Horton

Re: Logical replication timeout problem

Ashutosh Bapat <ashutosh.bapat.oss@gmail.com>

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From: Ashutosh Bapat <ashutosh.bapat.oss@gmail.com>
To: "wangw.fnst@fujitsu.com" <wangw.fnst@fujitsu.com>
Cc: Amit Kapila <amit.kapila16@gmail.com>, Fabrice Chapuis <fabrice636861@gmail.com>, Euler Taveira <euler@eulerto.com>, Masahiko Sawada <sawada.mshk@gmail.com>, "Hayato Kuroda (Fujitsu)" <kuroda.hayato@fujitsu.com>, Peter Smith <smithpb2250@gmail.com>, Simon Riggs <simon.riggs@enterprisedb.com>, Petr Jelinek <petr.jelinek@enterprisedb.com>, "tanghy.fnst@fujitsu.com" <tanghy.fnst@fujitsu.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>, Ajin Cherian <itsajin@gmail.com>
Date: 2023-01-18T12:07:19Z
Lists: pgsql-hackers 
On Wed, Jan 18, 2023 at 1:49 PM wangw.fnst@fujitsu.com
<wangw.fnst@fujitsu.com> wrote:
>
> On Wed, Jan 18, 2023 at 13:29 PM Amit Kapila <amit.kapila16@gmail.com> wrote:
> > On Tue, Jan 17, 2023 at 6:41 PM Ashutosh Bapat
> > <ashutosh.bapat.oss@gmail.com> wrote:
> > >
> > > On Tue, Jan 17, 2023 at 3:34 PM Amit Kapila <amit.kapila16@gmail.com> wrote:
> > >
> > > > >
> > > > > I am a bit worried about the indirections that the wrappers and hooks
> > > > > create. Output plugins call OutputPluginUpdateProgress() in callbacks
> > > > > but I don't see why  ReorderBufferProcessTXN() needs a callback to
> > > > > call OutputPluginUpdateProgress.
> > > > >
> > > >
> > > > Yeah, I think we can do it as we are doing the previous approach but
> > > > we need an additional wrapper (update_progress_cb_wrapper()) as the
> > > > current patch has so that we can add error context information. This
> > > > is similar to why we have a wrapper for all other callbacks like
> > > > change_cb_wrapper.
> > > >
> > >
> > > Ultimately OutputPluginUpdateProgress() will be called - which in turn
> > > will call ctx->update_progress.
> > >
> >
> > No, update_progress_cb_wrapper() should directly call
> > ctx->update_progress(). The key reason to have a
> > update_progress_cb_wrapper() is that it allows us to add error context
> > information (see the usage of output_plugin_error_callback).
>
> I think it makes sense. This also avoids the need for every output plugin to
> implement the callback. So I tried to improve the patch based on this approach.
>
> And I tried to add some comments for this new callback to distinguish it from
> ctx->update_progress.

Comments don't help when using cscope or some such code browsing tool.
Better to use a different variable name.

-- 
Best Wishes,
Ashutosh Bapat

Commits

  1. Fix the logical replication timeout during large DDLs.

  2. Fix the logical replication timeout during large transactions.

  3. Rethink the delay-checkpoint-end mechanism in the back-branches.

  4. Revert "Logical decoding of sequences"

  5. Skip empty transactions for logical replication.

  6. Allow specifying column lists for logical replication

  7. Add decoding of sequences to built-in replication

  8. Fix ABI break introduced by commit 4daa140a2f.

  9. Lag tracking for logical replication