On Mon, Sep 21, 2020 at 3:26 PM Ashutosh Sharma <ashu.coek88@gmail.com> wrote:
>
> Hi All,
>
> Today, while exploring logical replication in PostgreSQL, I noticed
> that logical replication from PG version 13 and below to PG v14
> (development version) is not working. It has stopped working from the
> following git commit onwards:
>
> commit 464824323e57dc4b397e8b05854d779908b55304
> Author: Amit Kapila <akapila@postgresql.org>
> Date: Thu Sep 3 07:54:07 2020 +0530
>
> Add support for streaming to built-in logical replication.
>
> ...
> ...
>
> Here is the experiment that I performed to verify this:
>
> Publisher (PG-v12/13):
> ==================
> CREATE TABLE pg2pg (id serial PRIMARY KEY, whatever text);
>
> INSERT INTO pg2pg (whatever) SELECT 'str-' || i FROM generate_series(1, 5) i;
>
> SELECT * FROM pg2pg;
>
> CREATE PUBLICATION pg2pg_pub FOR TABLE pg2pg;
>
> Subscriber (PG-v14 HEAD or commit 46482432):
> =====================================
> CREATE TABLE pg2pg (id serial PRIMARY KEY, whatever text);
>
> CREATE SUBSCRIPTION pg2pg_sub CONNECTION 'host=127.0.0.1 port=5433
> dbname=postgres user=ashu' PUBLICATION pg2pg_pub;
>
> SELECT * FROM pg2pg;
>
> Above select query produces no result. When this experiment is
> performed below the mentioned git commit, it works fine.
>
> After spending some time looking into this issue, I observed that
> above git commit has bumped the logical replication protocol version.
> Due to this, the logical replication apply worker process is unable to
> do WAL streaming which causes it to terminate. Therefore, the data
> inserted in the publication table is not applied on the subscription
> table (i.e. no data replication happens)
Seems like this commit, should have only set the
LOGICALREP_PROTO_STREAM_VERSION_NUM to 2 but the
LOGICALREP_PROTO_VERSION_NUM shouln't have been changed.
--
Regards,
Dilip Kumar
EnterpriseDB: http://www.enterprisedb.com
