"Slawek Jarosz" <Slawek.Jarosz at advantechamt.com> writes:
> From the Slony log file I can see some errors which occur every 30 seconds or so:
>
> 2007-09-12 13:39:15 GMT ERROR  remoteWorkerThread_1: "begin transaction; set transaction isolation level serializable; lock table "_t1".sl_config_lock; select
> "_t1".failoverSet_int(1, 2, 1, 10787); notify "_t1_Event"; notify "_t1_Confirm"; insert into "_t1".sl_event     (ev_origin, ev_seqno, ev_timestamp,      ev_minxid,
> ev_maxxid, ev_xip, ev_type , ev_data1, ev_data2, ev_data3    ) values ('1', '10787', '2007-09-12 07:34:50.791482', '9692768', '9692769', '', 'FAILOVER_SET', '1', '2',
> '1'); insert into "_t1".sl_confirm      (con_origin, con_received, con_seqno, con_timestamp)    values (1, 2, '10787', now()); commit transaction;" PGRES_FATAL_ERROR
> ERROR:  duplicate key violates unique constraint "pg_trigger_tgrelid_tgname_index"

The error suggests that someone has been hacking on indexes by hand.  

Probably one of the tables has a trigger on it, which gets hidden, via
catalog trickery, on the subscribers.

Then someone added the "apparently missing" trigger by hand, rather
than via the slonik STORE TRIGGER command, and so there are now two
triggers, one "hidden by trickery," the other visible.

The FAILOVER attempts to restore the "hidden-by-trickery" triggers,
and fails, because you hacked the same trigger back into place.

And thus the problem every 30s...

Use DROP TRIGGER on the node to drop the visible version of the
trigger, and that should resolve that issue.  With some luck, that is
the only thing you need to do...

> From log file slon-smsdb-node2.err (where smsdb is the name of my database)
>
>  
>
> WATCHDOG: No Slon is running for node node2!
> WATCHDOG: You ought to check the postmaster and slon for evidence of a crash!
> WATCHDOG: I'm going to restart slon for node2...
> WATCHDOG: Restarted slon for the t1 cluster, PID 3240

This is probably just falling out of the other issues - the slon hits
a fatal problem, and dies, so the watchdog finds it gone...
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