Re: Need help identifying a periodic performance issue. - Mailing list pgsql-performance

From Thomas Munro
Subject Re: Need help identifying a periodic performance issue.
Date
Msg-id CA+hUKG+iKkdeS9g1=866pypHZwPMQL2ho+oFWLSpRjV=-PvuCg@mail.gmail.com
Whole thread Raw
In response to Need help identifying a periodic performance issue.  (Robert Creager <robertc@spectralogic.com>)
Responses Re: Need help identifying a periodic performance issue.  (Robert Creager <robertc@spectralogic.com>)
Re: Need help identifying a periodic performance issue.  (Robert Creager <robertc@spectralogic.com>)
List pgsql-performance
On Tue, Nov 16, 2021 at 5:43 PM Robert Creager <robertc@spectralogic.com> wrote:
> One CPU is pegged, the data has been sent over STDIN, so Postgres is not waiting for more, there are no other queries
runningusing this select:
 

So PostgreSQL is eating 100% CPU, with no value shown in
wait_event_type, and small numbers of system calls are counted.  In
that case, is there an interesting user stack that jumps out with a
profiler during the slowdown (or the kernel version, stack())?

sudo dtrace -n 'profile-99 /arg0/ { @[ustack()] = count(); } tick-10s
{ exit(0); }'



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