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Overview
Comment:Add a fix for the assert() statements added by the previous commit.
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SHA1: 19345416ed5e1ab5b0b35993b0b9069c2fb1683b
User & Date: dan 2013-03-22 17:46:11.890
Context
2013-03-22
18:20
Allow the database file to be memory mapped in wal mode. (check-in: d190ddabc3 user: dan tags: experimental-mmap)
17:46
Add a fix for the assert() statements added by the previous commit. (check-in: 19345416ed user: dan tags: experimental-mmap)
08:58
Add assert statements to os_unix.c to ensure that any mapped region of the database file is not being read or written using the xRead() or xWrite() methods. (check-in: 765615f9fb user: dan tags: experimental-mmap)
Changes
Side-by-Side Diff Ignore Whitespace Patch
Changes to src/os_unix.c.
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    ** that effectively updates the change counter.  This might happen
    ** when restoring a database using the backup API from a zero-length
    ** source.
    */
    if( pFile->inNormalWrite && nByte==0 ){
      pFile->transCntrChng = 1;
    }

    /* If the file was just truncated to a size smaller than the currently
    ** mapped region, reduce the effective mapping size as well. SQLite will
    ** use read() and write() to access data beyond this point from now on.  
    */
    if( nByte<pFile->mmapSize ){
      pFile->mmapSize = nByte;
    }
#endif

    return SQLITE_OK;
  }
}

/*
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  unixFile *p = (unixFile *)fd;   /* The underlying database file */
  int rc = SQLITE_OK;             /* Return code */
  void *pNew = 0;                 /* New mapping */
  i64 nNewRnd;                    /* nNew rounded up */
  i64 nOldRnd;                    /* nOld rounded up */

  assert( iOff==0 );
  assert( p->mmapSize==nOld );
  /* assert( p->mmapSize==nOld ); */
  assert( p->pMapRegion==0 || p->pMapRegion==(*ppMap) );

  /* If the SQLITE_MREMAP_EXTEND flag is set, then the size of the requested 
  ** mapping (nNew bytes) may be greater than the size of the database file.
  ** If this is the case, extend the file on disk using ftruncate().  */
  assert( nNew>0 || (flags & SQLITE_MREMAP_EXTEND)==0 );
  if( flags & SQLITE_MREMAP_EXTEND ){
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