Our live/production master db (master node) [node 2] server crashed 
yesterday, and we had to failover to the slave [node 1]. We're using pg 
7.4.6 and slony 1.0.5 on linux.

We had to failover (not switchover) to [node 1] because of the crash, 
and accept missing data (should be minimal at 3:45 am in our case), plus 
we were syncing at 10 sec intervals with almost no load at the time.

We have a full dump (prior to the crash) from 3am (45 mins prior to the 
crash) and have loaded that into a new database. We intend to export 
each table in turn from both databases and diff the results to check for 
identical data up to the time of the last successful full dump to 
reassure ourselves.

Question 1) Is a psql script writing the ordered table data to a file 
and then diff the files from the two databases the best way to do this?

Question 2) We have noticed one sequence that wasn't being replicated 
(our mistake) and we want to add that to one of the existing sets. Is 
SET ADD SEQUENCE (to a new set), MERGE SET (new set, existing set) the 
correct way to do this? Can the new set ID be an existing one? And can 
the new ID be re-used after the merge command?

Question 3) We want to check that all sequence values are >= max PK 
value for the tables in which they are used. Does anyone know how to 
check this without calling nextval() - is it possible to query the 
system tables (and if so how)?

We then uninstalled the cluster and configured a new cluster where [node 
1] is the master and [node 3] the new slave.

Question 4) We now want to replicate from [node 3] to [node 2] when 
[node 2] comes back online. Therefore we want to change [node 2] to be a 
forwarder (which it currently is not), is this possible? Do we have to 
unregister, and re-register [node 3], before giving the subscribe 
commands for [node 2] to use [node 3] as its origin?

Question 5) When adding the new [node 2], is it sufficient to define 4 
new store and listener paths for the existing cluster, eg

store path (server=1, client=2, conninfo='dbname=db1 host=dba user=pg');
store path (server=2, client=1, conninfo='dbname=db1 host=dbb user=pg');
store path (server=2, client=3, conninfo='dbname=db1 host=dbb user=pg');
store path (server=3, client=2, conninfo='dbname=db1 host=dbc user=pg');

store listen (origin = 1, receiver = 2, provider = 1);
store listen (origin = 2, receiver = 1, provider = 2);
store listen (origin = 2, receiver = 3, provider = 1);
store listen (origin = 3, receiver = 2, provider = 1);

Apologies for the stupied questions, but we only installed slony two 
days before the crash so we're very green with it and a little worried 
about damaging our database...

Any help or answers to the above questions would be gratefully appreciated.

Thanks

John Sidney-Woollett