database.
    execsql {
      PRAGMA page_size = 1024;
      BEGIN;
      CREATE TABLE t1(a, b);
      CREATE INDEX i1 ON t1(a, b);

} {
  sqlite3 db $zSrcFile
  sqlite3 db2 $zDestFile
  set db_dest db2
  set file_dest temp
}] {
foreach rows_dest {0 3 10} {
foreach pgsz_dest {512 1024 2048 4096} {
foreach nPagePerStep {1 200} {

  # Open the databases.
  catch { delete_file test.db }
  catch { delete_file test2.db }
  eval $zOpenScript

  # Set to true if copying to an in-memory destination. Copying to an 
  # in-memory destination is only possible if the initial destination
  # page size is the same as the source page size (in this case 1024 bytes).
  #

  set isMemDest [expr { $zDestFile eq ":memory:" || $file_dest eq "temp" }]



  if 0 {
    puts -nonewline "Test $iTest: src=$zSrcFile dest=$zDestFile"
    puts -nonewline " (as $db_dest.$file_dest)"
    puts -nonewline " rows_dest=$rows_dest pgsz_dest=$pgsz_dest"
    puts ""
  }

  if { $isMemDest==0 || $pgsz_dest==1024 || $rows_dest==0 } {

    # Set up the content of the source database.
    execsql {
      PRAGMA page_size = 1024;
      BEGIN;
      CREATE TABLE t1(a, b);
      CREATE INDEX i1 ON t1(a, b);

#
# This file contains fault-injection test cases for the 
# sqlite3_db_cacheflush API.
#

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

# Run the supplied SQL on a copy of the database currently stored on 
# disk in file $dbfile.
proc diskquery {dbfile sql} {
  forcecopy $dbfile dq.db
  sqlite3 dq dq.db

#
# This file contains fault-injection test cases for the 
# sqlite3_db_cacheflush API.
#

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

# Run the supplied SQL on a copy of the database currently stored on 
# disk in file $dbfile.
proc diskquery {dbfile sql} {
  forcecopy $dbfile dq.db
  sqlite3 dq dq.db

# At one point the following set of conditions would cause SQLite to 
# retain a RESERVED or EXCLUSIVE lock after the transaction was committed:
# 
#   * The journal-mode is set to something other than 'delete', and
#   * there exists one or more active read-only statements, and
#   * a transaction that modified zero database pages is committed.
# 
set temp_status unlocked
if {$TEMP_STORE>=2} {set temp_status unknown}

do_test lock-7.1 {
  set STMT [sqlite3_prepare $DB "SELECT * FROM sqlite_master" -1 TAIL]
  sqlite3_step $STMT
} {SQLITE_ROW}
do_test lock-7.2 {
  execsql { PRAGMA lock_status }
} [list main shared temp $temp_status]

# At one point the following set of conditions would cause SQLite to 
# retain a RESERVED or EXCLUSIVE lock after the transaction was committed:
# 
#   * The journal-mode is set to something other than 'delete', and
#   * there exists one or more active read-only statements, and
#   * a transaction that modified zero database pages is committed.
# 
#set temp_status unlocked
#if {$TEMP_STORE>=2} {set temp_status unknown}
set temp_status unknown
do_test lock-7.1 {
  set STMT [sqlite3_prepare $DB "SELECT * FROM sqlite_master" -1 TAIL]
  sqlite3_step $STMT
} {SQLITE_ROW}
do_test lock-7.2 {
  execsql { PRAGMA lock_status }
} [list main shared temp $temp_status]

