/ Check-in [7222ad26]
Login

Many hyperlinks are disabled.
Use anonymous login to enable hyperlinks.

Overview
Comment:Simplifications to pager.c in support of structural coverage testing. (CVS 6927)
Downloads: Tarball | ZIP archive | SQL archive
Timelines: family | ancestors | descendants | both | trunk
Files: files | file ages | folders
SHA1: 7222ad2667b95d6021d9ae47f548b76b224f46aa
User & Date: drh 2009-07-24 16:32:01
Context
2009-07-24
17:58
Allow virtual tables to be used in shared-cache mode. (CVS 6928) check-in: 5d9e767a user: danielk1977 tags: trunk
16:32
Simplifications to pager.c in support of structural coverage testing. (CVS 6927) check-in: 7222ad26 user: drh tags: trunk
12:35
Simplifications and comment improvements in pager.c. (CVS 6926) check-in: 2d2f42ca user: drh tags: trunk
Changes
Hide Diffs Unified Diffs Ignore Whitespace Patch

Changes to src/pager.c.

14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
....
3946
3947
3948
3949
3950
3951
3952
3953

3954
3955
3956
3957
3958
3959
3960
3961
3962
3963
3964
3965
3966
....
4023
4024
4025
4026
4027
4028
4029
4030
4031

4032
4033
4034
4035
4036
4037
4038
4039
4040
....
4180
4181
4182
4183
4184
4185
4186
4187

4188
4189
4190
4191
4192

4193
4194
4195
4196
4197
4198
4199
4200
4201
....
4500
4501
4502
4503
4504
4505
4506
4507


4508
4509

4510
4511
4512
4513
4514
4515
4516
....
4540
4541
4542
4543
4544
4545
4546

4547
4548
4549
4550
4551
4552
4553
4554
....
4581
4582
4583
4584
4585
4586
4587



4588
4589
4590
4591
4592
4593
4594
....
4655
4656
4657
4658
4659
4660
4661



4662
4663
4664
4665
4666
4667
4668
4669
4670
4671
4672
** 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 1.614 2009/07/24 12:35:57 drh Exp $
*/
#ifndef SQLITE_OMIT_DISKIO
#include "sqliteInt.h"

/*
** Macros for troubleshooting.  Normally turned off
*/
................................................................................
** returns NULL if the page is not in cache or if a disk I/O error 
** has ever happened.
*/
DbPage *sqlite3PagerLookup(Pager *pPager, Pgno pgno){
  PgHdr *pPg = 0;
  assert( pPager!=0 );
  assert( pgno!=0 );


  if( (pPager->state!=PAGER_UNLOCK)
   && (pPager->errCode==SQLITE_OK || pPager->errCode==SQLITE_FULL)
  ){
    sqlite3PcacheFetch(pPager->pPCache, pgno, 0, &pPg);
  }

  return pPg;
}

/*
** Release a page reference.
**
** If the number of references to the page drop to zero, then the
................................................................................
  int rc = SQLITE_OK;                        /* Return code */
  sqlite3_vfs * const pVfs = pPager->pVfs;   /* Local cache of vfs pointer */

  assert( pPager->state>=PAGER_RESERVED );
  assert( pPager->useJournal );
  assert( pPager->pInJournal==0 );
  
  /* If already in the error state, this function is a no-op. */
  if( pPager->errCode ){

    return pPager->errCode;
  }

  /* TODO: Is it really possible to get here with dbSizeValid==0? If not,
  ** the call to PagerPagecount() can be removed.
  */
  testcase( pPager->dbSizeValid==0 );
  sqlite3PagerPagecount(pPager, 0);

................................................................................
** of any open savepoints as appropriate.
*/
static int pager_write(PgHdr *pPg){
  void *pData = pPg->pData;
  Pager *pPager = pPg->pPager;
  int rc = SQLITE_OK;

  /* Check for errors

  */
  if( pPager->errCode ){ 
    return pPager->errCode;
  }
  if( pPager->readOnly ){

    return SQLITE_PERM;
  }

  assert( !pPager->setMaster );

  CHECK_PAGE(pPg);

  /* Mark the page as dirty.  If the page has already been written
  ** to the journal then we can return right away.
................................................................................
    assert( !pPager->tempFile && isOpen(pPager->fd) );

    /* Open page 1 of the file for writing. */
    rc = sqlite3PagerGet(pPager, 1, &pPgHdr);
    assert( pPgHdr==0 || rc==SQLITE_OK );

    /* If page one was fetched successfully, and this function is not
    ** operating in direct-mode, make page 1 writable.


