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Date: Mon, 22 Jul 2024 09:13:49 +0700
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From: Andrei Lepikhov <lepihov@gmail.com>
Subject: Re: Removing unneeded self joins
To: Alexander Korotkov <aekorotkov@gmail.com>,
 Dean Rasheed <dean.a.rasheed@gmail.com>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, Robert Haas <robertmhaas@gmail.com>,
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On 20/7/2024 18:38, Alexander Korotkov wrote:
> On Fri, Jul 19, 2024 at 11:30 AM Dean Rasheed <dean.a.rasheed@gmail.com> wrote:
>> On Wed, 17 Jul 2024 at 01:45, Alexander Korotkov <aekorotkov@gmail.com> wrote:
> We initially didn't use ChangeVarNodes() in SJE at all.  See the last
> patch version without it [1].  We're trying to address Tom Lane's
> proposal to re-use more of existing tree-manipulation infrastructure
> [2].  I agree with you that the case with ChangeVarNodes() looks
> questionable.  Do you have other ideas how we can re-use some more of
> existing tree-manipulation infrastructure in SJE?
As I can see, ChangeVarNodes is dedicated to working with the query tree 
before the planning phase. SJE works right in the middle of the planning 
process. So, it may be more practical to keep it separate as a walker, 
as Dean has proposed. If the optimisation stuff changes, the walker code 
will be changed, too.

-- 
regards, Andrei Lepikhov