I use test_slony_state and see some informations like :

Check of event info
---------------------------------------------------
 Problem : Events not propagating to node 2
 Problem : Events not propagating to node 4
 Problem : Events not propagating to node 3

Check of sl_confirm aging
---------------------------------------------------
 Confirmations not propagating from 2 to 1
 Confirmations not propagating from 2 to 3
 Confirmations not propagating from 2 to 4
 Confirmations not propagating from 3 to 1
 Confirmations not propagating from 3 to 2
 Confirmations not propagating from 3 to 4
 Confirmations not propagating from 4 to 1
 Confirmations not propagating from 4 to 2
 Confirmations not propagating from 4 to 3

You can see the results on one of my databases :

- for Confirmations

select con_origin, con_received, min(con_seqno) as minseq, max(con_seqno) as maxseq, date_trunc('minutes', min(now()-con_timestamp)) as age1, date_trunc('minutes', max(now()-con_timestamp)) as age2, min(now() - con_timestamp) > '00:30:00' as tooold from _pns_slony_voila_archi_0.sl_confirm group by con_origin, con_received order by con_origin, con_received;
 con_origin | con_received | minseq  | maxseq  |   age1   |   age2   | tooold 
------------+--------------+---------+---------+----------+----------+--------
        101 |          102 | 4464029 | 4464792 | 00:00:00 | 00:16:00 | f
        101 |          103 | 4464027 | 4464792 | 00:00:00 | 00:16:00 | f
        101 |          104 | 4464024 | 4464792 | 00:00:00 | 00:16:00 | f
        102 |          101 |      29 |      29 | 03:39:00 | 03:39:00 | t
        102 |          103 |      29 |      29 | 03:39:00 | 03:39:00 | t
        102 |          104 |      29 |      29 | 03:39:00 | 03:39:00 | t
        103 |          101 |      62 |      62 | 03:39:00 | 03:39:00 | t
        103 |          102 |      62 |      62 | 03:39:00 | 03:39:00 | t
        103 |          104 |      62 |      62 | 03:39:00 | 03:39:00 | t
        104 |          101 |      57 |      57 | 03:39:00 | 03:39:00 | t
        104 |          102 |      57 |      57 | 03:39:00 | 03:39:00 | t
        104 |          103 |      57 |      57 | 03:39:00 | 03:39:00 | t


- for Events

select ev_origin, min(ev_seqno), max(ev_seqno),
         date_trunc('minutes', min(now() - ev_timestamp)),
         date_trunc('minutes', max(now() - ev_timestamp)),
         min(now() - ev_timestamp) > '00:30:00' as agehi
     from _pns_slony_voila_archi_0.sl_event group by ev_origin;
 ev_origin |   min   |   max   | date_trunc | date_trunc | agehi
-----------+---------+---------+------------+------------+-------
       103 |      62 |      62 | 03:49:00   | 03:49:00   | t
       104 |      57 |      57 | 03:49:00   | 03:49:00   | t
       102 |      29 |      29 | 03:49:00   | 03:49:00   | t
       101 | 4464493 | 4465346 | 00:00:00   | 00:14:00   | f


What can be the source of these errors and how to track them ? FYI, I 
have logs but in debug level 1.

I did not have issues in 1.2.15.

Regards.
-- 
Cyril SCETBON