SPUG: Perl Question?

dleonard at dleonard.net dleonard at dleonard.net
Wed May 4 09:36:17 PDT 2005

As someone who has been rewriting code that uses lockfiles to determine whether it should launch I have to say this it definitely not an optimal way of doing things.  If a mount becomes unavailable, the filesystem becomes read-only, or a user or other process modifies the filesystem, this design breaks down.

I would recommend instead querying the process table for other processes running as $0.


<Douglas Leonard>
<dleonard at dleonard.net>
<Perfection should always be the goal.	Settling for excellence is
sometimes acceptable.>

On Tue, 3 May 2005, Rick Croote wrote:

> I agree with Aaron response, but I would make a very simple statement and
> solution.  Repeatedly running things at 15 minute intervals, when that may
> extend past 15 minutes just isn't a good idea.  Simply modify the batch
> file with a simple locking mechanism that says if a flagfile exist, do not
> start, and if it doesn't exist, create the flagfile and continue with your
> process, and finally remove the flagfile at the end.  In this way you will
> never fall into at least the quicksand, I'm sure others are waiting
> though.  This will automatically push emailed reports to be every 30
> minutes, or longer, if the 15 minute interval is too short.  Then, if you
> are not getting your reports often enough, you can then at least look into
> why that is, but at least your 15 minute cycle will not be part of the
> problem.
> ---
> Rick Croote
> Software Engineer
> Environment and Tools Team
> Philips Medical Systems
> Bothell, WA
> Rick.Croote at Philips.com
> Phone: 425-487-7834
> Mike Alba <michaelpalba at yahoo.com>
> Sent by:
> spug-list-bounces at pm.org
> 05/03/2005 03:27 PM
>         To:     spug-list at pm.org
>         cc:     (bcc: Rick Croote/ATL-BTL/MS/PHILIPS)
>         Subject:        SPUG: Perl Question?
>         Classification:
> Hi,
>   I have a question regarding perl performance.
> I have batch file that executes the same perl
> program a few times but with different parameters.
> In other words there are different operations
> being performed, sql reports are generated from
> the database, files are moved around, files are
> emailled, etc. This batch runs every 15 minutes
> and occasionally there seems to be performance
> problems. The thinking was that maybe some of the
> perl calls are bumping into each other. For instance
> a database call may be taking longer then expected.
> Is there a way I can monitor this? When I have
> tried to duplicate this it seems that each perl
> call isnt made until the previous one finishes,
> from the batch file. Am I incorrect here and
> there might be other factors at play as far as
> why performance issues are occuring? Any tools
> available that I can use to monitor each running
> perl call? Also since it only happens intermittently
> I guess I am going to have to capture a lot of data?
> Thanks in advance for your help!!!
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