From: Andrei Lepikhov <lepihov@gmail.com>
To: Richard Guo <guofenglinux@gmail.com>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: exclusion@gmail.com
Cc: pgsql-bugs@lists.postgresql.org
Subject: Re: BUG #18652: Planner can not find pathkey item to sort for query with expression and expression index
Date: Fri, 11 Oct 2024 11:25:47 +0700
Message-ID: <40c8a5c2-0040-4fe6-ab11-6dca23353a07@gmail.com> (raw)
In-Reply-To: <CAMbWs49Pcnm_cX=7azYY9d8+qRrOOKDjJDCa0KGRk9kWWMOz3A@mail.gmail.com>
References: <18652-deaa782ebcca85d1@postgresql.org>
<2527690.1728510183@sss.pgh.pa.us>
<CAMbWs49Pcnm_cX=7azYY9d8+qRrOOKDjJDCa0KGRk9kWWMOz3A@mail.gmail.com>
On 10/10/24 10:52, Richard Guo wrote:
> On Thu, Oct 10, 2024 at 5:43 AM Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> It looks like we are generating a Path tree in which one of the
>> inputs to a MergeAppend is a plain unsorted seqscan, which'd
>> be all right except it doesn't expose the required sort value
>> in its targetlist.
> I think this is because find_computable_ec_member() only tries to
> match Vars. Maybe we should teach it to also match OpExprs?
Why not look if some entry of the TargetList contains the var? Something
like attached?
If I understand correctly, MergeAppend will still add a resjunk column
and Sort according to the column.
--
regards, Andrei Lepikhov
Attachments:
[text/x-patch] probe.patch (727B, ../40c8a5c2-0040-4fe6-ab11-6dca23353a07@gmail.com/2-probe.patch)
download | inline diff:diff --git a/src/backend/optimizer/path/equivclass.c b/src/backend/optimizer/path/equivclass.cindex 8f6f005ecb..89ab29fe8e 100644--- a/src/backend/optimizer/path/equivclass.c+++ b/src/backend/optimizer/path/equivclass.c@@ -899,11 +899,19 @@ is_exprlist_member(Expr *node, List *exprs)
foreach(lc, exprs)
{
Expr *expr = (Expr *) lfirst(lc);
+ List *tlexprs;
if (expr && IsA(expr, TargetEntry))
+ {
expr = ((TargetEntry *) expr)->expr;
+ }++ tlexprs = pull_var_clause((Node *) expr,+ PVC_INCLUDE_AGGREGATES |+ PVC_INCLUDE_WINDOWFUNCS |+ PVC_INCLUDE_PLACEHOLDERS);- if (equal(node, expr))+ if (list_member(tlexprs, node))
return true;
}
return false;
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Cc: lepihov@gmail.com, guofenglinux@gmail.com, tgl@sss.pgh.pa.us, exclusion@gmail.com, pgsql-bugs@lists.postgresql.org
Subject: Re: BUG #18652: Planner can not find pathkey item to sort for query with expression and expression index
In-Reply-To: <40c8a5c2-0040-4fe6-ab11-6dca23353a07@gmail.com>
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