Original problem was fixed by Magnus (see BUG25807).
Currently only windows debug build causes assertion failure. This patch assures
that my_tell gets correct file descriptor on any platform by DBUG_ASSERT macro.
tables
In case system doesn't have native pread/pwrite calls (e.g. Windows)
and there is CHECK TABLE runs concurrently with another statement that
reads from a table, the table may be reported as crashed.
This is fixed by locking file descriptor when my_seek is executed on
MyISAM index file and emulated pread/pwrite may be executed concurrently.
Affects MyISAM tables on platforms that do not have native
pread/pwrite calls (e.g. Windows).
No deterministic test case for this bug.
(Mostly in DBUG_PRINT() and unused arguments)
Fixed bug in query cache when used with traceing (--with-debug)
Fixed memory leak in mysqldump
Removed warnings from mysqltest scripts (replaced -- with #)
- Because my_seek actually is capable of returning an error code we should
exploit that in the best possible way.
- There might be kernel errors or other errors we can't predict and capturing
the return value of all system calls gives us better understanding of
possible errors.
- The io cache flag seek_not_done was not set properly in the reinit_
io_chache function call and this led my_seek to be called despite an
invalid file handle.
- Added a test in reinit_io_cache to ensure we have a valid file handle
before setting seek_not_done flag.
The problem where is that Visual Studio 8 includes new security features to help write more secure code. One of these features is parameter validation. Many of the CRT functions, including lseek, assert on illegal parameter values in debug builds. They also call parameter validation callback routines that can be registered. We solve this problem by defaulting the error value to -1 and then only calling lseek if the fd != -1.
my_seek.c:
Only call lseek if the fd is not -1 on Windows
