EXPLAIN output now comes out as a query result, not a NOTICE message.

Also, fix debug logging of parse/plan trees so that the messages actually
go through elog(), not directly to stdout.

src/backend/commands/explain.c

@@ -5,12 +5,14 @@
  * Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994-5, Regents of the University of California
  *
- * $Header: /cvsroot/pgsql/src/backend/commands/explain.c,v 1.73 2002/03/22 02:56:31 tgl Exp $
+ * $Header: /cvsroot/pgsql/src/backend/commands/explain.c,v 1.74 2002/03/24 04:31:07 tgl Exp $
  *
  */
 
 #include "postgres.h"
 
+#include "access/heapam.h"
+#include "catalog/pg_type.h"
 #include "commands/explain.h"
 #include "executor/instrument.h"
 #include "lib/stringinfo.h"
@@ -22,6 +24,7 @@
 #include "rewrite/rewriteHandler.h"
 #include "tcop/pquery.h"
 #include "utils/builtins.h"
+#include "utils/guc.h"
 #include "utils/lsyscache.h"
 #include "utils/relcache.h"
 
@@ -35,9 +38,15 @@ typedef struct ExplainState
 	List	   *rtable;			/* range table */
 } ExplainState;
 
+typedef struct TextOutputState
+{
+	TupleDesc	tupdesc;
+	DestReceiver *destfunc;
+} TextOutputState;
+
 static StringInfo Explain_PlanToString(Plan *plan, ExplainState *es);
-static void ExplainOneQuery(Query *query, bool verbose, bool analyze,
-							CommandDest dest);
+static void ExplainOneQuery(Query *query, ExplainStmt *stmt,
+							TextOutputState *tstate);
 static void explain_outNode(StringInfo str, Plan *plan, Plan *outer_plan,
 							int indent, ExplainState *es);
 static void show_scan_qual(List *qual, bool is_or_qual, const char *qlabel,
@@ -48,6 +57,10 @@ static void show_upper_qual(List *qual, const char *qlabel,
 							const char *inner_name, int inner_varno, Plan *inner_plan,
 							StringInfo str, int indent, ExplainState *es);
 static Node *make_ors_ands_explicit(List *orclauses);
+static TextOutputState *begin_text_output(CommandDest dest, char *title);
+static void do_text_output(TextOutputState *tstate, char *aline);
+static void do_text_output_multiline(TextOutputState *tstate, char *text);
+static void end_text_output(TextOutputState *tstate);
 
 /* Convert a null string pointer into "<>" */
 #define stringStringInfo(s) (((s) == NULL) ? "<>" : (s))
@@ -55,42 +68,47 @@ static Node *make_ors_ands_explicit(List *orclauses);
 
 /*
  * ExplainQuery -
- *	  print out the execution plan for a given query
+ *	  execute an EXPLAIN command
  */
 void
-ExplainQuery(Query *query, bool verbose, bool analyze, CommandDest dest)
+ExplainQuery(ExplainStmt *stmt, CommandDest dest)
 {
+	Query	   *query = stmt->query;
+	TextOutputState *tstate;
 	List	   *rewritten;
 	List	   *l;
 
-	/* rewriter and planner may not work in aborted state? */
-	if (IsAbortedTransactionBlockState())
-	{
-		elog(WARNING, "(transaction aborted): %s",
-			 "queries ignored until END");
-		return;
-	}
+	tstate = begin_text_output(dest, "QUERY PLAN");
 
-	/* rewriter will not cope with utility statements */
 	if (query->commandType == CMD_UTILITY)
 	{
-		elog(NOTICE, "Utility statements have no plan structure");
-		return;
+		/* rewriter will not cope with utility statements */
+		do_text_output(tstate, "Utility statements have no plan structure");
 	}
-
-	/* Rewrite through rule system */
-	rewritten = QueryRewrite(query);
-
-	/* In the case of an INSTEAD NOTHING, tell at least that */
-	if (rewritten == NIL)
+	else
 	{
-		elog(NOTICE, "Query rewrites to nothing");
-		return;
+		/* Rewrite through rule system */
+		rewritten = QueryRewrite(query);
+
+		if (rewritten == NIL)
+		{
+			/* In the case of an INSTEAD NOTHING, tell at least that */
+			do_text_output(tstate, "Query rewrites to nothing");
+		}
+		else
+		{
+			/* Explain every plan */
+			foreach(l, rewritten)
+			{
+				ExplainOneQuery(lfirst(l), stmt, tstate);
+				/* put a blank line between plans */
+				if (lnext(l) != NIL)
+					do_text_output(tstate, "");
+			}
+		}
 	}
 
