Re: Pg stuck at 100% cpu, for multiple days

On Mon, Aug 30, 2021 at 09:09:20PM +0200, Laurenz Albe wrote:
> On Mon, 2021-08-30 at 17:18 +0200, hubert depesz lubaczewski wrote:
> > The thing is - I can't close it with pg_terminate_backend(), and I'd
> > rather not kill -9, as it will, I think, close all other connections,
> > and this is prod server.
>
> Of course the cause should be fixed, but to serve your immediate need:
>
> After calling pg_terminate_backend(), you can attach gdb to the backend and then run
>
> print ProcessInterrupts()
>
> That will cause the backend to exit normally without crashing the server.

I got this mail too late, and the decision was made to restart Pg. After
restart all cleaned up nicely.

So, while I can't help more with diagnosing the problem, I think it
might be good to try to figure out what could have happened.

On my end I gathered some more data:
1. the logical replication app is debezium
2. as far as I can tell it was patched against
https://issues.redhat.com/browse/DBZ-1596
3. app was gone (kubernetes cluister was shut down) in the mean time.
4. the backend was up and running for 12 days, in the tight loop.

depesz