postgres
diff --git a/‎src/backend/commands/explain.c
Copy file name to clipboardExpand all lines: src/backend/commands/explain.c
+7-11Lines changed: 7 additions & 11 deletions b/‎src/backend/commands/explain.c
Copy file name to clipboardExpand all lines: src/backend/commands/explain.c
+7-11Lines changed: 7 additions & 11 deletions
diff --git a/‎src/backend/utils/misc/guc.c
Copy file name to clipboardExpand all lines: src/backend/utils/misc/guc.c
+15-39Lines changed: 15 additions & 39 deletions b/‎src/backend/utils/misc/guc.c
Copy file name to clipboardExpand all lines: src/backend/utils/misc/guc.c
+15-39Lines changed: 15 additions & 39 deletions
diff --git a/‎src/test/regress/expected/explain.out
Copy file name to clipboardExpand all lines: src/test/regress/expected/explain.out
+20Lines changed: 20 additions & 0 deletions b/‎src/test/regress/expected/explain.out
Copy file name to clipboardExpand all lines: src/test/regress/expected/explain.out
+20Lines changed: 20 additions & 0 deletions
diff --git a/‎src/test/regress/sql/explain.sql
Copy file name to clipboardExpand all lines: src/test/regress/sql/explain.sql
+12Lines changed: 12 additions & 0 deletions b/‎src/test/regress/sql/explain.sql
Copy file name to clipboardExpand all lines: src/test/regress/sql/explain.sql
+12Lines changed: 12 additions & 0 deletions
@@ -626,17 +626,11 @@ ExplainPrintSettings(ExplainState *es)
 	/* request an array of relevant settings */
 	gucs = get_explain_guc_options(&num);
 
-	/* also bail out of there are no options */
-	if (!num)
-		return;
-
 	if (es->format != EXPLAIN_FORMAT_TEXT)
 	{
-		int			i;
-
 		ExplainOpenGroup("Settings", "Settings", true, es);
 
-		for (i = 0; i < num; i++)
+		for (int i = 0; i < num; i++)
 		{
 			char	   *setting;
 			struct config_generic *conf = gucs[i];
@@ -650,12 +644,15 @@ ExplainPrintSettings(ExplainState *es)
 	}
 	else
 	{
-		int			i;
 		StringInfoData str;
 
+		/* In TEXT mode, print nothing if there are no options */
+		if (num <= 0)
+			return;
+
 		initStringInfo(&str);
 
-		for (i = 0; i < num; i++)
+		for (int i = 0; i < num; i++)
 		{
 			char	   *setting;
 			struct config_generic *conf = gucs[i];
@@ -671,8 +668,7 @@ ExplainPrintSettings(ExplainState *es)
 				appendStringInfo(&str, "%s = NULL", conf->name);
 		}
 
-		if (num > 0)
-			ExplainPropertyText("Settings", str.data, es);
+		ExplainPropertyText("Settings", str.data, es);
 	}
 }
 
 
@@ -4663,9 +4663,6 @@ static struct config_generic **guc_variables;
 /* Current number of variables contained in the vector */
 static int	num_guc_variables;
 
-/* Current number of variables marked with GUC_EXPLAIN */
-static int	num_guc_explain_variables;
-
 /* Vector capacity */
 static int	size_guc_variables;
 
@@ -4929,7 +4926,6 @@ build_guc_variables(void)
 {
 	int			size_vars;
 	int			num_vars = 0;
-	int			num_explain_vars = 0;
 	struct config_generic **guc_vars;
 	int			i;
 
