Re: [ldm-users] 20200423: Re: Efficiency of splitting pqacts

• To: Tom Yoksas <yoksas@xxxxxxxx>
• Subject: Re: [ldm-users] 20200423: Re: Efficiency of splitting pqacts
• From: Mike Zuranski <zuranski.wx@xxxxxxxxx>
• Date: Thu, 23 Apr 2020 14:20:13 -0500

That all makes sense.

Thanks for the quick response, Tom.  I appreciate it.

-Mike

======================
Mike Zuranski
Meteorology Support Analyst
College of DuPage - Nexlab
Weather.cod.edu <http://weather.cod.edu/>
======================


On Thu, Apr 23, 2020 at 2:15 PM Tom Yoksas <yoksas@xxxxxxxx> wrote:

> Hi Mike,
>
> On 4/23/20 12:39 PM, Mike Zuranski wrote:
> > I'm wondering if there is a difference in speed/efficiency of the LDM,
> > or in system resource allocation, between grouping all my pqact
> > statements in one file vs. splitting them up into different pqact
> > files.
>
> Since all actions in an LDM pattern-action file are processed
> sequentially, there is a benefit to distributing actions in multiple
> pattern-action files that are each processed by a separate 'pqact'
> instance.
>
> re:
> > Does LDM do anything differently or is it a wash either way?
>
> No, each 'pqact' instance will work through the list of actions in
> the pattern-action file that it works in sequence.  So, if one has
> a monolithic pattern-action file with, say 10K actions, it will take
> significantly longer than having 10 'pqact' instances operating
> on pattern-action files that each have 100 actions.
>
> re:
> > I vaguely remember this coming up at one point but I couldn't find any
> > documentation or old email threads about it.  I'm mostly just asking out
> > of curiosity, I don't have a specific problem that I'm trying to solve
> > or anything.  But if I were to redo my pqact organization I'm wondering
> > if there is a preferred methodology.
>
> The best rule of thumb is to have multiple 'pqact' instances operating
> on multiple pattern-action files when the list of actions to be
> performed is large, or when some of the actions are slow.  There is no
> "best practice" for, say, having only N actions in a pattern-action
> file since the speed that the actions will be performed is a function
> of how fast/slow each action is.  Sites invariably will need to do
> their own tuning to find the right balance of speed and use of
> resources (more 'pqact' instances will, of course, use more resources
> like CPU, RAM, etc.).
>
> Cheers,
>
> Tom
> --
> +----------------------------------------------------------------------+
> * Tom Yoksas                                      UCAR Unidata Program *
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> * yoksas@xxxxxxxx                                    Boulder, CO 80307 *
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• References:
  • [ldm-users] Efficiency of splitting pqacts
    • From: Mike Zuranski
  • [ldm-users] 20200423: Re: Efficiency of splitting pqacts
    • From: Tom Yoksas