-	/* Explain every plan */
-	foreach(l, rewritten)
-		ExplainOneQuery(lfirst(l), verbose, analyze, dest);
+	end_text_output(tstate);
 }
 
 /*
@@ -98,7 +116,7 @@ ExplainQuery(Query *query, bool verbose, bool analyze, CommandDest dest)
  *	  print out the execution plan for one query
  */
 static void
-ExplainOneQuery(Query *query, bool verbose, bool analyze, CommandDest dest)
+ExplainOneQuery(Query *query, ExplainStmt *stmt, TextOutputState *tstate)
 {
 	Plan	   *plan;
 	ExplainState *es;
@@ -108,9 +126,9 @@ ExplainOneQuery(Query *query, bool verbose, bool analyze, CommandDest dest)
 	if (query->commandType == CMD_UTILITY)
 	{
 		if (query->utilityStmt && IsA(query->utilityStmt, NotifyStmt))
-			elog(INFO, "QUERY PLAN:\n\nNOTIFY\n");
+			do_text_output(tstate, "NOTIFY");
 		else
-			elog(INFO, "QUERY PLAN:\n\nUTILITY\n");
+			do_text_output(tstate, "UTILITY");
 		return;
 	}
 
@@ -122,7 +140,7 @@ ExplainOneQuery(Query *query, bool verbose, bool analyze, CommandDest dest)
 		return;
 
 	/* Execute the plan for statistics if asked for */
-	if (analyze)
+	if (stmt->analyze)
 	{
 		struct timeval starttime;
 		struct timeval endtime;
@@ -154,7 +172,7 @@ ExplainOneQuery(Query *query, bool verbose, bool analyze, CommandDest dest)
 
 	es->printCost = true;		/* default */
 
-	if (verbose)
+	if (stmt->verbose)
 		es->printNodes = true;
 
 	es->rtable = query->rtable;
@@ -162,12 +180,20 @@ ExplainOneQuery(Query *query, bool verbose, bool analyze, CommandDest dest)
 	if (es->printNodes)
 	{
 		char	   *s;
+		char	   *f;
 
 		s = nodeToString(plan);
 		if (s)
 		{
-			elog(INFO, "QUERY DUMP:\n\n%s", 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);
+			if (es->printCost)
+				do_text_output(tstate, "");	/* separator line */
 		}
 	}
 
@@ -176,17 +202,14 @@ ExplainOneQuery(Query *query, bool verbose, bool analyze, CommandDest dest)
 		StringInfo	str;
 
 		str = Explain_PlanToString(plan, es);
-		if (analyze)
+		if (stmt->analyze)
 			appendStringInfo(str, "Total runtime: %.2f msec\n",
 							 1000.0 * totaltime);
-		elog(INFO, "QUERY PLAN:\n\n%s", str->data);
+		do_text_output_multiline(tstate, str->data);
 		pfree(str->data);
 		pfree(str);
 	}
 
-	if (es->printNodes)
-		pprint(plan);			/* display in postmaster log file */
-
 	pfree(es);
 }
 
