Patch to implement pg_current_logfile() function

diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 4b5ee81..e6a18fc 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -15026,6 +15026,11 @@ SELECT * FROM pg_ls_dir('.') WITH ORDINALITY AS t(ls,n);
        <entry>channel names that the session is currently listening on</entry>
       </row>
 
+      <entry><literal><function>pg_current_logfile()</function></literal></entry>
+       <entry><type>text</type></entry>
+       <entry>current log file used by the logging collector</entry>
+      </row>
+
       <row>
        <entry><literal><function>pg_notification_queue_usage()</function></literal></entry>
        <entry><type>double</type></entry>
@@ -15264,6 +15269,16 @@ SET search_path TO <replaceable>schema</> <optional>, <replaceable>schema</>, ..
    </para>
 
    <indexterm>
+    <primary>pg_current_logfile</primary>
+   </indexterm>
+
+   <para>
+    <function>pg_current_logfile</function> returns the name of the current log
+    file used by the logging collector, as a <type>text</type>. Log collection
+    must be active.
+   </para>
+
+   <indexterm>
     <primary>pg_postmaster_start_time</primary>
    </indexterm>
 
diff --git a/src/backend/postmaster/syslogger.c b/src/backend/postmaster/syslogger.c
index e7e488a..4769dc5 100644
--- a/src/backend/postmaster/syslogger.c
+++ b/src/backend/postmaster/syslogger.c
@@ -145,6 +145,7 @@ static char *logfile_getname(pg_time_t timestamp, const char *suffix);
 static void set_next_rotation_time(void);
 static void sigHupHandler(SIGNAL_ARGS);
 static void sigUsr1Handler(SIGNAL_ARGS);
+static void store_current_log_filename(char *filename);
 
 
 /*
@@ -571,6 +572,9 @@ SysLogger_Start(void)
 
 	syslogFile = logfile_open(filename, "a", false);
 
+	/* store information about current log filename used by log collection */
+	store_current_log_filename(filename);
+
 	pfree(filename);
 
 #ifdef EXEC_BACKEND
@@ -1209,6 +1213,9 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for)
 		fclose(syslogFile);
 		syslogFile = fh;
 
+		/* store information about current log filename used by log collection */
+		store_current_log_filename(filename);
+
 		/* instead of pfree'ing filename, remember it for next time */
 		if (last_file_name != NULL)
 			pfree(last_file_name);
@@ -1253,6 +1260,9 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for)
 		fclose(csvlogFile);
 		csvlogFile = fh;
 
+		/* store information about current log filename used by log collection */
+		store_current_log_filename(csvfilename);
+
 		/* instead of pfree'ing filename, remember it for next time */
 		if (last_csv_file_name != NULL)
 			pfree(last_csv_file_name);
@@ -1362,3 +1372,35 @@ sigUsr1Handler(SIGNAL_ARGS)
 
 	errno = save_errno;
 }
+
+/*
+ * Store the name of the file where current log messages are written when
+ * log collector is enabled. Useful to find the name of the current log file
+ * when a time-based rotation is defined. 
+ */
+static void
+store_current_log_filename(char *filename)
+{
+	FILE       *fh;
+	char        logpathfilename[MAXPGPATH];
+
+	snprintf(logpathfilename, sizeof(logpathfilename), "%s",
+						 CURRENT_LOG_FILENAME);
+	if ((fh = fopen(logpathfilename, "w")) == NULL)
+	{
+		ereport(ERROR,
+				(errcode_for_file_access(),
+				errmsg("could not open log file \"%s\": %m",
+						logpathfilename)));
+		return;
+	}
+	if (fprintf(fh, "%s\n", filename) < 0)
+	{
+		ereport(ERROR,
+				(errcode_for_file_access(),
+				errmsg("could not write log file \"%s\": %m",
+						logpathfilename)));
+	}
+	fclose(fh);
+}
+
diff --git a/src/backend/utils/adt/misc.c b/src/backend/utils/adt/misc.c
index 43f36db..d9b6435 100644
--- a/src/backend/utils/adt/misc.c
+++ b/src/backend/utils/adt/misc.c
@@ -719,3 +719,62 @@ pg_column_is_updatable(PG_FUNCTION_ARGS)
 
 	PG_RETURN_BOOL((events & REQ_EVENTS) == REQ_EVENTS);
 }
+
+/*
+ * Report current log file used by log collector
+ */
+Datum
+pg_current_logfile(PG_FUNCTION_ARGS)
+{
+	FILE	*fd;
+	char	log_filename[MAXPGPATH];
+
+	if (!Logging_collector)
+	{
+		ereport(WARNING,
+		(errmsg("current log can not be reported because log collection is not active")));
+		PG_RETURN_NULL();
+	}
+
+	/*
+	 * See if current log file is present
+	 */
+	fd = AllocateFile(CURRENT_LOG_FILENAME, "r");
+	if (fd == NULL)
+	{
+		if (errno != ENOENT)
+			ereport(ERROR,
+					(errcode_for_file_access(),
+					 errmsg("could not read file \"%s\": %m",
+							CURRENT_LOG_FILENAME)));
+		PG_RETURN_NULL();
+	}
+
+	/*
+	 * Read first line of the file to gather current log filename
+	 * registered by the syslogger.
+	 */
+	fgets(log_filename, sizeof(log_filename), fd);
+
+	/* Check for a read error. */
+	if (ferror(fd))
+		ereport(ERROR,
+				(errcode_for_file_access(),
+			   errmsg("could not read file \"%s\": %m", CURRENT_LOG_FILENAME)));
+
+	/* Close the current log filename file. */
+	if (FreeFile(fd))
+		ereport(ERROR,
+				(errcode_for_file_access(),
+			  errmsg("could not close file \"%s\": %m", CURRENT_LOG_FILENAME)));
+
+	/* remove trailing newline */
+	if (strchr(log_filename, '\n') != NULL)
+		*strchr(log_filename, '\n') = '\0';
+
+	if (log_filename[0] == '\0')
+		PG_RETURN_NULL();
+
+	PG_RETURN_TEXT_P(cstring_to_text(log_filename));
+}
+
diff --git a/src/include/catalog/pg_proc.h b/src/include/catalog/pg_proc.h
index 451bad7..0dc44cf 100644
--- a/src/include/catalog/pg_proc.h
+++ b/src/include/catalog/pg_proc.h
@@ -3125,6 +3125,8 @@ DATA(insert OID = 2621 ( pg_reload_conf			PGNSP PGUID 12 1 0 0 0 f f f f t f v s
 DESCR("reload configuration files");
 DATA(insert OID = 2622 ( pg_rotate_logfile		PGNSP PGUID 12 1 0 0 0 f f f f t f v s 0 0 16 "" _null_ _null_ _null_ _null_ _null_ pg_rotate_logfile _null_ _null_ _null_ ));
 DESCR("rotate log file");
+DATA(insert OID = 3794 ( pg_current_logfile            PGNSP PGUID 12 1 0 0 0 f f f f t f v s 0 0 25 "" _null_ _null_ _null_ _null_ _null_ pg_current_logfile _null_ _null_ _null_ ));
+DESCR("current logging collector file location");
 
 DATA(insert OID = 2623 ( pg_stat_file		PGNSP PGUID 12 1 0 0 0 f f f f t f v s 1 0 2249 "25" "{25,20,1184,1184,1184,1184,16}" "{i,o,o,o,o,o,o}" "{filename,size,access,modification,change,creation,isdir}" _null_ _null_ pg_stat_file_1arg _null_ _null_ _null_ ));
 DESCR("get information about file");
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index cc7833e..5a388ba 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -464,4 +464,13 @@ extern bool has_rolreplication(Oid roleid);
 extern bool BackupInProgress(void);
 extern void CancelBackup(void);
 
+/* in backend/utils/adt/misc.c and backend/postmaster/syslogger.c */
+/*
+ * Name of file where current log messages are written when log collector is
+ * enabled. Useful to find the name of the current log file when a time-based
+ * rotation is defined.
+ */
+#define CURRENT_LOG_FILENAME  "pg_log_filename"
+
+
 #endif   /* MISCADMIN_H */
diff --git a/src/include/utils/builtins.h b/src/include/utils/builtins.h
index 115f8af..fd2c4ea 100644
--- a/src/include/utils/builtins.h
+++ b/src/include/utils/builtins.h
@@ -509,6 +509,7 @@ extern Datum pg_typeof(PG_FUNCTION_ARGS);
 extern Datum pg_collation_for(PG_FUNCTION_ARGS);
 extern Datum pg_relation_is_updatable(PG_FUNCTION_ARGS);
 extern Datum pg_column_is_updatable(PG_FUNCTION_ARGS);
+extern Datum pg_current_logfile(PG_FUNCTION_ARGS);
 
 /* oid.c */
 extern Datum oidin(PG_FUNCTION_ARGS);

diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index ae93e69..155e76b 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -15158,6 +15158,11 @@ SELECT * FROM pg_ls_dir('.') WITH ORDINALITY AS t(ls,n);
        (0 if not called, directly or indirectly, from inside a trigger)</entry>
       </row>
 
+      <entry><literal><function>pg_current_logfile()</function></literal></entry>
+       <entry><type>text</type></entry>
+       <entry>current log file used by the logging collector</entry>
+      </row>
+
       <row>
        <entry><literal><function>session_user</function></literal></entry>
        <entry><type>name</type></entry>
@@ -15365,6 +15370,16 @@ SET search_path TO <replaceable>schema</> <optional>, <replaceable>schema</>, ..
     <primary>pg_notification_queue_usage</primary>
    </indexterm>
 
+   <indexterm>
+    <primary>pg_current_logfile</primary>
+   </indexterm>
+
+   <para>
+    <function>pg_current_logfile</function> returns the name of the current log
+    file used by the logging collector, as a <type>text</type>. Log collection
+    must be active.
+   </para>
+
    <para>
     <function>pg_listening_channels</function> returns a set of names of
     asynchronous notification channels that the current session is listening
diff --git a/doc/src/sgml/storage.sgml b/doc/src/sgml/storage.sgml
index 9b2e09e..6284d54 100644
--- a/doc/src/sgml/storage.sgml
+++ b/doc/src/sgml/storage.sgml
@@ -170,6 +170,13 @@ last started with</entry>
   (this file is not present after server shutdown)</entry>
 </row>
 
+<row>
+ <entry><filename>pg_log_file</></entry>
+ <entry>A file recording the current log file used by the syslogger
+  when log collection is active</entry>
+</row>
+
+
 </tbody>
 </tgroup>
 </table>
diff --git a/src/backend/postmaster/syslogger.c b/src/backend/postmaster/syslogger.c
index e7e488a..c3bf672 100644
--- a/src/backend/postmaster/syslogger.c
+++ b/src/backend/postmaster/syslogger.c
@@ -145,6 +145,7 @@ static char *logfile_getname(pg_time_t timestamp, const char *suffix);
 static void set_next_rotation_time(void);
 static void sigHupHandler(SIGNAL_ARGS);
 static void sigUsr1Handler(SIGNAL_ARGS);
+static void store_current_log_filename(char *filename);
 
 
 /*
@@ -571,6 +572,9 @@ SysLogger_Start(void)
 
 	syslogFile = logfile_open(filename, "a", false);
 
+	/* store information about current log filename used by log collection */
+	store_current_log_filename(filename);
+
 	pfree(filename);
 
 #ifdef EXEC_BACKEND
@@ -1209,6 +1213,9 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for)
 		fclose(syslogFile);
 		syslogFile = fh;
 
+		/* store information about current log filename used by log collection */
+		store_current_log_filename(filename);
+
 		/* instead of pfree'ing filename, remember it for next time */
 		if (last_file_name != NULL)
 			pfree(last_file_name);
@@ -1253,6 +1260,9 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for)
 		fclose(csvlogFile);
 		csvlogFile = fh;
 
+		/* store information about current log filename used by log collection */
+		store_current_log_filename(csvfilename);
+
 		/* instead of pfree'ing filename, remember it for next time */
 		if (last_csv_file_name != NULL)
 			pfree(last_csv_file_name);
@@ -1362,3 +1372,35 @@ sigUsr1Handler(SIGNAL_ARGS)
 
 	errno = save_errno;
 }
+
+
+/*
+ * Store the name of the file where current log messages are written when
+ * log collector is enabled. Useful to find the name of the current log file
+ * when a time-based rotation is defined. 
+ */
+static void
+store_current_log_filename(char *filename)
+{
+	FILE       *fh;
+	char        logpathfilename[MAXPGPATH];
+
+	snprintf(logpathfilename, sizeof(logpathfilename), "%s",
+						CURRENT_LOG_FILENAME);
+	if ((fh = fopen(logpathfilename, "w")) == NULL)
+	{
+	       ereport(WARNING,
+			       (errcode_for_file_access(),
+			       errmsg("could not open log file \"%s\": %m",
+					       logpathfilename)));
+	       return;
+	}
+	if (fprintf(fh, "%s\n", filename) < 0)
+	{
+	       ereport(WARNING,
+			       (errcode_for_file_access(),
+			       errmsg("could not write log file \"%s\": %m",
+					       logpathfilename)));
+	}
+	fclose(fh);
+}
diff --git a/src/backend/utils/adt/misc.c b/src/backend/utils/adt/misc.c
index 4dcc5a6..fbcd1d4 100644
--- a/src/backend/utils/adt/misc.c
+++ b/src/backend/utils/adt/misc.c
@@ -943,3 +943,61 @@ parse_ident(PG_FUNCTION_ARGS)
 
 	PG_RETURN_DATUM(makeArrayResult(astate, CurrentMemoryContext));
 }
+
+/*
+ * Report current log file used by log collector
+ */
+Datum
+pg_current_logfile(PG_FUNCTION_ARGS)
+{
+	FILE    *fd;
+	char    log_filename[MAXPGPATH];
+
+	if (!Logging_collector)
+	{
+		ereport(NOTICE,
+		(errmsg("current log can not be reported, log collection is not active")));
+		PG_RETURN_NULL();
+	}
+
+	/*
+	* See if current log file is present
+	*/
+	fd = AllocateFile(CURRENT_LOG_FILENAME, "r");
+	if (fd == NULL)
+	{
+		if (errno != ENOENT)
+			ereport(ERROR,
+					(errcode_for_file_access(),
+				errmsg("could not read file \"%s\": %m",
+					CURRENT_LOG_FILENAME)));
+		PG_RETURN_NULL();
+	}
+
+	/*
+	* Read first line of the file to gather current log filename
+	* registered by the syslogger.
+	*/
+	fgets(log_filename, sizeof(log_filename), fd);
+
+	/* Check for a read error. */
+	if (ferror(fd))
+		ereport(ERROR,
+				(errcode_for_file_access(),
+			errmsg("could not read file \"%s\": %m", CURRENT_LOG_FILENAME)));
+
+	/* Close the current log filename file. */
+	if (FreeFile(fd))
+		ereport(ERROR,
+				(errcode_for_file_access(),
+			errmsg("could not close file \"%s\": %m", CURRENT_LOG_FILENAME)));
+
+	/* remove trailing newline */
+	if (strchr(log_filename, '\n') != NULL)
+		*strchr(log_filename, '\n') = '\0';
+
+	if (log_filename[0] == '\0')
+		PG_RETURN_NULL();
+
+	PG_RETURN_TEXT_P(cstring_to_text(log_filename));
+}
diff --git a/src/include/catalog/pg_proc.h b/src/include/catalog/pg_proc.h
index a595327..f0caf6f 100644
--- a/src/include/catalog/pg_proc.h
+++ b/src/include/catalog/pg_proc.h
@@ -3125,6 +3125,8 @@ DATA(insert OID = 2621 ( pg_reload_conf			PGNSP PGUID 12 1 0 0 0 f f f f t f v s
 DESCR("reload configuration files");
 DATA(insert OID = 2622 ( pg_rotate_logfile		PGNSP PGUID 12 1 0 0 0 f f f f t f v s 0 0 16 "" _null_ _null_ _null_ _null_ _null_ pg_rotate_logfile _null_ _null_ _null_ ));
 DESCR("rotate log file");
+DATA(insert OID = 3794 ( pg_current_logfile		PGNSP PGUID 12 1 0 0 0 f f f f t f v s 0 0 25 "" _null_ _null_ _null_ _null_ _null_ pg_current_logfile _null_ _null_ _null_ ));
+DESCR("current logging collector file location");
 
 DATA(insert OID = 2623 ( pg_stat_file		PGNSP PGUID 12 1 0 0 0 f f f f t f v s 1 0 2249 "25" "{25,20,1184,1184,1184,1184,16}" "{i,o,o,o,o,o,o}" "{filename,size,access,modification,change,creation,isdir}" _null_ _null_ pg_stat_file_1arg _null_ _null_ _null_ ));
 DESCR("get information about file");
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 9200f04..a25cd5e 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -465,4 +465,12 @@ extern bool has_rolreplication(Oid roleid);
 extern bool BackupInProgress(void);
 extern void CancelBackup(void);
 
+/* in backend/utils/adt/misc.c and backend/postmaster/syslogger.c */
+/*
+ * Name of file where current log messages are written when log collector is
+ * enabled. Useful to find the name of the current log file when a time-based
+ * rotation is defined.
+ */
+#define CURRENT_LOG_FILENAME  "pg_log_file"
+
 #endif   /* MISCADMIN_H */
diff --git a/src/include/utils/builtins.h b/src/include/utils/builtins.h
index 206288d..bdc3922 100644
--- a/src/include/utils/builtins.h
+++ b/src/include/utils/builtins.h
@@ -511,6 +511,7 @@ extern Datum pg_collation_for(PG_FUNCTION_ARGS);
 extern Datum pg_relation_is_updatable(PG_FUNCTION_ARGS);
 extern Datum pg_column_is_updatable(PG_FUNCTION_ARGS);
 extern Datum parse_ident(PG_FUNCTION_ARGS);
+extern Datum pg_current_logfile(PG_FUNCTION_ARGS);
 
 /* oid.c */
 extern Datum oidin(PG_FUNCTION_ARGS);

diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 3f627dc..7100881 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -15293,6 +15293,12 @@ SELECT * FROM pg_ls_dir('.') WITH ORDINALITY AS t(ls,n);
       </row>
 
       <row>
+       <entry><literal><function>pg_current_logfile()</function></literal></entry>
+       <entry><type>text</type></entry>
+       <entry>current log file used by the logging collector</entry>
+      </row>
+
+      <row>
        <entry><literal><function>session_user</function></literal></entry>
        <entry><type>name</type></entry>
        <entry>session user name</entry>
@@ -15499,6 +15505,17 @@ SET search_path TO <replaceable>schema</> <optional>, <replaceable>schema</>, ..
     <primary>pg_notification_queue_usage</primary>
    </indexterm>
 
+   <indexterm>
+    <primary>pg_current_logfile</primary>
+   </indexterm>
+
+   <para>
+    <function>pg_current_logfile</function> returns the name of the
+    current log file used by the logging collector, as
+    <type>text</type>. Log collection must be active or the
+    return value is undefined.
+   </para>
+
    <para>
     <function>pg_listening_channels</function> returns a set of names of
     asynchronous notification channels that the current session is listening
diff --git a/doc/src/sgml/storage.sgml b/doc/src/sgml/storage.sgml
index 1b812bd..7dae000 100644
--- a/doc/src/sgml/storage.sgml
+++ b/doc/src/sgml/storage.sgml
@@ -170,6 +170,13 @@ last started with</entry>
   (this file is not present after server shutdown)</entry>
 </row>
 
