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Overview
Comment:Defend against disk I/O errors that happen during an sqlite3OsSeek(). (CVS 2679)
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SHA1:461e3a0a27ff083b0bae10c9880e3b41bb85ee31
User & Date: drh 2005-09-09 01:32:06
Context
2005-09-09
01:33
Infrastructure for the DISTINCT keyword in aggregate functions. But it does not work yet. If you try to use it you get an error message. (CVS 2680) check-in: 4d62e36f user: drh tags: trunk
01:32
Defend against disk I/O errors that happen during an sqlite3OsSeek(). (CVS 2679) check-in: 461e3a0a user: drh tags: trunk
2005-09-08
20:37
SUM returns NULL when it has no inputs. Ticket #1413. (CVS 2678) check-in: 62818594 user: drh tags: trunk
Changes
Hide Diffs Unified Diffs Ignore Whitespace Patch

Changes to src/os_unix.c.

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/*
** Move the read/write pointer in a file.
*/
int sqlite3OsSeek(OsFile *id, i64 offset){
  assert( id->isOpen );
  SEEK(offset/1024 + 1);



  lseek(id->h, offset, SEEK_SET);
  return SQLITE_OK;
}

#ifdef SQLITE_TEST
/*
** Count the number of fullsyncs and normal syncs.  This is used to test







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/*
** Move the read/write pointer in a file.
*/
int sqlite3OsSeek(OsFile *id, i64 offset){
  assert( id->isOpen );
  SEEK(offset/1024 + 1);
#ifdef SQLITE_TEST
  if( offset ) SimulateDiskfullError
#endif
  lseek(id->h, offset, SEEK_SET);
  return SQLITE_OK;
}

#ifdef SQLITE_TEST
/*
** Count the number of fullsyncs and normal syncs.  This is used to test

Changes to src/os_win.c.

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** Move the read/write pointer in a file.
*/
int sqlite3OsSeek(OsFile *id, i64 offset){
  LONG upperBits = offset>>32;
  LONG lowerBits = offset & 0xffffffff;
  DWORD rc;
  assert( id->isOpen );



  SEEK(offset/1024 + 1);
  rc = SetFilePointer(id->h, lowerBits, &upperBits, FILE_BEGIN);
  TRACE3("SEEK %d %lld\n", id->h, offset);
  return SQLITE_OK;
}

/*







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** Move the read/write pointer in a file.
*/
int sqlite3OsSeek(OsFile *id, i64 offset){
  LONG upperBits = offset>>32;
  LONG lowerBits = offset & 0xffffffff;
  DWORD rc;
  assert( id->isOpen );
#ifdef SQLITE_TEST
  if( offset ) SimulateDiskfullError
#endif
  SEEK(offset/1024 + 1);
  rc = SetFilePointer(id->h, lowerBits, &upperBits, FILE_BEGIN);
  TRACE3("SEEK %d %lld\n", id->h, offset);
  return SQLITE_OK;
}

/*

Changes to src/pager.c.

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** 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 1.211 2005/09/08 12:38:42 drh Exp $
*/
#ifndef SQLITE_OMIT_DISKIO
#include "sqliteInt.h"
#include "os.h"
#include "pager.h"
#include <assert.h>
#include <string.h>
................................................................................
    rc = write32bits(&pPager->jfd, pPager->sectorSize);
  }

  /* The journal header has been written successfully. Seek the journal
  ** file descriptor to the end of the journal header sector.
  */
  if( rc==SQLITE_OK ){
    sqlite3OsSeek(&pPager->jfd, pPager->journalOff-1);

    rc = sqlite3OsWrite(&pPager->jfd, "\000", 1);

  }
  return rc;
}

/*
** The journal file must be open when this is called. A journal header file
** (JOURNAL_HDR_SZ bytes) is read from the current location in the journal
................................................................................
  ** page content is in the main journal either because the page is not in
  ** cache or else it is marked as needSync==0.
  */
  pPg = pager_lookup(pPager, pgno);
  assert( pPager->state>=PAGER_EXCLUSIVE || pPg!=0 );
  TRACE3("PLAYBACK %d page %d\n", PAGERID(pPager), pgno);
  if( pPager->state>=PAGER_EXCLUSIVE && (pPg==0 || pPg->needSync==0) ){
    sqlite3OsSeek(&pPager->fd, (pgno-1)*(i64)pPager->pageSize);

    rc = sqlite3OsWrite(&pPager->fd, aData, pPager->pageSize);

    if( pPg ) pPg->dirty = 0;
  }
  if( pPg ){
    /* No page should ever be explicitly rolled back that is in use, except
    ** for page 1 which is held in use in order to keep the lock on the
    ** database active. However such a page may be rolled back as a result
    ** of an internal error resulting in an automatic call to
................................................................................
static int pager_reload_cache(Pager *pPager){
  PgHdr *pPg;
  int rc = SQLITE_OK;
  for(pPg=pPager->pAll; pPg; pPg=pPg->pNextAll){
    char zBuf[SQLITE_MAX_PAGE_SIZE];
    if( !pPg->dirty ) continue;
    if( (int)pPg->pgno <= pPager->origDbSize ){
      sqlite3OsSeek(&pPager->fd, pPager->pageSize*(i64)(pPg->pgno-1));

      rc = sqlite3OsRead(&pPager->fd, zBuf, pPager->pageSize);

