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Overview
Comment:Fix an incorrect comment and possible integer overflow in pager resulting from check-in [23ca23894af352ea]. Problem reported by forum post e2ea1a3f61. Also change the datatype of Pager.pageSize to i64 even though page size never exceeds 65536, in order to help prevent future problems of this kind.
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SHA3-256: f4a552ed9f4ab35520b634954c39748cc7bda535f426280b79da1b99f70599ac
User & Date: drh 2021-09-13 13:53:13
Context
2021-09-13
16:36
Add new test file rtreedoc.test. (check-in: 8c4b1482 user: dan tags: trunk)
13:53
Fix an incorrect comment and possible integer overflow in pager resulting from check-in [23ca23894af352ea]. Problem reported by forum post e2ea1a3f61. Also change the datatype of Pager.pageSize to i64 even though page size never exceeds 65536, in order to help prevent future problems of this kind. (check-in: f4a552ed user: drh tags: trunk)
2021-09-10
22:00
Make replace.tcl useful with TCL 8.4 (check-in: 2dd61dd9 user: larrybr tags: trunk)
Changes
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Changes to src/pager.c.

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  ** End of the routinely-changing class members
  ***************************************************************************/

  u16 nExtra;                 /* Add this many bytes to each in-memory page */
  i16 nReserve;               /* Number of unused bytes at end of each page */
  u32 vfsFlags;               /* Flags for sqlite3_vfs.xOpen() */
  u32 sectorSize;             /* Assumed sector size during rollback */
  int pageSize;               /* Number of bytes in a page */
  Pgno mxPgno;                /* Maximum allowed size of the database */

  i64 journalSizeLimit;       /* Size limit for persistent journal files */
  char *zFilename;            /* Name of the database file */
  char *zJournal;             /* Name of the journal file */
  int (*xBusyHandler)(void*); /* Function to call when busy */
  void *pBusyHandlerArg;      /* Context argument for xBusyHandler */
  int aStat[4];               /* Total cache hits, misses, writes, spills */
#ifdef SQLITE_TEST








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  ** End of the routinely-changing class members
  ***************************************************************************/

  u16 nExtra;                 /* Add this many bytes to each in-memory page */
  i16 nReserve;               /* Number of unused bytes at end of each page */
  u32 vfsFlags;               /* Flags for sqlite3_vfs.xOpen() */
  u32 sectorSize;             /* Assumed sector size during rollback */

  Pgno mxPgno;                /* Maximum allowed size of the database */
  i64 pageSize;               /* Number of bytes in a page */
  i64 journalSizeLimit;       /* Size limit for persistent journal files */
  char *zFilename;            /* Name of the database file */
  char *zJournal;             /* Name of the journal file */
  int (*xBusyHandler)(void*); /* Function to call when busy */
  void *pBusyHandlerArg;      /* Context argument for xBusyHandler */
  int aStat[4];               /* Total cache hits, misses, writes, spills */
#ifdef SQLITE_TEST
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    */
    nNew = iSavepoint + (( op==SAVEPOINT_RELEASE ) ? 0 : 1);
    for(ii=nNew; ii<pPager->nSavepoint; ii++){
      sqlite3BitvecDestroy(pPager->aSavepoint[ii].pInSavepoint);
    }
    pPager->nSavepoint = nNew;

    /* If this is a release of the outermost savepoint, truncate 
    ** the sub-journal to zero bytes in size. */

    if( op==SAVEPOINT_RELEASE ){
      PagerSavepoint *pRel = &pPager->aSavepoint[nNew];
      if( pRel->bTruncateOnRelease && isOpen(pPager->sjfd) ){
        /* Only truncate if it is an in-memory sub-journal. */
        if( sqlite3JournalIsInMemory(pPager->sjfd) ){
          i64 sz = (pPager->pageSize+4)*pRel->iSubRec;
          rc = sqlite3OsTruncate(pPager->sjfd, sz);
          assert( rc==SQLITE_OK );
        }
        pPager->nSubRec = pRel->iSubRec;
      }
    }
    /* Else this is a rollback operation, playback the specified savepoint.








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    */
    nNew = iSavepoint + (( op==SAVEPOINT_RELEASE ) ? 0 : 1);
    for(ii=nNew; ii<pPager->nSavepoint; ii++){
      sqlite3BitvecDestroy(pPager->aSavepoint[ii].pInSavepoint);
    }
    pPager->nSavepoint = nNew;


    /* Truncate the sub-journal so that it only includes the parts
    ** that are still in use. */
    if( op==SAVEPOINT_RELEASE ){
      PagerSavepoint *pRel = &pPager->aSavepoint[nNew];
      if( pRel->bTruncateOnRelease && isOpen(pPager->sjfd) ){
        /* Only truncate if it is an in-memory sub-journal. */
        if( sqlite3JournalIsInMemory(pPager->sjfd) ){
          i64 sz = (pPager->pageSize+4)*(i64)pRel->iSubRec;
          rc = sqlite3OsTruncate(pPager->sjfd, sz);
          assert( rc==SQLITE_OK );
        }
        pPager->nSubRec = pRel->iSubRec;
      }
    }
    /* Else this is a rollback operation, playback the specified savepoint.
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