    */
    if( rc==SQLITE_OK && !DIRECT_MODE ){

      rc = sqlite3PagerWrite(pPgHdr);
    }

    if( rc==SQLITE_OK ){
      /* Increment the value just read and write it back to byte 24. */
      change_counter = sqlite3Get4byte((u8*)pPager->dbFileVers);
      change_counter++;
................................................................................
** or pages with the Pager.noSync flag set.
**
** If successful, or called on a pager for which it is a no-op, this
** function returns SQLITE_OK. Otherwise, an IO error code is returned.
*/
int sqlite3PagerSync(Pager *pPager){
  int rc;                              /* Return code */

  if( MEMDB || pPager->noSync ){
    rc = SQLITE_OK;
  }else{
    rc = sqlite3OsSync(pPager->fd, pPager->sync_flags);
  }
  return rc;
}

................................................................................
int sqlite3PagerCommitPhaseOne(
  Pager *pPager,                  /* Pager object */
  const char *zMaster,            /* If not NULL, the master journal name */
  int noSync                      /* True to omit the xSync on the db file */
){
  int rc = SQLITE_OK;             /* Return code */




  /* If a prior error occurred, this routine should not be called.  ROLLBACK
  ** is the appropriate response to an error, not COMMIT.  Guard against
  ** coding errors by repeating the prior error. */
  if( NEVER(pPager->errCode) ) return pPager->errCode;

  PAGERTRACE(("DATABASE SYNC: File=%s zMaster=%s nSize=%d\n", 
      pPager->zFilename, zMaster, pPager->dbSize));
................................................................................
    ** file. This can only happen in auto-vacuum mode.
    **
    ** Before reading the pages with page numbers larger than the 
    ** current value of Pager.dbSize, set dbSize back to the value
    ** that it took at the start of the transaction. Otherwise, the
    ** calls to sqlite3PagerGet() return zeroed pages instead of 
    ** reading data from the database file.



    */
#ifndef SQLITE_OMIT_AUTOVACUUM
    if( pPager->dbSize<pPager->dbOrigSize
     && pPager->journalMode!=PAGER_JOURNALMODE_OFF 
    ){
      Pgno i;                                   /* Iterator variable */
      const Pgno iSkip = PAGER_MJ_PGNO(pPager); /* Pending lock page */
      const Pgno dbSize = pPager->dbSize;       /* Database image size */ 
      pPager->dbSize = pPager->dbOrigSize;
      for( i=dbSize+1; i<=pPager->dbOrigSize; i++ ){
        if( !sqlite3BitvecTest(pPager->pInJournal, i) && i!=iSkip ){







|







 







<
>
|
<
<
|
<
<







 







|
|
>
|
<







 







|
>

<
|
|
|
>
|
<







 







|
>
>

<
>







 







>
|







 







>
>
>







 







>
>
>


|
|







14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
....
3946
3947
3948
3949
3950
3951
3952

3953
3954


3955


3956
3957
3958
3959
3960
3961
3962
....
4019
4020
4021
4022
4023
4024
4025
4026
4027
4028
4029

4030
4031
4032
4033
4034
4035
4036
....
4176
4177
4178
4179
4180
4181
4182
4183
4184
4185

4186
4187
4188
4189
4190

4191
4192
4193
4194
4195
4196
4197
....
4496
4497
4498
4499
4500
4501
4502
4503
4504
4505
4506