      TRACE3("REFETCH %d page %d\n", PAGERID(pPager), pPg->pgno);
      if( rc ) break;
      CODEC(pPager, zBuf, pPg->pgno, 2);
    }else{
      memset(zBuf, 0, pPager->pageSize);
    }
    if( pPg->nRef==0 || memcmp(zBuf, PGHDR_TO_DATA(pPg), pPager->pageSize) ){
................................................................................
        ** it as a candidate for rollback. 
        */
        if( pPager->fullSync ){
          TRACE2("SYNC journal of %d\n", PAGERID(pPager));
          rc = sqlite3OsSync(&pPager->jfd, 0);
          if( rc!=0 ) return rc;
        }

        sqlite3OsSeek(&pPager->jfd, pPager->journalHdr + sizeof(aJournalMagic));

        rc = write32bits(&pPager->jfd, pPager->nRec);
        if( rc ) return rc;

        sqlite3OsSeek(&pPager->jfd, pPager->journalOff);

      }
      TRACE2("SYNC journal of %d\n", PAGERID(pPager));
      rc = sqlite3OsSync(&pPager->jfd, pPager->fullSync);
      if( rc!=0 ) return rc;
      pPager->journalStarted = 1;
    }
    pPager->needSync = 0;
................................................................................
  rc = pager_wait_on_lock(pPager, EXCLUSIVE_LOCK);
  if( rc!=SQLITE_OK ){
    return rc;
  }

  while( pList ){
    assert( pList->dirty );
    sqlite3OsSeek(&pPager->fd, (pList->pgno-1)*(i64)pPager->pageSize);

    /* If there are dirty pages in the page cache with page numbers greater
    ** than Pager.dbSize, this means sqlite3pager_truncate() was called to
    ** make the file smaller (presumably by auto-vacuum code). Do not write
    ** any such pages to the file.
    */
    if( pList->pgno<=pPager->dbSize ){
      CODEC(pPager, PGHDR_TO_DATA(pList), pList->pgno, 6);
................................................................................
      return rc;
    }
    if( sqlite3pager_pagecount(pPager)<(int)pgno ){
      memset(PGHDR_TO_DATA(pPg), 0, pPager->pageSize);
    }else{
      int rc;
      assert( MEMDB==0 );
      sqlite3OsSeek(&pPager->fd, (pgno-1)*(i64)pPager->pageSize);

      rc = sqlite3OsRead(&pPager->fd, PGHDR_TO_DATA(pPg), pPager->pageSize);

      TRACE3("FETCH %d page %d\n", PAGERID(pPager), pPg->pgno);
      CODEC(pPager, PGHDR_TO_DATA(pPg), pPg->pgno, 3);
      if( rc!=SQLITE_OK ){
        i64 fileSize;
        if( sqlite3OsFileSize(&pPager->fd,&fileSize)!=SQLITE_OK
               || fileSize>=pgno*pPager->pageSize ){
          sqlite3pager_unref(PGHDR_TO_DATA(pPg));







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** 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 1.212 2005/09/09 01:32:06 drh Exp $
*/
#ifndef SQLITE_OMIT_DISKIO
#include "sqliteInt.h"
#include "os.h"
#include "pager.h"
#include <assert.h>
#include <string.h>
................................................................................
    rc = write32bits(&pPager->jfd, pPager->sectorSize);
  }

  /* The journal header has been written successfully. Seek the journal
  ** file descriptor to the end of the journal header sector.
  */
  if( rc==SQLITE_OK ){
    rc = sqlite3OsSeek(&pPager->jfd, pPager->journalOff-1);
    if( rc==SQLITE_OK ){
      rc = sqlite3OsWrite(&pPager->jfd, "\000", 1);
    }
  }
  return rc;
}