}

# If TEMP_STORE is 2 or greater, then the database [db2] will be created
# as an in-memory database. This test will not work in that case, as it
# is not possible to change the page-size of an in-memory database. Even
# using the backup API.
#
if {$TEMP_STORE<2} {


  do_faultsim_test pagerfault-14b -prep {
    catch { db2 close }
    faultsim_restore_and_reopen
    sqlite3 db2 ""
    db2 eval { PRAGMA page_size = 4096; CREATE TABLE xx(a) }
  } -body {
    sqlite3_backup B db2 main db main
    B step 200
    set rc [B finish]
    if {[string match SQLITE_IOERR_* $rc]} {set rc SQLITE_IOERR}
    if {$rc != "SQLITE_OK"} { error [sqlite3_test_errstr $rc] }
    set {} {}
  } -test {

    faultsim_test_result {0 {}} {1 {sqlite3_backup_init() failed}}
  }
}

do_faultsim_test pagerfault-14c -prep {
  catch { db2 close }
  faultsim_restore_and_reopen
  sqlite3 db2 test.db2
  db2 eval { 

}

# If TEMP_STORE is 2 or greater, then the database [db2] will be created
# as an in-memory database. This test will not work in that case, as it
# is not possible to change the page-size of an in-memory database. Even
# using the backup API.
#
# Update: It is no longer possible to change the page size of any temp
# database after it has been created.
#
do_faultsim_test pagerfault-14b -prep {
  catch { db2 close }
  faultsim_restore_and_reopen
    sqlite3 db2 ""
    db2 eval { PRAGMA page_size = 4096; CREATE TABLE xx(a) }
} -body {
  sqlite3_backup B db2 main db main
  B step 200
  set rc [B finish]
  if {[string match SQLITE_IOERR_* $rc]} {set rc SQLITE_IOERR}
  if {$rc != "SQLITE_OK"} { error [sqlite3_test_errstr $rc] }
  set {} {}
} -test {
  faultsim_test_result {1 {attempt to write a readonly database}} \
                       {1 {sqlite3_backup_init() failed}}

}

do_faultsim_test pagerfault-14c -prep {
  catch { db2 close }
  faultsim_restore_and_reopen
  sqlite3 db2 test.db2
  db2 eval { 

} {-450}
} ; # ifcapable schema_version

# Check to see if TEMP_STORE is memory or disk.  Return strings
# "memory" or "disk" as appropriate.
#
proc check_temp_store {} {


  db eval {CREATE TEMP TABLE IF NOT EXISTS a(b)}











  db eval {PRAGMA database_list} {
    if {$name=="temp"} {
      set bt [btree_from_db db 1]
      if {[btree_ismemdb $bt]} {
        return "memory"
      }
      return "disk"

} {-450}
} ; # ifcapable schema_version

# Check to see if TEMP_STORE is memory or disk.  Return strings
# "memory" or "disk" as appropriate.
#
proc check_temp_store {} {
  db eval {
    PRAGMA temp.cache_size = 1;
    CREATE TEMP TABLE IF NOT EXISTS a(b);
    DELETE FROM a;
    INSERT INTO a VALUES(randomblob(1000));
    INSERT INTO a SELECT * FROM a;
    INSERT INTO a SELECT * FROM a;
    INSERT INTO a SELECT * FROM a;
    INSERT INTO a SELECT * FROM a;
    INSERT INTO a SELECT * FROM a;
    INSERT INTO a SELECT * FROM a;
    INSERT INTO a SELECT * FROM a;
    INSERT INTO a SELECT * FROM a;
  }
  db eval {PRAGMA database_list} {
    if {$name=="temp"} {
      set bt [btree_from_db db 1]
      if {[btree_ismemdb $bt]} {
        return "memory"
      }
      return "disk"

# 2016 April 11
#
# 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 contains tests for fault-injection when SQLite is used with
# a temp file database.
#

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

# sqlite3_memdebug_vfs_oom_test 0

do_faultsim_test 1 -faults * -prep {
  sqlite3 db ""
  db eval {
    PRAGMA page_size = 1024;
    CREATE TABLE t1(a, b);
    INSERT INTO t1 VALUES(1, 2);
    INSERT INTO t1 VALUES(3, 4);
  }
} -body {
  execsql { INSERT INTO t1 VALUES(5, 6) }
} -test {
  faultsim_test_result {0 {}}
  set rc [catch { execsql { SELECT * FROM t1 } } msg]
  if {$rc==0 && $msg != "1 2 3 4 5 6" && $msg != "1 2 3 4"} {
    error "data mismatch 1: $msg"
  }
  if {$testrc==0 && $msg != "1 2 3 4 5 6"} {
    error "data mismatch 2: $msg"
  }
  faultsim_integrity_check
}

