Hello there folks, I have a bit of a special issue. I'll start by disclosing myself for what i am doing. I am a postgraduate student and I really have good reasons to do what I am doing. At least i think so.
And not the issue. I am building a python web service. This web service has some generic objects and I use a metaclass to customize the classes. Second I use a non-conventional object oriented database, dybase (http://www.garret.ru/dybase/doc/dybase.html#introduction) Now these is a OODBMS claiming to support ACID transactions. The instances of my objects are recursively organizing themselves into a hierarchical tree-like structure. When I make an instance of this object persistent dybase actually can recursively save all tree structure. Everything works well here. I altered the main class situated at the root of my class hierarchy to actually store inside the__dict__ not the instances of its children but their unique ID's. Then when I set a child attribute I create it and instead of being stored in the instance the child goes to a database index object. Thus it becomes Universally addressable. The a parent retrieves the child it actually fetches it from the database. In this way I ended up with very small objects.However these objects can regenerate the treelike structure as if they were storing there children in the __dict__. The issue is how to give the instances access to the database and properly handle the opening and closing of the database. It seems futile to me to actually open/close the connection through a context. Because the database is a file it will issue an IO operation on every attribute access and we all know __getattribute__ is used extremely often. For this reason I thought the best way would be to wrap the dybase Storage (main class) into a local storage version which would have __del__ method. The local Storage is a new style class..it opens the DB file but the __del__ is never called. This is because the Storage class has at least 2 cyclic references. So my Storage class never closes the database. I would like this class to close the database when it is garbage collected. The class is a Singleton FYI as well but this might not be relevant or even necessary. So my question is: what s the best way to force __del__ on a singleton that has cyclic references. Should i use weakref and alter the original source? Is there a way i can force a singleton to garbage collect itself?. I am by no means a software engineer so i would appreciate any advice from some experts on the matter. Thank you in advance. -- http://mail.python.org/mailman/listinfo/python-list
