id summary reporter owner description type status component version severity resolution keywords cc stage has_patch needs_docs needs_tests needs_better_patch easy ui_ux 31373 Django 3.x / uwsgi is leaking connections Marcin Nowak nobody "Project upgraded from 2.x to 3.0.4 is leaking PostgreSQL database connections. ATOMIC_REQUESTS=False, AUTOCOMMIT=True, CONN_MAX_AGE=0 UWSGi threads are enabled (`--enable-threads`) Python 3.8.1 and 3.7.3 After few hours all posgtress connections are used (too many connections error). pg_stat_activity is reporting idle connections with part of queries visible. I would try to deliver more details later. [[Image(Firefox_Screenshot_2020-03-17T15-05-35.104Z.png)]] ---- Facts: - setting up CONN_MAX_AGE > 0 does not help - CONN_MAX_AGE = 30, starting `runserver` and making many calls with `ab -c 10 -n 100 http://127.0.0.1:8000/` uses all available connections and ends with error 500 (due to no available connections) - CONN_MAX_AGE = 30, starting `runserver --nothreading` and making calls with `ab -c 100 -n 100 http://127.0.0.1:8000/` works fine - CONN_MAX_AGE=30 + runserver + ab scenario is reproducible on clean install. Called view must access database. - CONN_MAX_AGE=0 + runserver + ab -> cannot reproduce. - Django 2.x has similar issue for CONN_MAX_AGE=30, but can reuse connections (still there are several errors on high traffic, but app server can ""recover"" and handle bunch of incoming requests) - Looks like Django 3.x cannot reuse connections - uwsgi + threads + CONN_MAX_AGE=0 on localhost -> cannot reproduce ---- Runserver (with threads) test results: `ab -c 10 -n 200 ` Django 3.0.4: Complete requests: 200 Failed requests: 108 `ab -c 10 -n 1000` Django 2.2.11: Complete requests: 1000 Failed requests: 37 ---- There may be two separate cases: 1. not reusing connection when CONN_MAX_AGE is greater than 0 2. leaking (not closing?) connections on uwsgi (?) with enabled threads (?) and CONN_MAX_AGE set to 0" Uncategorized new Uncategorized 3.0 Normal Unreviewed 0 0 0 0 0 0