Horton

Re: Skipping logical replication transactions on subscriber side

Masahiko Sawada <sawada.mshk@gmail.com>

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From: Masahiko Sawada <sawada.mshk@gmail.com>
To: Amit Kapila <amit.kapila16@gmail.com>
Cc: Noah Misch <noah@leadboat.com>, Euler Taveira <euler@eulerto.com>, "osumi.takamichi@fujitsu.com" <osumi.takamichi@fujitsu.com>, Peter Eisentraut <peter.eisentraut@enterprisedb.com>, "David G. Johnston" <david.g.johnston@gmail.com>, "tanghy.fnst@fujitsu.com" <tanghy.fnst@fujitsu.com>, vignesh C <vignesh21@gmail.com>, Greg Nancarrow <gregn4422@gmail.com>, "houzj.fnst@fujitsu.com" <houzj.fnst@fujitsu.com>, Alexey Lesovsky <lesovsky@gmail.com>, pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2022-04-02T07:33:44Z
Lists: pgsql-hackers

Attachments

On Sat, Apr 2, 2022 at 1:08 PM Amit Kapila <amit.kapila16@gmail.com> wrote:
>
> On Sat, Apr 2, 2022 at 7:29 AM Noah Misch <noah@leadboat.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/

Commits

  1. Test ALIGNOF_DOUBLE==4 compatibility under ALIGNOF_DOUBLE==8.

  2. Reorder subskiplsn in pg_subscription to avoid alignment issues.

  3. Add ALTER SUBSCRIPTION ... SKIP.

  4. Optionally disable subscriptions on error.

  5. Update docs of logical replication for commit 8d74fc96db.

  6. Respect permissions within logical replication.

  7. Fix regression test failure caused by commit 8d74fc96db.

  8. Add a view to show the stats of subscription workers.

  9. Add logical change details to logical replication worker errcontext.

  10. Rename LOGICAL_REP_MSG_STREAM_END to LOGICAL_REP_MSG_STREAM_STOP.

  11. Fix typo in protocol.sgml.

  12. Remove unused argument in apply_handle_commit_internal().

  13. Fix replication of in-progress transactions in tablesync worker.

  14. Reorder pg_sequence columns to avoid alignment issue