+<row>
+ <entry><filename>pg_log_file</></entry>
+ <entry>A file recording the current log file used by the syslogger
+  when log collection is active</entry>
+</row>
+
+
 </tbody>
 </tgroup>
 </table>
diff --git a/src/backend/postmaster/syslogger.c b/src/backend/postmaster/syslogger.c
index e7e488a..0e25aa6 100644
--- a/src/backend/postmaster/syslogger.c
+++ b/src/backend/postmaster/syslogger.c
@@ -145,6 +145,7 @@ static char *logfile_getname(pg_time_t timestamp, const char *suffix);
 static void set_next_rotation_time(void);
 static void sigHupHandler(SIGNAL_ARGS);
 static void sigUsr1Handler(SIGNAL_ARGS);
+static void logfile_writename(char *filename);
 
 
 /*
@@ -571,6 +572,8 @@ SysLogger_Start(void)
 
 	syslogFile = logfile_open(filename, "a", false);
 
+	logfile_writename(filename);
+
 	pfree(filename);
 
 #ifdef EXEC_BACKEND
@@ -1209,6 +1212,8 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for)
 		fclose(syslogFile);
 		syslogFile = fh;
 
+		logfile_writename(filename);
+
 		/* instead of pfree'ing filename, remember it for next time */
 		if (last_file_name != NULL)
 			pfree(last_file_name);
@@ -1253,6 +1258,8 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for)
 		fclose(csvlogFile);
 		csvlogFile = fh;
 
+		logfile_writename(csvfilename);
+
 		/* instead of pfree'ing filename, remember it for next time */
 		if (last_csv_file_name != NULL)
 			pfree(last_csv_file_name);
@@ -1362,3 +1369,47 @@ sigUsr1Handler(SIGNAL_ARGS)
 
 	errno = save_errno;
 }
+
+
+/*
+ * Store the name of the file where current log messages are written when
+ * log collector is enabled. Useful to find the name of the current log file
+ * when a time-based rotation is defined. Filename is first stored into a
+ * temporary file and renamed into the final destination.
+ */
+static void
+logfile_writename(char *filename)
+{
+	FILE	*fh;
+	char	tempfn[MAXPGPATH];
+	char	logpathfilename[MAXPGPATH];
+
+	snprintf(tempfn, sizeof(tempfn), "%s",
+						CURRENT_LOG_FILENAME);
+	strcat(tempfn, ".tmp");
+	snprintf(logpathfilename, sizeof(logpathfilename), "%s",
+						CURRENT_LOG_FILENAME);
+	if ((fh = logfile_open(tempfn, "w", true) ) == NULL)
+	{
+		return;
+	}
+	if (fprintf(fh, "%s\n", filename) < 0)
+	{
+		ereport(LOG,
+				(errcode_for_file_access(),
+				errmsg("could not write log file \"%s\": %m",
+					tempfn)));
+		fclose(fh);
+		return;
+	}
+	fclose(fh);
+
+	if (rename(tempfn, logpathfilename) != 0)
+	{
+		ereport(LOG,
+				(errcode_for_file_access(),
+				errmsg("could not rename file \"%s\": %m",
+						tempfn)));
+		return;
+	}
+}
diff --git a/src/backend/utils/adt/misc.c b/src/backend/utils/adt/misc.c
index a44fa38..c67e07b 100644
--- a/src/backend/utils/adt/misc.c
+++ b/src/backend/utils/adt/misc.c
@@ -890,3 +890,59 @@ parse_ident(PG_FUNCTION_ARGS)
 
 	PG_RETURN_DATUM(makeArrayResult(astate, CurrentMemoryContext));
 }
+
+/*
+ * Report current log file used by log collector
+ */
+Datum
+pg_current_logfile(PG_FUNCTION_ARGS)
+{
+	FILE    *fd;
+	char    log_filename[MAXPGPATH];
+
+	if (!Logging_collector)
+	{
+		PG_RETURN_NULL();
+	}
+
+	/*
+	* See if current log file is present
+	*/
+	fd = AllocateFile(CURRENT_LOG_FILENAME, "r");
+	if (fd == NULL)
+	{
+		if (errno != ENOENT)
+			ereport(ERROR,
+					(errcode_for_file_access(),
+				errmsg("could not read file \"%s\": %m",
+					CURRENT_LOG_FILENAME)));
+		PG_RETURN_NULL();
+	}
+
+	/*
+	* Read first line of the file to gather current log filename
+	* registered by the syslogger.
+	*/
+	fgets(log_filename, sizeof(log_filename), fd);
+
+	/* Check for a read error. */
+	if (ferror(fd))
+		ereport(ERROR,
+				(errcode_for_file_access(),
+			errmsg("could not read file \"%s\": %m", CURRENT_LOG_FILENAME)));
+
+	/* Close the current log filename file. */
+	if (FreeFile(fd))
+		ereport(ERROR,
+				(errcode_for_file_access(),
+			errmsg("could not close file \"%s\": %m", CURRENT_LOG_FILENAME)));
+
+	/* remove trailing newline */
+	if (strchr(log_filename, '\n') != NULL)
+		*strchr(log_filename, '\n') = '\0';
+
+	if (log_filename[0] == '\0')
+		PG_RETURN_NULL();
+
+	PG_RETURN_TEXT_P(cstring_to_text(log_filename));
+}
diff --git a/src/include/catalog/pg_proc.h b/src/include/catalog/pg_proc.h
index d94943b..32b419a 100644
--- a/src/include/catalog/pg_proc.h
+++ b/src/include/catalog/pg_proc.h
@@ -3159,6 +3159,8 @@ DATA(insert OID = 2621 ( pg_reload_conf			PGNSP PGUID 12 1 0 0 0 f f f f t f v s
 DESCR("reload configuration files");
 DATA(insert OID = 2622 ( pg_rotate_logfile		PGNSP PGUID 12 1 0 0 0 f f f f t f v s 0 0 16 "" _null_ _null_ _null_ _null_ _null_ pg_rotate_logfile _null_ _null_ _null_ ));
 DESCR("rotate log file");
+DATA(insert OID = 3794 ( pg_current_logfile		PGNSP PGUID 12 1 0 0 0 f f f f t f v s 0 0 25 "" _null_ _null_ _null_ _null_ _null_ pg_current_logfile _null_ _null_ _null_ ));
+DESCR("current logging collector file location");
 
 DATA(insert OID = 2623 ( pg_stat_file		PGNSP PGUID 12 1 0 0 0 f f f f t f v s 1 0 2249 "25" "{25,20,1184,1184,1184,1184,16}" "{i,o,o,o,o,o,o}" "{filename,size,access,modification,change,creation,isdir}" _null_ _null_ pg_stat_file_1arg _null_ _null_ _null_ ));
 DESCR("get information about file");
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 356fcc6..4b3f0e9 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -466,4 +466,12 @@ extern bool has_rolreplication(Oid roleid);
 extern bool BackupInProgress(void);
 extern void CancelBackup(void);
 
+/* in backend/utils/adt/misc.c and backend/postmaster/syslogger.c */
+/*
+ * Name of file where current log messages are written when log collector is
+ * enabled. Useful to find the name of the current log file when a time-based
+ * rotation is defined.
+ */
+#define CURRENT_LOG_FILENAME  "pg_log_file"
+
 #endif   /* MISCADMIN_H */
diff --git a/src/include/utils/builtins.h b/src/include/utils/builtins.h
index 01976a1..c27f6a8 100644
--- a/src/include/utils/builtins.h
+++ b/src/include/utils/builtins.h
@@ -516,6 +516,7 @@ extern Datum pg_collation_for(PG_FUNCTION_ARGS);
 extern Datum pg_relation_is_updatable(PG_FUNCTION_ARGS);
 extern Datum pg_column_is_updatable(PG_FUNCTION_ARGS);
 extern Datum parse_ident(PG_FUNCTION_ARGS);
+extern Datum pg_current_logfile(PG_FUNCTION_ARGS);
 
 /* oid.c */
 extern Datum oidin(PG_FUNCTION_ARGS);

diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index a588350..69a74af 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -15480,6 +15480,12 @@ SELECT * FROM pg_ls_dir('.') WITH ORDINALITY AS t(ls,n);
       </row>
 
       <row>
+       <entry><literal><function>pg_current_logfile()</function></literal></entry>
+       <entry><type>setof record</type></entry>
+       <entry>current log file(s) used by the logging collector</entry>
+      </row>
+
+      <row>
        <entry><literal><function>session_user</function></literal></entry>
        <entry><type>name</type></entry>
        <entry>session user name</entry>
@@ -15686,6 +15692,17 @@ SET search_path TO <replaceable>schema</> <optional>, <replaceable>schema</>, ..
     <primary>pg_notification_queue_usage</primary>
    </indexterm>
 
+   <indexterm>
+    <primary>pg_current_logfile</primary>
+   </indexterm>
+
+   <para>
+    <function>pg_current_logfile</function> returns the names of the
+    current log files used by the logging collector, as
+    <type>setof record</type>. Log collection must be active or the
+    return value is undefined.
+   </para>
+
    <para>
     <function>pg_listening_channels</function> returns a set of names of
     asynchronous notification channels that the current session is listening
diff --git a/doc/src/sgml/storage.sgml b/doc/src/sgml/storage.sgml
index 1b812bd..8f909a7 100644
--- a/doc/src/sgml/storage.sgml
+++ b/doc/src/sgml/storage.sgml
@@ -170,6 +170,13 @@ last started with</entry>
   (this file is not present after server shutdown)</entry>
 </row>
 
+<row>
+ <entry><filename>pg_log_file</></entry>
+ <entry>A file recording the current log file(s) used by the syslogger
+  when log collection is active (this file is not present when logging_collector is not activated)</entry>
+</row>
+
+
 </tbody>
 </tgroup>
 </table>
diff --git a/src/backend/postmaster/syslogger.c b/src/backend/postmaster/syslogger.c
index fd62d66..7b09349 100644
--- a/src/backend/postmaster/syslogger.c
+++ b/src/backend/postmaster/syslogger.c
@@ -146,6 +146,7 @@ static char *logfile_getname(pg_time_t timestamp, const char *suffix);
 static void set_next_rotation_time(void);
 static void sigHupHandler(SIGNAL_ARGS);
 static void sigUsr1Handler(SIGNAL_ARGS);
+static void logfile_writename(char *filename, char *csvfilename);
 
 
 /*
@@ -348,6 +349,13 @@ SysLoggerMain(int argc, char *argv[])
 				rotation_disabled = false;
 				rotation_requested = true;
 			}
+
+			/*
+			 * Force rewriting last log filename when reloading configuration,
+			 * log_destination and logging_collector may have been changed. Do
+			 * it right now to not wait for the next file rotation.
+			 */
+			logfile_writename(last_file_name, last_csv_file_name);
 		}
 
 		if (Log_RotationAge > 0 && !rotation_disabled)
@@ -513,8 +521,14 @@ SysLogger_Start(void)
 	pid_t		sysloggerPid;
 	char	   *filename;
 
-	if (!Logging_collector)
+	if (!Logging_collector) {
+		/* If logging collector is not enabled, remove current log
+		 * filename as we don't know where messages are logged and
+		 * information contained in this file are obsolete.
+		 */
+		unlink(CURRENT_LOG_FILENAME);
 		return 0;
+	}
 
 	/*
 	 * If first time through, create the pipe which will receive stderr
@@ -574,6 +588,8 @@ SysLogger_Start(void)
 
 	syslogFile = logfile_open(filename, "a", false);
 
+	logfile_writename(filename, NULL);
+
 	pfree(filename);
 
 #ifdef EXEC_BACKEND
@@ -988,8 +1004,10 @@ write_syslogger_file(const char *buffer, int count, int destination)
 	int			rc;
 	FILE	   *logfile;
 
-	if (destination == LOG_DESTINATION_CSVLOG && csvlogFile == NULL)
+	if (destination == LOG_DESTINATION_CSVLOG && csvlogFile == NULL) {
 		open_csvlogfile();
+		logfile_writename(last_file_name, last_csv_file_name);
+	}
 
 	logfile = destination == LOG_DESTINATION_CSVLOG ? csvlogFile : syslogFile;
 	rc = fwrite(buffer, 1, count, logfile);
@@ -1209,6 +1227,8 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for)
 			return;
 		}
 
+		logfile_writename(filename, csvfilename);
+
 		fclose(syslogFile);
 		syslogFile = fh;
 
@@ -1220,7 +1240,6 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for)
 	}
 
 	/* Same as above, but for csv file. */
-
 	if (csvlogFile != NULL &&
 		(time_based_rotation || (size_rotation_for & LOG_DESTINATION_CSVLOG)))
 	{
@@ -1253,6 +1272,8 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for)
 			return;
 		}
 
+		logfile_writename(last_file_name, csvfilename);
+
 		fclose(csvlogFile);
 		csvlogFile = fh;
 
@@ -1365,3 +1386,60 @@ sigUsr1Handler(SIGNAL_ARGS)
 
 	errno = save_errno;
 }
+
+/*
+ * Store the name of the files where current log messages are written when
+ * log collector is enabled. Useful to find the name of the current log file
+ * when a time-based rotation is defined. Filenames are first stored into a
+ * temporary file and renamed into the final destination.
+ */
+static void
+logfile_writename(char *filename, char *csvfilename)
+{
+	FILE	*fh;
+	char	tempfn[MAXPGPATH];
+	char	logpathfilename[MAXPGPATH];
+
+	snprintf(tempfn, sizeof(tempfn), "%s",
+						CURRENT_LOG_FILENAME);
+	strcat(tempfn, ".tmp");
+	snprintf(logpathfilename, sizeof(logpathfilename), "%s",
+						CURRENT_LOG_FILENAME);
+	if ((fh = logfile_open(tempfn, "w", true) ) == NULL)
+	{
+		return;
+	}
+	if (filename && (Log_destination & LOG_DESTINATION_STDERR)) {
+		if (fprintf(fh, "%s\n", filename) < 0)
+		{
+			ereport(LOG,
+					(errcode_for_file_access(),
+					errmsg("could not write log file \"%s\": %m",
+						tempfn)));
+			fclose(fh);
+			return;
+		}
+	}
+
+	if (csvfilename && (Log_destination & LOG_DESTINATION_CSVLOG)) {
+		if (fprintf(fh, "%s\n", csvfilename) < 0)
+		{
+			ereport(LOG,
+					(errcode_for_file_access(),
+					errmsg("could not write log file \"%s\": %m",
+						tempfn)));
+			fclose(fh);
+			return;
+		}
+	}
+	fclose(fh);
+
+	if (rename(tempfn, logpathfilename) != 0)
+	{
+		ereport(LOG,
+				(errcode_for_file_access(),
+				errmsg("could not rename file \"%s\": %m",
+						tempfn)));
+		return;
+	}
+}
diff --git a/src/backend/utils/adt/misc.c b/src/backend/utils/adt/misc.c
index 0da051a..3b0f38a 100644
--- a/src/backend/utils/adt/misc.c
+++ b/src/backend/utils/adt/misc.c
@@ -892,3 +892,79 @@ parse_ident(PG_FUNCTION_ARGS)
 
 	PG_RETURN_DATUM(makeArrayResult(astate, CurrentMemoryContext));
 }
+
+/*
+ * Report current log file used by log collector
+ */
+typedef struct
+{
+        char      *location;
+	FILE      *filedesc;
+	
+} logfilename_fctx;
+
+
+Datum
+pg_current_logfile(PG_FUNCTION_ARGS)
+{
+	FuncCallContext *funcctx;
+	char      log_filename[MAXPGPATH];
+	logfilename_fctx *fctx;
+	MemoryContext oldcontext;
+
+	if (!Logging_collector)
+		PG_RETURN_NULL();
+
+	if (SRF_IS_FIRSTCALL())
+	{
+		funcctx = SRF_FIRSTCALL_INIT();
+		oldcontext = MemoryContextSwitchTo(funcctx->multi_call_memory_ctx);
+
+		fctx = palloc(sizeof(logfilename_fctx));
+		fctx->location = CURRENT_LOG_FILENAME;
+		fctx->filedesc = AllocateFile(fctx->location, "r");
+
+		if (!fctx->filedesc)
+		{
+			if (errno != ENOENT)
+				ereport(ERROR,
+						(errcode_for_file_access(),
+					errmsg("could not read file \"%s\": %m",
+						fctx->location)));
+		}
+
+		funcctx->user_fctx = fctx;
+		MemoryContextSwitchTo(oldcontext);
+	}
+
+	funcctx = SRF_PERCALL_SETUP();
+	fctx = (logfilename_fctx *) funcctx->user_fctx;
+
+	/*
+	* Read first line of the file to gather current log filename
+	* registered by the syslogger.
+	*/
+	while (fgets(log_filename, sizeof(log_filename), fctx->filedesc) != NULL) {
+
+		/* Check for a read error. */
+		if (ferror(fctx->filedesc)) {
+			ereport(ERROR,
+					(errcode_for_file_access(),
+				errmsg("could not read file \"%s\": %m", fctx->location)));
+			break;
+		}
+
+		/* remove trailing newline */
+		if (strchr(log_filename, '\n') != NULL)
+			*strchr(log_filename, '\n') = '\0';
+
+		if (log_filename[0] == '\0')
+			break;
+
+		 SRF_RETURN_NEXT(funcctx, CStringGetTextDatum(log_filename));
+	}
+	FreeFile(fctx->filedesc);
+
+	SRF_RETURN_DONE(funcctx);
+}
+
diff --git a/src/include/catalog/pg_proc.h b/src/include/catalog/pg_proc.h
index e2d08ba..79a5a1d 100644
--- a/src/include/catalog/pg_proc.h
+++ b/src/include/catalog/pg_proc.h
@@ -3182,6 +3182,8 @@ DATA(insert OID = 2621 ( pg_reload_conf			PGNSP PGUID 12 1 0 0 0 f f f f t f v s
 DESCR("reload configuration files");
 DATA(insert OID = 2622 ( pg_rotate_logfile		PGNSP PGUID 12 1 0 0 0 f f f f t f v s 0 0 16 "" _null_ _null_ _null_ _null_ _null_ pg_rotate_logfile _null_ _null_ _null_ ));
 DESCR("rotate log file");
+DATA(insert OID = 3800 (  pg_current_logfile		PGNSP PGUID 12 1 0 0 0    f f f f t t v s 0 0 25 "" _null_ _null_ _null_ _null_ _null_ pg_current_logfile _null_ _null_ _null_ ));
+DESCR("current logging collector file location");
 
 DATA(insert OID = 2623 ( pg_stat_file		PGNSP PGUID 12 1 0 0 0 f f f f t f v s 1 0 2249 "25" "{25,20,1184,1184,1184,1184,16}" "{i,o,o,o,o,o,o}" "{filename,size,access,modification,change,creation,isdir}" _null_ _null_ pg_stat_file_1arg _null_ _null_ _null_ ));
 DESCR("get information about file");
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 78545da..15e1214 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -466,4 +466,12 @@ extern bool has_rolreplication(Oid roleid);
 extern bool BackupInProgress(void);
 extern void CancelBackup(void);
 
+/* in backend/utils/adt/misc.c and backend/postmaster/syslogger.c */
+/*
+ * Name of file where current log messages are written when log collector is
+ * enabled. Useful to find the name of the current log file when a time-based
+ * rotation is defined.
+ */
+#define CURRENT_LOG_FILENAME  "current_logfile"
+
 #endif   /* MISCADMIN_H */

diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index a588350..3cd9535 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -15480,6 +15480,12 @@ SELECT * FROM pg_ls_dir('.') WITH ORDINALITY AS t(ls,n);
       </row>
 
       <row>
+       <entry><literal><function>pg_current_logfile(<optional> <parameter>destination</> <type>text</></optional>)</function></literal></entry>
+       <entry><type>text</type></entry>
+       <entry>current log file used by the logging collector</entry>
+      </row>
+
+      <row>
        <entry><literal><function>session_user</function></literal></entry>
        <entry><type>name</type></entry>
        <entry>session user name</entry>
@@ -15686,6 +15692,23 @@ SET search_path TO <replaceable>schema</> <optional>, <replaceable>schema</>, ..
     <primary>pg_notification_queue_usage</primary>
    </indexterm>
 
