Cause EXPLAIN's VERBOSE option to print the target list (output column list)

of each plan node, instead of its former behavior of dumping the internal
representation of the plan tree.  The latter display is still available for
those who really want it (see debug_print_plan), but uses for it are certainly
few and and far between.  Per discussion.

This patch also removes the explain_pretty_print GUC, which is obsoleted
by the change.

doc/src/sgml/config.sgml

-<!-- $PostgreSQL: pgsql/doc/src/sgml/config.sgml,v 1.174 2008/03/30 04:08:14 neilc Exp $ -->
+<!-- $PostgreSQL: pgsql/doc/src/sgml/config.sgml,v 1.175 2008/04/18 01:42:17 tgl Exp $ -->
 
 <chapter Id="runtime-config">
   <title>Server Configuration</title>
@@ -4187,20 +4187,6 @@ SET XML OPTION { DOCUMENT | CONTENT };
 
      <variablelist>
 
-     <varlistentry id="guc-explain-pretty-print" xreflabel="explain_pretty_print">
-      <term><varname>explain_pretty_print</varname> (<type>boolean</type>)</term>
-      <indexterm>
-       <primary><varname>explain_pretty_print</> configuration parameter</primary>
-      </indexterm>
-      <listitem>
-       <para>
-        Determines whether <command>EXPLAIN VERBOSE</> uses the
-        indented or non-indented format for displaying detailed
-        query-tree dumps. The default is <literal>on</>.
-       </para>
-      </listitem>
-     </varlistentry>
-
      <varlistentry id="guc-dynamic-library-path" xreflabel="dynamic_library_path">
       <term><varname>dynamic_library_path</varname> (<type>string</type>)</term>
       <indexterm>

doc/src/sgml/ref/explain.sgml

 <!--
-$PostgreSQL: pgsql/doc/src/sgml/ref/explain.sgml,v 1.41 2007/11/28 15:42:31 petere Exp $
+$PostgreSQL: pgsql/doc/src/sgml/ref/explain.sgml,v 1.42 2008/04/18 01:42:17 tgl Exp $
 PostgreSQL documentation
 -->
 
@@ -106,12 +106,7 @@ ROLLBACK;
     <term><literal>VERBOSE</literal></term>
     <listitem>
      <para>
-      Show the full internal representation of the plan tree, rather
-      than just a summary.  Usually this option is only useful for
-      specialized debugging purposes.  The
-      <literal>VERBOSE</literal> output is either pretty-printed or
-      not, depending on the setting of the <xref
-      linkend="guc-explain-pretty-print"> configuration parameter.
+      Include the output column list for each node in the plan tree.
      </para>
     </listitem>
    </varlistentry>

src/backend/commands/explain.c

@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1994-5, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/commands/explain.c,v 1.172 2008/04/17 18:30:18 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/commands/explain.c,v 1.173 2008/04/18 01:42:17 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -20,7 +20,6 @@
 #include "commands/prepare.h"
 #include "commands/trigger.h"
 #include "executor/instrument.h"
-#include "nodes/print.h"
 #include "optimizer/clauses.h"
 #include "optimizer/planner.h"
 #include "optimizer/var.h"
@@ -44,7 +43,7 @@ explain_get_index_name_hook_type explain_get_index_name_hook = NULL;
 typedef struct ExplainState
 {
 	/* options */
-	bool		printNodes;		/* do nodeToString() too */
+	bool		printTList;		/* print plan targetlists */
 	bool		printAnalyze;	/* print actual times */
 	/* other states */
 	PlannedStmt *pstmt;			/* top of plan */
@@ -271,30 +270,11 @@ ExplainOnePlan(PlannedStmt *plannedstmt, ParamListInfo params,
 
 	es = (ExplainState *) palloc0(sizeof(ExplainState));
 
-	es->printNodes = stmt->verbose;
+	es->printTList = stmt->verbose;
 	es->printAnalyze = stmt->analyze;
 	es->pstmt = queryDesc->plannedstmt;
 	es->rtable = queryDesc->plannedstmt->rtable;
 
