> On 13/05/2023 00:12 CEST Alex Balashov <abalashov@xxxxxxxxxxxxxxx> wrote: > > We have an application that has a preforked worker pool architecture and > opens a relatively large (70+) number of persistent connections to PostgreSQL > 14, and have `max_connections` set to 200 accordingly. Which pg14 minor version exactly? > Occasionally, about once every 2 months, we'll get a slow-motion implosion > over a period of about 24 hours, where the resident memory size of some of > the backends shoots up from a reasonable few hundred MB to several gigs -- > and will keep growing, e.g. > > PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND > 3932733 postgres 20 0 637740 327124 323840 R 10.7 0.5 0:00.11 postgres > 782930 postgres 20 0 3151360 2.8g 551704 S 9.7 4.5 221:43.17 postgres > 782839 postgres 20 0 2999896 2.7g 551832 S 8.7 4.3 220:54.55 postgres > 3932734 postgres 20 0 636128 338168 336096 R 8.7 0.5 0:00.09 postgres > 3932735 postgres 20 0 636128 319824 317768 R 8.7 0.5 0:00.09 postgres > 782851 postgres 20 0 3142152 2.8g 551872 S 7.8 4.5 221:22.62 postgres > 782855 postgres 20 0 3155144 2.8g 551828 S 7.8 4.5 221:38.59 postgres > 782897 postgres 20 0 3148808 2.8g 551724 S 7.8 4.5 220:05.94 postgres > 783106 postgres 20 0 3152416 2.8g 551912 S 7.8 4.5 221:24.40 postgres > 783168 postgres 20 0 2992592 2.7g 551968 S 7.8 4.2 220:36.06 postgres > 782843 postgres 20 0 3146772 2.8g 551944 R 4.9 4.5 221:38.46 postgres > 782778 postgres 20 0 3150956 2.8g 551852 R 3.9 4.5 220:49.88 postgres Function pg_log_backend_memory_contexts(pid int) may give you some insights on on the memory allocation for specific backends. https://www.postgresql.org/docs/14/functions-admin.html#FUNCTIONS-ADMIN-SIGNAL-TABLE -- Erik
