Can I synchronize two master DB clusters using logical replication?

[JaeWon Lee <thejaewon@xxxxxxxxx>]

Hi ^^

I have two DB clusters. One is in South Korea, and the other is in US.

Each cluster generates its own DML commands. (INSERT, UPDATE, DELETE)

And I want to synchronize this two DB clusters using logical replication.

I tried  this, but it failed.

Specifically, I succeeded to replicate one DB cluster to the other.

But when I set logical replication in both cluster, only the former which I set first works.

Can I use logical replication to synchronize two master DB clusters?

The following is what I did.

[ In Korea cluster ] ------------------------------------------------------------------------------------

- postgresql.conf

wal_level = logical

- pg_hba.conf
# IPv4 local connections:
host    <KR DB name>            postgres        <US server IP>/32        md5

CREATE PUBLICATION mypubKR FOR ALL TABLES;

CREATE SUBSCRIPTION mysubKR CONNECTION 'host=<US server IP> port=5432 user=postgres dbname=<US DB name> password=<password>' PUBLICATION mypubUS;

[ In US cluster ] -----------------------------------------------------------------------------------------

- postgresql.conf

wal_level = logical

- pg_hba.conf# IPv4 local connections:
host    <US DB name>           postgres        <KR server IP>/32         md5

CREATE PUBLICATION mypubUS FOR ALL TABLES;

CREATE SUBSCRIPTION mysubUS CONNECTION 'host=<KR server IP> port=5432 user=postgres dbname=<KR DB name> password=<password>' PUBLICATION mypubKR;
---------------------------------------------------------------------------------------------------------------------

If I make 'mysubKR' first and 'mysubUS' later, replication from US to Korea works well. But Korea to US doesn't work.

If I make 'mysubUS' first and 'mysubKR' later, replication from Korea to US works well. But US to Korea doesn't work.

I hope both direction work well.

How can I solve this problem?