@@ -4940,9 +4936,6 @@ build_guc_variables(void)
 		/* Rather than requiring vartype to be filled in by hand, do this: */
 		conf->gen.vartype = PGC_BOOL;
 		num_vars++;
-
-		if (conf->gen.flags & GUC_EXPLAIN)
-			num_explain_vars++;
 	}
 
 	for (i = 0; ConfigureNamesInt[i].gen.name; i++)
@@ -4951,9 +4944,6 @@ build_guc_variables(void)
 
 		conf->gen.vartype = PGC_INT;
 		num_vars++;
-
-		if (conf->gen.flags & GUC_EXPLAIN)
-			num_explain_vars++;
 	}
 
 	for (i = 0; ConfigureNamesReal[i].gen.name; i++)
@@ -4962,9 +4952,6 @@ build_guc_variables(void)
 
 		conf->gen.vartype = PGC_REAL;
 		num_vars++;
-
-		if (conf->gen.flags & GUC_EXPLAIN)
-			num_explain_vars++;
 	}
 
 	for (i = 0; ConfigureNamesString[i].gen.name; i++)
@@ -4973,9 +4960,6 @@ build_guc_variables(void)
 
 		conf->gen.vartype = PGC_STRING;
 		num_vars++;
-
-		if (conf->gen.flags & GUC_EXPLAIN)
-			num_explain_vars++;
 	}
 
 	for (i = 0; ConfigureNamesEnum[i].gen.name; i++)
@@ -4984,9 +4968,6 @@ build_guc_variables(void)
 
 		conf->gen.vartype = PGC_ENUM;
 		num_vars++;
-
-		if (conf->gen.flags & GUC_EXPLAIN)
-			num_explain_vars++;
 	}
 
 	/*
@@ -5018,7 +4999,6 @@ build_guc_variables(void)
 		free(guc_variables);
 	guc_variables = guc_vars;
 	num_guc_variables = num_vars;
-	num_guc_explain_variables = num_explain_vars;
 	size_guc_variables = size_vars;
 	qsort((void *) guc_variables, num_guc_variables,
 		  sizeof(struct config_generic *), guc_var_compare);
@@ -8967,41 +8947,40 @@ ShowAllGUCConfig(DestReceiver *dest)
 }
 
 /*
- * Returns an array of modified GUC options to show in EXPLAIN. Only options
- * related to query planning (marked with GUC_EXPLAIN), with values different
- * from built-in defaults.
+ * Return an array of modified GUC options to show in EXPLAIN.
+ *
+ * We only report options related to query planning (marked with GUC_EXPLAIN),
+ * with values different from their built-in defaults.
  */
 struct config_generic **
 get_explain_guc_options(int *num)
 {
-	int			i;
 	struct config_generic **result;
 
 	*num = 0;
 
 	/*
-	 * Allocate enough space to fit all GUC_EXPLAIN options. We may not need
-	 * all the space, but there are fairly few such options so we don't waste
-	 * a lot of memory.
+	 * While only a fraction of all the GUC variables are marked GUC_EXPLAIN,
+	 * it doesn't seem worth dynamically resizing this array.
 	 */
-	result = palloc(sizeof(struct config_generic *) * num_guc_explain_variables);
+	result = palloc(sizeof(struct config_generic *) * num_guc_variables);
 
-	for (i = 0; i < num_guc_variables; i++)
+	for (int i = 0; i < num_guc_variables; i++)
 	{
 		bool		modified;
 		struct config_generic *conf = guc_variables[i];
 
-		/* return only options visible to the user */
+		/* return only parameters marked for inclusion in explain */
+		if (!(conf->flags & GUC_EXPLAIN))
+			continue;
+
+		/* return only options visible to the current user */
 		if ((conf->flags & GUC_NO_SHOW_ALL) ||
 			((conf->flags & GUC_SUPERUSER_ONLY) &&
 			 !is_member_of_role(GetUserId(), DEFAULT_ROLE_READ_ALL_SETTINGS)))
 			continue;
 
-		/* only parameters explicitly marked for inclusion in explain */
-		if (!(conf->flags & GUC_EXPLAIN))
-			continue;
-
-		/* return only options that were modified (w.r.t. config file) */
+		/* return only options that are different from their boot values */
 		modified = false;
 
 		switch (conf->vartype)
@@ -9050,15 +9029,12 @@ get_explain_guc_options(int *num)
 				elog(ERROR, "unexpected GUC type: %d", conf->vartype);
 		}
 
-		/* skip GUC variables that match the built-in default */
 		if (!modified)
 			continue;
 
-		/* assign to the values array */
+		/* OK, report it */
 		result[*num] = conf;
 		*num = *num + 1;
-
-		Assert(*num <= num_guc_explain_variables);
 	}
 
 	return result;
 
