Re: Skipping logical replication transactions on subscriber side

On Sat, Apr 2, 2022 at 1:08 PM Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> wrote:
>
> On Sat, Apr 2, 2022 at 7:29 AM Noah Misch <noah(at)leadboat(dot)com> wrote:
> >
> > On Sat, Apr 02, 2022 at 06:49:20AM +0530, Amit Kapila wrote:
> >
> > After applying datum_to_lsn_skiplsn_1.patch, I get another failure. Logs
> > attached.
> >
>
> The failure is for the same reason. I noticed that even when skip lsn
> value should be 0/0, it is some invalid value, see: "LOG: not started
> skipping changes: my_skiplsn 0/B0706F72 finish_lsn 0/14EB7D8". Here,
> my_skiplsn should be 0/0 instead of 0/B0706F72. Now, I am not sure why
> the LSN's 4 bytes are correct and the other 4 bytes have some random
> value.

It seems that 0/B0706F72 is not a random value. Two subscriber logs
show the same value. Since 0x70 = 'p', 0x6F = 'o', and 0x72 = 'r', it
might show the next field in the pg_subscription catalog, i.e.,
subconninfo. The subscription is created by "CREATE SUBSCRIPTION sub
CONNECTION 'port=57851 host=/tmp/6u2vRwQYik dbname=postgres'
PUBLICATION pub WITH (disable_on_error = true, streaming = on,
two_phase = on)".

Given subscription.sql passes, something is wrong when we read the
subskiplsn value by like "sub->skiplsn = subform->subskiplsn;".

Is it possible to run the test again with the attached patch?

Regards,

--
Masahiko Sawada
EDB: https://www.enterprisedb.com/