Re: Oracle RAC 12.2 High Load on CPU from gdb when Node Missing

Interesting that Oracle uses the GDB approach to capture stack traces (pstack - wrapper for GDB). GDB suspends the process (based on ptrace() syscall) and is known to have an impact on communication to kernel or other processes. They could use much better (and safer) tools like perf.  

Best Regards
Stefan Koehler

Independent Oracle performance consultant and researcher Website: http://www.soocs.de
Twitter: _at_OracleSK  

> Martin Klier - Performing Databases GmbH <martin.klier_at_performing-db.com> hat am 20. Juni 2017 um 14:59 geschrieben:
>
> Hi Listers,
>
> just in case you are about to put a 12.2 RAC in service, maybe you are interested in a little twist to make it more reliable when running degraded
> (Node down / unavailable).
>
> I had unexpectedly high load on a surviving node, and wondered why gdb is running wild there. Seems that there is a new debug function in CHM with
> a serious bug that was not in in beta3, and that should be fixed in first PSU, as I was told. A workaround is available:
>
> Link:
> http://www.usn-it.de/index.php/2017/06/20/oracle-rac-12-2-high-load-on-cpu-from-gdb-when-node-missing/
>
> All comments are appreciated, as well as explanations about the background I may have missed.
>
> Best regards
> --
> Martin Klier | Performing Databases GmbH
> Managing Partner | Senior DB Consultant
> Oracle ACE
>
> martin.klier_at_performing-db.com | http://www.performing-databases.com

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