I created 2 databases (master & slave) and use the following setup script:

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#!/bin/sh
CLUSTER=sql_cluster
DB1=contactdb
DB2=contactdb_slave
H1=localhost
H2=localhost
U=postgres
slonik <<_EOF_
cluster name = $CLUSTER;
node 1 admin conninfo = 'dbname=$DB1 host=$H1 user=$U';
node 2 admin conninfo = 'dbname=$DB2 host=$H2 user=$U';
init cluster (id = 1, comment = 'Node 1');
create set (id = 1, origin = 1, comment = 'contact table');
set add table (set id = 1, origin = 1, id = 1, full qualified name =
'public.contact', comment = 'Table contact');
set add sequence (set id = 1, origin = 1, id = 2, full qualified name =
'public.contact_seq', comment = 'Sequence contact_seq');
store node (id = 2, comment = 'Node 2');
store path (server = 1, client = 2,
conninfo = 'dbname=$DB1 host=$H1 user=$U');
store path (server = 2, client = 1,
conninfo = 'dbname=$DB2 host=$H2 user=$U');
store listen (origin = 1, provider = 1, receiver = 2);
store listen (origin = 2, provider = 2, receiver = 1);
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Then I tried to run a subscribe script below:

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#!/bin/sh
CLUSTER=sql_cluster
DB1=contactdb
DB2=contactdb_slave
H1=localhost
H2=localhost
U=postgres
slonik <<_EOF_
cluster name = $CLUSTER;
node 1 admin conninfo = 'dbname=$DB1 host=$H1 user=$U';
node 2 admin conninfo = 'dbname=$DB2 host=$H2 user=$U';
subscribe set (id = 1, provider = 1, receiver = 2, forward = yes);
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I got the following error message:

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<stdin>:4: Error: namespace "_sql_cluster" already exists in database of
node 1
-bash-3.00$ ./cluster_setup.sh
-bash-3.00$ ./subscribe.sh
<stdin>:4: NOTICE:  subscribeSet:: set 1 has no tables - risk of problems -
see bug 1226
<stdin>:4: NOTICE:
http://gborg.postgresql.org/project/slony1/bugs/bugupdate.php?1226
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The weird thing is, the database is NOT empty. The table "contact" is there,
so the error message doesn't make sense. Please help. Thanks.