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Re: Scheduling type daemon

by hippo (Abbot)
on Sep 13, 2017 at 11:22 UTC ( #1199288=note: print w/replies, xml ) Need Help??

in reply to Scheduling type daemon

Some every quarter hour. Every hour. Once a day. It's too many processes for cron to cope with. The every minute ones, for example, I want to stagger over the minute so they're not all firing right bang on the zero seconds mark.

So, you need 4 shell (or perl or whatever) scripts like: which sit in some directory somewhere. Each script then runs all the jobs to be run on that schedule and does so sequentially (or uses GNU parallel or similar if you want a farm). Then your cron config only needs 4 entries and cron can quite happily cope with that.

* * * * * /foo/ */15 * * * * /foo/ 0 * * * * /foo/ 0 0 * * * /foo/

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Re^2: Scheduling type daemon
by Laurielounge (Acolyte) on Sep 13, 2017 at 20:18 UTC
    The four crons is an acceptable approach but doesn't solve the other bit of the problem.

    Take the every minute job as an example. At stay time either all of the jobs fire in series (or in parallel, doesn't really matter). What I'm trying to do is stretch the load over the period, in the case, the minute.
    As I said, I've got the scheduling database ready. So on the minute when the cron fires, I want to run these few jobs immediately, at the five second mark (say) these ones... for the every 15 minute job, I want to immediately run these jobs, and at the three minute mark (say) run these ones... the five minute (say) run these ones... so the cron job fires a script which then times the execution of the jobs. Which may be timed to the second. The accuracy of the timing is not really important, its just about spreading the load a bit. I say "to the second" as that seems to me the only way to get that granularity in the "every minute" job.
      In the script, just run the scripts one by one in a loop. Add a sleep with the value of available seconds / number of jobs.
      ($q=q:Sq=~/;[c](.)(.)/;chr(-||-|5+lengthSq)`"S|oS2"`map{chr |+ord }map{substrSq`S_+|`|}3E|-|`7**2-3:)=~y+S|`+$1,++print+eval$q,q,a,

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