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Thanks Daryl, that's some great info. Splitting up radar like that (albeit L3 instead of L2) is one of the things on my todo list; I might borrow your method with sym links to make that happen. -Mike ====================== Mike Zuranski Meteorology Support Analyst College of DuPage - Nexlab Weather.cod.edu <http://weather.cod.edu/> ====================== On Thu, Apr 23, 2020 at 2:37 PM Herzmann, Daryl E [AGRON] < akrherz@xxxxxxxxxxx> wrote: > Well Howdy, > > I am sure Unidata will correct my ignorance / incorrect details, but my > understanding is that an individual pqact process can only do 32 "things" > at one time, or there's 32 slots available for work. > > Now, the above depends on the action. If you run `PIPE -close`, the slot > can be used for another product even with the PIPEd process still > running... This type of action can lead LDM to DOSing the server it is on > as it will fire off as many PIPE'd processes that it can. You old timers, > like me, will recall the lock file fun Chiz wrote into the GIF generation > script of NIDS data for this reason. > > If you are doing just FILE actions without a `-close`, there is some > benefit to spreading out the pqact.conf file into multiple files to keep > each pqact roughly touching 32 files each. For example with level2 data, > dividing the radars into chunks like so: > > exec "pqact -p BZIP2/K[A-D] -f CRAFT /local/ldm/etc/pqact-craft.conf" > exec "pqact -p BZIP2/K[E-H] -f CRAFT /local/ldm/etc/pqact-craft2.conf" > exec "pqact -p BZIP2/K[I-K] -f CRAFT /local/ldm/etc/pqact-craft3.conf" > exec "pqact -p BZIP2/K[L-O] -f CRAFT /local/ldm/etc/pqact-craft4.conf" > exec "pqact -p BZIP2/K[P-R] -f CRAFT /local/ldm/etc/pqact-craft5.conf" > exec "pqact -p BZIP2/K[S-Z] -f CRAFT /local/ldm/etc/pqact-craft6.conf" > exec "pqact -p BZIP2/[A-J] -f CRAFT /local/ldm/etc/pqact-craft7.conf" > exec "pqact -p BZIP2/[L-Z] -f CRAFT /local/ldm/etc/pqact-craft8.conf" > > Behold, another caveat here. While with the above, each pqact process has > its own uniquely named file, this file can be the same file on the > filesystem and managed with sym links. They need to be unique to the pqact > process so that pqact can write its `.state` file to a unique location. > > You should consider the processes being run, how long their lifetime is, > and your server's capacity. If you have a bunch of long running GEMPAK > decoders that totals something less than 32 total, then just keep them in > one file but perhaps isolate that pqact process to just those tasks. > > So hold tight until Unidata corrects my above as FUD :) > > daryl > > -- > /** > * daryl herzmann > * Systems Analyst III -- Iowa Environmental Mesonet > * https://mesonet.agron.iastate.edu > */ > > ________________________________________ > From: ldm-users <ldm-users-bounces@xxxxxxxxxxxxxxxx> on behalf of Tom > Yoksas <yoksas@xxxxxxxx> > Sent: Thursday, April 23, 2020 2:15 PM > To: ldm-users@xxxxxxxxxxxxxxxx > Subject: [ldm-users] 20200423: Re: Efficiency of splitting pqacts > > 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 * > * (303) 497-8642 (last resort) P.O. Box 3000 * > * yoksas@xxxxxxxx Boulder, CO 80307 * > * Unidata WWW Service http://www.unidata.ucar.edu/ * > +----------------------------------------------------------------------+ > > _______________________________________________ > NOTE: All exchanges posted to Unidata maintained email lists are > recorded in the Unidata inquiry tracking system and made publicly > available through the web. Users who post to any of the lists we > maintain are reminded to remove any personal information that they > do not want to be made public. > > > ldm-users mailing list > ldm-users@xxxxxxxxxxxxxxxx > For list information or to unsubscribe, visit: > https://www.unidata.ucar.edu/mailing_lists/ > > _______________________________________________ > NOTE: All exchanges posted to Unidata maintained email lists are > recorded in the Unidata inquiry tracking system and made publicly > available through the web. Users who post to any of the lists we > maintain are reminded to remove any personal information that they > do not want to be made public. > > > ldm-users mailing list > ldm-users@xxxxxxxxxxxxxxxx > For list information or to unsubscribe, visit: > https://www.unidata.ucar.edu/mailing_lists/ >
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