@@ -709,3 +732,78 @@ make_ors_ands_explicit(List *orclauses)
 		return (Node *) make_orclause(args);
 	}
 }
+
+
+/*
+ * Functions for sending text to the frontend (or other specified destination)
+ * as though it is a SELECT result.
+ *
+ * We tell the frontend that the table structure is a single TEXT column.
+ */
+
+static TextOutputState *
+begin_text_output(CommandDest dest, char *title)
+{
+	TextOutputState *tstate;
+	TupleDesc	tupdesc;
+
+	tstate = (TextOutputState *) palloc(sizeof(TextOutputState));
+
+	/* need a tuple descriptor representing a single TEXT column */
+	tupdesc = CreateTemplateTupleDesc(1);
+	TupleDescInitEntry(tupdesc, (AttrNumber) 1, title,
+					   TEXTOID, -1, 0, false);
+
+	tstate->tupdesc = tupdesc;
+	tstate->destfunc = DestToFunction(dest);
+
+	(*tstate->destfunc->setup) (tstate->destfunc, (int) CMD_SELECT,
+								NULL, tupdesc);
+
+	return tstate;
+}
+
+/* write a single line of text */
+static void
+do_text_output(TextOutputState *tstate, char *aline)
+{
+	HeapTuple	tuple;
+	Datum		values[1];
+	char		nulls[1];
+
+	/* form a tuple and send it to the receiver */
+	values[0] = DirectFunctionCall1(textin, CStringGetDatum(aline));
+	nulls[0] = ' ';
+	tuple = heap_formtuple(tstate->tupdesc, values, nulls);
+	(*tstate->destfunc->receiveTuple) (tuple,
+									   tstate->tupdesc,
+									   tstate->destfunc);
+	pfree(DatumGetPointer(values[0]));
+	heap_freetuple(tuple);
+}
+
+/* write a chunk of text, breaking at newline characters */
+/* NB: scribbles on its input! */
+static void
+do_text_output_multiline(TextOutputState *tstate, char *text)
+{
+	while (*text)
+	{
+		char   *eol;
+
+		eol = strchr(text, '\n');
+		if (eol)
+			*eol++ = '\0';
+		else
+			eol = text + strlen(text);
+		do_text_output(tstate, text);
+		text = eol;
+	}
+}
+
+static void
+end_text_output(TextOutputState *tstate)
+{
+	(*tstate->destfunc->cleanup) (tstate->destfunc);
+	pfree(tstate);
+}

src/backend/nodes/print.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/nodes/print.c,v 1.53 2002/03/22 02:56:32 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/nodes/print.c,v 1.54 2002/03/24 04:31:07 tgl Exp $
  *
  * HISTORY
  *	  AUTHOR			DATE			MAJOR EVENT
@@ -21,6 +21,7 @@
 
 #include "access/printtup.h"
 #include "catalog/pg_type.h"
+#include "lib/stringinfo.h"
 #include "nodes/print.h"
 #include "optimizer/clauses.h"
 #include "parser/parsetree.h"
@@ -37,31 +38,129 @@ void
 print(void *obj)
 {
 	char	   *s;
+	char	   *f;
 
 	s = nodeToString(obj);
-	printf("%s\n", s);
-	fflush(stdout);
+	f = format_node_dump(s);
 	pfree(s);
+	printf("%s\n", f);
+	fflush(stdout);
+	pfree(f);
 }
 
 /*
- * pretty print hack extraordinaire.  -ay 10/94
+ * pprint
+ *	  pretty-print contents of Node to stdout
  */
 void
 pprint(void *obj)
 {
-#define INDENTSTOP	3
-#define MAXINDENT	60
-#define LINELEN		80
 	char	   *s;
-	int			i;
-	char		line[LINELEN];
-	int			indentLev;
-	int			indentDist;
-	int			j;
+	char	   *f;
 
 	s = nodeToString(obj);
+	f = pretty_format_node_dump(s);
+	pfree(s);
+	printf("%s\n", f);
+	fflush(stdout);
+	pfree(f);
+}
 
