We're running into a strange problem with slony. We have a fairly  
simple slony set up, one master node, two slave nodes, all running  
slony 1.1.5 against postgresql 8.1.4 on debian testing boxes.

We tried to push a DDL change using the EXECUTE SCRIPT command on the  
master node to alter one of the slonied tables (adding a column with  
a foreign key constraint). The slony event failed with the following  
output  on one of the slave nodes:

2006-06-27 16:28:56 EDT DEBUG2 remoteWorkerThread_1: Received event  
1,359373 DDL_SCRIPT
2006-06-27 16:28:56 EDT DEBUG2 remoteWorkerThread_3: forward confirm  
1,359372 received by 3
2006-06-27 16:28:56 EDT ERROR  remoteWorkerThread_1: "begin  
transaction; set transaction isolation level serializable;
lock table "_tmc_replication".sl_config_lock;
select "_tmc_replication".ddlScript_int(1, 'alter table exchange_info  
add column locale varchar(25) REFERENCES public.locale(city);', -1);
notify "_tmc_replication_Event"; notify "_tmc_replication_Confirm";
insert into "_tmc_replication".sl_event
(ev_origin, ev_seqno, ev_timestamp,      ev_minxid, ev_maxxid,  
ev_xip, ev_type , ev_data1, ev_data2, ev_data3    )
values ('1', '359373', '2006-06-27 16:28:54.370245', '87886162',  
'87886163', '', 'DDL_SCRIPT', '1',
'alter table exchange_info add column locale varchar(25) REFERENCES  
public.locale(city);', '-1');
insert into "_tmc_replication".sl_confirm  (con_origin, con_received,  
con_seqno, con_timestamp)
values (1, 2, '359373', now()); commit transaction;"
PGRES_FATAL_ERROR ERROR:  duplicate key violates unique constraint  
"pg_trigger_tgrelid_tgname_index"
CONTEXT:  SQL statement "update "pg_catalog".pg_trigger set tgrelid  
=  $1  where tgrelid =  $2 "
PL/pgSQL function "altertablerestore" line 68 at SQL statement
SQL statement "SELECT  "_tmc_replication".alterTableRestore( $1 )"
PL/pgSQL function "ddlscript_int" line 47 at perform

As far as I can see, the other node didn't complain. But slony was  
stuck until i (shudder) deleted this ev_seqno from sl_event and  
backed out the change from the master node.

The slony replication is working fine for data at the moment. But  
what should/can I do to fix this problem. Any ideas? I would hate to  
re-create the slave nodes from scratch, as it takes about 28 hours to  
sync the tables and re-create our setup.

(The test_slony_state-dbi.pl script runs cleanly, with no errors, for  
whatever that's worth.)


######################################################################
This e-mail is confidential and should not be redistributed or
forwarded by the recipient.  The information contained in this e-mail
message is intended only for the use of the individual or entity named
above.  If the reader of this message is not the intended recipient or
you have received this communication in error, please immediately
notify us by telephone.  Receipt by anyone other than the intended
recipient is not a waiver of any work-product or, if applicable,
attorney-client privilege.

This e-mail does not constitute an offering of any security.  Such an
offering may only be made by means of a private placement memorandum
or other disclosure document.  Nothing in this e-mail constitutes
investment advice.  Past performance is not indicative of future
results.  All e-mail to and from Millburn Ridgefield Corporation and
its affiliates is monitored, stored and made available to regulators
if requested.
######################################################################