do_faultsim_test 2 -faults * -prep {
  sqlite3 db ""
  db eval {
    PRAGMA page_size = 1024;
    PRAGMA cache_size = 10;
    CREATE TABLE t1(a, b);
    CREATE INDEX i1 ON t1(b, a);
    WITH x(i) AS (SELECT 1 UNION ALL SELECT i+1 FROM x WHERE i<100)
    INSERT INTO t1 SELECT randomblob(100), randomblob(100) FROM x;
  }
} -body {
  execsql { UPDATE t1 SET a = randomblob(99) }
} -test {
  faultsim_test_result {0 {}}
  faultsim_integrity_check db
}

catch { db close }
do_faultsim_test 2.1 -faults * -prep {
  if {[info commands db]==""} {
    sqlite3 db ""
    execsql {
      PRAGMA page_size = 1024;
      PRAGMA cache_size = 10;
      CREATE TABLE t1(a, b);
      CREATE INDEX i1 ON t1(b, a);
      WITH x(i) AS (SELECT 1 UNION ALL SELECT i+1 FROM x WHERE i<100)
          INSERT INTO t1 SELECT randomblob(100), randomblob(100) FROM x;
    }
  } 
} -body {
  execsql { UPDATE t1 SET a = randomblob(99) }
} -test {
  faultsim_test_result {0 {}}
  faultsim_integrity_check db
}

do_faultsim_test 3 -faults * -prep {
  sqlite3 db ""
  db eval {
    PRAGMA page_size = 1024;
    PRAGMA cache_size = 10;
    CREATE TABLE t1(a, b);
    CREATE INDEX i1 ON t1(b, a);
    WITH x(i) AS (SELECT 1 UNION ALL SELECT i+1 FROM x WHERE i<50)
    INSERT INTO t1 SELECT randomblob(100), randomblob(100) FROM x;
  }
} -body {
  execsql { 
    BEGIN;
      UPDATE t1 SET a = randomblob(99);
      SAVEPOINT abc;
        UPDATE t1 SET a = randomblob(98) WHERE (rowid%10)==0;
      ROLLBACK TO abc;
        UPDATE t1 SET a = randomblob(97) WHERE (rowid%5)==0;
      ROLLBACK TO abc;
    COMMIT;
  }
} -test {
  faultsim_test_result {0 {}}
  faultsim_integrity_check db
}

do_faultsim_test 4 -faults * -prep {
  sqlite3 db ""
  db eval {
    PRAGMA page_size = 1024;
    PRAGMA cache_size = 10;
    CREATE TABLE t1(a, b);
    CREATE INDEX i1 ON t1(b, a);
    WITH x(i) AS (SELECT 1 UNION ALL SELECT i+1 FROM x WHERE i<50)
    INSERT INTO t1 SELECT randomblob(100), randomblob(100) FROM x;
  }
} -body {
  execsql { 
    BEGIN;
      UPDATE t1 SET a = randomblob(99);
      SAVEPOINT abc;
        UPDATE t1 SET a = randomblob(98) WHERE (rowid%10)==0;
      ROLLBACK TO abc;
        UPDATE t1 SET a = randomblob(97) WHERE (rowid%5)==0;
      ROLLBACK TO abc;
    COMMIT;
  }
} -test {
  faultsim_test_result {0 {}}
}

sqlite3_memdebug_vfs_oom_test 1
finish_test

# 2016 March 3
#
# 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.
#
#***********************************************************************

set testdir [file dirname $argv0]
source $testdir/tester.tcl
set testprefix temptable2

do_execsql_test 1.1 {
  CREATE TEMP TABLE t1(a, b);
  CREATE INDEX i1 ON t1(a, b);
}