+   <indexterm>
+    <primary>pg_current_logfile</primary>
+   </indexterm>
+
+   <para>
+    <function>pg_current_logfile</function> returns the name of the
+    current log file used by the logging collector, as <type>text</type>.
+    Log collection must be active or the return value is undefined. When
+    csvlog is used as log destination, the csv filename is returned, when
+    it is set to stderr, the stderr filename is returned. When both are
+    used, it returns the stderr filename.
+    There is an optional parameter of type <type>text</type> to determines
+    the log filename to return following the log destination, values can
+    be 'csvlog' or 'stderr'. When the log format asked is not used as log
+    destination then the return value is undefined.
+   </para>
+
    <para>
     <function>pg_listening_channels</function> returns a set of names of
     asynchronous notification channels that the current session is listening
diff --git a/doc/src/sgml/storage.sgml b/doc/src/sgml/storage.sgml
index 1b812bd..8f909a7 100644
--- a/doc/src/sgml/storage.sgml
+++ b/doc/src/sgml/storage.sgml
@@ -170,6 +170,13 @@ last started with</entry>
   (this file is not present after server shutdown)</entry>
 </row>
 
+<row>
+ <entry><filename>pg_log_file</></entry>
+ <entry>A file recording the current log file(s) used by the syslogger
+  when log collection is active (this file is not present when logging_collector is not activated)</entry>
+</row>
+
+
 </tbody>
 </tgroup>
 </table>
diff --git a/src/backend/postmaster/syslogger.c b/src/backend/postmaster/syslogger.c
index fd62d66..7b09349 100644
--- a/src/backend/postmaster/syslogger.c
+++ b/src/backend/postmaster/syslogger.c
@@ -146,6 +146,7 @@ static char *logfile_getname(pg_time_t timestamp, const char *suffix);
 static void set_next_rotation_time(void);
 static void sigHupHandler(SIGNAL_ARGS);
 static void sigUsr1Handler(SIGNAL_ARGS);
+static void logfile_writename(char *filename, char *csvfilename);
 
 
 /*
@@ -348,6 +349,13 @@ SysLoggerMain(int argc, char *argv[])
 				rotation_disabled = false;
 				rotation_requested = true;
 			}
+
+			/*
+			 * Force rewriting last log filename when reloading configuration,
+			 * log_destination and logging_collector may have been changed. Do
+			 * it right now to not wait for the next file rotation.
+			 */
+			logfile_writename(last_file_name, last_csv_file_name);
 		}
 
 		if (Log_RotationAge > 0 && !rotation_disabled)
@@ -513,8 +521,14 @@ SysLogger_Start(void)
 	pid_t		sysloggerPid;
 	char	   *filename;
 
-	if (!Logging_collector)
+	if (!Logging_collector) {
+		/* If logging collector is not enabled, remove current log
+		 * filename as we don't know where messages are logged and
+		 * information contained in this file are obsolete.
+		 */
+		unlink(CURRENT_LOG_FILENAME);
 		return 0;
+	}
 
 	/*
 	 * If first time through, create the pipe which will receive stderr
@@ -574,6 +588,8 @@ SysLogger_Start(void)
 
 	syslogFile = logfile_open(filename, "a", false);
 
+	logfile_writename(filename, NULL);
+
 	pfree(filename);
 
 #ifdef EXEC_BACKEND
@@ -988,8 +1004,10 @@ write_syslogger_file(const char *buffer, int count, int destination)
 	int			rc;
 	FILE	   *logfile;
 
-	if (destination == LOG_DESTINATION_CSVLOG && csvlogFile == NULL)
+	if (destination == LOG_DESTINATION_CSVLOG && csvlogFile == NULL) {
 		open_csvlogfile();
+		logfile_writename(last_file_name, last_csv_file_name);
+	}
 
 	logfile = destination == LOG_DESTINATION_CSVLOG ? csvlogFile : syslogFile;
 	rc = fwrite(buffer, 1, count, logfile);
@@ -1209,6 +1227,8 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for)
 			return;
 		}
 
+		logfile_writename(filename, csvfilename);
+
 		fclose(syslogFile);
 		syslogFile = fh;
 
@@ -1220,7 +1240,6 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for)
 	}
 
 	/* Same as above, but for csv file. */
-
 	if (csvlogFile != NULL &&
 		(time_based_rotation || (size_rotation_for & LOG_DESTINATION_CSVLOG)))
 	{
@@ -1253,6 +1272,8 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for)
 			return;
 		}
 
+		logfile_writename(last_file_name, csvfilename);
+
 		fclose(csvlogFile);
 		csvlogFile = fh;
 
@@ -1365,3 +1386,60 @@ sigUsr1Handler(SIGNAL_ARGS)
 
 	errno = save_errno;
 }
+
+/*
+ * Store the name of the files where current log messages are written when
+ * log collector is enabled. Useful to find the name of the current log file
+ * when a time-based rotation is defined. Filenames are first stored into a
+ * temporary file and renamed into the final destination.
+ */
+static void
+logfile_writename(char *filename, char *csvfilename)
+{
+	FILE	*fh;
+	char	tempfn[MAXPGPATH];
+	char	logpathfilename[MAXPGPATH];
+
+	snprintf(tempfn, sizeof(tempfn), "%s",
+						CURRENT_LOG_FILENAME);
+	strcat(tempfn, ".tmp");
+	snprintf(logpathfilename, sizeof(logpathfilename), "%s",
+						CURRENT_LOG_FILENAME);
+	if ((fh = logfile_open(tempfn, "w", true) ) == NULL)
+	{
+		return;
+	}
+	if (filename && (Log_destination & LOG_DESTINATION_STDERR)) {
+		if (fprintf(fh, "%s\n", filename) < 0)
+		{
+			ereport(LOG,
+					(errcode_for_file_access(),
+					errmsg("could not write log file \"%s\": %m",
+						tempfn)));
+			fclose(fh);
+			return;
+		}
+	}
+
+	if (csvfilename && (Log_destination & LOG_DESTINATION_CSVLOG)) {
+		if (fprintf(fh, "%s\n", csvfilename) < 0)
+		{
+			ereport(LOG,
+					(errcode_for_file_access(),
+					errmsg("could not write log file \"%s\": %m",
+						tempfn)));
+			fclose(fh);
+			return;
+		}
+	}
+	fclose(fh);
+
+	if (rename(tempfn, logpathfilename) != 0)
+	{
+		ereport(LOG,
+				(errcode_for_file_access(),
+				errmsg("could not rename file \"%s\": %m",
+						tempfn)));
+		return;
+	}
+}
diff --git a/src/backend/utils/adt/misc.c b/src/backend/utils/adt/misc.c
index 0da051a..6763055 100644
--- a/src/backend/utils/adt/misc.c
+++ b/src/backend/utils/adt/misc.c
@@ -19,6 +19,7 @@
 #include <dirent.h>
 #include <math.h>
 #include <unistd.h>
+#include <sys/stat.h>
 
 #include "access/sysattr.h"
 #include "catalog/pg_authid.h"
@@ -892,3 +893,122 @@ parse_ident(PG_FUNCTION_ARGS)
 
 	PG_RETURN_DATUM(makeArrayResult(astate, CurrentMemoryContext));
 }
+
+/*
+ * Report current log file used by log collector
+ */
+Datum
+pg_current_logfile(PG_FUNCTION_ARGS)
+{
+	FILE    *fd;
+	char    log_filename[MAXPGPATH];
+	text    *fmt;
+	char    *logfmt;
+	struct stat stat_buf;
+
+	if (PG_NARGS() == 1) {
+		fmt = PG_ARGISNULL(0) ? NULL : PG_GETARG_TEXT_PP(0);
+		if (fmt != NULL) {
+			logfmt = text_to_cstring(fmt);
+			if ( (strcmp(logfmt, "stderr") != 0) &&
+				(strcmp(logfmt, "csvlog") != 0) ) {
+				ereport(ERROR,
+		(errmsg("log format %s not supported, possible values are stderr or csvlog", logfmt)));
+				PG_RETURN_NULL();
+			}
+		}
+	} else {
+		logfmt = NULL;
+	}
+
+	if (!Logging_collector)
+		PG_RETURN_NULL();
+
+	/* Check if current log file is present */
+	if (stat(CURRENT_LOG_FILENAME, &stat_buf) != 0)
+		PG_RETURN_NULL();
+
+	fd = AllocateFile(CURRENT_LOG_FILENAME, "r");
+	if (fd == NULL)
+	{
+		if (errno != ENOENT)
+			ereport(ERROR,
+				(errcode_for_file_access(),
+				errmsg("could not read file \"%s\": %m",
+				CURRENT_LOG_FILENAME)));
+		PG_RETURN_NULL();
+	}
+
+	/*
+	* Read the file to gather current log filename(s) registered
+	* by the syslogger.
+	*/
+	while (fgets(log_filename, sizeof(log_filename), fd) != NULL) {
+
+		/* Check for a read error. */
+		if (ferror(fd)) {
+			ereport(ERROR,
+				(errcode_for_file_access(),
+				errmsg("could not read file \"%s\": %m", CURRENT_LOG_FILENAME)));
+			FreeFile(fd);
+			break;
+		}
+
+		/* remove trailing newline */
+		if (strchr(log_filename, '\n') != NULL)
+			*strchr(log_filename, '\n') = '\0';
+
+		/*
+		 * When no format is provided as argument, always reports
+		 * the first registered log file. I will be the stderr log
+		 * if csvlog is not set or if both csvlog and stderr are
+		 * set in log_destination. stderr log is always the first
+		 * entry in CURRENT_LOG_FILENAME, see logfile_writename()
+		 * in syslogger.c
+		 */
+		if (logfmt == NULL)
+			break;
+
+		/*
+		 * When the log format requested is set to stderr and
+		 * log_destination have the stderr format set, return
+		 * the current filename if this is not the csv one.
+		 */
+		if ( (strcmp(logfmt, "stderr") == 0) && 
+			(Log_destination & LOG_DESTINATION_STDERR) &&
+				(strstr(log_filename, ".csv") == NULL) )
+			break;
+
+		/*
+		 * When the log format requested is set to csvlog and
+		 * log_destination have the csvlog format set, return
+		 * the current filename if this is the csv one.
+		 */
+		if ( (strcmp(logfmt, "csvlog") == 0) && 
+			(Log_destination & LOG_DESTINATION_CSVLOG) &&
+				(strstr(log_filename, ".csv") != NULL) )
+				break;
+	}
+	/* Close the current log filename file. */
+	if (FreeFile(fd))
+	       ereport(ERROR,
+			       (errcode_for_file_access(),
+		       errmsg("could not close file \"%s\": %m", CURRENT_LOG_FILENAME)));
+
+
+	if (log_filename[0] == '\0')
+		PG_RETURN_NULL();
+
+	/* Return null when csvlog is requested but we have a stderr log */
+	if ( (logfmt != NULL) && (strcmp(logfmt, "csvlog") == 0)
+			&& (strstr(log_filename, ".csv") == NULL) )
+		PG_RETURN_NULL();
+
+	/* Return null when stderr is requested but we have a csv log */
+	if ( (logfmt != NULL) && (strcmp(logfmt, "stderr") == 0)
+			&& (strstr(log_filename, ".csv") != NULL) )
+		PG_RETURN_NULL();
+
+	PG_RETURN_TEXT_P(cstring_to_text(log_filename));
+}
+
diff --git a/src/include/catalog/pg_proc.h b/src/include/catalog/pg_proc.h
index 17ec71d..6d9653e 100644
--- a/src/include/catalog/pg_proc.h
+++ b/src/include/catalog/pg_proc.h
@@ -3179,6 +3179,10 @@ DATA(insert OID = 2621 ( pg_reload_conf			PGNSP PGUID 12 1 0 0 0 f f f f t f v s
 DESCR("reload configuration files");
 DATA(insert OID = 2622 ( pg_rotate_logfile		PGNSP PGUID 12 1 0 0 0 f f f f t f v s 0 0 16 "" _null_ _null_ _null_ _null_ _null_ pg_rotate_logfile _null_ _null_ _null_ ));
 DESCR("rotate log file");
+DATA(insert OID = 3800 ( pg_current_logfile             PGNSP PGUID 12 1 0 0 0 f f f f t f v s 0 0 25 "" _null_ _null_ _null_ _null_ _null_ pg_current_logfile _null_ _null_ _null_ ));
+DESCR("current logging collector file location");
+DATA(insert OID = 3801 ( pg_current_logfile             PGNSP PGUID 12 1 0 0 0 f f f f t f v s 1 0 25 "25" _null_ _null_ _null_ _null_ _null_ pg_current_logfile _null_ _null_ _null_ ));
+DESCR("current logging collector file location");
 
 DATA(insert OID = 2623 ( pg_stat_file		PGNSP PGUID 12 1 0 0 0 f f f f t f v s 1 0 2249 "25" "{25,20,1184,1184,1184,1184,16}" "{i,o,o,o,o,o,o}" "{filename,size,access,modification,change,creation,isdir}" _null_ _null_ pg_stat_file_1arg _null_ _null_ _null_ ));
 DESCR("get information about file");
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 78545da..15e1214 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -466,4 +466,12 @@ extern bool has_rolreplication(Oid roleid);
 extern bool BackupInProgress(void);
 extern void CancelBackup(void);
 
+/* in backend/utils/adt/misc.c and backend/postmaster/syslogger.c */
+/*
+ * Name of file where current log messages are written when log collector is
+ * enabled. Useful to find the name of the current log file when a time-based
+ * rotation is defined.
+ */
+#define CURRENT_LOG_FILENAME  "current_logfile"
+
 #endif   /* MISCADMIN_H */
diff --git a/src/include/utils/builtins.h b/src/include/utils/builtins.h
index 90f5132..df9a1e1 100644
--- a/src/include/utils/builtins.h
+++ b/src/include/utils/builtins.h
@@ -522,6 +522,7 @@ extern Datum pg_collation_for(PG_FUNCTION_ARGS);
 extern Datum pg_relation_is_updatable(PG_FUNCTION_ARGS);
 extern Datum pg_column_is_updatable(PG_FUNCTION_ARGS);
 extern Datum parse_ident(PG_FUNCTION_ARGS);
+extern Datum pg_current_logfile(PG_FUNCTION_ARGS);
 
 /* oid.c */
 extern Datum oidin(PG_FUNCTION_ARGS);

diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index d1a5b96..54e10af 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -15443,6 +15443,12 @@ SELECT * FROM pg_ls_dir('.') WITH ORDINALITY AS t(ls,n);
       </row>
 
       <row>
+       <entry><literal><function>pg_current_logfile(<optional><type>text</></optional>)</function></literal></entry>
+       <entry><type>text</type></entry>
+       <entry>log file in use by the logging collector</entry>
+      </row>
+
+      <row>
        <entry><literal><function>pg_my_temp_schema()</function></literal></entry>
        <entry><type>oid</type></entry>
        <entry>OID of session's temporary schema, or 0 if none</entry>
@@ -15480,12 +15486,6 @@ SELECT * FROM pg_ls_dir('.') WITH ORDINALITY AS t(ls,n);
       </row>
 
       <row>
-       <entry><literal><function>pg_current_logfile(<optional> <parameter>destination</> <type>text</></optional>)</function></literal></entry>
-       <entry><type>text</type></entry>
-       <entry>current log file used by the logging collector</entry>
-      </row>
-
-      <row>
        <entry><literal><function>session_user</function></literal></entry>
        <entry><type>name</type></entry>
        <entry>session user name</entry>
@@ -15667,6 +15667,27 @@ SET search_path TO <replaceable>schema</> <optional>, <replaceable>schema</>, ..
    </para>
 
    <indexterm>
+    <primary>pg_current_logfile</primary>
+   </indexterm>
+
+   <para>
+    <function>pg_current_logfile</function> returns, as <type>text</type>
+    the name of the log file currently in use by the logging collector.
+    Log collection must be active or the return value is undefined.  When
+    the <xref linkend="guc-log-destination"> configuration parameter
+    contains both <systemitem>csvlog</> and <systemitem>stderr</>
+    <function>pg_current_logfile</function> returns the stderr filename.
+    When <xref linkend="guc-log-destination"> does not
+    contain <systemitem>stderr</> the csv filename is returned.  When it
+    does not contains <systemitem>csvlog</> the stderr filename is
+    returned.  To request a specific file format supply either
+    <systemitem>csvlog</> or <systemitem>stderr</> as the value of the
+    optional, type <type>text</type>, parameter. The return value is
+    undefined when the log format requested is not a configured log
+    destination.
+   </para>
+
+   <indexterm>
     <primary>pg_my_temp_schema</primary>
    </indexterm>
 
@@ -15692,23 +15713,6 @@ SET search_path TO <replaceable>schema</> <optional>, <replaceable>schema</>, ..
     <primary>pg_notification_queue_usage</primary>
    </indexterm>
 
-   <indexterm>
-    <primary>pg_current_logfile</primary>
-   </indexterm>
-
-   <para>
-    <function>pg_current_logfile</function> returns the name of the
-    current log file used by the logging collector, as <type>text</type>.
-    Log collection must be active or the return value is undefined. When
-    csvlog is used as log destination, the csv filename is returned, when
-    it is set to stderr, the stderr filename is returned. When both are
-    used, it returns the stderr filename.
-    There is an optional parameter of type <type>text</type> to determines
-    the log filename to return following the log destination, values can
-    be 'csvlog' or 'stderr'. When the log format asked is not used as log
-    destination then the return value is undefined.
-   </para>
-
    <para>
     <function>pg_listening_channels</function> returns a set of names of
     asynchronous notification channels that the current session is listening
diff --git a/doc/src/sgml/storage.sgml b/doc/src/sgml/storage.sgml
index 6cecd81..6420597 100644
--- a/doc/src/sgml/storage.sgml
+++ b/doc/src/sgml/storage.sgml
@@ -83,6 +83,16 @@ Item
 </row>
 
 <row>
+ <entry><filename>pg_log_file</></entry>
+ <entry>A file recording the current log file(s) used by the syslogger, one
+  file name per line.  Only file names are present
+  in <filename>pg_log_file</>; the <xref linkend="guc-log-directory">
+  configuration parameter sets the location of the files.  This file is
+  present only when <xref linkend="guc-logging-collector"> is
+  activated.</entry>
+</row>
+
+<row>
  <entry><filename>pg_logical</></entry>
  <entry>Subdirectory containing status data for logical decoding</entry>
 </row>
@@ -170,13 +180,6 @@ last started with</entry>
   (this file is not present after server shutdown)</entry>
 </row>
 
-<row>
- <entry><filename>pg_log_file</></entry>
- <entry>A file recording the current log file(s) used by the syslogger
-  when log collection is active (this file is not present when logging_collector is not activated)</entry>
-</row>
-
-
 </tbody>
 </tgroup>
 </table>

diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index d1a5b96..958e634 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -15443,6 +15443,19 @@ SELECT * FROM pg_ls_dir('.') WITH ORDINALITY AS t(ls,n);
       </row>
 
       <row>
+       <entry><literal><function>pg_current_logfile()</function></literal></entry>
+       <entry><type>text</type></entry>
+       <entry>primary log file name in use by the logging collector</entry>
+      </row>
+
+      <row>
+       <entry><literal><function>pg_current_logfile(<type>text</>)</function></literal></entry>
+       <entry><type>text</type></entry>
+       <entry>log file name, of log in the requested format, in use by the
+       logging collector</entry>
+      </row>
+
+      <row>
        <entry><literal><function>pg_my_temp_schema()</function></literal></entry>
        <entry><type>oid</type></entry>
        <entry>OID of session's temporary schema, or 0 if none</entry>
@@ -15480,12 +15493,6 @@ SELECT * FROM pg_ls_dir('.') WITH ORDINALITY AS t(ls,n);
       </row>
 
