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From: Henson Choi <assam258@gmail.com>
Date: Fri, 3 Apr 2026 10:53:54 +0900
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 <CAAAe_zD3==epK=KufoBiLfogztpKbimxc498TUshTOQkkpgOjg@mail.gmail.com>
Subject: Re: SQL/PGQ: All properties reference
To: Ashutosh Bapat <ashutosh.bapat.oss@gmail.com>,
 Junwang Zhao <zhjwpku@gmail.com>
Cc: Peter Eisentraut <peter@eisentraut.org>,
 pgsql-hackers <pgsql-hackers@postgresql.org>
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Hi Ashutosh,

I am starting a new thread to discuss all properties reference feature
> which was not committed with the main patch. [1]
>
> A <variable>.* is called all properties reference and it is allowed
> only in COLUMNs clause. Interpreting subclause 9.2 and 9.3 together,
> it expands to a list of graph property references <variable>.p1, ...
> <variable>.pn where p1, ..., pn are the properties of the labels which
> satisfy the label expression in the element pattern identified by
> <variable>. The graph property references are added to the COLUMNs
> clause in place of the all property reference, just like how <table>.*
> expands in SELECT's targetlist.
>
> In the current implementation, we delay resolving graph property
> references (<variable>.<property>) till the time query is generated
> (generate_query_for_graph_path()). If we delay the all properties
> reference till that time, we can not determine the data types and
> names of the columns in the COLUMNs list. So we need to do that when
> the COLUMNs clause is resolved. This means that the properties
> associated with the labels needs to be resolved earlier. Since the
> properties are not associated with labels directly but through the
> elements, we need to find at least one element for every label in the
> label expression. In brief, all the namespace resolution need to
> happen before we transform COLUMNs clause. The patch rearranges the
> code that way.
>

I tried applying v20260318 on top of master to review it, but ran
into merge conflicts in two files:

- parse_graphtable.c
- rewriteGraphTable.c

The conflicts come from this commit that was added after the main PGQ
commit (2f094e7ac69):

- a0dd0702e46 Fix cross variable references in graph pattern causing
  segfault

Would it be possible to rebase the patch on the current master so
I can review it cleanly?

Best Regards,
Henson

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<div dir=3D"ltr"><div dir=3D"ltr"><div dir=3D"ltr">Hi Ashutosh,</div><div d=
ir=3D"ltr"><br></div><div class=3D"gmail_quote"><blockquote class=3D"gmail_=
quote" style=3D"margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,=
204);padding-left:1ex">
I am starting a new thread to discuss all properties reference feature<br>
which was not committed with the main patch. [1]<br>
<br>
A &lt;variable&gt;.* is called all properties reference and it is allowed<b=
r>
only in COLUMNs clause. Interpreting subclause 9.2 and 9.3 together,<br>
it expands to a list of graph property references &lt;variable&gt;.p1, ...<=
br>
&lt;variable&gt;.pn where p1, ..., pn are the properties of the labels whic=
h<br>
satisfy the label expression in the element pattern identified by<br>
&lt;variable&gt;. The graph property references are added to the COLUMNs<br=
>
clause in place of the all property reference, just like how &lt;table&gt;.=
*<br>
expands in SELECT&#39;s targetlist.<br>
<br>
In the current implementation, we delay resolving graph property<br>
references (&lt;variable&gt;.&lt;property&gt;) till the time query is gener=
ated<br>
(generate_query_for_graph_path()). If we delay the all properties<br>
reference till that time, we can not determine the data types and<br>
names of the columns in the COLUMNs list. So we need to do that when<br>
the COLUMNs clause is resolved. This means that the properties<br>
associated with the labels needs to be resolved earlier. Since the<br>
properties are not associated with labels directly but through the<br>
elements, we need to find at least one element for every label in the<br>
label expression. In brief, all the namespace resolution need to<br>
happen before we transform COLUMNs clause. The patch rearranges the<br>
code that way.<br></blockquote><div><br></div>I tried applying v20260318 on=
 top of master to review it, but ran<br>into merge conflicts in two files:<=
br><br>- parse_graphtable.c<br>- rewriteGraphTable.c<br><br>The conflicts c=
ome from this commit that was added after the main PGQ<br>commit (2f094e7ac=
69):<br><br>- a0dd0702e46 Fix cross variable references in graph pattern ca=
using<br>=C2=A0 segfault<br><br>Would it be possible to rebase the patch on=
 the current master so<br>I can review it cleanly?<br><br>Best Regards,<br>=
Henson=C2=A0</div></div>
</div>

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