do_execsql_test 1.2 {
  WITH x(i) AS ( SELECT 1 UNION ALL SELECT i+1 FROM x WHERE i<100000 )
  INSERT INTO t1 SELECT randomblob(100), randomblob(100) FROM X;
} {}

do_execsql_test 1.3 {
  PRAGMA temp.integrity_check;
} {ok}

#-------------------------------------------------------------------------
#
reset_db
do_execsql_test 2.1 {
  CREATE TEMP TABLE t2(a, b);
  INSERT INTO t2 VALUES(1, 2);
} {}

do_execsql_test 2.2 {
  BEGIN;
    INSERT INTO t2 VALUES(3, 4);
    SELECT * FROM t2;
} {1 2 3 4}

do_execsql_test 2.3 {
  ROLLBACK;
  SELECT * FROM t2;
} {1 2}

#-------------------------------------------------------------------------
#
reset_db
do_execsql_test 3.1.1 {
  PRAGMA main.cache_size = 10;
  PRAGMA temp.cache_size = 10;

  CREATE TEMP TABLE t1(a, b);
  CREATE INDEX i1 ON t1(a, b);

  WITH x(i) AS ( SELECT 1 UNION ALL SELECT i+1 FROM x WHERE i<1000 )
  INSERT INTO t1 SELECT randomblob(100), randomblob(100) FROM x;

  SELECT count(*) FROM t1;
} {1000}
do_execsql_test 3.1.2 {
  BEGIN;
    UPDATE t1 SET b=randomblob(100) WHERE (rowid%10)==0;
  ROLLBACK;
}
do_execsql_test 3.1.3 {
  SELECT count(*) FROM t1;
} {1000}
do_execsql_test 3.1.4 { PRAGMA temp.integrity_check } {ok}

do_execsql_test 3.2.1 {
  BEGIN;
    UPDATE t1 SET b=randomblob(100) WHERE (rowid%10)==0;
    SAVEPOINT abc;
      UPDATE t1 SET b=randomblob(100) WHERE (rowid%10)==1;
    ROLLBACK TO abc;
    UPDATE t1 SET b=randomblob(100) WHERE (rowid%10)==2;
  COMMIT;
}
do_execsql_test 3.2.2 { PRAGMA temp.integrity_check } {ok}

#-------------------------------------------------------------------------
#
reset_db
do_execsql_test 4.1.1 {
  PRAGMA main.cache_size = 10;
  PRAGMA temp.cache_size = 10;

  CREATE TEMP TABLE t1(a, b);
  CREATE INDEX i1 ON t1(a, b);

  WITH x(i) AS ( SELECT 1 UNION ALL SELECT i+1 FROM x WHERE i<10 )
  INSERT INTO t1 SELECT randomblob(100), randomblob(100) FROM x;

  SELECT count(*) FROM t1;
  PRAGMA temp.page_count;
} {10 9}

do_execsql_test 4.1.2 {
  BEGIN;
    UPDATE t1 SET b=randomblob(100);
  ROLLBACK;
}

do_execsql_test 4.1.3 {
  CREATE TEMP TABLE t2(a, b);
  CREATE INDEX i2 ON t2(a, b);
  WITH x(i) AS ( SELECT 1 UNION ALL SELECT i+1 FROM x WHERE i<500 )
  INSERT INTO t2 SELECT randomblob(100), randomblob(100) FROM x;

  SELECT count(*) FROM t2;
  SELECT count(*) FROM t1;
} {500 10}

do_test 4.1.4 {
  set n [db one { PRAGMA temp.page_count }]
  expr ($n >280 && $n < 300) 
} 1

do_execsql_test 4.1.4 { PRAGMA temp.integrity_check } {ok}

#-------------------------------------------------------------------------
#
reset_db
do_execsql_test 5.1.1 {
  PRAGMA main.cache_size = 10;
  PRAGMA temp.cache_size = 10;

  CREATE TEMP TABLE t2(a, b);
  CREATE INDEX i2 ON t2(a, b);
  WITH x(i) AS ( SELECT 1 UNION ALL SELECT i+1 FROM x WHERE i<500 )
  INSERT INTO t2 SELECT randomblob(100), randomblob(100) FROM x;