       <row>
-       <entry><literal><function>pg_current_logfile(<optional> <parameter>destination</> <type>text</></optional>)</function></literal></entry>
-       <entry><type>text</type></entry>
-       <entry>current log file used by the logging collector</entry>
-      </row>
-
-      <row>
        <entry><literal><function>session_user</function></literal></entry>
        <entry><type>name</type></entry>
        <entry>session user name</entry>
@@ -15667,6 +15674,27 @@ SET search_path TO <replaceable>schema</> <optional>, <replaceable>schema</>, ..
    </para>
 
    <indexterm>
+    <primary>pg_current_logfile</primary>
+   </indexterm>
+
+   <para>
+    <function>pg_current_logfile</function> returns, as <type>text</type>
+    the name of the log file currently in use by the logging collector.
+    Log collection must be active or the return value is undefined.  When
+    the <xref linkend="guc-log-destination"> configuration parameter
+    contains both <systemitem>csvlog</> and <systemitem>stderr</>
+    <function>pg_current_logfile</function> returns the stderr filename.
+    When <xref linkend="guc-log-destination"> does not
+    contain <systemitem>stderr</> the csv filename is returned.  When it
+    does not contains <systemitem>csvlog</> the stderr filename is
+    returned.  To request a specific file format supply either
+    <systemitem>csvlog</> or <systemitem>stderr</> as the value of the
+    optional, type <type>text</type>, parameter. The return value is
+    undefined when the log format requested is not a configured log
+    destination.
+   </para>
+
+   <indexterm>
     <primary>pg_my_temp_schema</primary>
    </indexterm>
 
@@ -15692,23 +15720,6 @@ SET search_path TO <replaceable>schema</> <optional>, <replaceable>schema</>, ..
     <primary>pg_notification_queue_usage</primary>
    </indexterm>
 
-   <indexterm>
-    <primary>pg_current_logfile</primary>
-   </indexterm>
-
-   <para>
-    <function>pg_current_logfile</function> returns the name of the
-    current log file used by the logging collector, as <type>text</type>.
-    Log collection must be active or the return value is undefined. When
-    csvlog is used as log destination, the csv filename is returned, when
-    it is set to stderr, the stderr filename is returned. When both are
-    used, it returns the stderr filename.
-    There is an optional parameter of type <type>text</type> to determines
-    the log filename to return following the log destination, values can
-    be 'csvlog' or 'stderr'. When the log format asked is not used as log
-    destination then the return value is undefined.
-   </para>
-
    <para>
     <function>pg_listening_channels</function> returns a set of names of
     asynchronous notification channels that the current session is listening
diff --git a/doc/src/sgml/storage.sgml b/doc/src/sgml/storage.sgml
index 6cecd81..6420597 100644
--- a/doc/src/sgml/storage.sgml
+++ b/doc/src/sgml/storage.sgml
@@ -83,6 +83,16 @@ Item
 </row>
 
 <row>
+ <entry><filename>pg_log_file</></entry>
+ <entry>A file recording the current log file(s) used by the syslogger, one
+  file name per line.  Only file names are present
+  in <filename>pg_log_file</>; the <xref linkend="guc-log-directory">
+  configuration parameter sets the location of the files.  This file is
+  present only when <xref linkend="guc-logging-collector"> is
+  activated.</entry>
+</row>
+
+<row>
  <entry><filename>pg_logical</></entry>
  <entry>Subdirectory containing status data for logical decoding</entry>
 </row>
@@ -170,13 +180,6 @@ last started with</entry>
   (this file is not present after server shutdown)</entry>
 </row>
 
-<row>
- <entry><filename>pg_log_file</></entry>
- <entry>A file recording the current log file(s) used by the syslogger
-  when log collection is active (this file is not present when logging_collector is not activated)</entry>
-</row>
-
-
 </tbody>
 </tgroup>
 </table>

diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index d1a5b96..c91d6ac 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -15443,6 +15443,19 @@ SELECT * FROM pg_ls_dir('.') WITH ORDINALITY AS t(ls,n);
       </row>
 
       <row>
+       <entry><literal><function>pg_current_logfile()</function></literal></entry>
+       <entry><type>text</type></entry>
+       <entry>primary log file name in use by the logging collector</entry>
+      </row>
+
+      <row>
+       <entry><literal><function>pg_current_logfile(<type>text</>)</function></literal></entry>
+       <entry><type>text</type></entry>
+       <entry>log file name, of log in the requested format, in use by the
+       logging collector</entry>
+      </row>
+
+      <row>
        <entry><literal><function>pg_my_temp_schema()</function></literal></entry>
        <entry><type>oid</type></entry>
        <entry>OID of session's temporary schema, or 0 if none</entry>
@@ -15480,12 +15493,6 @@ SELECT * FROM pg_ls_dir('.') WITH ORDINALITY AS t(ls,n);
       </row>
 
       <row>
-       <entry><literal><function>pg_current_logfile(<optional> <parameter>destination</> <type>text</></optional>)</function></literal></entry>
-       <entry><type>text</type></entry>
-       <entry>current log file used by the logging collector</entry>
-      </row>
-
-      <row>
        <entry><literal><function>session_user</function></literal></entry>
        <entry><type>name</type></entry>
        <entry>session user name</entry>
@@ -15667,6 +15674,29 @@ SET search_path TO <replaceable>schema</> <optional>, <replaceable>schema</>, ..
    </para>
 
    <indexterm>
+    <primary>pg_current_logfile</primary>
+   </indexterm>
+
+   <para>
+    <function>pg_current_logfile</function> returns, as <type>text</type>
+    the name of either the csv or stderr log file currently in use by the
+    logging collector.  This is a file name, not a path.  The file is
+    found in the <xref linkend="guc-log-directory"> directory.  Log
+    collection must be active or the return value
+    is <literal>NULL</literal>.  When called without arguments the stderr
+    log file name is returned if
+    <xref linkend="guc-log-destination"> was supplied
+    <systemitem>stderr</>, otherwise if <systemitem>csvlog</> was supplied
+    to <xref linkend="guc-log-destination"> the csv log filename is
+    returned.  Otherwise <literal>NULL</literal> is returned.  To request
+    a specific file format supply either <systemitem>csvlog</>
+    or <systemitem>stderr</> as the value of the optional,
+    type <type>text</type>, parameter. The return value
+    is <literal>NULL</literal> when the log format requested is not a
+    configured log destination.
+   </para>
+
+   <indexterm>
     <primary>pg_my_temp_schema</primary>
    </indexterm>
 
@@ -15692,23 +15722,6 @@ SET search_path TO <replaceable>schema</> <optional>, <replaceable>schema</>, ..
     <primary>pg_notification_queue_usage</primary>
    </indexterm>
 
-   <indexterm>
-    <primary>pg_current_logfile</primary>
-   </indexterm>
-
-   <para>
-    <function>pg_current_logfile</function> returns the name of the
-    current log file used by the logging collector, as <type>text</type>.
-    Log collection must be active or the return value is undefined. When
-    csvlog is used as log destination, the csv filename is returned, when
-    it is set to stderr, the stderr filename is returned. When both are
-    used, it returns the stderr filename.
-    There is an optional parameter of type <type>text</type> to determines
-    the log filename to return following the log destination, values can
-    be 'csvlog' or 'stderr'. When the log format asked is not used as log
-    destination then the return value is undefined.
-   </para>
-
    <para>
     <function>pg_listening_channels</function> returns a set of names of
     asynchronous notification channels that the current session is listening
diff --git a/doc/src/sgml/storage.sgml b/doc/src/sgml/storage.sgml
index 6cecd81..6420597 100644
--- a/doc/src/sgml/storage.sgml
+++ b/doc/src/sgml/storage.sgml
@@ -83,6 +83,16 @@ Item
 </row>
 
 <row>
+ <entry><filename>pg_log_file</></entry>
+ <entry>A file recording the current log file(s) used by the syslogger, one
+  file name per line.  Only file names are present
+  in <filename>pg_log_file</>; the <xref linkend="guc-log-directory">
+  configuration parameter sets the location of the files.  This file is
+  present only when <xref linkend="guc-logging-collector"> is
+  activated.</entry>
+</row>
+
+<row>
  <entry><filename>pg_logical</></entry>
  <entry>Subdirectory containing status data for logical decoding</entry>
 </row>
@@ -170,13 +180,6 @@ last started with</entry>
   (this file is not present after server shutdown)</entry>
 </row>
 
-<row>
- <entry><filename>pg_log_file</></entry>
- <entry>A file recording the current log file(s) used by the syslogger
-  when log collection is active (this file is not present when logging_collector is not activated)</entry>
-</row>
-
-
 </tbody>
 </tgroup>
 </table>

diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index d1a5b96..50ab506 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -15443,6 +15443,19 @@ SELECT * FROM pg_ls_dir('.') WITH ORDINALITY AS t(ls,n);
       </row>
 
       <row>
+       <entry><literal><function>pg_current_logfile()</function></literal></entry>
+       <entry><type>text</type></entry>
+       <entry>primary log file name in use by the logging collector</entry>
+      </row>
+
+      <row>
+       <entry><literal><function>pg_current_logfile(<type>text</>)</function></literal></entry>
+       <entry><type>text</type></entry>
+       <entry>log file name, of log in the requested format, in use by the
+       logging collector</entry>
+      </row>
+
+      <row>
        <entry><literal><function>pg_my_temp_schema()</function></literal></entry>
        <entry><type>oid</type></entry>
        <entry>OID of session's temporary schema, or 0 if none</entry>
@@ -15480,12 +15493,6 @@ SELECT * FROM pg_ls_dir('.') WITH ORDINALITY AS t(ls,n);
       </row>
 
       <row>
-       <entry><literal><function>pg_current_logfile(<optional> <parameter>destination</> <type>text</></optional>)</function></literal></entry>
-       <entry><type>text</type></entry>
-       <entry>current log file used by the logging collector</entry>
-      </row>
-
-      <row>
        <entry><literal><function>session_user</function></literal></entry>
        <entry><type>name</type></entry>
        <entry>session user name</entry>
@@ -15667,6 +15674,29 @@ SET search_path TO <replaceable>schema</> <optional>, <replaceable>schema</>, ..
    </para>
 
    <indexterm>
+    <primary>pg_current_logile</primary>
+   </indexterm>
+
+   <para>
+    <function>pg_current_logfile</function> returns, as <type>text</type>,
+    the name of either the csv or stderr log file currently in use by the
+    logging collector.  This is a file name, not a path.  The file is
+    found in the <xref linkend="guc-log-directory"> directory.  Log
+    collection must be active or the return value
+    is <literal>NULL</literal>.  When multiple logfiles exist, each in a
+    different format, <function>pg_current_logfile</function> called
+    without arguments returns the name of the file having the first format
+    found in the ordered
+    list: <systemitem>stderr</>, <systemitem>csvlog</>.
+    <literal>NULL</literal> is returned when no log file has any of these
+    formats.  To request a specific file format supply,
+    as <type>text</type>, either <systemitem>csvlog</>
+    or <systemitem>stderr</> as the value of the optional parameter. The
+    return value is <literal>NULL</literal> when the log format requested
+    is not a configured <xref linkend="guc-log-destination">.
+   </para>
+
+   <indexterm>
     <primary>pg_my_temp_schema</primary>
    </indexterm>
 
@@ -15692,23 +15722,6 @@ SET search_path TO <replaceable>schema</> <optional>, <replaceable>schema</>, ..
     <primary>pg_notification_queue_usage</primary>
    </indexterm>
 
-   <indexterm>
-    <primary>pg_current_logfile</primary>
-   </indexterm>
-
-   <para>
-    <function>pg_current_logfile</function> returns the name of the
-    current log file used by the logging collector, as <type>text</type>.
-    Log collection must be active or the return value is undefined. When
-    csvlog is used as log destination, the csv filename is returned, when
-    it is set to stderr, the stderr filename is returned. When both are
-    used, it returns the stderr filename.
-    There is an optional parameter of type <type>text</type> to determines
-    the log filename to return following the log destination, values can
-    be 'csvlog' or 'stderr'. When the log format asked is not used as log
-    destination then the return value is undefined.
-   </para>
-
    <para>
     <function>pg_listening_channels</function> returns a set of names of
     asynchronous notification channels that the current session is listening
diff --git a/doc/src/sgml/storage.sgml b/doc/src/sgml/storage.sgml
index 6cecd81..6420597 100644
--- a/doc/src/sgml/storage.sgml
+++ b/doc/src/sgml/storage.sgml
@@ -83,6 +83,16 @@ Item
 </row>
 
 <row>
+ <entry><filename>pg_log_file</></entry>
+ <entry>A file recording the current log file(s) used by the syslogger, one
+  file name per line.  Only file names are present
+  in <filename>pg_log_file</>; the <xref linkend="guc-log-directory">
+  configuration parameter sets the location of the files.  This file is
+  present only when <xref linkend="guc-logging-collector"> is
+  activated.</entry>
+</row>
+
+<row>
  <entry><filename>pg_logical</></entry>
  <entry>Subdirectory containing status data for logical decoding</entry>
 </row>
@@ -170,13 +180,6 @@ last started with</entry>
   (this file is not present after server shutdown)</entry>
 </row>
 
-<row>
- <entry><filename>pg_log_file</></entry>
- <entry>A file recording the current log file(s) used by the syslogger
-  when log collection is active (this file is not present when logging_collector is not activated)</entry>
-</row>
-
-
 </tbody>
 </tgroup>
 </table>

diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 2e64cc4..bdae4c6 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -15442,6 +15442,18 @@ SELECT * FROM pg_ls_dir('.') WITH ORDINALITY AS t(ls,n);
        <entry>configuration load time</entry>
       </row>
 
+       <entry><literal><function>pg_current_logfile()</function></literal></entry>
+       <entry><type>text</type></entry>
+       <entry>primary log file name in use by the logging collector</entry>
+      </row>
+
+      <row>
+       <entry><literal><function>pg_current_logfile(<type>text</>)</function></literal></entry>
+       <entry><type>text</type></entry>
+       <entry>log file name, of log in the requested format, in use by the
+       logging collector</entry>
+      </row>
+
       <row>
        <entry><literal><function>pg_my_temp_schema()</function></literal></entry>
        <entry><type>oid</type></entry>
@@ -15660,6 +15672,29 @@ SET search_path TO <replaceable>schema</> <optional>, <replaceable>schema</>, ..
     the time when the postmaster process re-read the configuration files.)
    </para>
 
+    <indexterm>
+    <primary>pg_current_logile</primary>
+   </indexterm>
+
+   <para>
+    <function>pg_current_logfile</function> returns, as <type>text</type>,
+    the path of either the csv or stderr log file currently in use by the
+    logging collector.  This is a path including the
+    <xref linkend="guc-log-directory"> directory and the log file name.
+    Log collection must be active or the return value
+    is <literal>NULL</literal>.  When multiple logfiles exist, each in a
+    different format, <function>pg_current_logfile</function> called
+    without arguments returns the path of the file having the first format
+    found in the ordered
+    list: <systemitem>stderr</>, <systemitem>csvlog</>.
+    <literal>NULL</literal> is returned when no log file has any of these
+    formats.  To request a specific file format supply,
+    as <type>text</type>, either <systemitem>csvlog</>
+    or <systemitem>stderr</> as the value of the optional parameter. The
+    return value is <literal>NULL</literal> when the log format requested
+    is not a configured <xref linkend="guc-log-destination">.
+   </para>
+
    <indexterm>
     <primary>pg_my_temp_schema</primary>
    </indexterm>
diff --git a/doc/src/sgml/storage.sgml b/doc/src/sgml/storage.sgml
index fddb69b..b5faf52 100644
--- a/doc/src/sgml/storage.sgml
+++ b/doc/src/sgml/storage.sgml
@@ -61,6 +61,15 @@ Item
 </row>
 
 <row>
+ <entry><filename>current_logfile</></entry>
+ <entry>A file recording the current log file(s) used by the syslogger,
+  one file name per line.  Full path to log file(s) including the value of
+  <xref linkend="guc-log-directory"> are stored in <filename>current_logfile</>.
+  This file is present only when <xref linkend="guc-logging-collector"> is
+  activated.</entry>
+</row>
+
+<row>
  <entry><filename>global</></entry>
  <entry>Subdirectory containing cluster-wide tables, such as
  <structname>pg_database</></entry>
diff --git a/src/backend/postmaster/syslogger.c b/src/backend/postmaster/syslogger.c
index fd62d66..7b09349 100644
--- a/src/backend/postmaster/syslogger.c
+++ b/src/backend/postmaster/syslogger.c
@@ -146,6 +146,7 @@ static char *logfile_getname(pg_time_t timestamp, const char *suffix);
 static void set_next_rotation_time(void);
 static void sigHupHandler(SIGNAL_ARGS);
 static void sigUsr1Handler(SIGNAL_ARGS);
+static void logfile_writename(char *filename, char *csvfilename);
 
 
 /*
@@ -348,6 +349,13 @@ SysLoggerMain(int argc, char *argv[])
 				rotation_disabled = false;
 				rotation_requested = true;
 			}
+
+			/*
+			 * Force rewriting last log filename when reloading configuration,
+			 * log_destination and logging_collector may have been changed. Do
+			 * it right now to not wait for the next file rotation.
+			 */
+			logfile_writename(last_file_name, last_csv_file_name);
 		}
 
 		if (Log_RotationAge > 0 && !rotation_disabled)
@@ -513,8 +521,14 @@ SysLogger_Start(void)
 	pid_t		sysloggerPid;
 	char	   *filename;
 
-	if (!Logging_collector)
+	if (!Logging_collector) {
+		/* If logging collector is not enabled, remove current log
+		 * filename as we don't know where messages are logged and
+		 * information contained in this file are obsolete.
+		 */
+		unlink(CURRENT_LOG_FILENAME);
 		return 0;
+	}
 
 	/*
 	 * If first time through, create the pipe which will receive stderr
@@ -574,6 +588,8 @@ SysLogger_Start(void)
 
 	syslogFile = logfile_open(filename, "a", false);
 
+	logfile_writename(filename, NULL);
+
 	pfree(filename);
 
 #ifdef EXEC_BACKEND
@@ -988,8 +1004,10 @@ write_syslogger_file(const char *buffer, int count, int destination)
 	int			rc;
 	FILE	   *logfile;
 
-	if (destination == LOG_DESTINATION_CSVLOG && csvlogFile == NULL)
+	if (destination == LOG_DESTINATION_CSVLOG && csvlogFile == NULL) {
 		open_csvlogfile();
+		logfile_writename(last_file_name, last_csv_file_name);
+	}
 
 	logfile = destination == LOG_DESTINATION_CSVLOG ? csvlogFile : syslogFile;
 	rc = fwrite(buffer, 1, count, logfile);
@@ -1209,6 +1227,8 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for)
 			return;
 		}
 
+		logfile_writename(filename, csvfilename);
+
 		fclose(syslogFile);
 		syslogFile = fh;
 
@@ -1220,7 +1240,6 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for)
 	}
 
 	/* Same as above, but for csv file. */
-
 	if (csvlogFile != NULL &&
 		(time_based_rotation || (size_rotation_for & LOG_DESTINATION_CSVLOG)))
 	{
@@ -1253,6 +1272,8 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for)
 			return;
 		}
 
+		logfile_writename(last_file_name, csvfilename);
+
 		fclose(csvlogFile);
 		csvlogFile = fh;
 
