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: Amit Kapila <amit.kapila16@gmail.com>
Cc: "wangw.fnst@fujitsu.com" <wangw.fnst@fujitsu.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: 2023-01-17T13:11:46Z
Lists: pgsql-hackers 
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. I don't see wrappers around
OutputPluginWrite or OutputPluginPrepareWrite. But I see that those
two are called always from output plugin, so indirectly those are
called through a wrapper. I also see that update_progress_cb_wrapper()
is similar, as far as wrapper is concerned, to
ReorderBufferUpdateProgress() in the earlier patch.
ReorderBufferUpdateProgress() looks more readable than the wrapper.

If we want to keep the wrapper at least we should use a different
variable name. update_progress is also there LogicalDecodingContext
and will be indirectly called from ReorderBuffer::update_progress.
Somebody might think that there's some recursion involved there.
That's a mighty confusion.

-- 
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