GoKawiilPython 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.
We investigate how memory management works in Python and workloads that perform best and worst for the incremental garbage collector.
You are getting early access to this article as a subscriber. Your support makes articles like this possible. Thank you.
Python 3.14.5 was just released and is the current latest stable version of Python. Python 3.14.0 (released in October, 2025) changed the garbage collector (GC) from traditional generational garbage collection to incremental garbage collection. We’ll get into what this means in this article.
From the pull request merging this change into Python:
The cycle garbage collector is now incremental. This means that maximum pause times are reduced by an order of magnitude or more for larger heaps.
There are now only two generations: young and old. When gc.collect() is not called directly, the GC is invoked a little less frequently. When invoked, it collects the young generation and an increment of the old generation, instead of collecting one or more generations.
This pull request made it into Python’s main branch in 2024 but was removed from the 3.13 release branch. Python 3.14.0 was the first release that included this change.
But users reported “memory pressure” so the Python team reverted changes to the garbage collector in the 3.14.5 release. We’ll get into what “memory pressure” means in this article as well.
... continue reading