@@ -1365,3 +1386,60 @@ sigUsr1Handler(SIGNAL_ARGS)
 
 	errno = save_errno;
 }
+
+/*
+ * Store the name of the files where current log messages are written when
+ * log collector is enabled. Useful to find the name of the current log file
+ * when a time-based rotation is defined. Filenames are first stored into a
+ * temporary file and renamed into the final destination.
+ */
+static void
+logfile_writename(char *filename, char *csvfilename)
+{
+	FILE	*fh;
+	char	tempfn[MAXPGPATH];
+	char	logpathfilename[MAXPGPATH];
+
+	snprintf(tempfn, sizeof(tempfn), "%s",
+						CURRENT_LOG_FILENAME);
+	strcat(tempfn, ".tmp");
+	snprintf(logpathfilename, sizeof(logpathfilename), "%s",
+						CURRENT_LOG_FILENAME);
+	if ((fh = logfile_open(tempfn, "w", true) ) == NULL)
+	{
+		return;
+	}
+	if (filename && (Log_destination & LOG_DESTINATION_STDERR)) {
+		if (fprintf(fh, "%s\n", filename) < 0)
+		{
+			ereport(LOG,
+					(errcode_for_file_access(),
+					errmsg("could not write log file \"%s\": %m",
+						tempfn)));
+			fclose(fh);
+			return;
+		}
+	}
+
+	if (csvfilename && (Log_destination & LOG_DESTINATION_CSVLOG)) {
+		if (fprintf(fh, "%s\n", csvfilename) < 0)
+		{
+			ereport(LOG,
+					(errcode_for_file_access(),
+					errmsg("could not write log file \"%s\": %m",
+						tempfn)));
+			fclose(fh);
+			return;
+		}
+	}
+	fclose(fh);
+
+	if (rename(tempfn, logpathfilename) != 0)
+	{
+		ereport(LOG,
+				(errcode_for_file_access(),
+				errmsg("could not rename file \"%s\": %m",
+						tempfn)));
+		return;
+	}
+}
diff --git a/src/backend/utils/adt/misc.c b/src/backend/utils/adt/misc.c
index 0da051a..dca711b 100644
--- a/src/backend/utils/adt/misc.c
+++ b/src/backend/utils/adt/misc.c
@@ -19,6 +19,7 @@
 #include <dirent.h>
 #include <math.h>
 #include <unistd.h>
+#include <sys/stat.h>
 
 #include "access/sysattr.h"
 #include "catalog/pg_authid.h"
@@ -892,3 +893,113 @@ parse_ident(PG_FUNCTION_ARGS)
 
 	PG_RETURN_DATUM(makeArrayResult(astate, CurrentMemoryContext));
 }
+
+/*
+ * Report current log file used by log collector
+ */
+Datum
+pg_current_logfile(PG_FUNCTION_ARGS)
+{
+	FILE    *fd;
+	char    log_filename[MAXPGPATH];
+	text    *fmt;
+	char    *logfmt;
+	struct stat stat_buf;
+
+	if (PG_NARGS() == 1) {
+		fmt = PG_ARGISNULL(0) ? NULL : PG_GETARG_TEXT_PP(0);
+		if (fmt != NULL) {
+			logfmt = text_to_cstring(fmt);
+			if ( (strcmp(logfmt, "stderr") != 0) &&
+				(strcmp(logfmt, "csvlog") != 0) ) {
+				ereport(ERROR,
+		(errmsg("log format %s not supported, possible values are stderr or csvlog", logfmt)));
+				PG_RETURN_NULL();
+			}
+		}
+	} else {
+		logfmt = NULL;
+	}
+
+	if (!Logging_collector)
+		PG_RETURN_NULL();
+
+	/* Check if current log file is present */
+	if (stat(CURRENT_LOG_FILENAME, &stat_buf) != 0)
+		PG_RETURN_NULL();
+
+	fd = AllocateFile(CURRENT_LOG_FILENAME, "r");
+	if (fd == NULL)
+	{
+		if (errno != ENOENT)
+			ereport(ERROR,
+				(errcode_for_file_access(),
+				errmsg("could not read file \"%s\": %m",
+				CURRENT_LOG_FILENAME)));
+		PG_RETURN_NULL();
+	}
+
+	/*
+	* Read the file to gather current log filename(s) registered
+	* by the syslogger.
+	*/
+	while (fgets(log_filename, sizeof(log_filename), fd) != NULL) {
+
+		/* Check for a read error. */
+		if (ferror(fd)) {
+			ereport(ERROR,
+				(errcode_for_file_access(),
+				errmsg("could not read file \"%s\": %m", CURRENT_LOG_FILENAME)));
+			FreeFile(fd);
+			break;
+		}
+
+		/* remove trailing newline */
+		if (strchr(log_filename, '\n') != NULL)
+			*strchr(log_filename, '\n') = '\0';
+
+		/*
+		 * When no log format is provided as argument or stderr format
+		 * is requested, always reports the first registered log file.
+		 * stderr log is always the first entry in CURRENT_LOG_FILENAME
+		 * see logfile_writename() * in syslogger.c . If only csvlog is
+		 * defined, log format will be rechecked later and NULL will
+		 * be returned.
+		 */
+		if ( (logfmt == NULL) || (strcmp(logfmt, "stderr") == 0) )
+			break;
+
+		/*
+		 * When the log format requested is set to csvlog and
+		 * log_destination have the csvlog format set, return
+		 * the current filename when stderr is not defined too.
+		 * If both stderr and csvlog are defined the last entry
+		 * of CURRENT_LOG_FILENAME will be reported.
+		 */
+		if ( (strcmp(logfmt, "csvlog") == 0) &&
+			(Log_destination & LOG_DESTINATION_CSVLOG) && 
+			!(Log_destination & LOG_DESTINATION_STDERR) )
+				break;
+	}
+	/* Close the current log filename file. */
+	if (FreeFile(fd))
+		ereport(ERROR,
+				(errcode_for_file_access(),
+			errmsg("could not close file \"%s\": %m", CURRENT_LOG_FILENAME)));
+
+
+	if (log_filename[0] == '\0')
+		PG_RETURN_NULL();
+
+	/* Return null when csvlog is requested but we have a stderr log */
+	if ( (logfmt != NULL) && (strcmp(logfmt, "csvlog") == 0)
+			&& !(Log_destination & LOG_DESTINATION_CSVLOG) )
+		PG_RETURN_NULL();
+
+	/* Return null when stderr is requested but we have a csv log */
+	if ( (logfmt != NULL) && (strcmp(logfmt, "stderr") == 0)
+			&& !(Log_destination & LOG_DESTINATION_STDERR) )
+		PG_RETURN_NULL();
+
+	PG_RETURN_TEXT_P(cstring_to_text(log_filename));
+}
diff --git a/src/include/catalog/pg_proc.h b/src/include/catalog/pg_proc.h
index 17ec71d..78e23a6 100644
--- a/src/include/catalog/pg_proc.h
+++ b/src/include/catalog/pg_proc.h
@@ -3179,6 +3179,8 @@ DATA(insert OID = 2621 ( pg_reload_conf			PGNSP PGUID 12 1 0 0 0 f f f f t f v s
 DESCR("reload configuration files");
 DATA(insert OID = 2622 ( pg_rotate_logfile		PGNSP PGUID 12 1 0 0 0 f f f f t f v s 0 0 16 "" _null_ _null_ _null_ _null_ _null_ pg_rotate_logfile _null_ _null_ _null_ ));
 DESCR("rotate log file");
+DATA(insert OID = 3800 ( pg_current_logfile             PGNSP PGUID 12 1 0 0 0 f f f f f f v s 1 0 25 "25" _null_ _null_ _null_ _null_ _null_ pg_current_logfile _null_ _null_ _null_ ));
+DESCR("current logging collector file location");
 
 DATA(insert OID = 2623 ( pg_stat_file		PGNSP PGUID 12 1 0 0 0 f f f f t f v s 1 0 2249 "25" "{25,20,1184,1184,1184,1184,16}" "{i,o,o,o,o,o,o}" "{filename,size,access,modification,change,creation,isdir}" _null_ _null_ pg_stat_file_1arg _null_ _null_ _null_ ));
 DESCR("get information about file");
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 78545da..15e1214 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -466,4 +466,12 @@ extern bool has_rolreplication(Oid roleid);
 extern bool BackupInProgress(void);
 extern void CancelBackup(void);
 
+/* in backend/utils/adt/misc.c and backend/postmaster/syslogger.c */
+/*
+ * Name of file where current log messages are written when log collector is
+ * enabled. Useful to find the name of the current log file when a time-based
+ * rotation is defined.
+ */
+#define CURRENT_LOG_FILENAME  "current_logfile"
+
 #endif   /* MISCADMIN_H */
diff --git a/src/include/utils/builtins.h b/src/include/utils/builtins.h
index 90f5132..df9a1e1 100644
--- a/src/include/utils/builtins.h
+++ b/src/include/utils/builtins.h
@@ -522,6 +522,7 @@ extern Datum pg_collation_for(PG_FUNCTION_ARGS);
 extern Datum pg_relation_is_updatable(PG_FUNCTION_ARGS);
 extern Datum pg_column_is_updatable(PG_FUNCTION_ARGS);
 extern Datum parse_ident(PG_FUNCTION_ARGS);
+extern Datum pg_current_logfile(PG_FUNCTION_ARGS);
 
 /* oid.c */
 extern Datum oidin(PG_FUNCTION_ARGS);

diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 2e64cc4..bdae4c6 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -15442,6 +15442,18 @@ SELECT * FROM pg_ls_dir('.') WITH ORDINALITY AS t(ls,n);
        <entry>configuration load time</entry>
       </row>
 
+       <entry><literal><function>pg_current_logfile()</function></literal></entry>
+       <entry><type>text</type></entry>
+       <entry>primary log file name in use by the logging collector</entry>
+      </row>
+
+      <row>
+       <entry><literal><function>pg_current_logfile(<type>text</>)</function></literal></entry>
+       <entry><type>text</type></entry>
+       <entry>log file name, of log in the requested format, in use by the
+       logging collector</entry>
+      </row>
+
       <row>
        <entry><literal><function>pg_my_temp_schema()</function></literal></entry>
        <entry><type>oid</type></entry>
@@ -15660,6 +15672,29 @@ SET search_path TO <replaceable>schema</> <optional>, <replaceable>schema</>, ..
     the time when the postmaster process re-read the configuration files.)
    </para>
 
+    <indexterm>
+    <primary>pg_current_logile</primary>
+   </indexterm>
+
+   <para>
+    <function>pg_current_logfile</function> returns, as <type>text</type>,
+    the path of either the csv or stderr log file currently in use by the
+    logging collector.  This is a path including the
+    <xref linkend="guc-log-directory"> directory and the log file name.
+    Log collection must be active or the return value
+    is <literal>NULL</literal>.  When multiple logfiles exist, each in a
+    different format, <function>pg_current_logfile</function> called
+    without arguments returns the path of the file having the first format
+    found in the ordered
+    list: <systemitem>stderr</>, <systemitem>csvlog</>.
+    <literal>NULL</literal> is returned when no log file has any of these
+    formats.  To request a specific file format supply,
+    as <type>text</type>, either <systemitem>csvlog</>
+    or <systemitem>stderr</> as the value of the optional parameter. The
+    return value is <literal>NULL</literal> when the log format requested
+    is not a configured <xref linkend="guc-log-destination">.
+   </para>
+
    <indexterm>
     <primary>pg_my_temp_schema</primary>
    </indexterm>
diff --git a/doc/src/sgml/storage.sgml b/doc/src/sgml/storage.sgml
index fddb69b..6e8ae05 100644
--- a/doc/src/sgml/storage.sgml
+++ b/doc/src/sgml/storage.sgml
@@ -61,6 +61,17 @@ Item
 </row>
 
 <row>
+ <entry><filename>current_logfiles</></entry>
+ <entry>A file recording the current log file(s) used by the syslogger and
+  its log format, stderr or csvlog. Each line of the file is a space separated
+  list of two elements: the log format and the full path to the log file
+  including the value of <xref linkend="guc-log-directory">. The log format
+  must be present in <xref linkend="guc-log-destination"> to be listed in the
+  file. This file is present only when <xref linkend="guc-logging-collector">
+  is activated.</entry>
+</row>
+
+<row>
  <entry><filename>global</></entry>
  <entry>Subdirectory containing cluster-wide tables, such as
  <structname>pg_database</></entry>
diff --git a/src/backend/postmaster/syslogger.c b/src/backend/postmaster/syslogger.c
index fd62d66..5cb44d6 100644
--- a/src/backend/postmaster/syslogger.c
+++ b/src/backend/postmaster/syslogger.c
@@ -146,6 +146,7 @@ static char *logfile_getname(pg_time_t timestamp, const char *suffix);
 static void set_next_rotation_time(void);
 static void sigHupHandler(SIGNAL_ARGS);
 static void sigUsr1Handler(SIGNAL_ARGS);
+static void logfile_writename(char *filename, char *csvfilename);
 
 
 /*
@@ -348,6 +349,13 @@ SysLoggerMain(int argc, char *argv[])
 				rotation_disabled = false;
 				rotation_requested = true;
 			}
+
+			/*
+			 * Force rewriting last log filename when reloading configuration,
+			 * log_destination and logging_collector may have been changed. Do
+			 * it right now to not wait for the next file rotation.
+			 */
+			logfile_writename(last_file_name, last_csv_file_name);
 		}
 
 		if (Log_RotationAge > 0 && !rotation_disabled)
@@ -513,8 +521,14 @@ SysLogger_Start(void)
 	pid_t		sysloggerPid;
 	char	   *filename;
 
-	if (!Logging_collector)
+	if (!Logging_collector) {
+		/* If logging collector is not enabled, remove current log
+		 * filename as we don't know where messages are logged and
+		 * information contained in this file are obsolete.
+		 */
+		unlink(CURRENT_LOG_FILENAME);
 		return 0;
+	}
 
 	/*
 	 * If first time through, create the pipe which will receive stderr
@@ -574,6 +588,8 @@ SysLogger_Start(void)
 
 	syslogFile = logfile_open(filename, "a", false);
 
+	logfile_writename(filename, NULL);
+
 	pfree(filename);
 
 #ifdef EXEC_BACKEND
@@ -988,8 +1004,10 @@ write_syslogger_file(const char *buffer, int count, int destination)
 	int			rc;
 	FILE	   *logfile;
 
-	if (destination == LOG_DESTINATION_CSVLOG && csvlogFile == NULL)
+	if (destination == LOG_DESTINATION_CSVLOG && csvlogFile == NULL) {
 		open_csvlogfile();
+		logfile_writename(last_file_name, last_csv_file_name);
+	}
 
 	logfile = destination == LOG_DESTINATION_CSVLOG ? csvlogFile : syslogFile;
 	rc = fwrite(buffer, 1, count, logfile);
@@ -1209,6 +1227,8 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for)
 			return;
 		}
 
+		logfile_writename(filename, csvfilename);
+
 		fclose(syslogFile);
 		syslogFile = fh;
 
@@ -1220,7 +1240,6 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for)
 	}
 
 	/* Same as above, but for csv file. */
-
 	if (csvlogFile != NULL &&
 		(time_based_rotation || (size_rotation_for & LOG_DESTINATION_CSVLOG)))
 	{
@@ -1253,6 +1272,8 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for)
 			return;
 		}
 
+		logfile_writename(last_file_name, csvfilename);
+
 		fclose(csvlogFile);
 		csvlogFile = fh;
 
@@ -1365,3 +1386,60 @@ sigUsr1Handler(SIGNAL_ARGS)
 
 	errno = save_errno;
 }
+
+/*
+ * Store the name of the files where current log messages are written when
+ * log collector is enabled. Useful to find the name of the current log file
+ * when a time-based rotation is defined. Filenames are first stored into a
+ * temporary file and renamed into the final destination.
+ */
+static void
+logfile_writename(char *filename, char *csvfilename)
+{
+	FILE	*fh;
+	char	tempfn[MAXPGPATH];
+	char	logpathfilename[MAXPGPATH];
+
+	snprintf(tempfn, sizeof(tempfn), "%s",
+						CURRENT_LOG_FILENAME);
+	strcat(tempfn, ".tmp");
+	snprintf(logpathfilename, sizeof(logpathfilename), "%s",
+						CURRENT_LOG_FILENAME);
+	if ((fh = logfile_open(tempfn, "w", true) ) == NULL)
+	{
+		return;
+	}
+	if (filename && (Log_destination & LOG_DESTINATION_STDERR)) {
+		if (fprintf(fh, "stderr %s\n", filename) < 0)
+		{
+			ereport(LOG,
+					(errcode_for_file_access(),
+					errmsg("could not write log file \"%s\": %m",
+						tempfn)));
+			fclose(fh);
+			return;
+		}
+	}
+
+	if (csvfilename && (Log_destination & LOG_DESTINATION_CSVLOG)) {
+		if (fprintf(fh, "csvlog %s\n", csvfilename) < 0)
+		{
+			ereport(LOG,
+					(errcode_for_file_access(),
+					errmsg("could not write log file \"%s\": %m",
+						tempfn)));
+			fclose(fh);
+			return;
+		}
+	}
+	fclose(fh);
+
+	if (rename(tempfn, logpathfilename) != 0)
+	{
+		ereport(LOG,
+				(errcode_for_file_access(),
+				errmsg("could not rename file \"%s\": %m",
+						tempfn)));
+		return;
+	}
+}
diff --git a/src/backend/utils/adt/misc.c b/src/backend/utils/adt/misc.c
index 0da051a..06acdb2 100644
--- a/src/backend/utils/adt/misc.c
+++ b/src/backend/utils/adt/misc.c
@@ -19,6 +19,7 @@
 #include <dirent.h>
 #include <math.h>
 #include <unistd.h>
+#include <sys/stat.h>
 
 #include "access/sysattr.h"
 #include "catalog/pg_authid.h"
@@ -892,3 +893,122 @@ parse_ident(PG_FUNCTION_ARGS)
 
