RE: pg_upgrade and logical replication

Dear Vignesh,

>
> Recently there was a failure in 004_subscription tap test at [1].
> In this failure, the tab_upgraded1 table was expected to have 51
> records but has only 50 records. Before the upgrade both publisher and
> subscriber have 50 records.

Good catch!

> After the upgrade we have inserted one record in the publisher, now
> tab_upgraded1 will have 51 records in the publisher. Then we start the
> subscriber after changing max_logical_replication_workers so that
> apply workers get started and apply the changes received. After
> starting we enable regress_sub5, wait for sync of regress_sub5
> subscription and check for tab_upgraded1 and tab_upgraded2 table data.
> In a few random cases the one record that was inserted into
> tab_upgraded1 table will not get replicated as we have not waited for
> regress_sub4 subscription to apply the changes from the publisher.
> The attached patch has changes to wait for regress_sub4 subscription
> to apply the changes from the publisher before verifying the data.
>
> [1] -
> https://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=mamba&dt=2024-03-
> 26%2004%3A23%3A13

Yeah, I think it is an oversight in f17529. Previously subscriptions which
receiving changes were confirmed to be caught up, I missed to add the line while
restructuring the script. +1 for your fix.

Best Regards,
Hayato Kuroda
FUJITSU LIMITED
https://www.fujitsu.com/