Re: Logical replication timeout problem

On Mon, Jan 30, 2023 at 10:36 AM wangw.fnst@fujitsu.com
<wangw.fnst@fujitsu.com> wrote:
>
> On Mon, Jan 30, 2023 11:37 AM Shi, Yu/侍 雨 <shiy.fnst@cn.fujitsu.com> wrote:
> > On Sun, Jan 29, 2023 3:41 PM wangw.fnst@fujitsu.com
> > <wangw.fnst@fujitsu.com> wrote:
>
> Yes, I think you are right.
> Fixed this problem.
>

+ /*
+ * Trying to send keepalive message after every change has some
+ * overhead, but testing showed there is no noticeable overhead if
+ * we do it after every ~100 changes.
+ */
+#define CHANGES_THRESHOLD 100
+
+ if (++changes_count < CHANGES_THRESHOLD)
+ return;
...
+ changes_count = 0;

I think it is better to have this threshold-related code in that
caller as we have in the previous version. Also, let's modify the
comment as follows:"
It is possible that the data is not sent to downstream for a long time
either because the output plugin filtered it or there is a DDL that
generates a lot of data that is not processed by the plugin. So, in
such cases, the downstream can timeout. To avoid that we try to send a
keepalive message if required. Trying to send a keepalive message
after every change has some overhead, but testing showed there is no
noticeable overhead if we do it after every ~100 changes."

--
With Regards,
Amit Kapila.