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From: Xuneng Zhou <xunengzhou@gmail.com>
Date: Sat, 18 Apr 2026 12:19:50 +0800
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 <CABPTF7VouG5DSvdgPSg1ko6ybHhNPQk5sxJQMiy8r_gr_bEtug@mail.gmail.com>
Subject: Re: test: avoid redundant standby catchup in 049_wait_for_lsn
To: Michael Paquier <michael@paquier.xyz>
Cc: pgsql-hackers <pgsql-hackers@lists.postgresql.org>,
	Alexander Korotkov <aekorotkov@gmail.com>
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Hi Michael,


On Fri, Apr 17, 2026 at 08:25:35PM +0800, Xuneng Zhou wrote:
> > The change preserves the same coverage while removing one redundant
> > replay catch-up on the delayed standby. It appears to reduce the test
> > runtime by about 7 seconds, though I have looked into why much of the
> > improvement comes from this change alone.
>
> Alexander may think differently and remove that, but I disagree.  The
> test is clearly written so as we want two wait checks to happen, for
> for CREATE FUNCTION, and one for CREATE PROCEDURE.  Removing the first
> check to keep only the second one removes its meaning.  In short, I
> see nothing wrong to deal with here.
>

Thank you for the review. I agree that the two wait checks serve distinct
purposes and are not redundant. The main motivation for this patch was
efficiency. In my testing, the new test added approximately 7 seconds to
the runtime, while the creation of the procedure and function completed
quickly. I suspect the latency stems from the wait-for-catch-up step. When
I removed it, the test runtime dropped by about 7 seconds.I haven't yet
investigated why the wait is so costly in this case. I should probably look
into that before proposing this change.

Best,
Xuneng

>

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<div dir=3D"auto"><div dir=3D"auto"><div dir=3D"auto"><div dir=3D"auto">Hi =
Michael,</div><div dir=3D"auto"><br></div><div class=3D"gmail_quote" dir=3D=
"auto"><div dir=3D"ltr" class=3D"gmail_attr"><br></div><blockquote class=3D=
"gmail_quote" style=3D"margin:0 0 0 .8ex;border-left:1px #ccc solid;padding=
-left:1ex">On Fri, Apr 17, 2026 at 08:25:35PM +0800, Xuneng Zhou wrote:<br>
&gt; The change preserves the same coverage while removing one redundant<br=
>
&gt; replay catch-up on the delayed standby. It appears to reduce the test<=
br>
&gt; runtime by about 7 seconds, though I have looked into why much of the<=
br>
&gt; improvement comes from this change alone.<br>
<br>
Alexander may think differently and remove that, but I disagree.=C2=A0 The<=
br>
test is clearly written so as we want two wait checks to happen, for<br>
for CREATE FUNCTION, and one for CREATE PROCEDURE.=C2=A0 Removing the first=
<br>
check to keep only the second one removes its meaning.=C2=A0 In short, I<br=
>
see nothing wrong to deal with here.<br></blockquote></div></div><div dir=
=3D"auto"><br></div><div dir=3D"auto"><div dir=3D"auto">Thank you for the r=
eview. I agree that the two wait checks serve distinct purposes and are not=
 redundant. The main motivation for this patch was efficiency. In my testin=
g, the new test added approximately 7 seconds to the runtime, while the cre=
ation of the procedure and function completed quickly. I suspect the latenc=
y stems from the wait-for-catch-up step. When I removed it, the test runtim=
e dropped by about 7 seconds.I haven&#39;t yet investigated why the wait is=
 so costly in this case. I should probably look into that before proposing =
this change.</div><div dir=3D"auto"><br></div><div data-smartmail=3D"gmail_=
signature" dir=3D"auto"><div dir=3D"ltr">Best,<br>Xuneng</div></div></div><=
div dir=3D"auto"><div class=3D"gmail_quote" dir=3D"auto"><blockquote class=
=3D"gmail_quote" style=3D"margin:0 0 0 .8ex;border-left:1px #ccc solid;padd=
ing-left:1ex"></blockquote></div></div><br></div>
<br><br></div>

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