+/*
+ * elog_node_display
+ *	  send pretty-printed contents of Node to postmaster log
+ */
+void
+elog_node_display(int lev, const char *title, void *obj, bool pretty)
+{
+	char	   *s;
+	char	   *f;
+
+	s = nodeToString(obj);
+	if (pretty)
+		f = pretty_format_node_dump(s);
+	else
+		f = format_node_dump(s);
+	pfree(s);
+	elog(lev, "%s:\n%s", title, f);
+	pfree(f);
+}
+
+/*
+ * Format a nodeToString output for display on a terminal.
+ *
+ * The result is a palloc'd string.
+ *
+ * This version just tries to break at whitespace.
+ */
+char *
+format_node_dump(const char *dump)
+{
+#define LINELEN		78
+	char		line[LINELEN+1];
+	StringInfoData str;
+	int			i;
+	int			j;
+	int			k;
+
+	initStringInfo(&str);
+	i = 0;
+	for (;;)
+	{
+		for (j = 0; j < LINELEN && dump[i] != '\0'; i++, j++)
+			line[j] = dump[i];
+		if (dump[i] == '\0')
+			break;
+		if (dump[i] == ' ')
+		{
+			/* ok to break at adjacent space */
+			i++;
+		}
+		else
+		{
+			for (k = j-1; k > 0; k--)
+				if (line[k] == ' ')
+					break;
+			if (k > 0)
+			{
+				/* back up; will reprint all after space */
+				i -= (j-k-1);
+				j = k;
+			}
+		}
+		line[j] = '\0';
+		appendStringInfo(&str, "%s\n", line);
+	}
+	if (j > 0)
+	{
+		line[j] = '\0';
+		appendStringInfo(&str, "%s\n", line);
+	}
+	return str.data;
+#undef LINELEN
+}
+
+/*
+ * Format a nodeToString output for display on a terminal.
+ *
+ * The result is a palloc'd string.
+ *
+ * This version tries to indent intelligently.
+ */
+char *
+pretty_format_node_dump(const char *dump)
+{
+#define INDENTSTOP	3
+#define MAXINDENT	60
+#define LINELEN		78
+	char		line[LINELEN+1];
+	StringInfoData str;
+	int			indentLev;
+	int			indentDist;
+	int			i;
+	int			j;
+
+	initStringInfo(&str);
 	indentLev = 0;				/* logical indent level */
 	indentDist = 0;				/* physical indent distance */
 	i = 0;
@@ -69,9 +168,9 @@ pprint(void *obj)
 	{
 		for (j = 0; j < indentDist; j++)
 			line[j] = ' ';
-		for (; j < LINELEN-1 && s[i] != '\0'; i++, j++)
+		for (; j < LINELEN && dump[i] != '\0'; i++, j++)
 		{
-			line[j] = s[i];
+			line[j] = dump[i];
 			switch (line[j])
 			{
 				case '}':
@@ -79,11 +178,12 @@ pprint(void *obj)
 					{
 						/* print data before the } */
 						line[j] = '\0';
-						printf("%s\n", line);
+						appendStringInfo(&str, "%s\n", line);
 					}
 					/* print the } at indentDist */
-					line[indentDist] = '\0';
-					printf("%s}\n", line);
+					line[indentDist] = '}';
+					line[indentDist+1] = '\0';
+					appendStringInfo(&str, "%s\n", line);
 					/* outdent */
 					if (indentLev > 0)
 					{
@@ -96,7 +196,7 @@ pprint(void *obj)
 				case ')':
 					/* force line break after ')' */
 					line[j + 1] = '\0';
-					printf("%s\n", line);
+					appendStringInfo(&str, "%s\n", line);
 					j = indentDist - 1;
 					break;
 				case '{':
@@ -104,36 +204,38 @@ pprint(void *obj)
 					if (j != indentDist)
 					{
 						line[j] = '\0';
-						printf("%s\n", line);
+						appendStringInfo(&str, "%s\n", line);
 					}
 					/* indent */
 					indentLev++;
 					indentDist = Min(indentLev * INDENTSTOP, MAXINDENT);
 					for (j = 0; j < indentDist; j++)
 						line[j] = ' ';
-					line[j] = s[i];
+					line[j] = dump[i];
 					break;
 				case ':':
 					/* force line break before : */
 					if (j != indentDist)
 					{
 						line[j] = '\0';
-						printf("%s\n", line);
+						appendStringInfo(&str, "%s\n", line);
 					}
 					j = indentDist;
-					line[j] = s[i];
+					line[j] = dump[i];
 					break;
 			}
 		}
 		line[j] = '\0';
-		if (s[i] == '\0')
+		if (dump[i] == '\0')
 			break;
-		printf("%s\n", line);
+		appendStringInfo(&str, "%s\n", line);
 	}
-	if (j != 0)
-		printf("%s\n", line);
-	fflush(stdout);
-	pfree(s);
+	if (j > 0)
+		appendStringInfo(&str, "%s\n", line);
+	return str.data;
+#undef INDENTSTOP
+#undef MAXINDENT
+#undef LINELEN
 }
 
