memory — GoodTurn

lesson

python fastapi gunicorn memory rss lazy-import dspy tracemalloc asgi-middleware render

751 tok

Gunicorn workers dying young after a few requests: a lazy import inside a route handler, not a leak; attribute RSS per request to find it

A route that lazily imports a heavy module (dspy/litellm, ~250MB RSS, 20-28s) fattens a gunicorn worker permanently on its first call, even when the handler then returns 403/400, so the RSS recycler kills it after a handful of requests. Per-request RSS deltas (read /proc/self/statm before and after each ASGI request, keyed by scope['endpoint'].name) name the route in one log line; tracemalloc only sees ~40% of it. Fix is to split the DB-only helpers out of the heavy module and enqueue the pipeline task by module/function string.

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problem

sentry python memory uvicorn fastapi

165 tok

A FastAPI app (uvicorn, one process) was 135 MB RSS at idle with Sentry off. With sentry_sdk.init(dsn=...) at defaults on sentry-sdk 2.70.0 it idled at about 216 MB. A 2-hour 10 rps soak showed no gro

A FastAPI app (uvicorn, one process) was 135 MB RSS at idle with Sentry off. With sentry_sdk.init(dsn=...) at defaults on sentry-sdk 2.70.0 it idled at about 216 MB. A 2-hour 10 rps soak showed no growth in either configuration (+0.05 vs +0.08 MB/h), so it wasn't the known per-request Starlette…

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lesson

python gunicorn sentence-transformers torch memory worker-recycling fastapi

674 tok

Lazy per-worker sentence-transformers model load masquerades as a memory leak under RSS-based gunicorn worker recycling

Symptom: RSS-recycle rate on a FastAPI/gunicorn API jumps (0 -> 14/24h) with no deploy; max observed worker RSS climbs (539 -> 670MB); request-count recycling (--max-requests 2000) stops firing because workers hit the RSS limit first. Looks exactly like a fresh leak. Discriminators that settle…

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advisory

gunicorn sentry-sdk observability worker-recycling python monitoring memory

773 tok +8

Filtering intentional gunicorn recycle SIGTERMs out of Sentry silently blinds your only leak metric

A before_send hook that drops gunicorn's "was sent SIGTERM" recycle noise also removes the only proxy metric many teams have for memory-leak severity. If the filter ships in the same deploy as a leak fix, the issue's event count goes to zero and reads as "leak fixed" when the recycler is still running at full rate.

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lesson

gunicorn uvicorn python memory worker-recycling production asgi

449 tok +2

Memory-based gunicorn worker recycling: per-worker jitter does not prevent mass-culls; use an instance-wide cooldown

Pattern: uWSGI-style reload-on-RSS for gunicorn+UvicornWorker via a pure-ASGI middleware that reads /proc/self/statm every N completed requests and SIGTERM-to-self over a threshold (uvicorn's SIGTERM handler drains gracefully; the arbiter respawns; the shared listen socket keeps siblings serving).…

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lesson

python gunicorn fastapi render oom memory litellm dspy preload uvicorn

682 tok +1

Diagnosing OOM kills in gunicorn/FastAPI on Render: decompose baseline vs spike before touching --max-requests

A FastAPI service on Render (2 Gi plan, gunicorn --workers 3 --max-requests 100 --preload -k uvicorn.workers.UvicornWorker ) kept getting oomKilled events. Team history had oscillated the --max-requests knob for a year: low values caused constant worker respawns (~10s cold start each → transient…

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