  CREATE TEMP TABLE t1(a, b);
  CREATE INDEX i1 ON t1(a, b);
  INSERT INTO t1 VALUES(1, 2);
}

# Test that the temp database is now much bigger than the configured
# cache size (10 pages).
do_test 5.1.2 {
  set n [db one { PRAGMA temp.page_count }]
  expr ($n > 270 && $n < 290)
} {1}

do_execsql_test 5.1.3 {
  BEGIN;
    UPDATE t1 SET a=2;
    UPDATE t2 SET a=randomblob(100);
    SELECT count(*) FROM t1;
  ROLLBACK;
} {1}

do_execsql_test 5.1.4 {
  UPDATE t2 SET a=randomblob(100);

  SELECT * FROM t1;
} {1 2}

do_execsql_test 5.1.5 { PRAGMA temp.integrity_check } {ok}

#-------------------------------------------------------------------------
# Test this:
#
#   1. Page is DIRTY at the start of a transaction.
#   2. Page is written out as part of the transaction.
#   3. Page is then read back in.
#   4. Transaction is rolled back. Is the page now clean or dirty?
#
# This actually does work. Step 4 marks the page as clean. But it also
# writes to the database file itself. So marking it clean is correct - 
# the page does match the contents of the db file.
#
reset_db

do_execsql_test 6.1 {
  PRAGMA main.cache_size = 10;
  PRAGMA temp.cache_size = 10;

  CREATE TEMP TABLE t1(x);
  INSERT INTO t1 VALUES('one');

  CREATE TEMP TABLE t2(a, b);
  CREATE INDEX i2 ON t2(a, b);
  WITH x(i) AS ( SELECT 1 UNION ALL SELECT i+1 FROM x WHERE i<500 )
  INSERT INTO t2 SELECT randomblob(100), randomblob(100) FROM x;
}

do_execsql_test 6.2 {
  UPDATE t1 SET x='two';             -- step 1
  BEGIN;
    UPDATE t2 SET a=randomblob(100); -- step 2
    SELECT * FROM t1;                -- step 3
  ROLLBACK;                          -- step 4

  SELECT count(*) FROM t2;
  SELECT * FROM t1;
} {two 500 two}

#-------------------------------------------------------------------------
#
reset_db
sqlite3 db ""
do_execsql_test 7.1 {
  PRAGMA auto_vacuum=INCREMENTAL;
  CREATE TABLE t1(x);
  INSERT INTO t1 VALUES(zeroblob(900));
  INSERT INTO t1 VALUES(zeroblob(900));
  INSERT INTO t1 SELECT x FROM t1;
  INSERT INTO t1 SELECT x FROM t1;
  INSERT INTO t1 SELECT x FROM t1;
  INSERT INTO t1 SELECT x FROM t1;
  BEGIN;
  DELETE FROM t1 WHERE rowid%2;
  PRAGMA incremental_vacuum(4);
  ROLLBACK;
  PRAGMA integrity_check;
} {ok}

#-------------------------------------------------------------------------
# Try changing the page size using a backup operation when pages are
# stored in main-memory only.
#
reset_db
do_execsql_test 8.1 {
  PRAGMA auto_vacuum = OFF;
  CREATE TABLE t2(a, b);
  CREATE INDEX i2 ON t2(a, b);
  WITH x(i) AS ( SELECT 1 UNION ALL SELECT i+1 FROM x WHERE i<20 )
  INSERT INTO t2 SELECT randomblob(100), randomblob(100) FROM x;
  PRAGMA page_count;
} {13}

do_test 8.2 {
  sqlite3 tmp ""
  execsql {
    PRAGMA auto_vacuum = OFF;
    PRAGMA page_size = 8192;
    CREATE TABLE t1(a, b);
    CREATE INDEX i1 ON t1(a, b);
    WITH x(i) AS ( SELECT 1 UNION ALL SELECT i+1 FROM x WHERE i<100 )
    INSERT INTO t1 SELECT randomblob(100), randomblob(100) FROM x;
    PRAGMA page_count;
  } tmp
} {10}

