Andreas Pflug <pgadmin at pse-consulting.de> writes:
> Having all machine's clocks in time sync is a requirement of slony
> that seems quite obvious. Still, if this requirement is not met for
> whatever reason (maybe an admin is 110 % sure ntpd is running, but it
> stalled), things might get screwed up in a way that's not easy to
> debug.
> After a brief look at slon, it seems that local time is used for
> checking timeouts only (the only insert into a timestamp column uses
> now()), so problems from clock drift are unlikely to appear from
> that. But databases servers still might deviate, how about a check in
> slon that checks regularly if the servers in use are sufficiently in
> sync? Maybe slon should even refuse to run/stop working if server
> clocks (checked with now(), not timeofday()) are not sufficiently
> in-sync.

It seems an excellent idea to run some utility completely outside slon
that checks for clock deviations and warns someone.

I could see it being an interesting possiblity for that to lead to
knocking down the slons, but that seems like a local policy that
Slony-I doesn't need to impose itself.
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Christopher Browne
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