All 15 Memory Management & Garbage Collection questions
More in Memory Management & Garbage Collection
How does Python primarily manage memory for objects? What does it mean that Python has 'automatic' memory management, and what's the trade-off compared to manual memory management in languages like C? What is a reference cycle, and why can't simple reference counting free it? What is the sys.getsizeof() function, and what are its limitations for measuring memory usage? How do context managers and the `del` statement relate to timely memory cleanup versus relying on garbage collection? How does the gc module let you inspect and debug memory leaks caused by uncollectable objects? How do mutable default arguments create a subtle memory and correctness pitfall related to object lifetime? How does the tracemalloc module help track where memory is being allocated in a running program? How does the weakref module help avoid reference cycles and memory leaks? How does object interning (like small integer caching and string interning) affect memory and identity comparisons?
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How does Python's generational garbage collector work, and why generations?

Intermediate

Answer

CPython's gc module divides tracked objects into three generations (0, 1, 2) based on survival: new objects start in generation 0; objects that survive a collection are promoted to the next generation. Younger generations are collected more frequently since most objects die young (the generational hypothesis), while older, longer-lived objects are scanned less often, improving overall efficiency.
import gc

print(gc.get_threshold())  # e.g., (700, 10, 10) -- collection thresholds per generation
gc.collect()  # force a full collection
print(gc.get_count())  # current allocation counts per generation
Real-world example A long-running server process periodically calls gc.collect() during idle periods to proactively reclaim cyclic garbage before it accumulates and causes memory pressure spikes.

Common follow-ups: What triggers an automatic collection cycle?;How do you tune the thresholds for a specific workload?

Concurrency (asyncio/threading/multiprocessing);Debugging & Profiling
All 15 Memory Management & Garbage Collection questions