EDIT: It seems to have been fixed thanks to @[email protected]. Running analyze verbose; in postgres.
After updating to 0.19.5 from 0.19.3 my postgres is often using up 500%+ of CPU according to docker stats and often going to 100% CPU on most cores according to htop. Also noticed in the uptime monitor:
htop shows one of the 5 postgres processes constantly on UPDATE. I think this might be part of the problem.
I’m not comfortable with postgres and am honestly completely in the dark how or where to mitigate or even pinpoint this issue.
Any help would be appreciated.
Did you update postgres as well? 0.19.4 needs a newer version.
I have. It’s running postgres v16.3
Sometimes after upgrades, even minor ones, I find it useful to run analyze on all of the tables. I usually do
analyze verbose;so I can see which tables are getting analyzed. This will assess every table so the query planner can make better decisions about how to resolve queries. If the query planner is making bad decisions I/O and CPU will be high and query performance will be poor.Thanks. I ran it. Hopefully it’ll make a difference.
Edit: It looks like this did the trick. I’ll keep monitoring to see if it sticks. Thanks again!
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You can use pg_stat_statements to find slow queries. Try sorting by top
total_exec_time.ERROR: extension "pg_stats_statements" is not availableEven though it’s added in the customPostgresql.conf
shared_preload_libraries = 'auto_explain,pg_stat_statements'I know you already found a solution, but fwiw, it seems you have a typo in calling the extension. You have “stats” plural instead of “stat” singular.
Well that would do it. Thanks for pointing out!
Oh man, i just remembered cve-2024-3094 lol
commit “fixed stuff”
2.8k blob of crypto mining code
Would be hilarious
Do you have any tweaks of pg settings? Eg. shm mem, shared_buffers etc. ?
If not you migh want to: https://pgtune.leopard.in.ua/
I have. And I tried to tweak it with no avail. But it was working within acceptable levels before the update.
hmm, how many connections are used
SELECT count(*) FROM pg_stat_activity;?
I am not a master postgres admin but my intuition has been that the amount of connections is a big factor in how pg behaves with cpu and mem.ERROR: extension "pg_stats_statements" is not availableEven though it’s added in the customPostgresql.conf
shared_preload_libraries = 'auto_explain,pg_stat_statements'extension “pg_stats_statements” is not available
According to this https://stackoverflow.com/a/72966651/5881796
The extension is not loaded:
CREATE EXTENSION pg_stat_statements;I added pg_stat_statements, and ran it. This was the result:
# SELECT count(*) FROM pg_stat_activity; count ------- 11 (1 row)do you also have pict-rs connected to this postgres instance? that is surprisingly low number to me, I would have expected anywhere between 20-50 active connections (I use 50 for lemmy and 20 for pict-rs, configured in their respective conf files)
I think so. I have lemmy and everything needed running through a single docker container using Lemmy-Easy-Deploy.