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Overview
Comment:Improve a comment in wal.c. No code changes.
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SHA1: 60b9f5e4dd2af54975ba78437239f0bebd472fd2
User & Date: dan 2013-03-23 17:29:06.036
Context
2013-03-23
21:00
Replace the sqlite3_io_methods.xMremap interface with sqlite3_io_methods.xFetch and xUnfetch. (check-in: 1431be9557 user: dan tags: experimental-mmap)
17:29
Improve a comment in wal.c. No code changes. (check-in: 60b9f5e4dd user: dan tags: experimental-mmap)
14:20
Fix a case where a checkpoint operation could write to an invalid part of a memory mapped region. (check-in: 8dbe89d05c user: dan tags: experimental-mmap)
Changes
Unified Diff Ignore Whitespace Patch
Changes to src/wal.c.
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    u32 nBackfill = pInfo->nBackfill;

    /* Sync the WAL to disk */
    if( sync_flags ){
      rc = sqlite3OsSync(pWal->pWalFd, sync_flags);
    }

    /* If the database file may grow as a result of this checkpoint, hint
    ** about the eventual size of the db file to the VFS layer. 

    */




    if( rc==SQLITE_OK ){
      i64 nReq = ((i64)mxPage * szPage);
      rc = sqlite3PagerSetFilesize(pWal->pPager, nReq); 
    }

    /* Iterate through the contents of the WAL, copying data to the db file. */
    while( rc==SQLITE_OK && 0==walIteratorNext(pIter, &iDbpage, &iFrame) ){
      i64 iOffset;
      assert( walFramePgno(pWal, iFrame)==iDbpage );
      if( iFrame<=nBackfill || iFrame>mxSafeFrame || iDbpage>mxPage ) continue;








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    u32 nBackfill = pInfo->nBackfill;

    /* Sync the WAL to disk */
    if( sync_flags ){
      rc = sqlite3OsSync(pWal->pWalFd, sync_flags);
    }

    /* If the database file is currently smaller than mxPage pages in size,
    ** the call below issues an SQLITE_FCNTL_SIZE_HINT to the OS layer to
    ** inform it that it is likely to grow to that size.
    **
    ** Additionally, if the pager is using mmap(), then the call to 
    ** SetFilesize() guarantees that the mapping is not larger than mxPage
    ** pages. This makes the sqlite3OsTruncate() call below safe - no pages
    ** that are part of the mapped region will be truncated away.  */
    if( rc==SQLITE_OK ){
      i64 nReq = ((i64)mxPage * szPage);
      rc = sqlite3PagerSetFilesize(pWal->pPager, nReq);
    }

    /* Iterate through the contents of the WAL, copying data to the db file. */
    while( rc==SQLITE_OK && 0==walIteratorNext(pIter, &iDbpage, &iFrame) ){
      i64 iOffset;
      assert( walFramePgno(pWal, iFrame)==iDbpage );
      if( iFrame<=nBackfill || iFrame>mxSafeFrame || iDbpage>mxPage ) continue;
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