[Python-3000] gc, timestamping

[Guido van Rossum]

On 1/24/07, Jim Jewett <jimjjewett at gmail.com> wrote:
> (on python-dev) Kristján V. Jónsson wrote:
>
> > We have been using gc.get_objects() but it has several problems:
> >  1) ... results in a list so long that it often kills the system.
>
> In Py3K, should this also return an iterator, rather than a list?
>
> In other words, is the dict.items change something specific to dicts,
> or something that could happen with any large sequence?

It should be considered on a case-by-case basis, depending on how the
result is most commonly used, or perhaps what's the most useful
result. I don't know if it makes sense given the GC implementation to
do it in this case.

(For example, I looked briefly into making os.listdir() an iterator,
but decided against it because you'd have a file descriptor open while
iterating, and the list is never truly long.)

> > 2) There is no way to frame certain operations and get just those
> > objects that were created during their execution.  ... storing the id()s of all objects
> >... the ambiguity of id() in the face of objects being created and destroyed.
>
> Changing id() to be something other than the address probably isn't
> practical, but with the elimination of old-style classes, everything
> should inherit from object.  Would it make sense to add optional
> timestamping (or other alternative id-like attributes)?
>
> Right now, the best solution I see is to use a debug build and a C
> debugger to inspect the serial number that _PyObject_DebugMalloc
> sticks after its FORBIDDENBYTE barrier.

-- 
--Guido van Rossum (home page: http://www.python.org/~guido/)