Re: Debugging a backend stuck consuming CPU - Mailing list pgsql-general

From Merlin Moncure
Subject Re: Debugging a backend stuck consuming CPU
Date
Msg-id CAHyXU0xNJ_UTu9AXWRWwbN_VCr7D0jBMCoEa2U_LL1Q_k1=g2w@mail.gmail.com
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In response to Debugging a backend stuck consuming CPU  ("ktm@rice.edu" <ktm@rice.edu>)
List pgsql-general
On Thu, May 19, 2016 at 8:46 AM, ktm@rice.edu <ktm@rice.edu> wrote:
> Hi PostgreSQL community,
>
> I am investigating a problem with a backend that appears to be stuck
> and spinning while performing a "DISCARD ALL" command. The system is
> running an older release 9.2.2. Are there any bugs that could be
> causing this behavior? How can I tell what the process is actually
> doing? It does not respond to either pg_cancel_backend() or to
> pg_terminate_backend() so it is acting like it is not receiving the
> signals. Any ideas on how to debug this would be appriciated.

1. Grab a stack trace and a 'perf top' for forensic analysis in case
it happens again
2. Install latest 9.2 binaries
3. Restart database

There's not much value in analyzing such an out of date database;
there's a very high probability your bug has already been fixed.

merlin


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