Re: [Condor-devel] Issues with output files and checkpointing

[Daniel Forrest <forrest@xxxxxxxxxxxxx>]

Pete,

> > Hack: A source level fix is to "ftruncate(fd, lseek(fd, 0L, SEEK_CUR))"
> > when the file is closed.  Of course, it would be preferable to not have
> > to modify all of our source code.
> 
> This one I need to inspect closer to see if we just can't have Condor
> do this for us.

This is something you can't really do generically.  It is only valid
in the case where you write the file sequentially from beginning to
end.  It would have real problems if you are reading or re-writing
parts of the file.

I have some patches for making compressed files robust in the case of
checkpoint failures and part of this involves keeping track of the
file size at checkpoint time.  It is then a simple matter to truncate
the file when it is re-opened to match.  I should be at your Tuesday
meeting and I can talk with you about it.

-- 
Daniel K. Forrest	Laboratory for Molecular and
forrest@xxxxxxxxxxxxx	Computational Genomics
(608) 262 - 9479	University of Wisconsin, Madison