@@ -181,6 +181,26 @@ select explain_filter('explain (analyze, buffers, format yaml) select * from int
    Execution Time: N.N
 (1 row)
 
+-- SETTINGS option
+-- We have to ignore other settings that might be imposed by the environment,
+-- so printing the whole Settings field unfortunately won't do.
+begin;
+set local plan_cache_mode = force_generic_plan;
+select true as "OK"
+  from explain_filter('explain (settings) select * from int8_tbl i8') ln
+  where ln ~ '^ *Settings: .*plan_cache_mode = ''force_generic_plan''';
+ OK 
+----
+ t
+(1 row)
+
+select explain_filter_to_json('explain (settings, format json) select * from int8_tbl i8') #> '{0,Settings,plan_cache_mode}';
+       ?column?       
+----------------------
+ "force_generic_plan"
+(1 row)
+
+rollback;
 --
 -- Test production of per-worker data
 --
 
@@ -57,6 +57,18 @@ select explain_filter('explain (analyze, buffers, format json) select * from int
 select explain_filter('explain (analyze, buffers, format xml) select * from int8_tbl i8');
 select explain_filter('explain (analyze, buffers, format yaml) select * from int8_tbl i8');
 
+-- SETTINGS option
+-- We have to ignore other settings that might be imposed by the environment,
+-- so printing the whole Settings field unfortunately won't do.
+
+begin;
+set local plan_cache_mode = force_generic_plan;
+select true as "OK"
+  from explain_filter('explain (settings) select * from int8_tbl i8') ln
+  where ln ~ '^ *Settings: .*plan_cache_mode = ''force_generic_plan''';
+select explain_filter_to_json('explain (settings, format json) select * from int8_tbl i8') #> '{0,Settings,plan_cache_mode}';
+rollback;
+
 --
 -- Test production of per-worker data
 --
Original file line number	Diff line number	Diff line change
`@@ -626,17 +626,11 @@ ExplainPrintSettings(ExplainState *es)`
`626`	`626`	`/* request an array of relevant settings */`
`627`	`627`	`gucs = get_explain_guc_options(&num);`
`628`	`628`
`629`		`- /* also bail out of there are no options */`
`630`		`- if (!num)`
`631`		`- return;`
`632`		`-`
`633`	`629`	`if (es->format != EXPLAIN_FORMAT_TEXT)`
`634`	`630`	`{`
`635`		`- int i;`
`636`		`-`
`637`	`631`	`ExplainOpenGroup("Settings", "Settings", true, es);`
`638`	`632`
`639`		`- for (i = 0; i < num; i++)`
	`633`	`+ for (int i = 0; i < num; i++)`
`640`	`634`	`{`
`641`	`635`	`char *setting;`
`642`	`636`	`struct config_generic *conf = gucs[i];`
`@@ -650,12 +644,15 @@ ExplainPrintSettings(ExplainState *es)`
`650`	`644`	`}`
`651`	`645`	`else`
`652`	`646`	`{`
`653`		`- int i;`
`654`	`647`	`StringInfoData str;`
`655`	`648`
	`649`	`+ /* In TEXT mode, print nothing if there are no options */`
	`650`	`+ if (num <= 0)`
	`651`	`+ return;`
	`652`	`+`
`656`	`653`	`initStringInfo(&str);`
`657`	`654`
`658`		`- for (i = 0; i < num; i++)`
	`655`	`+ for (int i = 0; i < num; i++)`
`659`	`656`	`{`
`660`	`657`	`char *setting;`
`661`	`658`	`struct config_generic *conf = gucs[i];`
`@@ -671,8 +668,7 @@ ExplainPrintSettings(ExplainState *es)`
`671`	`668`	`appendStringInfo(&str, "%s = NULL", conf->name);`
`672`	`669`	`}`
`673`	`670`
`674`		`- if (num > 0)`
`675`		`- ExplainPropertyText("Settings", str.data, es);`
	`671`	`+ ExplainPropertyText("Settings", str.data, es);`
`676`	`672`	`}`
`677`	`673`	`}`
`678`	`674`