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From: Bruce Momjian <[email protected]>
To: Andy Fan <[email protected]>
Cc: PostgreSQL-development <[email protected]>
Cc: [email protected]
Subject: Re: First draft of PG 17 release notes
Date: Tue, 14 May 2024 20:37:19 -0400
Message-ID: <[email protected]> (raw)
In-Reply-To: <[email protected]>
References: <[email protected]>
	<[email protected]>
	<[email protected]>
	<[email protected]>

On Tue, May 14, 2024 at 10:32:14AM +0800, Andy Fan wrote:
> Bruce Momjian <[email protected]> writes:
> > It was unclear from the commit message exactly what user-visible
> > optimization this allowed.  Do you have details?
> 
> Yes, It allows the query like "SELECT * FROM t1 WHERE t1.a in (SELECT a
> FROM t2 WHERE t2.b = t1.b)" be pulled up a semi join, hence more join
> methods / join orders are possible.
> 
> 
> Yes, for example:  (subquery-1) UNION ALL (subquery-2) LIMIT n;
> 
> When planning the subquery-1 or subquery-2, limit N should be
> considered. As a consequence, maybe hash join should be replaced with
> Nested Loop. Before this commits, it is ignored if it is flatten into 
> appendrel, and the "flatten" happens very often.
> 
> David provided a summary for the both commits in [1].

Okay, attached patch applied.

-- 
  Bruce Momjian  <[email protected]>        https://momjian.us
  EDB                                      https://enterprisedb.com

  Only you can decide what is important to you.


Attachments:

  [text/x-diff] master.diff (1022B, ../[email protected]/2-master.diff)
  download | inline diff:
diff --git a/doc/src/sgml/release-17.sgml b/doc/src/sgml/release-17.sgml
index 38c14970822..fa0a703629c 100644
--- a/doc/src/sgml/release-17.sgml
+++ b/doc/src/sgml/release-17.sgml
@@ -356,6 +356,28 @@ Improve optimization of range values when using containment operators &lt;@ and
 </para>
 </listitem>
 
+<!--
+Author: Alexander Korotkov <[email protected]>
+2024-02-15 [9f1337639] Pull up ANY-SUBLINK with the necessary lateral support.
+-->
+
+<listitem>
+<para>
+Allow correlated IN subqueries to be transformed into joins (Andy Fan, Tom Lane)
+</para>
+</listitem>
+
+<!--
+Author: David Rowley <[email protected]>
+2023-10-05 [a8a968a82] Consider cheap startup paths in add_paths_to_append_rel
+-->
+
+<listitem>
+<para>
+Improve optimization of the LIMIT clause on partitioned tables, inheritance parents, and UNION ALL queries (Andy Fan, David Rowley)
+</para>
+</listitem>
+
 <!--
 Author: Tom Lane <[email protected]>
 2023-07-14 [e08d74ca1] Allow plan nodes with initPlans to be considered paralle

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