 	PG_RETURN_DATUM(makeArrayResult(astate, CurrentMemoryContext));
 }
+
+/*
+ * Report current log file used by log collector
+ */
+Datum
+pg_current_logfile(PG_FUNCTION_ARGS)
+{
+	FILE    *fd;
+	char    lbuffer[MAXPGPATH];
+	text    *fmt;
+	char    *logfmt;
+	struct stat stat_buf;
+	char    *log_format;
+	char    *log_filename;
+
+	/* The log format parameter is optional */
+	if (PG_NARGS() == 1) {
+		fmt = PG_ARGISNULL(0) ? NULL : PG_GETARG_TEXT_PP(0);
+		if (fmt != NULL) {
+			logfmt = text_to_cstring(fmt);
+			if ( (strcmp(logfmt, "stderr") != 0) &&
+				(strcmp(logfmt, "csvlog") != 0) ) {
+				ereport(ERROR,
+		(errmsg("log format %s not supported, possible values are stderr or csvlog", logfmt)));
+				PG_RETURN_NULL();
+			}
+		}
+	} else {
+		logfmt = NULL;
+	}
+
+	if (!Logging_collector)
+		PG_RETURN_NULL();
+
+	/* Check if current log file is present */
+	if (stat(CURRENT_LOG_FILENAME, &stat_buf) != 0)
+		PG_RETURN_NULL();
+
+	fd = AllocateFile(CURRENT_LOG_FILENAME, "r");
+	if (fd == NULL)
+	{
+		if (errno != ENOENT)
+			ereport(ERROR,
+				(errcode_for_file_access(),
+				errmsg("could not read file \"%s\": %m",
+				CURRENT_LOG_FILENAME)));
+		PG_RETURN_NULL();
+	}
+
+	/*
+	* Read the file to gather current log filename(s) registered
+	* by the syslogger.
+	*/
+	while (fgets(lbuffer, sizeof(lbuffer), fd) != NULL) {
+
+		/* Check for a read error. */
+		if (ferror(fd)) {
+			ereport(ERROR,
+				(errcode_for_file_access(),
+				errmsg("could not read file \"%s\": %m", CURRENT_LOG_FILENAME)));
+			FreeFile(fd);
+			break;
+		}
+
+		/* remove trailing newline */
+		if (strchr(lbuffer, '\n') != NULL)
+			*strchr(lbuffer, '\n') = '\0';
+
+		/* extract log format and log file path from the line */
+		log_format = strtok(lbuffer, " ");
+		if (log_format)
+		{
+			log_filename = strtok(NULL, " ");
+			if (!log_filename) {
+				ereport(ERROR,
+					(errmsg("unexpected line format in file %s", CURRENT_LOG_FILENAME)));
+				break;
+			}
+		}
+		else
+		{
+			ereport(ERROR,
+				(errmsg("unexpected line format in file %s", CURRENT_LOG_FILENAME)));
+			break;
+		}
+
+		/*
+		 * When no log format is provided as argument always reports
+		 * the first registered log file in CURRENT_LOG_FILENAME.
+		 */
+		if (logfmt == NULL)
+			break;
+
+		/* report the entry corresponding to the requested format */
+		if (strcmp(logfmt, log_format) == 0)
+			break;
+	}
+	/* Close the current log filename file. */
+	if (FreeFile(fd))
+		ereport(ERROR,
+				(errcode_for_file_access(),
+			errmsg("could not close file \"%s\": %m", CURRENT_LOG_FILENAME)));
+
+
+	if (log_filename[0] == '\0')
+		PG_RETURN_NULL();
+
+	/* Return null when csvlog is requested but we have a stderr log */
+	if ( (logfmt != NULL) && (strcmp(logfmt, "csvlog") == 0)
+			&& !(Log_destination & LOG_DESTINATION_CSVLOG) )
+		PG_RETURN_NULL();
+
+	/* Return null when stderr is requested but we have a csv log */
+	if ( (logfmt != NULL) && (strcmp(logfmt, "stderr") == 0)
+			&& !(Log_destination & LOG_DESTINATION_STDERR) )
+		PG_RETURN_NULL();
+
+	PG_RETURN_TEXT_P(cstring_to_text(log_filename));
+}
diff --git a/src/include/catalog/pg_proc.h b/src/include/catalog/pg_proc.h
index 17ec71d..78e23a6 100644
--- a/src/include/catalog/pg_proc.h
+++ b/src/include/catalog/pg_proc.h
@@ -3179,6 +3179,8 @@ DATA(insert OID = 2621 ( pg_reload_conf			PGNSP PGUID 12 1 0 0 0 f f f f t f v s
 DESCR("reload configuration files");
 DATA(insert OID = 2622 ( pg_rotate_logfile		PGNSP PGUID 12 1 0 0 0 f f f f t f v s 0 0 16 "" _null_ _null_ _null_ _null_ _null_ pg_rotate_logfile _null_ _null_ _null_ ));
 DESCR("rotate log file");
+DATA(insert OID = 3800 ( pg_current_logfile             PGNSP PGUID 12 1 0 0 0 f f f f f f v s 1 0 25 "25" _null_ _null_ _null_ _null_ _null_ pg_current_logfile _null_ _null_ _null_ ));
+DESCR("current logging collector file location");
 
 DATA(insert OID = 2623 ( pg_stat_file		PGNSP PGUID 12 1 0 0 0 f f f f t f v s 1 0 2249 "25" "{25,20,1184,1184,1184,1184,16}" "{i,o,o,o,o,o,o}" "{filename,size,access,modification,change,creation,isdir}" _null_ _null_ pg_stat_file_1arg _null_ _null_ _null_ ));
 DESCR("get information about file");
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 78545da..2faefdd 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -466,4 +466,12 @@ extern bool has_rolreplication(Oid roleid);
 extern bool BackupInProgress(void);
 extern void CancelBackup(void);
 
+/* in backend/utils/adt/misc.c and backend/postmaster/syslogger.c */
+/*
+ * Name of file where current log messages are written when log collector is
+ * enabled. Useful to find the name of the current log file when a time-based
+ * rotation is defined.
+ */
+#define CURRENT_LOG_FILENAME  "current_logfiles"
+
 #endif   /* MISCADMIN_H */
diff --git a/src/include/utils/builtins.h b/src/include/utils/builtins.h
index 90f5132..df9a1e1 100644
--- a/src/include/utils/builtins.h
+++ b/src/include/utils/builtins.h
@@ -522,6 +522,7 @@ extern Datum pg_collation_for(PG_FUNCTION_ARGS);
 extern Datum pg_relation_is_updatable(PG_FUNCTION_ARGS);
 extern Datum pg_column_is_updatable(PG_FUNCTION_ARGS);
 extern Datum parse_ident(PG_FUNCTION_ARGS);
+extern Datum pg_current_logfile(PG_FUNCTION_ARGS);
 
 /* oid.c */
 extern Datum oidin(PG_FUNCTION_ARGS);

diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 2e64cc4..d577bac 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -15443,6 +15443,19 @@ SELECT * FROM pg_ls_dir('.') WITH ORDINALITY AS t(ls,n);
       </row>
 
       <row>
+       <entry><literal><function>pg_current_logfile()</function></literal></entry>
+       <entry><type>text</type></entry>
+       <entry>primary log file name in use by the logging collector</entry>
+      </row>
+
+      <row>
+       <entry><literal><function>pg_current_logfile(<type>text</>)</function></literal></entry>
+       <entry><type>text</type></entry>
+       <entry>log file name, of log in the requested format, in use by the
+       logging collector</entry>
+      </row>
+
+      <row>
        <entry><literal><function>pg_my_temp_schema()</function></literal></entry>
        <entry><type>oid</type></entry>
        <entry>OID of session's temporary schema, or 0 if none</entry>
@@ -15660,6 +15673,29 @@ SET search_path TO <replaceable>schema</> <optional>, <replaceable>schema</>, ..
     the time when the postmaster process re-read the configuration files.)
    </para>
 
+    <indexterm>
+    <primary>pg_current_logile</primary>
+   </indexterm>
+
+   <para>
+    <function>pg_current_logfile</function> returns, as <type>text</type>,
+    the path of either the csv or stderr log file currently in use by the
+    logging collector.  This is a path including the
+    <xref linkend="guc-log-directory"> directory and the log file name.
+    Log collection must be active or the return value
+    is <literal>NULL</literal>.  When multiple logfiles exist, each in a
+    different format, <function>pg_current_logfile</function> called
+    without arguments returns the path of the file having the first format
+    found in the ordered
+    list: <systemitem>stderr</>, <systemitem>csvlog</>.
+    <literal>NULL</literal> is returned when no log file has any of these
+    formats.  To request a specific file format supply,
+    as <type>text</type>, either <systemitem>csvlog</>
+    or <systemitem>stderr</> as the value of the optional parameter. The
+    return value is <literal>NULL</literal> when the log format requested
+    is not a configured <xref linkend="guc-log-destination">.
+   </para>
+
    <indexterm>
     <primary>pg_my_temp_schema</primary>
    </indexterm>
diff --git a/doc/src/sgml/storage.sgml b/doc/src/sgml/storage.sgml
index fddb69b..5bea196 100644
--- a/doc/src/sgml/storage.sgml
+++ b/doc/src/sgml/storage.sgml
@@ -61,6 +61,18 @@ Item
 </row>
 
 <row>
+ <entry><filename>current_logfiles</></entry>
+ <entry>A file recording the current log file(s) used by the syslogger and
+  its log format, <systemitem>stderr</> or <systemitem>csvlog</>. Each line
+  of the file is a space separated list of two elements: the log format and
+  the full path to the log file including the value
+  of <xref linkend="guc-log-directory">. The log format must be present
+  in <xref linkend="guc-log-destination"> to be listed in the file. This file
+  is present only when <xref linkend="guc-logging-collector"> is
+  activated.</entry>
+</row>
+
+<row>
  <entry><filename>global</></entry>
  <entry>Subdirectory containing cluster-wide tables, such as
  <structname>pg_database</></entry>
diff --git a/src/backend/postmaster/syslogger.c b/src/backend/postmaster/syslogger.c
index fd62d66..5cb44d6 100644
--- a/src/backend/postmaster/syslogger.c
+++ b/src/backend/postmaster/syslogger.c
@@ -146,6 +146,7 @@ static char *logfile_getname(pg_time_t timestamp, const char *suffix);
 static void set_next_rotation_time(void);
 static void sigHupHandler(SIGNAL_ARGS);
 static void sigUsr1Handler(SIGNAL_ARGS);
+static void logfile_writename(char *filename, char *csvfilename);
 
 
 /*
@@ -348,6 +349,13 @@ SysLoggerMain(int argc, char *argv[])
 				rotation_disabled = false;
 				rotation_requested = true;
 			}
+
+			/*
+			 * Force rewriting last log filename when reloading configuration,
+			 * log_destination and logging_collector may have been changed. Do
+			 * it right now to not wait for the next file rotation.
+			 */
+			logfile_writename(last_file_name, last_csv_file_name);
 		}
 
 		if (Log_RotationAge > 0 && !rotation_disabled)
@@ -513,8 +521,14 @@ SysLogger_Start(void)
 	pid_t		sysloggerPid;
 	char	   *filename;
 
-	if (!Logging_collector)
+	if (!Logging_collector) {
+		/* If logging collector is not enabled, remove current log
+		 * filename as we don't know where messages are logged and
+		 * information contained in this file are obsolete.
+		 */
+		unlink(CURRENT_LOG_FILENAME);
 		return 0;
+	}
 
 	/*
 	 * If first time through, create the pipe which will receive stderr
@@ -574,6 +588,8 @@ SysLogger_Start(void)
 
 	syslogFile = logfile_open(filename, "a", false);
 
+	logfile_writename(filename, NULL);
+
 	pfree(filename);
 
 #ifdef EXEC_BACKEND
@@ -988,8 +1004,10 @@ write_syslogger_file(const char *buffer, int count, int destination)
 	int			rc;
 	FILE	   *logfile;
 
-	if (destination == LOG_DESTINATION_CSVLOG && csvlogFile == NULL)
+	if (destination == LOG_DESTINATION_CSVLOG && csvlogFile == NULL) {
 		open_csvlogfile();
+		logfile_writename(last_file_name, last_csv_file_name);
+	}
 
 	logfile = destination == LOG_DESTINATION_CSVLOG ? csvlogFile : syslogFile;
 	rc = fwrite(buffer, 1, count, logfile);
@@ -1209,6 +1227,8 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for)
 			return;
 		}
 
+		logfile_writename(filename, csvfilename);
+
 		fclose(syslogFile);
 		syslogFile = fh;
 
@@ -1220,7 +1240,6 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for)
 	}
 
 	/* Same as above, but for csv file. */
-
 	if (csvlogFile != NULL &&
 		(time_based_rotation || (size_rotation_for & LOG_DESTINATION_CSVLOG)))
 	{
@@ -1253,6 +1272,8 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for)
 			return;
 		}
 
+		logfile_writename(last_file_name, csvfilename);
+
 		fclose(csvlogFile);
 		csvlogFile = fh;
 
@@ -1365,3 +1386,60 @@ sigUsr1Handler(SIGNAL_ARGS)
 
 	errno = save_errno;
 }
+
+/*
+ * Store the name of the files where current log messages are written when
+ * log collector is enabled. Useful to find the name of the current log file
+ * when a time-based rotation is defined. Filenames are first stored into a
+ * temporary file and renamed into the final destination.
+ */
+static void
+logfile_writename(char *filename, char *csvfilename)
+{
+	FILE	*fh;
+	char	tempfn[MAXPGPATH];
+	char	logpathfilename[MAXPGPATH];
+
+	snprintf(tempfn, sizeof(tempfn), "%s",
+						CURRENT_LOG_FILENAME);
+	strcat(tempfn, ".tmp");
+	snprintf(logpathfilename, sizeof(logpathfilename), "%s",
+						CURRENT_LOG_FILENAME);
+	if ((fh = logfile_open(tempfn, "w", true) ) == NULL)
+	{
+		return;
+	}
+	if (filename && (Log_destination & LOG_DESTINATION_STDERR)) {
+		if (fprintf(fh, "stderr %s\n", filename) < 0)
+		{
+			ereport(LOG,
+					(errcode_for_file_access(),
+					errmsg("could not write log file \"%s\": %m",
+						tempfn)));
+			fclose(fh);
+			return;
+		}
+	}
+
+	if (csvfilename && (Log_destination & LOG_DESTINATION_CSVLOG)) {
+		if (fprintf(fh, "csvlog %s\n", csvfilename) < 0)
+		{
+			ereport(LOG,
+					(errcode_for_file_access(),
+					errmsg("could not write log file \"%s\": %m",
+						tempfn)));
+			fclose(fh);
+			return;
+		}
+	}
+	fclose(fh);
+
+	if (rename(tempfn, logpathfilename) != 0)
+	{
+		ereport(LOG,
+				(errcode_for_file_access(),
+				errmsg("could not rename file \"%s\": %m",
+						tempfn)));
+		return;
+	}
+}
diff --git a/src/backend/utils/adt/misc.c b/src/backend/utils/adt/misc.c
index 0da051a..06acdb2 100644
--- a/src/backend/utils/adt/misc.c
+++ b/src/backend/utils/adt/misc.c
@@ -19,6 +19,7 @@
 #include <dirent.h>
 #include <math.h>
 #include <unistd.h>
+#include <sys/stat.h>
 
 #include "access/sysattr.h"
 #include "catalog/pg_authid.h"
@@ -892,3 +893,122 @@ parse_ident(PG_FUNCTION_ARGS)
 
 	PG_RETURN_DATUM(makeArrayResult(astate, CurrentMemoryContext));
 }
+
+/*
+ * Report current log file used by log collector
+ */
+Datum
+pg_current_logfile(PG_FUNCTION_ARGS)
+{
+	FILE    *fd;
+	char    lbuffer[MAXPGPATH];
+	text    *fmt;
+	char    *logfmt;
+	struct stat stat_buf;
+	char    *log_format;
+	char    *log_filename;
+
+	/* The log format parameter is optional */
+	if (PG_NARGS() == 1) {
+		fmt = PG_ARGISNULL(0) ? NULL : PG_GETARG_TEXT_PP(0);
+		if (fmt != NULL) {
+			logfmt = text_to_cstring(fmt);
+			if ( (strcmp(logfmt, "stderr") != 0) &&
+				(strcmp(logfmt, "csvlog") != 0) ) {
+				ereport(ERROR,
+		(errmsg("log format %s not supported, possible values are stderr or csvlog", logfmt)));
+				PG_RETURN_NULL();
+			}
+		}
+	} else {
+		logfmt = NULL;
+	}
+
+	if (!Logging_collector)
+		PG_RETURN_NULL();
+
+	/* Check if current log file is present */
+	if (stat(CURRENT_LOG_FILENAME, &stat_buf) != 0)
+		PG_RETURN_NULL();
+
+	fd = AllocateFile(CURRENT_LOG_FILENAME, "r");
+	if (fd == NULL)
+	{
+		if (errno != ENOENT)
+			ereport(ERROR,
+				(errcode_for_file_access(),
+				errmsg("could not read file \"%s\": %m",
+				CURRENT_LOG_FILENAME)));
+		PG_RETURN_NULL();
+	}
+
+	/*
+	* Read the file to gather current log filename(s) registered
+	* by the syslogger.
+	*/
+	while (fgets(lbuffer, sizeof(lbuffer), fd) != NULL) {
+
+		/* Check for a read error. */
+		if (ferror(fd)) {
+			ereport(ERROR,
+				(errcode_for_file_access(),
+				errmsg("could not read file \"%s\": %m", CURRENT_LOG_FILENAME)));
+			FreeFile(fd);
+			break;
+		}
+
+		/* remove trailing newline */
+		if (strchr(lbuffer, '\n') != NULL)
+			*strchr(lbuffer, '\n') = '\0';
+
+		/* extract log format and log file path from the line */
+		log_format = strtok(lbuffer, " ");
+		if (log_format)
+		{
+			log_filename = strtok(NULL, " ");
+			if (!log_filename) {
+				ereport(ERROR,
+					(errmsg("unexpected line format in file %s", CURRENT_LOG_FILENAME)));
+				break;
+			}
+		}
+		else
+		{
+			ereport(ERROR,
+				(errmsg("unexpected line format in file %s", CURRENT_LOG_FILENAME)));
+			break;
+		}
+
+		/*
+		 * When no log format is provided as argument always reports
+		 * the first registered log file in CURRENT_LOG_FILENAME.
+		 */
+		if (logfmt == NULL)
+			break;
+
+		/* report the entry corresponding to the requested format */
+		if (strcmp(logfmt, log_format) == 0)
+			break;
+	}
+	/* Close the current log filename file. */
+	if (FreeFile(fd))
+		ereport(ERROR,
+				(errcode_for_file_access(),
+			errmsg("could not close file \"%s\": %m", CURRENT_LOG_FILENAME)));
+
+
+	if (log_filename[0] == '\0')
+		PG_RETURN_NULL();
+
+	/* Return null when csvlog is requested but we have a stderr log */
+	if ( (logfmt != NULL) && (strcmp(logfmt, "csvlog") == 0)
+			&& !(Log_destination & LOG_DESTINATION_CSVLOG) )
+		PG_RETURN_NULL();
+
+	/* Return null when stderr is requested but we have a csv log */
+	if ( (logfmt != NULL) && (strcmp(logfmt, "stderr") == 0)
+			&& !(Log_destination & LOG_DESTINATION_STDERR) )
+		PG_RETURN_NULL();
+
+	PG_RETURN_TEXT_P(cstring_to_text(log_filename));
+}
diff --git a/src/include/catalog/pg_proc.h b/src/include/catalog/pg_proc.h
index 17ec71d..78e23a6 100644
--- a/src/include/catalog/pg_proc.h
+++ b/src/include/catalog/pg_proc.h
@@ -3179,6 +3179,8 @@ DATA(insert OID = 2621 ( pg_reload_conf			PGNSP PGUID 12 1 0 0 0 f f f f t f v s
 DESCR("reload configuration files");
 DATA(insert OID = 2622 ( pg_rotate_logfile		PGNSP PGUID 12 1 0 0 0 f f f f t f v s 0 0 16 "" _null_ _null_ _null_ _null_ _null_ pg_rotate_logfile _null_ _null_ _null_ ));
 DESCR("rotate log file");
+DATA(insert OID = 3800 ( pg_current_logfile             PGNSP PGUID 12 1 0 0 0 f f f f f f v s 1 0 25 "25" _null_ _null_ _null_ _null_ _null_ pg_current_logfile _null_ _null_ _null_ ));
+DESCR("current logging collector file location");
 
 DATA(insert OID = 2623 ( pg_stat_file		PGNSP PGUID 12 1 0 0 0 f f f f t f v s 1 0 2249 "25" "{25,20,1184,1184,1184,1184,16}" "{i,o,o,o,o,o,o}" "{filename,size,access,modification,change,creation,isdir}" _null_ _null_ pg_stat_file_1arg _null_ _null_ _null_ ));
 DESCR("get information about file");
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 78545da..2faefdd 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -466,4 +466,12 @@ extern bool has_rolreplication(Oid roleid);
 extern bool BackupInProgress(void);
 extern void CancelBackup(void);
 