4507
4508
4509
4510
4511
4512
4513
4514
....
4538
4539
4540
4541
4542
4543
4544
4545
4546
4547
4548
4549
4550
4551
4552
4553
....
4580
4581
4582
4583
4584
4585
4586
4587
4588
4589
4590
4591
4592
4593
4594
4595
4596
....
4657
4658
4659
4660
4661
4662
4663
4664
4665
4666
4667
4668
4669
4670
4671
4672
4673
4674
4675
4676
4677
** 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 1.615 2009/07/24 16:32:01 drh Exp $
*/
#ifndef SQLITE_OMIT_DISKIO
#include "sqliteInt.h"

/*
** Macros for troubleshooting.  Normally turned off
*/
................................................................................
** returns NULL if the page is not in cache or if a disk I/O error 
** has ever happened.
*/
DbPage *sqlite3PagerLookup(Pager *pPager, Pgno pgno){
  PgHdr *pPg = 0;
  assert( pPager!=0 );
  assert( pgno!=0 );

  assert( pPager->pPCache!=0 );
  assert( pPager->state > PAGER_UNLOCK );


  sqlite3PcacheFetch(pPager->pPCache, pgno, 0, &pPg);


  return pPg;
}

/*
** Release a page reference.
**
** If the number of references to the page drop to zero, then the
................................................................................
  int rc = SQLITE_OK;                        /* Return code */
  sqlite3_vfs * const pVfs = pPager->pVfs;   /* Local cache of vfs pointer */

  assert( pPager->state>=PAGER_RESERVED );
  assert( pPager->useJournal );
  assert( pPager->pInJournal==0 );
  
  /* If already in the error state, this function is a no-op.  But on
  ** the other hand, this routine is never called if we are already in
  ** an error state. */
  if( NEVER(pPager->errCode) ) return pPager->errCode;


  /* TODO: Is it really possible to get here with dbSizeValid==0? If not,
  ** the call to PagerPagecount() can be removed.
  */
  testcase( pPager->dbSizeValid==0 );
  sqlite3PagerPagecount(pPager, 0);

................................................................................
** of any open savepoints as appropriate.
*/
static int pager_write(PgHdr *pPg){
  void *pData = pPg->pData;
  Pager *pPager = pPg->pPager;
  int rc = SQLITE_OK;

  /* If an error has been previously detected, we should not be
  ** calling this routine.  Repeat the error for robustness.
  */

  if( NEVER(pPager->errCode) )  return pPager->errCode;

  /* Higher-level routines never call this function if database is not
  ** writable.  But check anyway, just for robustness. */
  if( NEVER(pPager->readOnly) ) return SQLITE_PERM;


  assert( !pPager->setMaster );

  CHECK_PAGE(pPg);

  /* Mark the page as dirty.  If the page has already been written
  ** to the journal then we can return right away.
................................................................................
    assert( !pPager->tempFile && isOpen(pPager->fd) );

    /* Open page 1 of the file for writing. */
    rc = sqlite3PagerGet(pPager, 1, &pPgHdr);
    assert( pPgHdr==0 || rc==SQLITE_OK );

    /* If page one was fetched successfully, and this function is not
    ** operating in direct-mode, make page 1 writable.  When not in 
    ** direct mode, page 1 is always held in cache and hence the PagerGet()
    ** above is always successful - hence the ALWAYS on rc==SQLITE_OK.
    */

    if( !DIRECT_MODE && ALWAYS(rc==SQLITE_OK) ){
      rc = sqlite3PagerWrite(pPgHdr);
    }

    if( rc==SQLITE_OK ){
      /* Increment the value just read and write it back to byte 24. */
      change_counter = sqlite3Get4byte((u8*)pPager->dbFileVers);
      change_counter++;
................................................................................
** or pages with the Pager.noSync flag set.
**
** If successful, or called on a pager for which it is a no-op, this
** function returns SQLITE_OK. Otherwise, an IO error code is returned.
*/
int sqlite3PagerSync(Pager *pPager){
  int rc;                              /* Return code */
  assert( !MEMDB );
  if( pPager->noSync ){
    rc = SQLITE_OK;
  }else{
    rc = sqlite3OsSync(pPager->fd, pPager->sync_flags);
  }
  return rc;
}

