Add pg_settings.pending_restart column

with input from David G. Johnston, Robert Haas, Michael Paquier

doc/src/sgml/catalogs.sgml

@@ -9042,6 +9042,14 @@ SELECT * FROM pg_locks pl LEFT JOIN pg_prepared_xacts ppx
       or when examined by a non-superuser)
       </entry>
      </row>
+     <row>
+      <entry><structfield>pending_restart</structfield></entry>
+      <entry><type>boolean</type></entry>
+      <entry><literal>true</literal> if the value has been changed in the
+      configuration file but needs a restart; or <literal>false</literal>
+      otherwise.
+      </entry>
+     </row>
     </tbody>
    </tgroup>
   </table>

src/backend/utils/misc/guc.c

@@ -5927,12 +5927,14 @@ set_config_option(const char *name, const char *value,
 				{
 					if (*conf->variable != newval)
 					{
+						record->status |= GUC_PENDING_RESTART;
 						ereport(elevel,
 								(errcode(ERRCODE_CANT_CHANGE_RUNTIME_PARAM),
 								 errmsg("parameter \"%s\" cannot be changed without restarting the server",
 										name)));
 						return 0;
 					}
+					record->status &= ~GUC_PENDING_RESTART;
 					return -1;
 				}
 
@@ -6015,12 +6017,14 @@ set_config_option(const char *name, const char *value,
 				{
 					if (*conf->variable != newval)
 					{
+						record->status |= GUC_PENDING_RESTART;
 						ereport(elevel,
 								(errcode(ERRCODE_CANT_CHANGE_RUNTIME_PARAM),
 								 errmsg("parameter \"%s\" cannot be changed without restarting the server",
 										name)));
 						return 0;
 					}
+					record->status &= ~GUC_PENDING_RESTART;
 					return -1;
 				}
 
@@ -6103,12 +6107,14 @@ set_config_option(const char *name, const char *value,
 				{
 					if (*conf->variable != newval)
 					{
+						record->status |= GUC_PENDING_RESTART;
 						ereport(elevel,
 								(errcode(ERRCODE_CANT_CHANGE_RUNTIME_PARAM),
 								 errmsg("parameter \"%s\" cannot be changed without restarting the server",
 										name)));
 						return 0;
 					}
+					record->status &= ~GUC_PENDING_RESTART;
 					return -1;
 				}
 
@@ -6209,12 +6215,14 @@ set_config_option(const char *name, const char *value,
 					if (*conf->variable == NULL || newval == NULL ||
 						strcmp(*conf->variable, newval) != 0)
 					{
+						record->status |= GUC_PENDING_RESTART;
 						ereport(elevel,
 								(errcode(ERRCODE_CANT_CHANGE_RUNTIME_PARAM),
 								 errmsg("parameter \"%s\" cannot be changed without restarting the server",
 										name)));
 						return 0;
 					}
+					record->status &= ~GUC_PENDING_RESTART;
 					return -1;
 				}
 
@@ -6302,12 +6310,14 @@ set_config_option(const char *name, const char *value,
 				{
 					if (*conf->variable != newval)
 					{
+						record->status |= GUC_PENDING_RESTART;
 						ereport(elevel,
 								(errcode(ERRCODE_CANT_CHANGE_RUNTIME_PARAM),
 								 errmsg("parameter \"%s\" cannot be changed without restarting the server",
 										name)));
 						return 0;
 					}
+					record->status &= ~GUC_PENDING_RESTART;
 					return -1;
 				}
 
@@ -8009,6 +8019,8 @@ GetConfigOptionByNum(int varnum, const char **values, bool *noshow)
 		values[14] = NULL;
 		values[15] = NULL;
 	}
+
+	values[16] = (conf->status & GUC_PENDING_RESTART) ? "t" : "f";
 }
 
 /*
@@ -8044,7 +8056,7 @@ show_config_by_name(PG_FUNCTION_ARGS)
  * show_all_settings - equiv to SHOW ALL command but implemented as
  * a Table Function.
  */
-#define NUM_PG_SETTINGS_ATTS	16
+#define NUM_PG_SETTINGS_ATTS	17
 
