[Python-Dev] large file support

Jeremy Hylton jeremy@zope.com
Mon, 17 Jun 2002 15:22:33 -0400

I've run into a problem with large files using Python 2.1.2 and a
Linux 2.4.9 box.  We've got a large file -- almost 6GB -- that Python
chokes on even though regular shell tools seem to be fine.

In particular, os.stat() of the file fails with EOVERFLOW and open()
of the file fails with EFBIG.  The stat() failure is really bad
because it means os.path.exists() returns false.

strace tells me that other tools open the file passing O_LARGEFILE,
but Python does not.  (They pass it even for small files.) I can't
find any succient explanation of O_LARGEFILE, but Google turns up all
sorts of pages that mention it.  It looks like the right way to open
large files, but it only seems to be defined in <asm/fcntl.h> on the
Linux box in question.

I haven't had any luck searching for a decent way to invoke stat() and
have it be prepared for a very large file.

I think Python is definitely broken here.  Can anyone offer any clues
or pointers to documentation?  Better yet, a fix.  I'm happy to help
integrate and test it.