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Python 3.14 garbage collection rigamarole

Python 3.14 garbage collection rigamarole

eatonphil

Comments (28)

  • zahlman
    Anthony Sottile had a video on the reversion over a month ago: https://www.youtube.com/watch?v=tQ3hnQiJ0YM
  • vlovich123
    I suspect 3.14.4 could have been tweaked slightly to address the issue without a revert - they could have prioritized checking the liveliness of objects sorted by size. I’m pretty sure that would fix the max RSS issue without needing a revert and the people unhappy with 3.14 could keep using 3.13 or switch to 3.14 and simply inject explicit calls to gc.gc().Figuring out how to measure the size of an object can be tricky of course, but I suspect there’s all sorts of things you could try including figuring out how much memory got deallocated after you gc a cycle and attributing it to where the object got allocated as a heuristic to measure the mean allocation size.
  • emil-lp
    Related. 31 days agoReverting the incremental GC in Python 3.14 and 3.15265 points, 130 commentshttps://news.ycombinator.com/item?id=48077924
  • zzzeek
    We definitely noticed behavioral differences in 3.14 regarding gc which could show up in particular test suites we have that are purposely ensuring all objects of a certain type were collected after a gc.collect() run. Between this and other issues (changes to the runtime API for typing, the first decently runnable version of free-threading, kind of a longer time for some C-based dependencies to catch up), the transition for my projects (SQLAlchemy) to 3.14 was generally more bumpy than that of say 3.12 or 3.13. will be interesting to see if 3.14.5 allows us to relax some changes we had to make to the test suite.
  • irishcoffee
    The folks running the show as it relates to python remind me a lot about the folks running the show at mozilla.That is not a compliment.
  • functionmouse
    > Python 3.14.0 introduced a new incremental garbage collector. But reports of higher memory usage caused the Python team to revert the garbage collector changes in 3.14.5.If they didn't have very good objective reasons the new GC is better, they never should have shipped it. If they do, they should not have reverted the change.