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From: nazgul@alfalfa.COM (Kee Hinckley)
Newsgroups: comp.windows.x
Subject: Translations, Resources and Storage Leaks
Message-ID: <9103140445.AA01983@alfalfa.com>
Date: 14 Mar 91 04:45:07 GMT
Sender: daemon@athena.mit.edu (Mr Background)
Organization: The Internet
Lines: 42

On and off I have seen people mention things like this on the Motif
list, but I've never seen anyone able to nail it down.  I'm going
to briefly describe the symptoms and I'd like to hear if anyone
has any ideas what might be going on.

We have an application that creates and destroys widgets on a
common basis.  A typical sequence involves the destruction and
recreation of half a dozen text widgets, a table, a two scrolled
windows and a couple paned windows.  (Yes we should do a better
job of cacheing, but anyway...)

Occasionally we start seeing massive storage leaks, on the order
of 200K a shot.  2K I could live with, but 200K is not going to
cut it.  I expect this sequence to occur hundreds of times a day!

What we have seen.

o  It seems like Motif is installing a lot more translations when
   this happens.  Looking at the Motif code I see several places
   where translations are installed (augmented) only if the widget currently
   has translations - otherwise it waits.  So I suspect that for
   some reason it thinks that they do.  Or maybe it has something
   to do with traversal - another place translations are installed.
   I really don't know, and we haven't had a chance to explore this
   avenue too far yet.

o  The leakage is dependant on the contents of the .Xdefaults/.Xresources
   file.  But it isn't dependant on any particular resource, or even one
   that has anything to do with the application.  We can cut the resource
   file in half, and use either half and we get no leakage.  But if
   we use the whole file, it leaks.  If we cut it down line by line
   at some point we cross a threshold and it stops.  If we take the resource
   definition we just deleted and make it some bogus definition
   "foo.bar: asdf", it doesn't matter - we still get the leakage.  All of
   this makes us suspect that there is some boundary condition in resource
   handling that causes something to be reallocated or something to change
   behavior - but we haven't been able to find it.

Does anyone have the vaguest idea what might be going on here?  Or how
we might track it down?

							-kee