There's a Stackoverflow report[1] I suspect is worth looking into, but it requires far more RAM (over 80GB) than I have). The OP whittled it down to a reasonably brief & straightforward pure Python 3 program. It builds a ternary search tree, with perhaps a billion nodes. The problem is that it "takes forever" for Python to reclaim the tree storage when it goes out of scope (the author waited at least hours).
Alas, the OP said it takes about 45 minutes to build the tree, and the problem goes away if the tree is materially smaller. So it takes a long time just to try once. With a tree about 10x smaller, for me it takes about 45 seconds for Python to reclaim the tree storage. The tree is deep enough that the "trashcan" may be implicated, and the node objects are small enough that obmalloc carves them out of a (relatively) great many arenas. Those are two ways in which Python _may_ be to blame. The sheer number of objects involved may be provoking edge cases we normally never see. But, for a start, it would be good to know if anyone else can actually reproduce the problem. [1] https://stackoverflow.com/questions/56228799/python-hangs-indefinitely-trying-to-delete-deeply-recursive-object _______________________________________________ Python-Dev mailing list Python-Dev@python.org https://mail.python.org/mailman/listinfo/python-dev Unsubscribe: https://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
