Add pg_conf_load_time() function to report when the Postgres configuration

files were last loaded.

George Gensure

doc/src/sgml/func.sgml

-<!-- $PostgreSQL: pgsql/doc/src/sgml/func.sgml,v 1.434 2008/04/28 14:48:57 alvherre Exp $ -->
+<!-- $PostgreSQL: pgsql/doc/src/sgml/func.sgml,v 1.435 2008/05/04 21:13:35 tgl Exp $ -->
 
  <chapter id="functions">
   <title>Functions and Operators</title>
@@ -10891,6 +10891,12 @@ postgres=# select * from unnest2(array[[1,2],[3,4]]);
        <entry>server start time</entry>
       </row>
 
+      <row>
+       <entry><literal><function>pg_conf_load_time</function>()</literal></entry>
+       <entry><type>timestamp with time zone</type></entry>
+       <entry>configuration load time</entry>
+      </row>
+
       <row>
        <entry><literal><function>session_user</function></literal></entry>
        <entry><type>name</type></entry>
@@ -11036,6 +11042,20 @@ SET search_path TO <replaceable>schema</> <optional>, <replaceable>schema</>, ..
     server started.
    </para>
 
+   <indexterm>
+    <primary>pg_conf_load_time</primary>
+   </indexterm>
+
+   <para>
+    <function>pg_conf_load_time</function> returns the
+    <type>timestamp with time zone</type> when the
+    server configuration files were last loaded.
+    (If the current session was alive at the time, this will be the time
+    when the session itself re-read the configuration files, so the
+    reading will vary a little in different sessions.  Otherwise it is
+    the time when the postmaster process re-read the configuration files.)
+   </para>
+
    <indexterm>
     <primary>version</primary>
    </indexterm>

src/backend/postmaster/postmaster.c

@@ -37,7 +37,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/postmaster/postmaster.c,v 1.556 2008/04/26 22:47:40 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/postmaster/postmaster.c,v 1.557 2008/05/04 21:13:35 tgl Exp $
  *
  * NOTES
  *
@@ -390,6 +390,7 @@ typedef struct
 	InheritableSocket pgStatSock;
 	pid_t		PostmasterPid;
 	TimestampTz PgStartTime;
+	TimestampTz PgReloadTime;
 	bool		redirection_done;
 #ifdef WIN32
 	HANDLE		PostmasterHandle;
@@ -4263,6 +4264,7 @@ save_backend_variables(BackendParameters * param, Port *port,
 
 	param->PostmasterPid = PostmasterPid;
 	param->PgStartTime = PgStartTime;
+	param->PgReloadTime = PgReloadTime;
 
 	param->redirection_done = redirection_done;
 
@@ -4468,6 +4470,7 @@ restore_backend_variables(BackendParameters * param, Port *port)
 
 	PostmasterPid = param->PostmasterPid;
 	PgStartTime = param->PgStartTime;
+	PgReloadTime = param->PgReloadTime;
 
 	redirection_done = param->redirection_done;
 

src/backend/utils/adt/timestamp.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/utils/adt/timestamp.c,v 1.187 2008/03/25 22:42:44 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/utils/adt/timestamp.c,v 1.188 2008/05/04 21:13:35 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -42,6 +42,8 @@
 
 /* Set at postmaster start */
 TimestampTz PgStartTime;
+/* Set at configuration reload */
+TimestampTz PgReloadTime;
 
 
 static TimeOffset time2t(const int hour, const int min, const int sec, const fsec_t fsec);
@@ -1157,11 +1159,17 @@ clock_timestamp(PG_FUNCTION_ARGS)
 }
 
 Datum
-pgsql_postmaster_start_time(PG_FUNCTION_ARGS)
+pg_postmaster_start_time(PG_FUNCTION_ARGS)
 {
 	PG_RETURN_TIMESTAMPTZ(PgStartTime);
 }
 