................................................................................
int sqlite3PagerCommitPhaseOne(
  Pager *pPager,                  /* Pager object */
  const char *zMaster,            /* If not NULL, the master journal name */
  int noSync                      /* True to omit the xSync on the db file */
){
  int rc = SQLITE_OK;             /* Return code */

  /* The dbOrigSize is never set if journal_mode=OFF */
  assert( pPager->journalMode!=PAGER_JOURNALMODE_OFF || pPager->dbOrigSize==0 );

  /* If a prior error occurred, this routine should not be called.  ROLLBACK
  ** is the appropriate response to an error, not COMMIT.  Guard against
  ** coding errors by repeating the prior error. */
  if( NEVER(pPager->errCode) ) return pPager->errCode;

  PAGERTRACE(("DATABASE SYNC: File=%s zMaster=%s nSize=%d\n", 
      pPager->zFilename, zMaster, pPager->dbSize));
................................................................................
    ** file. This can only happen in auto-vacuum mode.
    **
    ** Before reading the pages with page numbers larger than the 
    ** current value of Pager.dbSize, set dbSize back to the value
    ** that it took at the start of the transaction. Otherwise, the
    ** calls to sqlite3PagerGet() return zeroed pages instead of 
    ** reading data from the database file.
    **
    ** When journal_mode==OFF the dbOrigSize is always zero, so this
    ** block never runs if journal_mode=OFF.
    */
#ifndef SQLITE_OMIT_AUTOVACUUM
    if( pPager->dbSize<pPager->dbOrigSize 
     && ALWAYS(pPager->journalMode!=PAGER_JOURNALMODE_OFF)
    ){
      Pgno i;                                   /* Iterator variable */
      const Pgno iSkip = PAGER_MJ_PGNO(pPager); /* Pending lock page */
      const Pgno dbSize = pPager->dbSize;       /* Database image size */ 
      pPager->dbSize = pPager->dbOrigSize;
      for( i=dbSize+1; i<=pPager->dbOrigSize; i++ ){
        if( !sqlite3BitvecTest(pPager->pInJournal, i) && i!=iSkip ){

Changes to test/pager.test.

7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
..
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
#    May you find forgiveness for yourself and forgive others.
#    May you share freely, never taking more than you give.
#
#***********************************************************************
# This file implements regression tests for SQLite library.  The
# focus of this script is page cache subsystem.
#
# $Id: pager.test,v 1.35 2009/06/05 17:09:12 drh Exp $


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

if {[info commands pager_open]!=""} {
db close
................................................................................
} {0}
#do_test pager-2.2 {
#  set v [catch {
#    set ::g1 [page_get $::p1 0]
#  } msg]
#  lappend v $msg
#} {1 SQLITE_ERROR}
do_test pager-2.3.1 {
  set ::gx [page_lookup $::p1 1]
} {}
do_test pager-2.3.2 {
  pager_stats $::p1
} {ref 0 page 0 max 10 size -1 state 0 err 0 hit 0 miss 0 ovfl 0}
do_test pager-2.3.3 {
  set v [catch {
    set ::g1 [page_get $::p1 1]
  } msg]







|







 







|
|
|







7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
..
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
#    May you find forgiveness for yourself and forgive others.
#    May you share freely, never taking more than you give.
#
#***********************************************************************
# This file implements regression tests for SQLite library.  The
# focus of this script is page cache subsystem.
#
# $Id: pager.test,v 1.36 2009/07/24 16:32:01 drh Exp $


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

if {[info commands pager_open]!=""} {
db close
................................................................................
} {0}
#do_test pager-2.2 {
#  set v [catch {
#    set ::g1 [page_get $::p1 0]
#  } msg]
#  lappend v $msg
#} {1 SQLITE_ERROR}
#do_test pager-2.3.1 {
#  set ::gx [page_lookup $::p1 1]
#} {}
do_test pager-2.3.2 {
  pager_stats $::p1
} {ref 0 page 0 max 10 size -1 state 0 err 0 hit 0 miss 0 ovfl 0}
do_test pager-2.3.3 {
  set v [catch {
    set ::g1 [page_get $::p1 1]
  } msg]