Horton

Re: Skipping logical replication transactions on subscriber side

Amit Kapila <amit.kapila16@gmail.com>

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From: Amit Kapila <amit.kapila16@gmail.com>
To: "osumi.takamichi@fujitsu.com" <osumi.takamichi@fujitsu.com>
Cc: Masahiko Sawada <sawada.mshk@gmail.com>, Peter Eisentraut <peter.eisentraut@enterprisedb.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>, PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2022-01-21T05:29:45Z
Lists: pgsql-hackers 
On Fri, Jan 21, 2022 at 10:32 AM osumi.takamichi@fujitsu.com
<osumi.takamichi@fujitsu.com> wrote:
>
> On Friday, January 21, 2022 12:08 PM Masahiko Sawada <sawada.mshk@gmail.com> wrote:
> > I've attached an updated patch that incorporated these commends as well as
> > other comments I got so far.
> Thank you for your update !
>
> Few minor comments.
>
> (1) trivial question
>
> For the users,
> was it perfectly clear that in the cascading logical replication setup,
> we can't selectively skip an arbitrary transaction of one upper nodes,
> without skipping its all executions on subsequent nodes,
> when we refer to the current doc description of v9 ?
>
> IIUC, this is because we don't write changes WAL either and
> can't propagate the contents to subsequent nodes.
>
> I tested this case and it didn't, as I expected.
> This can apply to other measures for conflicts, though.
>

Right, there is nothing new as the user will same effect when she uses
existing function pg_replication_origin_advance(). So, not sure if we
want to add something specific to this.

>
> (3) minor question
>
> In the past, there was a discussion that
> it might be better if we reset the XID
> according to a change of subconninfo,
> which might be an opportunity to connect another
> publisher of a different XID space.
> Currently, we can regard it as user's responsibility.
> Was this correct ?
>

I think if the user points to another publisher, doesn't it similarly
needs to change slot_name as well? If so, I think this can be treated
in a similar way.

-- 
With Regards,
Amit Kapila.

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