 /*

src/backend/tcop/postgres.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/tcop/postgres.c,v 1.259 2002/03/22 02:56:35 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/tcop/postgres.c,v 1.260 2002/03/24 04:31:07 tgl Exp $
  *
  * NOTES
  *	  this is the "main" module of the postgres backend and
@@ -426,15 +426,8 @@ pg_analyze_and_rewrite(Node *parsetree)
 		querytree = (Query *) lfirst(list_item);
 
 		if (Debug_print_parse)
-		{
-			if (Debug_pretty_print)
-			{
-				elog(LOG, "parse tree:");
-				nodeDisplay(querytree);
-			}
-			else
-				elog(LOG, "parse tree: %s", nodeToString(querytree));
-		}
+			elog_node_display(LOG, "parse tree", querytree,
+							  Debug_pretty_print);
 
 		if (querytree->commandType == CMD_UTILITY)
 		{
@@ -470,27 +463,8 @@ pg_analyze_and_rewrite(Node *parsetree)
 #endif
 
 	if (Debug_print_rewritten)
-	{
-		if (Debug_pretty_print)
-		{
-			elog(LOG, "rewritten parse tree:");
-			foreach(list_item, querytree_list)
-			{
-				querytree = (Query *) lfirst(list_item);
-				nodeDisplay(querytree);
-				printf("\n");
-			}
-		}
-		else
-		{
-			elog(LOG, "rewritten parse tree:");
-			foreach(list_item, querytree_list)
-			{
-				querytree = (Query *) lfirst(list_item);
-				elog(LOG, "%s", nodeToString(querytree));
-			}
-		}
-	}
+		elog_node_display(LOG, "rewritten parse tree", querytree_list,
+						  Debug_pretty_print);
 
 	return querytree_list;
 }
@@ -538,15 +512,7 @@ pg_plan_query(Query *querytree)
 	 * Print plan if debugging.
 	 */
 	if (Debug_print_plan)
-	{
-		if (Debug_pretty_print)
-		{
-			elog(LOG, "plan:");
-			nodeDisplay(plan);
-		}
-		else
-			elog(LOG, "plan: %s", nodeToString(plan));
-	}
+		elog_node_display(LOG, "plan", plan, Debug_pretty_print);
 
 	return plan;
 }
@@ -1722,7 +1688,7 @@ PostgresMain(int argc, char *argv[], const char *username)
 	if (!IsUnderPostmaster)
 	{
 		puts("\nPOSTGRES backend interactive interface ");
-		puts("$Revision: 1.259 $ $Date: 2002/03/22 02:56:35 $\n");
+		puts("$Revision: 1.260 $ $Date: 2002/03/24 04:31:07 $\n");
 	}
 
 	/*

src/backend/tcop/utility.c

@@ -10,7 +10,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/tcop/utility.c,v 1.138 2002/03/22 02:56:35 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/tcop/utility.c,v 1.139 2002/03/24 04:31:08 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -650,11 +650,7 @@ ProcessUtility(Node *parsetree,
 			break;
 
 		case T_ExplainStmt:
-			{
-				ExplainStmt *stmt = (ExplainStmt *) parsetree;
-
-				ExplainQuery(stmt->query, stmt->verbose, stmt->analyze, dest);
-			}
+			ExplainQuery((ExplainStmt *) parsetree, dest);
 			break;
 
 #ifdef NOT_USED

src/backend/utils/misc/guc.c

@@ -4,7 +4,7 @@
  * Support for grand unified configuration scheme, including SET
  * command, configuration file, and command line options.
  *
- * $Header: /cvsroot/pgsql/src/backend/utils/misc/guc.c,v 1.62 2002/03/06 06:10:27 momjian Exp $
+ * $Header: /cvsroot/pgsql/src/backend/utils/misc/guc.c,v 1.63 2002/03/24 04:31:08 tgl Exp $
  *
  * Copyright 2000 by PostgreSQL Global Development Group
  * Written by Peter Eisentraut <peter_e@gmx.net>.
@@ -82,6 +82,8 @@ bool		Show_query_stats = false;	/* this is sort of all three above
 										 * together */
 bool		Show_btree_build_stats = false;
 
+bool		Explain_pretty_print = true;
+
 bool		SQL_inheritance = true;
 
 bool		Australian_timezones = false;
@@ -293,6 +295,10 @@ static struct config_bool
 	},
 #endif
 
+	{
+		"explain_pretty_print", PGC_USERSET, PGC_S_DEFAULT, &Explain_pretty_print, true, NULL
+	},
+
 	{
 		"stats_start_collector", PGC_POSTMASTER, PGC_S_DEFAULT, &pgstat_collect_startcollector, true, NULL
 	},

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

@@ -136,6 +136,8 @@
 #debug_print_plan = false
 #debug_pretty_print = false
 
+#explain_pretty_print = true
+
 # requires USE_ASSERT_CHECKING
 #debug_assertions = true