Re: Single transaction in the tablesync worker?

On Tue, Feb 2, 2021 at 9:03 PM Ajin Cherian <itsajin@gmail.com> wrote:

> I am sorry, my above steps were not correct. I think the reason for
> the failure I was seeing were some other steps I did prior to this. I
> will recreate this and update you with the appropriate steps.

The correct steps are as follows:

Publisher:

postgres=# CREATE TABLE tab_rep (a int primary key);
CREATE TABLE
postgres=# INSERT INTO tab_rep SELECT generate_series(1,1000000);
INSERT 0 1000000
postgres=# CREATE PUBLICATION tap_pub FOR ALL TABLES;
CREATE PUBLICATION

Subscriber:
postgres=# CREATE TABLE tab_rep (a int primary key);
CREATE TABLE
postgres=# CREATE SUBSCRIPTION tap_sub CONNECTION 'host=localhost
dbname=postgres port=6972' PUBLICATION tap_pub WITH (enabled = false);
NOTICE:  created replication slot "tap_sub" on publisher
CREATE SUBSCRIPTION
postgres=# ALTER SUBSCRIPTION tap_sub enable;
ALTER SUBSCRIPTION

Allow the tablesync to complete and then drop the subscription, the
table remains full and restarting the subscription should fail with a
constraint violation during tablesync but it does not.


Subscriber:
postgres=# drop subscription tap_sub ;
NOTICE:  dropped replication slot "tap_sub" on publisher
DROP SUBSCRIPTION
postgres=# CREATE SUBSCRIPTION tap_sub CONNECTION 'host=localhost
dbname=postgres port=6972' PUBLICATION tap_pub WITH (enabled = false);
NOTICE:  created replication slot "tap_sub" on publisher
CREATE SUBSCRIPTION
postgres=# ALTER SUBSCRIPTION tap_sub enable;
ALTER SUBSCRIPTION

This takes the subscriber into an error loop but no mention of what
the error was:

2021-02-02 05:01:34.698 EST [1549] LOG:  logical replication table
synchronization worker for subscription "tap_sub", table "tab_rep" has
started
2021-02-02 05:01:34.739 EST [1549] ERROR:  table copy could not
rollback transaction on publisher
2021-02-02 05:01:34.739 EST [1549] DETAIL:  The error was: another
command is already in progress
2021-02-02 05:01:34.740 EST [8028] LOG:  background worker "logical
replication worker" (PID 1549) exited with exit code 1
2021-02-02 05:01:40.107 EST [1711] LOG:  logical replication table
synchronization worker for subscription "tap_sub", table "tab_rep" has
started
2021-02-02 05:01:40.121 EST [1711] ERROR:  could not create
replication slot "pg_16479_sync_16435": ERROR:  replication slot
"pg_16479_sync_16435" already exists
2021-02-02 05:01:40.121 EST [8028] LOG:  background worker "logical
replication worker" (PID 1711) exited with exit code 1
2021-02-02 05:01:45.140 EST [1891] LOG:  logical replication table
synchronization worker for subscription "tap_sub", table "tab_rep" has
started

regards,
Ajin Cherian
Fujitsu Australia