/*
** The journal file must be open when this is called. A journal header file
** (JOURNAL_HDR_SZ bytes) is read from the current location in the journal
................................................................................
  ** page content is in the main journal either because the page is not in
  ** cache or else it is marked as needSync==0.
  */
  pPg = pager_lookup(pPager, pgno);
  assert( pPager->state>=PAGER_EXCLUSIVE || pPg!=0 );
  TRACE3("PLAYBACK %d page %d\n", PAGERID(pPager), pgno);
  if( pPager->state>=PAGER_EXCLUSIVE && (pPg==0 || pPg->needSync==0) ){
    rc = sqlite3OsSeek(&pPager->fd, (pgno-1)*(i64)pPager->pageSize);
    if( rc==SQLITE_OK ){
      rc = sqlite3OsWrite(&pPager->fd, aData, pPager->pageSize);
    }
    if( pPg ) pPg->dirty = 0;
  }
  if( pPg ){
    /* No page should ever be explicitly rolled back that is in use, except
    ** for page 1 which is held in use in order to keep the lock on the
    ** database active. However such a page may be rolled back as a result
    ** of an internal error resulting in an automatic call to
................................................................................
static int pager_reload_cache(Pager *pPager){
  PgHdr *pPg;
  int rc = SQLITE_OK;
  for(pPg=pPager->pAll; pPg; pPg=pPg->pNextAll){
    char zBuf[SQLITE_MAX_PAGE_SIZE];
    if( !pPg->dirty ) continue;
    if( (int)pPg->pgno <= pPager->origDbSize ){
      rc = sqlite3OsSeek(&pPager->fd, pPager->pageSize*(i64)(pPg->pgno-1));
      if( rc==SQLITE_OK ){
        rc = sqlite3OsRead(&pPager->fd, zBuf, pPager->pageSize);
      }
      TRACE3("REFETCH %d page %d\n", PAGERID(pPager), pPg->pgno);
      if( rc ) break;
      CODEC(pPager, zBuf, pPg->pgno, 2);
    }else{
      memset(zBuf, 0, pPager->pageSize);
    }
    if( pPg->nRef==0 || memcmp(zBuf, PGHDR_TO_DATA(pPg), pPager->pageSize) ){
................................................................................
        ** it as a candidate for rollback. 
        */
        if( pPager->fullSync ){
          TRACE2("SYNC journal of %d\n", PAGERID(pPager));
          rc = sqlite3OsSync(&pPager->jfd, 0);
          if( rc!=0 ) return rc;
        }
        rc = sqlite3OsSeek(&pPager->jfd,
                           pPager->journalHdr + sizeof(aJournalMagic));
        if( rc ) return rc;
        rc = write32bits(&pPager->jfd, pPager->nRec);
        if( rc ) return rc;

        rc = sqlite3OsSeek(&pPager->jfd, pPager->journalOff);
        if( rc ) return rc;
      }
      TRACE2("SYNC journal of %d\n", PAGERID(pPager));
      rc = sqlite3OsSync(&pPager->jfd, pPager->fullSync);
      if( rc!=0 ) return rc;
      pPager->journalStarted = 1;
    }
    pPager->needSync = 0;
................................................................................
  rc = pager_wait_on_lock(pPager, EXCLUSIVE_LOCK);
  if( rc!=SQLITE_OK ){
    return rc;
  }

  while( pList ){
    assert( pList->dirty );
    rc = sqlite3OsSeek(&pPager->fd, (pList->pgno-1)*(i64)pPager->pageSize);
    if( rc ) return rc;
    /* If there are dirty pages in the page cache with page numbers greater
    ** than Pager.dbSize, this means sqlite3pager_truncate() was called to
    ** make the file smaller (presumably by auto-vacuum code). Do not write
    ** any such pages to the file.
    */
    if( pList->pgno<=pPager->dbSize ){
      CODEC(pPager, PGHDR_TO_DATA(pList), pList->pgno, 6);
................................................................................
      return rc;
    }
    if( sqlite3pager_pagecount(pPager)<(int)pgno ){
      memset(PGHDR_TO_DATA(pPg), 0, pPager->pageSize);
    }else{
      int rc;
      assert( MEMDB==0 );
      rc = sqlite3OsSeek(&pPager->fd, (pgno-1)*(i64)pPager->pageSize);
      if( rc==SQLITE_OK ){
        rc = sqlite3OsRead(&pPager->fd, PGHDR_TO_DATA(pPg), pPager->pageSize);
      }
      TRACE3("FETCH %d page %d\n", PAGERID(pPager), pPg->pgno);
      CODEC(pPager, PGHDR_TO_DATA(pPg), pPg->pgno, 3);
      if( rc!=SQLITE_OK ){
        i64 fileSize;
        if( sqlite3OsFileSize(&pPager->fd,&fileSize)!=SQLITE_OK
               || fileSize>=pgno*pPager->pageSize ){
          sqlite3pager_unref(PGHDR_TO_DATA(pPg));