[AstroPy] PyFITS and mmap

Erik Tollerud erik.tollerud@gmail....
Fri Sep 23 20:44:52 CDT 2011

> I could try turning it on here at STScI and see if any problems arise.
> Warren and I also discussed adding a global default--something like
> pyfits.USE_MEMMAP--that can be used to easily control the default for
> all pyfits.open() calls.

I this idea of having changeable defaults like this is a great idea...
but I think even better than a global variable would be to adopt some
sort of very simple configuration file akin to matplotlibrc.  You
could stick a few other options in there too.  In particular, I would
love to be able to also set pyfits.core.EXTENSION_NAME_CASE_SENSITIVE
to default to True.  I usually end up change it by hand in pyfits once
I install it, but that's annoying to do at every version update (and
its a bit hackey).

Even with that, though, I think it's a good  decent idea to have
memmap be the default - I certainly have a number of scripts where I
force pyfits to memmap, and I've never been distressed by performance
problems - but the limited user testing is definitely a good idea in

>+1 on HDF5 for big datasets.
+1 here as well... but we're still stuck with plenty of other peoples'
gigantic fits tables for the foreseeable future...

Erik Tollerud

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