+Datum
+pg_conf_load_time(PG_FUNCTION_ARGS)
+{
+	PG_RETURN_TIMESTAMPTZ(PgReloadTime);
+}
+
 /*
  * GetCurrentTimestamp -- get the current operating system time
  *

src/backend/utils/misc/guc-file.l

@@ -4,7 +4,7 @@
  *
  * Copyright (c) 2000-2008, PostgreSQL Global Development Group
  *
- * $PostgreSQL: pgsql/src/backend/utils/misc/guc-file.l,v 1.53 2008/01/01 19:45:54 momjian Exp $
+ * $PostgreSQL: pgsql/src/backend/utils/misc/guc-file.l,v 1.54 2008/05/04 21:13:35 tgl Exp $
  */
 
 %{
@@ -309,6 +309,9 @@ ProcessConfigFile(GucContext context)
 						  PGC_S_FILE, GUC_ACTION_SET, true);
 	}
 
+	/* Remember when we last successfully loaded the config file. */
+	PgReloadTime = GetCurrentTimestamp();
+
  cleanup_list:
 	free_name_value_list(head);
 	if (cvc)

src/include/catalog/catversion.h

@@ -37,7 +37,7 @@
  * Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/catalog/catversion.h,v 1.453 2008/04/29 14:59:17 alvherre Exp $
+ * $PostgreSQL: pgsql/src/include/catalog/catversion.h,v 1.454 2008/05/04 21:13:35 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -53,6 +53,6 @@
  */
 
 /*							yyyymmddN */
-#define CATALOG_VERSION_NO	200804292
+#define CATALOG_VERSION_NO	200805041
 
 #endif

src/include/catalog/pg_proc.h

@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/catalog/pg_proc.h,v 1.494 2008/04/29 13:00:22 alvherre Exp $
+ * $PostgreSQL: pgsql/src/include/catalog/pg_proc.h,v 1.495 2008/05/04 21:13:36 tgl Exp $
  *
  * NOTES
  *	  The script catalog/genbki.sh reads this file and generates .bki
@@ -3922,8 +3922,11 @@ DATA(insert OID = 2559 ( lastval			   PGNSP PGUID 12 1 0 f f t f v 0 20 "" _null
 DESCR("current value from last used sequence");
 
 /* start time function */
-DATA(insert OID = 2560 (  pg_postmaster_start_time PGNSP PGUID 12 1 0 f f t f s 0 1184 "" _null_ _null_ _null_ pgsql_postmaster_start_time - _null_ _null_ ));
+DATA(insert OID = 2560 (  pg_postmaster_start_time	PGNSP PGUID 12 1 0 f f t f s 0 1184 "" _null_ _null_ _null_ pg_postmaster_start_time - _null_ _null_ ));
 DESCR("postmaster start time");
+/* config reload time function */
+DATA(insert OID = 2034 (  pg_conf_load_time			PGNSP PGUID 12 1 0 f f t f s 0 1184 "" _null_ _null_ _null_ pg_conf_load_time - _null_ _null_ ));
+DESCR("configuration load time");
 
 /* new functions for Y-direction rtree opclasses */
 DATA(insert OID = 2562 (  box_below		   PGNSP PGUID 12 1 0 f f t f i 2 16 "603 603" _null_ _null_ _null_ box_below - _null_ _null_ ));

src/include/utils/timestamp.h

@@ -6,7 +6,7 @@
  * Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/utils/timestamp.h,v 1.76 2008/03/21 01:31:43 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/utils/timestamp.h,v 1.77 2008/05/04 21:13:36 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -195,6 +195,8 @@ typedef struct
 
 /* Set at postmaster start */
 extern TimestampTz PgStartTime;
+/* Set at configuration reload */
+extern TimestampTz PgReloadTime;
 
 
 /*
@@ -303,7 +305,8 @@ extern Datum now(PG_FUNCTION_ARGS);
 extern Datum statement_timestamp(PG_FUNCTION_ARGS);
 extern Datum clock_timestamp(PG_FUNCTION_ARGS);
 
-extern Datum pgsql_postmaster_start_time(PG_FUNCTION_ARGS);
+extern Datum pg_postmaster_start_time(PG_FUNCTION_ARGS);
+extern Datum pg_conf_load_time(PG_FUNCTION_ARGS);
 
 /* Internal routines (not fmgr-callable) */