+/* in backend/utils/adt/misc.c and backend/postmaster/syslogger.c */
+/*
+ * Name of file where current log messages are written when log collector is
+ * enabled. Useful to find the name of the current log file when a time-based
+ * rotation is defined.
+ */
+#define CURRENT_LOG_FILENAME  "current_logfiles"
+
 #endif   /* MISCADMIN_H */
diff --git a/src/include/utils/builtins.h b/src/include/utils/builtins.h
index 90f5132..df9a1e1 100644
--- a/src/include/utils/builtins.h
+++ b/src/include/utils/builtins.h
@@ -522,6 +522,7 @@ extern Datum pg_collation_for(PG_FUNCTION_ARGS);
 extern Datum pg_relation_is_updatable(PG_FUNCTION_ARGS);
 extern Datum pg_column_is_updatable(PG_FUNCTION_ARGS);
 extern Datum parse_ident(PG_FUNCTION_ARGS);
+extern Datum pg_current_logfile(PG_FUNCTION_ARGS);
 
 /* oid.c */
 extern Datum oidin(PG_FUNCTION_ARGS);

diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index bdae4c6..d577bac 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -15442,6 +15442,7 @@ SELECT * FROM pg_ls_dir('.') WITH ORDINALITY AS t(ls,n);
        <entry>configuration load time</entry>
       </row>
 
+      <row>
        <entry><literal><function>pg_current_logfile()</function></literal></entry>
        <entry><type>text</type></entry>
        <entry>primary log file name in use by the logging collector</entry>
diff --git a/doc/src/sgml/storage.sgml b/doc/src/sgml/storage.sgml
index 6e8ae05..5bea196 100644
--- a/doc/src/sgml/storage.sgml
+++ b/doc/src/sgml/storage.sgml
@@ -63,12 +63,13 @@ Item
 <row>
  <entry><filename>current_logfiles</></entry>
  <entry>A file recording the current log file(s) used by the syslogger and
-  its log format, stderr or csvlog. Each line of the file is a space separated
-  list of two elements: the log format and the full path to the log file
-  including the value of <xref linkend="guc-log-directory">. The log format
-  must be present in <xref linkend="guc-log-destination"> to be listed in the
-  file. This file is present only when <xref linkend="guc-logging-collector">
-  is activated.</entry>
+  its log format, <systemitem>stderr</> or <systemitem>csvlog</>. Each line
+  of the file is a space separated list of two elements: the log format and
+  the full path to the log file including the value
+  of <xref linkend="guc-log-directory">. The log format must be present
+  in <xref linkend="guc-log-destination"> to be listed in the file. This file
+  is present only when <xref linkend="guc-logging-collector"> is
+  activated.</entry>
 </row>
 
 <row>

diff --git a/src/backend/postmaster/syslogger.c b/src/backend/postmaster/syslogger.c
index 5cb44d6..8fc4531 100644
--- a/src/backend/postmaster/syslogger.c
+++ b/src/backend/postmaster/syslogger.c
@@ -351,9 +351,8 @@ SysLoggerMain(int argc, char *argv[])
 			}
 
 			/*
-			 * Force rewriting last log filename when reloading configuration,
-			 * log_destination and logging_collector may have been changed. Do
-			 * it right now to not wait for the next file rotation.
+			 * log_destination and logging_collector may have changed; rewrite
+			 * current log filename.
 			 */
 			logfile_writename(last_file_name, last_csv_file_name);
 		}
@@ -522,9 +521,8 @@ SysLogger_Start(void)
 	char	   *filename;
 
 	if (!Logging_collector) {
-		/* If logging collector is not enabled, remove current log
-		 * filename as we don't know where messages are logged and
-		 * information contained in this file are obsolete.
+		/* Logging collector is not enabled.  We don't know where messages are
+		 * logged.  Remove outdated file holding the current log filenames.
 		 */
 		unlink(CURRENT_LOG_FILENAME);
 		return 0;
@@ -1388,10 +1386,10 @@ sigUsr1Handler(SIGNAL_ARGS)
 }
 
 /*
- * Store the name of the files where current log messages are written when
- * log collector is enabled. Useful to find the name of the current log file
- * when a time-based rotation is defined. Filenames are first stored into a
- * temporary file and renamed into the final destination.
+ * Store the name of the file(s) where the log collector, when enabled, writes
+ * log messages.  Useful for finding the name(s) of the current log file(s)
+ * when there is time-based logfile rotation.  Filenames are stored in a
+ * temporary file and renamed into the final destination for atomicity.
  */
 static void
 logfile_writename(char *filename, char *csvfilename)

diff --git a/src/backend/postmaster/syslogger.c b/src/backend/postmaster/syslogger.c
index 8fc4531..041d34d 100644
--- a/src/backend/postmaster/syslogger.c
+++ b/src/backend/postmaster/syslogger.c
@@ -1002,10 +1002,8 @@ write_syslogger_file(const char *buffer, int count, int destination)
 	int			rc;
 	FILE	   *logfile;
 
-	if (destination == LOG_DESTINATION_CSVLOG && csvlogFile == NULL) {
+	if (destination == LOG_DESTINATION_CSVLOG && csvlogFile == NULL)
 		open_csvlogfile();
-		logfile_writename(last_file_name, last_csv_file_name);
-	}
 
 	logfile = destination == LOG_DESTINATION_CSVLOG ? csvlogFile : syslogFile;
 	rc = fwrite(buffer, 1, count, logfile);
@@ -1114,6 +1112,8 @@ open_csvlogfile(void)
 		pfree(last_csv_file_name);
 
 	last_csv_file_name = filename;
+
+	logfile_writename(last_file_name, last_csv_file_name);
 }
 
 /*

diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 2e64cc4..d577bac 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -15443,6 +15443,19 @@ SELECT * FROM pg_ls_dir('.') WITH ORDINALITY AS t(ls,n);
       </row>
 
       <row>
+       <entry><literal><function>pg_current_logfile()</function></literal></entry>
+       <entry><type>text</type></entry>
+       <entry>primary log file name in use by the logging collector</entry>
+      </row>
+
+      <row>
+       <entry><literal><function>pg_current_logfile(<type>text</>)</function></literal></entry>
+       <entry><type>text</type></entry>
+       <entry>log file name, of log in the requested format, in use by the
+       logging collector</entry>
+      </row>
+
+      <row>
        <entry><literal><function>pg_my_temp_schema()</function></literal></entry>
        <entry><type>oid</type></entry>
        <entry>OID of session's temporary schema, or 0 if none</entry>
@@ -15660,6 +15673,29 @@ SET search_path TO <replaceable>schema</> <optional>, <replaceable>schema</>, ..
     the time when the postmaster process re-read the configuration files.)
    </para>
 
+    <indexterm>
+    <primary>pg_current_logile</primary>
+   </indexterm>
+
+   <para>
+    <function>pg_current_logfile</function> returns, as <type>text</type>,
+    the path of either the csv or stderr log file currently in use by the
+    logging collector.  This is a path including the
+    <xref linkend="guc-log-directory"> directory and the log file name.
+    Log collection must be active or the return value
+    is <literal>NULL</literal>.  When multiple logfiles exist, each in a
+    different format, <function>pg_current_logfile</function> called
+    without arguments returns the path of the file having the first format
+    found in the ordered
+    list: <systemitem>stderr</>, <systemitem>csvlog</>.
+    <literal>NULL</literal> is returned when no log file has any of these
+    formats.  To request a specific file format supply,
+    as <type>text</type>, either <systemitem>csvlog</>
+    or <systemitem>stderr</> as the value of the optional parameter. The
+    return value is <literal>NULL</literal> when the log format requested
+    is not a configured <xref linkend="guc-log-destination">.
+   </para>
+
    <indexterm>
     <primary>pg_my_temp_schema</primary>
    </indexterm>
diff --git a/doc/src/sgml/storage.sgml b/doc/src/sgml/storage.sgml
index fddb69b..5bea196 100644
--- a/doc/src/sgml/storage.sgml
+++ b/doc/src/sgml/storage.sgml
@@ -61,6 +61,18 @@ Item
 </row>
 
 <row>
+ <entry><filename>current_logfiles</></entry>
+ <entry>A file recording the current log file(s) used by the syslogger and
+  its log format, <systemitem>stderr</> or <systemitem>csvlog</>. Each line
+  of the file is a space separated list of two elements: the log format and
+  the full path to the log file including the value
+  of <xref linkend="guc-log-directory">. The log format must be present
+  in <xref linkend="guc-log-destination"> to be listed in the file. This file
+  is present only when <xref linkend="guc-logging-collector"> is
+  activated.</entry>
+</row>
+
+<row>
  <entry><filename>global</></entry>
  <entry>Subdirectory containing cluster-wide tables, such as
  <structname>pg_database</></entry>
diff --git a/src/backend/postmaster/syslogger.c b/src/backend/postmaster/syslogger.c
index fd62d66..83afc34 100644
--- a/src/backend/postmaster/syslogger.c
+++ b/src/backend/postmaster/syslogger.c
@@ -146,6 +146,7 @@ static char *logfile_getname(pg_time_t timestamp, const char *suffix);
 static void set_next_rotation_time(void);
 static void sigHupHandler(SIGNAL_ARGS);
 static void sigUsr1Handler(SIGNAL_ARGS);
+static void logfile_writename(char *filename, char *csvfilename);
 
 
 /*
@@ -348,6 +349,13 @@ SysLoggerMain(int argc, char *argv[])
 				rotation_disabled = false;
 				rotation_requested = true;
 			}
+
+			/*
+			 * Force rewriting last log filename when reloading configuration,
+			 * log_destination and logging_collector may have been changed. Do
+			 * it right now to not wait for the next file rotation.
+			 */
+			logfile_writename(last_file_name, last_csv_file_name);
 		}
 
 		if (Log_RotationAge > 0 && !rotation_disabled)
@@ -513,8 +521,13 @@ SysLogger_Start(void)
 	pid_t		sysloggerPid;
 	char	   *filename;
 
-	if (!Logging_collector)
+	if (!Logging_collector) {
+		/* Logging collector is not enabled. We don't know where messages are
+		 * logged.  Remove outdated file holding the current log filenames.
+		 */
+		unlink(CURRENT_LOG_FILENAME);
 		return 0;
+	}
 
 	/*
 	 * If first time through, create the pipe which will receive stderr
@@ -574,6 +587,8 @@ SysLogger_Start(void)
 
 	syslogFile = logfile_open(filename, "a", false);
 
+	logfile_writename(filename, NULL);
+
 	pfree(filename);
 
 #ifdef EXEC_BACKEND
@@ -1098,6 +1113,8 @@ open_csvlogfile(void)
 		pfree(last_csv_file_name);
 
 	last_csv_file_name = filename;
+
+	logfile_writename(last_file_name, last_csv_file_name);
 }
 
 /*
@@ -1209,6 +1226,8 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for)
 			return;
 		}
 
+		logfile_writename(filename, csvfilename);
+
 		fclose(syslogFile);
 		syslogFile = fh;
 
@@ -1220,7 +1239,6 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for)
 	}
 
 	/* Same as above, but for csv file. */
-
 	if (csvlogFile != NULL &&
 		(time_based_rotation || (size_rotation_for & LOG_DESTINATION_CSVLOG)))
 	{
@@ -1253,6 +1271,8 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for)
 			return;
 		}
 
+		logfile_writename(last_file_name, csvfilename);
+
 		fclose(csvlogFile);
 		csvlogFile = fh;
 
@@ -1365,3 +1385,60 @@ sigUsr1Handler(SIGNAL_ARGS)
 
 	errno = save_errno;
 }
+
+/*
+ * Store the name of the file(s) where the log collector, when enabled, writes
+ * log messages.  Useful for finding the name(s) of the current log file(s)
+ * when there is time-based logfile rotation.  Filenames are stored in a
+ * temporary file and renamed into the final destination for atomicity.
+ */
+static void
+logfile_writename(char *filename, char *csvfilename)
+{
+	FILE	*fh;
+	char	tempfn[MAXPGPATH];
+	char	logpathfilename[MAXPGPATH];
+
+	snprintf(tempfn, sizeof(tempfn), "%s",
+						CURRENT_LOG_FILENAME);
+	strcat(tempfn, ".tmp");
+	snprintf(logpathfilename, sizeof(logpathfilename), "%s",
+						CURRENT_LOG_FILENAME);
+	if ((fh = logfile_open(tempfn, "w", true) ) == NULL)
+	{
+		return;
+	}
+	if (filename && (Log_destination & LOG_DESTINATION_STDERR)) {
+		if (fprintf(fh, "stderr %s\n", filename) < 0)
+		{
+			ereport(LOG,
+					(errcode_for_file_access(),
+					errmsg("could not write log file \"%s\": %m",
+						tempfn)));
+			fclose(fh);
+			return;
+		}
+	}
+
+	if (csvfilename && (Log_destination & LOG_DESTINATION_CSVLOG)) {
+		if (fprintf(fh, "csvlog %s\n", csvfilename) < 0)
+		{
+			ereport(LOG,
+					(errcode_for_file_access(),
+					errmsg("could not write log file \"%s\": %m",
+						tempfn)));
+			fclose(fh);
+			return;
+		}
+	}
+	fclose(fh);
+
+	if (rename(tempfn, logpathfilename) != 0)
+	{
+		ereport(LOG,
+				(errcode_for_file_access(),
+				errmsg("could not rename file \"%s\": %m",
+						tempfn)));
+		return;
+	}
+}
diff --git a/src/backend/utils/adt/misc.c b/src/backend/utils/adt/misc.c
index 0da051a..06acdb2 100644
--- a/src/backend/utils/adt/misc.c
+++ b/src/backend/utils/adt/misc.c
@@ -19,6 +19,7 @@
 #include <dirent.h>
 #include <math.h>
 #include <unistd.h>
+#include <sys/stat.h>
 
 #include "access/sysattr.h"
 #include "catalog/pg_authid.h"
@@ -892,3 +893,122 @@ parse_ident(PG_FUNCTION_ARGS)
 
 	PG_RETURN_DATUM(makeArrayResult(astate, CurrentMemoryContext));
 }
+
+/*
+ * Report current log file used by log collector
+ */
+Datum
+pg_current_logfile(PG_FUNCTION_ARGS)
+{
+	FILE    *fd;
+	char    lbuffer[MAXPGPATH];
+	text    *fmt;
+	char    *logfmt;
+	struct stat stat_buf;
+	char    *log_format;
+	char    *log_filename;
+
+	/* The log format parameter is optional */
+	if (PG_NARGS() == 1) {
+		fmt = PG_ARGISNULL(0) ? NULL : PG_GETARG_TEXT_PP(0);
+		if (fmt != NULL) {
+			logfmt = text_to_cstring(fmt);
+			if ( (strcmp(logfmt, "stderr") != 0) &&
+				(strcmp(logfmt, "csvlog") != 0) ) {
+				ereport(ERROR,
+		(errmsg("log format %s not supported, possible values are stderr or csvlog", logfmt)));
+				PG_RETURN_NULL();
+			}
+		}
+	} else {
+		logfmt = NULL;
+	}
+
+	if (!Logging_collector)
+		PG_RETURN_NULL();
+
+	/* Check if current log file is present */
+	if (stat(CURRENT_LOG_FILENAME, &stat_buf) != 0)
+		PG_RETURN_NULL();
+
+	fd = AllocateFile(CURRENT_LOG_FILENAME, "r");
+	if (fd == NULL)
+	{
+		if (errno != ENOENT)
+			ereport(ERROR,
+				(errcode_for_file_access(),
+				errmsg("could not read file \"%s\": %m",
+				CURRENT_LOG_FILENAME)));
+		PG_RETURN_NULL();
+	}
+
+	/*
+	* Read the file to gather current log filename(s) registered
+	* by the syslogger.
+	*/
+	while (fgets(lbuffer, sizeof(lbuffer), fd) != NULL) {
+
+		/* Check for a read error. */
+		if (ferror(fd)) {
+			ereport(ERROR,
+				(errcode_for_file_access(),
+				errmsg("could not read file \"%s\": %m", CURRENT_LOG_FILENAME)));
+			FreeFile(fd);
+			break;
+		}
+
+		/* remove trailing newline */
+		if (strchr(lbuffer, '\n') != NULL)
+			*strchr(lbuffer, '\n') = '\0';
+
+		/* extract log format and log file path from the line */
+		log_format = strtok(lbuffer, " ");
+		if (log_format)
+		{
+			log_filename = strtok(NULL, " ");
+			if (!log_filename) {
+				ereport(ERROR,
+					(errmsg("unexpected line format in file %s", CURRENT_LOG_FILENAME)));
+				break;
+			}
+		}
+		else
+		{
+			ereport(ERROR,
+				(errmsg("unexpected line format in file %s", CURRENT_LOG_FILENAME)));
+			break;
+		}
+
+		/*
+		 * When no log format is provided as argument always reports
+		 * the first registered log file in CURRENT_LOG_FILENAME.
+		 */
+		if (logfmt == NULL)
+			break;
+
+		/* report the entry corresponding to the requested format */
+		if (strcmp(logfmt, log_format) == 0)
+			break;
+	}
+	/* Close the current log filename file. */
+	if (FreeFile(fd))
+		ereport(ERROR,
+				(errcode_for_file_access(),
+			errmsg("could not close file \"%s\": %m", CURRENT_LOG_FILENAME)));
+
+
+	if (log_filename[0] == '\0')
+		PG_RETURN_NULL();
+
+	/* Return null when csvlog is requested but we have a stderr log */
+	if ( (logfmt != NULL) && (strcmp(logfmt, "csvlog") == 0)
+			&& !(Log_destination & LOG_DESTINATION_CSVLOG) )
+		PG_RETURN_NULL();
+
+	/* Return null when stderr is requested but we have a csv log */
+	if ( (logfmt != NULL) && (strcmp(logfmt, "stderr") == 0)
+			&& !(Log_destination & LOG_DESTINATION_STDERR) )
+		PG_RETURN_NULL();
+
+	PG_RETURN_TEXT_P(cstring_to_text(log_filename));
+}
diff --git a/src/include/catalog/pg_proc.h b/src/include/catalog/pg_proc.h
index 17ec71d..78e23a6 100644
--- a/src/include/catalog/pg_proc.h
+++ b/src/include/catalog/pg_proc.h
@@ -3179,6 +3179,8 @@ DATA(insert OID = 2621 ( pg_reload_conf			PGNSP PGUID 12 1 0 0 0 f f f f t f v s
 DESCR("reload configuration files");
 DATA(insert OID = 2622 ( pg_rotate_logfile		PGNSP PGUID 12 1 0 0 0 f f f f t f v s 0 0 16 "" _null_ _null_ _null_ _null_ _null_ pg_rotate_logfile _null_ _null_ _null_ ));
 DESCR("rotate log file");
+DATA(insert OID = 3800 ( pg_current_logfile             PGNSP PGUID 12 1 0 0 0 f f f f f f v s 1 0 25 "25" _null_ _null_ _null_ _null_ _null_ pg_current_logfile _null_ _null_ _null_ ));
+DESCR("current logging collector file location");
 
 DATA(insert OID = 2623 ( pg_stat_file		PGNSP PGUID 12 1 0 0 0 f f f f t f v s 1 0 2249 "25" "{25,20,1184,1184,1184,1184,16}" "{i,o,o,o,o,o,o}" "{filename,size,access,modification,change,creation,isdir}" _null_ _null_ pg_stat_file_1arg _null_ _null_ _null_ ));
 DESCR("get information about file");
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 78545da..2faefdd 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -466,4 +466,12 @@ extern bool has_rolreplication(Oid roleid);
 extern bool BackupInProgress(void);
 extern void CancelBackup(void);
 
