SQLite

** 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 1.440 2008/05/06 18:13:26 danielk1977 Exp $
*/
#ifndef SQLITE_OMIT_DISKIO
#include "sqliteInt.h"
#include <assert.h>
#include <string.h>

/*

**
** Might might be the case that the file on disk is smaller than nPage.
** This can happen, for example, if we are in the middle of a transaction
** which has extended the file size and the new pages are still all held
** in cache, then an INSERT or UPDATE does a statement rollback.  Some
** operating system implementations can get confused if you try to
** truncate a file to some size that is larger than it currently is,
** so detect this case and write a single zero byte to the end of the new
** file instead.
*/
static int pager_truncate(Pager *pPager, int nPage){
  int rc = SQLITE_OK;
  if( pPager->state>=PAGER_EXCLUSIVE && pPager->fd->pMethods ){
    i64 currentSize, newSize;
    rc = sqlite3OsFileSize(pPager->fd, &currentSize);
    newSize = pPager->pageSize*(i64)nPage;
    if( rc==SQLITE_OK && currentSize!=newSize ){
      if( currentSize>newSize ){
        rc = sqlite3OsTruncate(pPager->fd, newSize);
      }else{
        rc = sqlite3OsWrite(pPager->fd, "", 1, newSize-1);
      }
    }
  }
  if( rc==SQLITE_OK ){
    pPager->dbSize = nPage;
    pager_truncate_cache(pPager);
  }
  return rc;

# This file implements regression tests for SQLite library.  The
# focus of this file is testing for correct handling of I/O errors
# such as writes failing because the disk is full.
# 
# The tests in this file use special facilities that are only
# available in the SQLite test fixture.
#
# $Id: incrvacuum_ioerr.test,v 1.3 2008/05/06 18:13:26 danielk1977 Exp $

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

# If this build of the library does not support auto-vacuum, omit this
# whole file.
ifcapable {!autovacuum} {

  INSERT INTO abc VALUES(randstr(1500,1500));
} -sqlbody {
  BEGIN;
  CREATE TABLE abc2(a);
  DELETE FROM abc;
  PRAGMA incremental_vacuum;
  COMMIT;
} 

# do_ioerr_test incrvacuum-ioerr-3 -start 1 -cksum 1 -tclprep {
#   db eval {
#     PRAGMA auto_vacuum = 'full';
#     PRAGMA cache_size = 10;
#     BEGIN;
#     CREATE TABLE abc(a, UNIQUE(a));

#   DELETE FROM abc WHERE (oid%3)==0;
#   INSERT INTO abc SELECT a || '1234567890' FROM abc WHERE oid%2;
#   CREATE INDEX abc_i ON abc(a);
#   DELETE FROM abc WHERE (oid%2)==0;
#   DROP INDEX abc_i;
#   COMMIT;
# }


do_ioerr_test incrvacuum-ioerr-2 -start 1 -cksum 1 -tclprep {
  db eval {
    PRAGMA auto_vacuum = 'full';
    PRAGMA cache_size = 10;
    BEGIN;
    CREATE TABLE abc(a, UNIQUE(a));

  CREATE INDEX abc_i ON abc(a);
  DELETE FROM abc WHERE (oid%2)==0;
  PRAGMA incremental_vacuum;
  DROP INDEX abc_i;
  PRAGMA incremental_vacuum;
  COMMIT;
}

do_ioerr_test incrvacuum-ioerr-3 -start 1 -cksum 1 -tclprep {
  db eval {
    PRAGMA auto_vacuum = 'incremental';
    BEGIN;
    CREATE TABLE a(i integer, b blob);
    INSERT INTO a VALUES(1, randstr(1500,1500));
    INSERT INTO a VALUES(2, randstr(1500,1500));
  }
  db eval COMMIT
  db eval {DELETE FROM a WHERE oid}
} -sqlbody {
  PRAGMA incremental_vacuum(5);
} -cleanup {
  sqlite3 db test.db
  integrity_check incrvacuum-ioerr-2.$n.integritycheck
  db close
}


finish_test