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[LDM #DAM-692844]: LDM 6.8.0 Bug - plotMetrics in Perl v5.6.1

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  • Subject: [LDM #DAM-692844]: LDM 6.8.0 Bug - plotMetrics in Perl v5.6.1
  • Date: Mon, 10 Aug 2009 17:57:00 -0600
Eric,

> Thank you for the wonderful workshop, it was a blast.

You're most welcome.

> Hate to have some bad news but we found something.
> 
> In Perl 5.6.1, it appears the close() command improperly triggers the
> die when you run the "top -b -n 1 |". I've tested and it appears to be a
> bug with the filehandle.

That does sound like a bug.  The Perl documentation explicitly gives that 
construction as an example for when you don't want to read all the input.

> Through testing in 5.6.1 I found you are required to complete the read
> of the handle, at least thats what my tests have shown. The line:
> 
> last if ($haveMem && $haveSwap);
> 
> breaks the loop. Since the filehandle still has data in it the close()
> seems to return a value. A second loop that just cycles through the
> remaining handle should do the trick. That is what we plan to implement.
> ie:
> 
> 
> I've tried to SEEK_END with no success. So it appears to be an issue
> with the the Perl IOLayer. We began receiving errors through the cron
> when we added the 'ldmadmin addmetrics' and investigation into it found
> this to be an issue.
> 
> Not that we SHOULD be using Perl 5.6.1 and we plan to upgrade. But this
> should be good for you to know if it comes up.

I'd upgrade the Perl installation (e.g., "yum install perl" as root).

> I've attached our patch if you'd want it.

Thanks.

> Thanks again!
> 
> --
> Eric M. Hudish
> Cell: +1.724.977.3314
> 359 Toftrees Avenue Apt. 302
> State College, PA 16803
> 
> PGP Security Available
> Search http://keyserver.pgp.com


Regards,
Steve Emmerson

Ticket Details
===================
Ticket ID: DAM-692844
Department: Support LDM
Priority: Normal
Status: Closed