-	if (es->printNodes)
-	{
-		char	   *s;
-		char	   *f;
-
-		s = nodeToString(queryDesc->plannedstmt->planTree);
-		if (s)
-		{
-			if (Explain_pretty_print)
-				f = pretty_format_node_dump(s);
-			else
-				f = format_node_dump(s);
-			pfree(s);
-			do_text_output_multiline(tstate, f);
-			pfree(f);
-			do_text_output_oneline(tstate, ""); /* separator line */
-		}
-	}
-
 	initStringInfo(&buf);
 	explain_outNode(&buf,
 					queryDesc->plannedstmt->planTree, queryDesc->planstate,
@@ -747,7 +727,8 @@ explain_outNode(StringInfo str,
 	appendStringInfoChar(str, '\n');
 
 	/* target list */
-	show_plan_tlist(plan, str, indent, es);
+	if (es->printTList)
+		show_plan_tlist(plan, str, indent, es);
 
 	/* quals, sort keys, etc */
 	switch (nodeTag(plan))
@@ -1055,7 +1036,6 @@ static void
 show_plan_tlist(Plan *plan,
 				StringInfo str, int indent, ExplainState *es)
 {
-#ifdef EXPLAIN_PRINT_TLISTS
 	List	   *context;
 	bool		useprefix;
 	ListCell   *lc;
@@ -1095,7 +1075,6 @@ show_plan_tlist(Plan *plan,
 	}
 
 	appendStringInfoChar(str, '\n');
-#endif /* EXPLAIN_PRINT_TLISTS */
 }
 
 /*

src/backend/utils/misc/guc.c

@@ -10,7 +10,7 @@
  * Written by Peter Eisentraut <peter_e@gmx.net>.
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/utils/misc/guc.c,v 1.446 2008/04/04 17:25:23 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/utils/misc/guc.c,v 1.447 2008/04/18 01:42:17 tgl Exp $
  *
  *--------------------------------------------------------------------
  */
@@ -282,7 +282,6 @@ bool		Debug_print_plan = false;
 bool		Debug_print_parse = false;
 bool		Debug_print_rewritten = false;
 bool		Debug_pretty_print = false;
-bool		Explain_pretty_print = true;
 
 bool		log_parser_stats = false;
 bool		log_planner_stats = false;
@@ -807,15 +806,6 @@ static struct config_bool ConfigureNamesBool[] =
 	},
 #endif
 
-	{
-		{"explain_pretty_print", PGC_USERSET, CLIENT_CONN_OTHER,
-			gettext_noop("Uses the indented output format for EXPLAIN VERBOSE."),
-			NULL
-		},
-		&Explain_pretty_print,
-		true, NULL, NULL
-	},
-
 	{
 		{"track_activities", PGC_SUSET, STATS_COLLECTOR,
 			gettext_noop("Collects information about executing commands."),

src/backend/utils/misc/postgresql.conf.sample

@@ -447,7 +447,6 @@
 
 # - Other Defaults -
 
-#explain_pretty_print = on
 #dynamic_library_path = '$libdir'
 #local_preload_libraries = ''
 

src/include/utils/guc.h

@@ -7,7 +7,7 @@
  * Copyright (c) 2000-2008, PostgreSQL Global Development Group
  * Written by Peter Eisentraut <peter_e@gmx.net>.
  *
- * $PostgreSQL: pgsql/src/include/utils/guc.h,v 1.93 2008/04/02 14:42:56 mha Exp $
+ * $PostgreSQL: pgsql/src/include/utils/guc.h,v 1.94 2008/04/18 01:42:17 tgl Exp $
  *--------------------------------------------------------------------
  */
 #ifndef GUC_H
@@ -127,7 +127,6 @@ extern bool Debug_print_plan;
 extern bool Debug_print_parse;
 extern bool Debug_print_rewritten;
 extern bool Debug_pretty_print;
-extern bool Explain_pretty_print;
 
 extern bool log_parser_stats;
 extern bool log_planner_stats;