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Date: Thu, 23 Apr 2020 13:06:26 -0400
From: Bruce Momjian <bruce@momjian.us>
To: Alvaro Herrera <alvherre@2ndquadrant.com>
Cc: Marc =?iso-8859-1?Q?Recht=E9?= <marc4@rechte.fr>,
	PostgreSQL www <pgsql-www@postgresql.org>
Subject: Re: Backend Flowchart / Developer doc
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Thread moved to www for patch application.  Please apply the attached
patch to update the text of the backend flowchart.  Thanks.

---------------------------------------------------------------------------

On Tue, Apr 21, 2020 at 11:31:09AM -0400, Bruce Momjian wrote:
> On Thu, Apr 16, 2020 at 11:17:29AM -0400, Alvaro Herrera wrote:
> > On 2020-Apr-15, Marc Rechté wrote:
> > 
> > > Hello,
> > > 
> > > Don't know if this the correct list to submit this issue.
> > > 
> > > On the https://www.postgresql.org/developer/backend/, it mentions a
> > > Query.qual field which does not exist in the Query structure.
> > 
> > I think that diagram (and the accompanying wiki page) requires a *lot*
> > of more significant updating than just that field.  It is wildly
> > outdated.
> 
> I developed the attached patch to fix the items I saw needed updating.

-- 
  Bruce Momjian  <bruce@momjian.us>        https://momjian.us
  EnterpriseDB                             https://enterprisedb.com

+ As you are, so once was I.  As I am, so you will be. +
+                      Ancient Roman grave inscription +

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diff --git a/templates/pages/developer/backend.html b/templates/pages/developer/backend.html
index ab7e5d6..7337a07 100644
--- a/templates/pages/developer/backend.html
+++ b/templates/pages/developer/backend.html
@@ -56,7 +56,7 @@ or <a
 href="https://git.postgresql.org/gitweb/?p=postgresql.git;a=blob;f=src/include/nodes/parsenodes.h">SelectStmt.</a></p>
 
 <p>The statement is then identified as complex (<em>SELECT / INSERT /
-UPDATE / DELETE</em>) or simple, e.g <em>CREATE USER, ANALYZE,</em>
+UPDATE / DELETE</em>) or simple, e.g <em>CREATE ROLE, ANALYZE,</em>
 etc.  Simple utility commands that do not require the executor are processed by statement-specific
 functions in the <a href="https://wiki.postgresql.org/wiki/Backend_flowchart#commands">commands</a> module.
 Complex statements require more handling.</p>
@@ -64,11 +64,12 @@ Complex statements require more handling.</p>
 <p>The parser takes a complex query, and creates a <a
 href="https://git.postgresql.org/gitweb/?p=postgresql.git;a=blob;f=src/include/nodes/parsenodes.h">Query</a>
 structure that contains all the elements used by complex queries.
-Query.qual holds the <em>WHERE</em> clause qualification, which is filled
+Query.jointree holds the <em>FROM</em> and <em>WHERE</em> clauses, which is filled
 in by <a
+href="https://git.postgresql.org/gitweb/?p=postgresql.git;a=blob;f=src/backend/parser/parse_clause.c">transformFromClause()</a> and
 href="https://git.postgresql.org/gitweb/?p=postgresql.git;a=blob;f=src/backend/parser/parse_clause.c">transformWhereClause().</a>
 Each table referenced in the query is represented by a <a
-href="https://git.postgresql.org/gitweb/?p=postgresql.git;a=blob;f=src/include/nodes/parsenodes.h">RangeTableEntry,</a>
+href="https://git.postgresql.org/gitweb/?p=postgresql.git;a=blob;f=src/include/nodes/parsenodes.h">RangeTblEntry,</a>
 and they are linked together to form the <em>range table</em> of the
 query, which is generated by <a
 href="https://git.postgresql.org/gitweb/?p=postgresql.git;a=blob;f=src/backend/parser/parse_clause.c">transformFromClause().</a>
@@ -95,8 +96,8 @@ system.</p>
 <p>The <a
 href="https://wiki.postgresql.org/wiki/Backend_flowchart#optimizer_path">optimizer</a>
 uses the Query structure to determine the best table join order and join
-type of each table in the RangeTable, using Query.qual(<em>WHERE</em>
-clause) to consider optimal index usage.</p>  The <a
+type of each table in the RangeTable, using Query.jointree(<em>FROM</em>
+and <em>WHERE</em> clauses) to consider optimal index usage.</p>  The <a
 href="https://wiki.postgresql.org/wiki/Backend_flowchart#optimizer_path">path</a>
 module  then generates an optimal <a
 href="https://git.postgresql.org/gitweb/?p=postgresql.git;a=blob;f=src/include/nodes/plannodes.h">Plan,</a>

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