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From: Richard Guo <guofenglinux@gmail.com>
Date: Wed, 25 Oct 2023 14:45:59 +0800
Message-ID: <CAMbWs4_Axa6sxMx4f5jk-iiJwVio_jv8PJijDMf6-Hg2g8Cifw@mail.gmail.com>
Subject: Re: A performance issue with Memoize
To: Pavel Stehule <pavel.stehule@gmail.com>
Cc: PostgreSQL-development <pgsql-hackers@postgresql.org>, David Rowley <dgrowleyml@gmail.com>, 
	Tom Lane <tgl@sss.pgh.pa.us>
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On Fri, Oct 20, 2023 at 7:43=E2=80=AFPM Pavel Stehule <pavel.stehule@gmail.=
com>
wrote:

> +1
>
> it would be great to fix this problem - I've seen this issue a few times.
>

Thanks for the input.  I guess this is not rare in the real world.  If
the subquery contains lateral reference to a Var that also appears in
the subquery's join clauses, we'd probably suffer from this issue.

Thanks
Richard

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<div dir=3D"ltr"><div dir=3D"ltr"><br></div><div class=3D"gmail_quote"><div=
 dir=3D"ltr" class=3D"gmail_attr">On Fri, Oct 20, 2023 at 7:43=E2=80=AFPM P=
avel Stehule &lt;<a href=3D"mailto:pavel.stehule@gmail.com">pavel.stehule@g=
mail.com</a>&gt; wrote:</div><blockquote class=3D"gmail_quote" style=3D"mar=
gin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1=
ex"><div dir=3D"ltr"><div class=3D"gmail_quote"><div>+1 <br></div><div><br>=
</div><div>it would be great to fix this problem - I&#39;ve seen this issue=
 a few times.</div></div></div></blockquote><div><br></div><div>Thanks for =
the input.=C2=A0 I guess this is not rare in the real world.=C2=A0 If<br>th=
e subquery contains lateral reference to a Var that also appears in<br>the =
subquery&#39;s join clauses, we&#39;d probably suffer from this issue.<br><=
br>Thanks<br>Richard<br></div></div></div>

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