On 5/4/07, Pat Maddox <pergesu at gmail.com> wrote:
> My only other question now is can I be sure that slony is still
> replicating properly as long as it's running?  The docs say that older
> versions were very fragile and would crash if they encountered any
> problem.  That'd be fine with my setup because I'm using monit, it'd
> just get restarted.  In 1.2 though it's supposedly a lot less
> fragile...but under what conditions will the daemon run but not be
> operating properly?  Can that happen at all?  Assume that the
> configuration is okay (i.e. nothing boneheaded like forgetting to
> subscribe a set).

I would suggest using something like the MRTG monitoring script as
described here:

http://slony.info/adminguide/slony1-1.2.6/doc/adminguide/monitoring.html#SLONYMRTG

When the lag gets too big, generate an alert to check on replication.

There are a number of other possible solutions described as well.

I recently had a case where I had to restart the replicate DB to clear
up a replication error, so not always restarting slon will fix things
(BTW, if anyone is interested in that I can dig up the logs and try to
figure out what happened in a new thread).

-Dave