do_test 8.3 {
  sqlite3_backup B tmp main db main
  B step 5
  B finish
} {SQLITE_READONLY}

do_test 8.4 {
  execsql {
    SELECT count(*) FROM t1;
    PRAGMA integrity_check;
    PRAGMA page_size;
  } tmp
} {100 ok 8192}

do_test 8.5 { 
  tmp eval { UPDATE t1 SET a=randomblob(100) }
} {}

do_test 8.6 {
  sqlite3_backup B tmp main db main
  B step 1000
  B finish
} {SQLITE_READONLY}

tmp close

#-------------------------------------------------------------------------
# Try inserts and deletes with a large db in auto-vacuum mode. Check
#
foreach {tn mode} {
  1 delete
  2 wal
} {
  reset_db
  sqlite3 db ""
  do_execsql_test 9.$tn.1.1 {
    PRAGMA cache_size = 15;
    PRAGMA auto_vacuum = 1;
  }
  execsql "PRAGMA journal_mode = $mode"

  do_execsql_test 9.$tn.1.2 {
    CREATE TABLE tx(a, b);
    CREATE INDEX i1 ON tx(a);
    CREATE INDEX i2 ON tx(b);
    WITH x(i) AS ( SELECT 1 UNION ALL SELECT i+1 FROM x WHERE i<1000 )
      INSERT INTO tx SELECT randomblob(100), randomblob(100) FROM x;
  }

  for {set i 2} {$i<20} {incr i} {
    do_execsql_test 9.$tn.$i.1 { DELETE FROM tx WHERE (random()%3)==0 }

    do_execsql_test 9.$tn.$i.2 { PRAGMA integrity_check } ok

      do_execsql_test 9.$tn.$i.3 { 
        WITH x(i) AS ( SELECT 1 UNION ALL SELECT i+1 FROM x WHERE i<400 )
          INSERT INTO tx SELECT randomblob(100), randomblob(100) FROM x;
      }

    do_execsql_test 9.$tn.$i.4 { PRAGMA integrity_check } ok

    do_execsql_test 9.$tn.$i.5 { 
      BEGIN;
      DELETE FROM tx WHERE (random()%3)==0;
      WITH x(i) AS ( SELECT 1 UNION ALL SELECT i+1 FROM x WHERE i<500 )
        INSERT INTO tx SELECT randomblob(100), randomblob(100) FROM x;
      COMMIT;
    }

    do_execsql_test 9.$tn.$i.6 { PRAGMA integrity_check } ok
  }
}

#-------------------------------------------------------------------------
# When using mmap mode with a temp file, SQLite must search the cache 
# before using a mapped page even when there is no write transaction
# open. For a temp file, the on-disk version may not be up to date.
#
sqlite3 db ""
do_execsql_test 10.0 {
  PRAGMA cache_size = 50;
  PRAGMA page_size = 1024;
  CREATE TABLE t1(a, b, PRIMARY KEY(a)) WITHOUT ROWID;
  CREATE INDEX i1 ON t1(a);
  CREATE TABLE t2(x, y);
  INSERT INTO t2 VALUES(1, 2);
}

do_execsql_test 10.1 {
  BEGIN;
    WITH x(i) AS ( SELECT 1 UNION ALL SELECT i+1 FROM x WHERE i<500 )
      INSERT INTO t1 SELECT randomblob(100), randomblob(100) FROM x;
  COMMIT;
  INSERT INTO t2 VALUES(3, 4);
}

if {[permutation]!="journaltest"} {
  # The journaltest permutation does not support mmap, so this part of
  # the test is omitted.
  do_execsql_test 10.2 { PRAGMA mmap_size = 512000 } 512000
}

do_execsql_test 10.3 { SELECT * FROM t2 } {1 2 3 4}
do_execsql_test 10.4 { PRAGMA integrity_check } ok

finish_test