Re: Scheduling Events?

Or if you are so paranoid about the stability of crond, you can probably do a
check to see whether crond is up when you update the database.

If crond is up then
update
else
mail root the error
reject the update
end

This is going to affect the performance dramatically though.

----- Original Message -----
From: "Tom Lane" <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: "Achilleus Mantzios" <achill(at)matrix(dot)gatewaynet(dot)com>
Cc: "David Durst" <ddurst(at)larubber(dot)com>; <pgsql-sql(at)postgresql(dot)org>
Sent: Friday, January 24, 2003 10:32 AM
Subject: Re: [SQL] Scheduling Events?

> Achilleus Mantzios <achill(at)matrix(dot)gatewaynet(dot)com> writes:
> > On Fri, 24 Jan 2003, David Durst wrote:
> >> Here is the basic problem w/ using CRON in an accounting situation.
> >>
> >> I can't be sure that cron will always be up when the DB is up,
> >> so lets say crond goes down for some random reason (User, System error,
> >> Etc..)
>
> > I you cannot depend on your system to run crond
> > then you should not depend on it to run postgresql either.
>
> Indeed. Cron is one of the oldest and most basic Unix daemons.
> I find it really, really, really hard to believe that any substitute
> code that anyone might come up with is going to be more reliable than
> cron.
>
> If it makes you feel better, you could institute some cross-checking.
> For example, have the cron-launched task update a timestamp in some
> database table whenever it finishes. Then make your user applications
> check that timestamp when they start up (or every so often) and complain
> if it's not within the range (now - expected cron frequency, now).
> That doesn't fix the problem, but at least makes some humans aware of it.
>
> regards, tom lane
>
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