 Datum
 show_all_settings(PG_FUNCTION_ARGS)
@@ -8104,6 +8116,8 @@ show_all_settings(PG_FUNCTION_ARGS)
 						   TEXTOID, -1, 0);
 		TupleDescInitEntry(tupdesc, (AttrNumber) 16, "sourceline",
 						   INT4OID, -1, 0);
+		TupleDescInitEntry(tupdesc, (AttrNumber) 17, "pending_restart",
+						   BOOLOID, -1, 0);
 
 		/*
 		 * Generate attribute metadata needed later to produce tuples from raw

src/include/catalog/catversion.h

@@ -53,6 +53,6 @@
  */
 
 /*							yyyymmddN */
-#define CATALOG_VERSION_NO	201505121
+#define CATALOG_VERSION_NO	201505141
 
 #endif

src/include/catalog/pg_proc.h

@@ -3067,7 +3067,7 @@ DATA(insert OID = 2077 (  current_setting	PGNSP PGUID 12 1 0 0 0 f f f f t f s 1
 DESCR("SHOW X as a function");
 DATA(insert OID = 2078 (  set_config		PGNSP PGUID 12 1 0 0 0 f f f f f f v 3 0 25 "25 25 16" _null_ _null_ _null_ _null_ _null_ set_config_by_name _null_ _null_ _null_ ));
 DESCR("SET X as a function");
-DATA(insert OID = 2084 (  pg_show_all_settings	PGNSP PGUID 12 1 1000 0 0 f f f f t t s 0 0 2249 "" "{25,25,25,25,25,25,25,25,25,25,25,1009,25,25,25,23}" "{o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}" "{name,setting,unit,category,short_desc,extra_desc,context,vartype,source,min_val,max_val,enumvals,boot_val,reset_val,sourcefile,sourceline}" _null_ _null_ show_all_settings _null_ _null_ _null_ ));
+DATA(insert OID = 2084 (  pg_show_all_settings	PGNSP PGUID 12 1 1000 0 0 f f f f t t s 0 0 2249 "" "{25,25,25,25,25,25,25,25,25,25,25,1009,25,25,25,23,16}" "{o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o,o}" "{name,setting,unit,category,short_desc,extra_desc,context,vartype,source,min_val,max_val,enumvals,boot_val,reset_val,sourcefile,sourceline,pending_restart}" _null_ _null_ show_all_settings _null_ _null_ _null_ ));
 DESCR("SHOW ALL as a function");
 DATA(insert OID = 3329 (  pg_show_all_file_settings	PGNSP PGUID 12 1 1000 0 0 f f f f t t s 0 0 2249 "" "{25,23,23,25,25}" "{o,o,o,o,o}" "{sourcefile,sourceline,seqno,name,setting}" _null_ _null_ show_all_file_settings _null_ _null_ _null_ ));
 DESCR("show config file settings");

src/include/utils/guc_tables.h

@@ -167,6 +167,7 @@ struct config_generic
  * Caution: the GUC_IS_IN_FILE bit is transient state for ProcessConfigFile.
  * Do not assume that its value represents useful information elsewhere.
  */
+#define GUC_PENDING_RESTART	0x0002
 
 
 /* GUC records for specific variable types */

src/test/regress/expected/rules.out

@@ -1616,8 +1616,9 @@ pg_settings| SELECT a.name,
     a.boot_val,
     a.reset_val,
     a.sourcefile,
-    a.sourceline
-   FROM pg_show_all_settings() a(name, setting, unit, category, short_desc, extra_desc, context, vartype, source, min_val, max_val, enumvals, boot_val, reset_val, sourcefile, sourceline);
+    a.sourceline,
+    a.pending_restart
+   FROM pg_show_all_settings() a(name, setting, unit, category, short_desc, extra_desc, context, vartype, source, min_val, max_val, enumvals, boot_val, reset_val, sourcefile, sourceline, pending_restart);
 pg_shadow| SELECT pg_authid.rolname AS usename,
     pg_authid.oid AS usesysid,
     pg_authid.rolcreatedb AS usecreatedb,