+/* in backend/utils/adt/misc.c and backend/postmaster/syslogger.c */
+/*
+ * Name of file where current log messages are written when log collector is
+ * enabled. Useful to find the name of the current log file when a time-based
+ * rotation is defined.
+ */
+#define CURRENT_LOG_FILENAME  "current_logfiles"
+
 #endif   /* MISCADMIN_H */
diff --git a/src/include/utils/builtins.h b/src/include/utils/builtins.h
index 90f5132..df9a1e1 100644
--- a/src/include/utils/builtins.h
+++ b/src/include/utils/builtins.h
@@ -522,6 +522,7 @@ extern Datum pg_collation_for(PG_FUNCTION_ARGS);
 extern Datum pg_relation_is_updatable(PG_FUNCTION_ARGS);
 extern Datum pg_column_is_updatable(PG_FUNCTION_ARGS);
 extern Datum parse_ident(PG_FUNCTION_ARGS);
+extern Datum pg_current_logfile(PG_FUNCTION_ARGS);
 
 /* oid.c */
 extern Datum oidin(PG_FUNCTION_ARGS);

diff --git a/src/backend/postmaster/syslogger.c b/src/backend/postmaster/syslogger.c
index 83afc34..9aa5247 100644
--- a/src/backend/postmaster/syslogger.c
+++ b/src/backend/postmaster/syslogger.c
@@ -45,6 +45,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "utils/guc.h"
+#include "utils/guc_values.h"
 #include "utils/ps_status.h"
 #include "utils/timestamp.h"
 
@@ -1409,7 +1410,7 @@ logfile_writename(char *filename, char *csvfilename)
 		return;
 	}
 	if (filename && (Log_destination & LOG_DESTINATION_STDERR)) {
-		if (fprintf(fh, "stderr %s\n", filename) < 0)
+		if (fprintf(fh, GUCV_STDERR " %s\n", filename) < 0)
 		{
 			ereport(LOG,
 					(errcode_for_file_access(),
@@ -1421,7 +1422,7 @@ logfile_writename(char *filename, char *csvfilename)
 	}
 
 	if (csvfilename && (Log_destination & LOG_DESTINATION_CSVLOG)) {
-		if (fprintf(fh, "csvlog %s\n", csvfilename) < 0)
+		if (fprintf(fh, GUCV_CSVLOG " %s\n", csvfilename) < 0)
 		{
 			ereport(LOG,
 					(errcode_for_file_access(),
diff --git a/src/backend/utils/adt/misc.c b/src/backend/utils/adt/misc.c
index 06acdb2..e2d1939 100644
--- a/src/backend/utils/adt/misc.c
+++ b/src/backend/utils/adt/misc.c
@@ -43,6 +43,7 @@
 #include "tcop/tcopprot.h"
 #include "utils/acl.h"
 #include "utils/builtins.h"
+#include "utils/guc_values.h"
 #include "utils/timestamp.h"
 
 #define atooid(x)  ((Oid) strtoul((x), NULL, 10))
@@ -913,10 +914,11 @@ pg_current_logfile(PG_FUNCTION_ARGS)
 		fmt = PG_ARGISNULL(0) ? NULL : PG_GETARG_TEXT_PP(0);
 		if (fmt != NULL) {
 			logfmt = text_to_cstring(fmt);
-			if ( (strcmp(logfmt, "stderr") != 0) &&
-				(strcmp(logfmt, "csvlog") != 0) ) {
+			if ( (strcmp(logfmt, GUCV_STDERR) != 0) &&
+				(strcmp(logfmt, GUCV_CSVLOG) != 0) ) {
 				ereport(ERROR,
-		(errmsg("log format %s not supported, possible values are stderr or csvlog", logfmt)));
+		(errmsg("log format %s not supported, possible values are "
+				GUCV_STDERR " or " GUCV_CSVLOG, logfmt)));
 				PG_RETURN_NULL();
 			}
 		}
@@ -1001,12 +1003,12 @@ pg_current_logfile(PG_FUNCTION_ARGS)
 		PG_RETURN_NULL();
 
 	/* Return null when csvlog is requested but we have a stderr log */
-	if ( (logfmt != NULL) && (strcmp(logfmt, "csvlog") == 0)
+	if ( (logfmt != NULL) && (strcmp(logfmt, GUCV_CSVLOG) == 0)
 			&& !(Log_destination & LOG_DESTINATION_CSVLOG) )
 		PG_RETURN_NULL();
 
 	/* Return null when stderr is requested but we have a csv log */
-	if ( (logfmt != NULL) && (strcmp(logfmt, "stderr") == 0)
+	if ( (logfmt != NULL) && (strcmp(logfmt, GUCV_STDERR) == 0)
 			&& !(Log_destination & LOG_DESTINATION_STDERR) )
 		PG_RETURN_NULL();
 

diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index 65660c1..eb77a3c 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -75,6 +75,7 @@
 #include "utils/builtins.h"
 #include "utils/bytea.h"
 #include "utils/guc_tables.h"
+#include "utils/guc_values.h"
 #include "utils/memutils.h"
 #include "utils/pg_locale.h"
 #include "utils/plancache.h"
@@ -3256,13 +3257,13 @@ static struct config_string ConfigureNamesString[] =
 	{
 		{"log_destination", PGC_SIGHUP, LOGGING_WHERE,
 			gettext_noop("Sets the destination for server log output."),
-			gettext_noop("Valid values are combinations of \"stderr\", "
-						 "\"syslog\", \"csvlog\", and \"eventlog\", "
-						 "depending on the platform."),
+			gettext_noop("Valid values are combinations of \"" GUCV_STDERR
+						  "\", \"" GUCV_SYSLOG "\", \"" GUCV_CSVLOG "\", and "
+						 "\"" GUCV_EVENTLOG "\", depending on the platform."),
 			GUC_LIST_INPUT
 		},
 		&Log_destination_string,
-		"stderr",
+		GUCV_STDERR,
 		check_log_destination, assign_log_destination, NULL
 	},
 	{
@@ -9892,16 +9893,16 @@ check_log_destination(char **newval, void **extra, GucSource source)
 	{
 		char	   *tok = (char *) lfirst(l);
 
-		if (pg_strcasecmp(tok, "stderr") == 0)
+		if (pg_strcasecmp(tok, GUCV_STDERR) == 0)
 			newlogdest |= LOG_DESTINATION_STDERR;
-		else if (pg_strcasecmp(tok, "csvlog") == 0)
+		else if (pg_strcasecmp(tok, GUCV_CSVLOG) == 0)
 			newlogdest |= LOG_DESTINATION_CSVLOG;
 #ifdef HAVE_SYSLOG
-		else if (pg_strcasecmp(tok, "syslog") == 0)
+		else if (pg_strcasecmp(tok, GUCV_SYSLOG) == 0)
 			newlogdest |= LOG_DESTINATION_SYSLOG;
 #endif
 #ifdef WIN32
-		else if (pg_strcasecmp(tok, "eventlog") == 0)
+		else if (pg_strcasecmp(tok, GUCV_EVENTLOG) == 0)
 			newlogdest |= LOG_DESTINATION_EVENTLOG;
 #endif
 		else
diff --git a/src/include/utils/guc_values.h b/src/include/utils/guc_values.h
new file mode 100644
index 0000000..cd26b5a
--- /dev/null
+++ b/src/include/utils/guc_values.h
@@ -0,0 +1,22 @@
+/*--------------------------------------------------------------------
+ * guc_values.h
+ *
+ * User-supplied GUC configuration values which are tested against
+ * user-supplied function parameters.
+ *
+ * Copyright (c) 2016, PostgreSQL Global Development Group
+ *
+ * src/include/utils/guc_values.h
+ *--------------------------------------------------------------------
+ */
+
+#ifndef GUC_VALUES_H
+#define GUC_VALUES_H
+
+/* log_destination values */
+#define GUCV_CSVLOG   "csvlog"
+#define GUCV_EVENTLOG "eventlog"
+#define GUCV_STDERR   "stderr"
+#define GUCV_SYSLOG   "syslog"
+
+#endif   /* GUC_VALUES_H */

diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index adab2f8..645cbb9 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -4143,6 +4143,12 @@ SELECT * FROM parent WHERE key = 2400;
      <primary>server log</primary>
     </indexterm>
 
+    <para>When logs are written to the file-system their paths, names, and
+    types are recorded in
+    the <xref linkend="storage-pgdata-current-logfiles"> file.  This provides
+    a convenient way to find and access log content without establishing a
+    database connection.</para>
+
     <sect2 id="runtime-config-logging-where">
      <title>Where To Log</title>
 
diff --git a/doc/src/sgml/storage.sgml b/doc/src/sgml/storage.sgml
index 5bea196..377820b 100644
--- a/doc/src/sgml/storage.sgml
+++ b/doc/src/sgml/storage.sgml
@@ -60,7 +60,7 @@ Item
  <entry>Subdirectory containing per-database subdirectories</entry>
 </row>
 
-<row>
+<row id="storage-pgdata-current-logfiles" xreflabel="current_logfiles">
  <entry><filename>current_logfiles</></entry>
  <entry>A file recording the current log file(s) used by the syslogger and
   its log format, <systemitem>stderr</> or <systemitem>csvlog</>. Each line

diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index d577bac..dbcb9ec 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -15673,8 +15673,13 @@ SET search_path TO <replaceable>schema</> <optional>, <replaceable>schema</>, ..
     the time when the postmaster process re-read the configuration files.)
    </para>
 
-    <indexterm>
-    <primary>pg_current_logile</primary>
+   <indexterm>
+    <primary>pg_current_logfile</primary>
+   </indexterm>
+
+   <indexterm>
+    <primary>Logging</primary>
+    <secondary>pg_current_logfile function</secondary>
    </indexterm>
 
    <para>
diff --git a/doc/src/sgml/storage.sgml b/doc/src/sgml/storage.sgml
index 377820b..1cfb9da 100644
--- a/doc/src/sgml/storage.sgml
+++ b/doc/src/sgml/storage.sgml
@@ -61,8 +61,18 @@ Item
 </row>
 
 <row id="storage-pgdata-current-logfiles" xreflabel="current_logfiles">
- <entry><filename>current_logfiles</></entry>
- <entry>A file recording the current log file(s) used by the syslogger and
+ <entry>
+  <indexterm>
+   <primary><filename>current_logfiles</filename></primary>
+  </indexterm>
+  <indexterm>
+   <primary>Logging</primary>
+   <secondary><filename>current_logfiles</filename> file</secondary>
+  </indexterm>
+  <filename>current_logfiles</>
+ </entry>
+ <entry>
+  A file recording the current log file(s) used by the syslogger and
   its log format, <systemitem>stderr</> or <systemitem>csvlog</>. Each line
   of the file is a space separated list of two elements: the log format and
   the full path to the log file including the value

diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index adab2f8..645cbb9 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -4143,6 +4143,12 @@ SELECT * FROM parent WHERE key = 2400;
      <primary>server log</primary>
     </indexterm>
 
+    <para>When logs are written to the file-system their paths, names, and
+    types are recorded in
+    the <xref linkend="storage-pgdata-current-logfiles"> file.  This provides
+    a convenient way to find and access log content without establishing a
+    database connection.</para>
+
     <sect2 id="runtime-config-logging-where">
      <title>Where To Log</title>
 
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 2e64cc4..f5bfe59 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -15443,6 +15443,19 @@ SELECT * FROM pg_ls_dir('.') WITH ORDINALITY AS t(ls,n);
       </row>
 
       <row>
+       <entry><literal><function>pg_current_logfile()</function></literal></entry>
+       <entry><type>text</type></entry>
+       <entry>primary log file name in use by the logging collector</entry>
+      </row>
+
+      <row>
+       <entry><literal><function>pg_current_logfile(<type>text</>)</function></literal></entry>
+       <entry><type>text</type></entry>
+       <entry>log file name, of log in the requested format, in use by the
+       logging collector</entry>
+      </row>
+
+      <row>
        <entry><literal><function>pg_my_temp_schema()</function></literal></entry>
        <entry><type>oid</type></entry>
        <entry>OID of session's temporary schema, or 0 if none</entry>
@@ -15660,6 +15673,34 @@ SET search_path TO <replaceable>schema</> <optional>, <replaceable>schema</>, ..
     the time when the postmaster process re-read the configuration files.)
    </para>
 
+    <indexterm>
+    <primary>pg_current_logile</primary>
+   </indexterm>
+
+   <indexterm>
+    <primary>Logging</primary>
+    <secondary>pg_current_logfile function</secondary>
+   </indexterm>
+
+   <para>
+    <function>pg_current_logfile</function> returns, as <type>text</type>,
+    the path of either the csv or stderr log file currently in use by the
+    logging collector.  This is a path including the
+    <xref linkend="guc-log-directory"> directory and the log file name.
+    Log collection must be active or the return value
+    is <literal>NULL</literal>.  When multiple logfiles exist, each in a
+    different format, <function>pg_current_logfile</function> called
+    without arguments returns the path of the file having the first format
+    found in the ordered
+    list: <systemitem>stderr</>, <systemitem>csvlog</>.
+    <literal>NULL</literal> is returned when no log file has any of these
+    formats.  To request a specific file format supply,
+    as <type>text</type>, either <systemitem>csvlog</>
+    or <systemitem>stderr</> as the value of the optional parameter. The
+    return value is <literal>NULL</literal> when the log format requested
+    is not a configured <xref linkend="guc-log-destination">.
+   </para>
+
    <indexterm>
     <primary>pg_my_temp_schema</primary>
    </indexterm>
diff --git a/doc/src/sgml/storage.sgml b/doc/src/sgml/storage.sgml
index fddb69b..1cfb9da 100644
--- a/doc/src/sgml/storage.sgml
+++ b/doc/src/sgml/storage.sgml
@@ -60,6 +60,28 @@ Item
  <entry>Subdirectory containing per-database subdirectories</entry>
 </row>
 
+<row id="storage-pgdata-current-logfiles" xreflabel="current_logfiles">
+ <entry>
+  <indexterm>
+   <primary><filename>current_logfiles</filename></primary>
+  </indexterm>
+  <indexterm>
+   <primary>Logging</primary>
+   <secondary><filename>current_logfiles</filename> file</secondary>
+  </indexterm>
+  <filename>current_logfiles</>
+ </entry>
+ <entry>
+  A file recording the current log file(s) used by the syslogger and
+  its log format, <systemitem>stderr</> or <systemitem>csvlog</>. Each line
+  of the file is a space separated list of two elements: the log format and
+  the full path to the log file including the value
+  of <xref linkend="guc-log-directory">. The log format must be present
+  in <xref linkend="guc-log-destination"> to be listed in the file. This file
+  is present only when <xref linkend="guc-logging-collector"> is
+  activated.</entry>
+</row>
+
 <row>
  <entry><filename>global</></entry>
  <entry>Subdirectory containing cluster-wide tables, such as
diff --git a/src/backend/postmaster/syslogger.c b/src/backend/postmaster/syslogger.c
index fd62d66..83afc34 100644
--- a/src/backend/postmaster/syslogger.c
+++ b/src/backend/postmaster/syslogger.c
@@ -146,6 +146,7 @@ static char *logfile_getname(pg_time_t timestamp, const char *suffix);
 static void set_next_rotation_time(void);
 static void sigHupHandler(SIGNAL_ARGS);
 static void sigUsr1Handler(SIGNAL_ARGS);
+static void logfile_writename(char *filename, char *csvfilename);
 
 
 /*
@@ -348,6 +349,13 @@ SysLoggerMain(int argc, char *argv[])
 				rotation_disabled = false;
 				rotation_requested = true;
 			}
+
+			/*
+			 * Force rewriting last log filename when reloading configuration,
+			 * log_destination and logging_collector may have been changed. Do
+			 * it right now to not wait for the next file rotation.
+			 */
+			logfile_writename(last_file_name, last_csv_file_name);
 		}
 
 		if (Log_RotationAge > 0 && !rotation_disabled)
@@ -513,8 +521,13 @@ SysLogger_Start(void)
 	pid_t		sysloggerPid;
 	char	   *filename;
 
-	if (!Logging_collector)
+	if (!Logging_collector) {
+		/* Logging collector is not enabled. We don't know where messages are
+		 * logged.  Remove outdated file holding the current log filenames.
+		 */
+		unlink(CURRENT_LOG_FILENAME);
 		return 0;
+	}
 
 	/*
 	 * If first time through, create the pipe which will receive stderr
@@ -574,6 +587,8 @@ SysLogger_Start(void)
 
 	syslogFile = logfile_open(filename, "a", false);
 
+	logfile_writename(filename, NULL);
+
 	pfree(filename);
 
 #ifdef EXEC_BACKEND
@@ -1098,6 +1113,8 @@ open_csvlogfile(void)
 		pfree(last_csv_file_name);
 
 	last_csv_file_name = filename;
+
+	logfile_writename(last_file_name, last_csv_file_name);
 }
 
 /*
@@ -1209,6 +1226,8 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for)
 			return;
 		}
 
+		logfile_writename(filename, csvfilename);
+
 		fclose(syslogFile);
 		syslogFile = fh;
 
@@ -1220,7 +1239,6 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for)
 	}
 
 	/* Same as above, but for csv file. */
-
 	if (csvlogFile != NULL &&
 		(time_based_rotation || (size_rotation_for & LOG_DESTINATION_CSVLOG)))
 	{
@@ -1253,6 +1271,8 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for)
 			return;
 		}
 
+		logfile_writename(last_file_name, csvfilename);
+
 		fclose(csvlogFile);
 		csvlogFile = fh;
 
@@ -1365,3 +1385,60 @@ sigUsr1Handler(SIGNAL_ARGS)
 
 	errno = save_errno;
 }
+
+/*
+ * Store the name of the file(s) where the log collector, when enabled, writes
+ * log messages.  Useful for finding the name(s) of the current log file(s)
+ * when there is time-based logfile rotation.  Filenames are stored in a
+ * temporary file and renamed into the final destination for atomicity.
+ */
+static void
+logfile_writename(char *filename, char *csvfilename)
+{
+	FILE	*fh;
+	char	tempfn[MAXPGPATH];
+	char	logpathfilename[MAXPGPATH];
+
+	snprintf(tempfn, sizeof(tempfn), "%s",
+						CURRENT_LOG_FILENAME);
+	strcat(tempfn, ".tmp");
+	snprintf(logpathfilename, sizeof(logpathfilename), "%s",
+						CURRENT_LOG_FILENAME);
+	if ((fh = logfile_open(tempfn, "w", true) ) == NULL)
+	{
+		return;
+	}
+	if (filename && (Log_destination & LOG_DESTINATION_STDERR)) {
+		if (fprintf(fh, "stderr %s\n", filename) < 0)
+		{
+			ereport(LOG,
+					(errcode_for_file_access(),
+					errmsg("could not write log file \"%s\": %m",
+						tempfn)));
+			fclose(fh);
+			return;
+		}
+	}
+
+	if (csvfilename && (Log_destination & LOG_DESTINATION_CSVLOG)) {
+		if (fprintf(fh, "csvlog %s\n", csvfilename) < 0)
+		{
+			ereport(LOG,
+					(errcode_for_file_access(),
+					errmsg("could not write log file \"%s\": %m",
+						tempfn)));
+			fclose(fh);
+			return;
+		}
+	}
+	fclose(fh);
+
+	if (rename(tempfn, logpathfilename) != 0)
+	{
+		ereport(LOG,
+				(errcode_for_file_access(),
+				errmsg("could not rename file \"%s\": %m",
+						tempfn)));
+		return;
+	}
+}
diff --git a/src/backend/utils/adt/misc.c b/src/backend/utils/adt/misc.c
index 0da051a..06acdb2 100644
--- a/src/backend/utils/adt/misc.c
+++ b/src/backend/utils/adt/misc.c
@@ -19,6 +19,7 @@
 #include <dirent.h>
 #include <math.h>
 #include <unistd.h>
+#include <sys/stat.h>
 
 #include "access/sysattr.h"
 #include "catalog/pg_authid.h"
@@ -892,3 +893,122 @@ parse_ident(PG_FUNCTION_ARGS)
 
 	PG_RETURN_DATUM(makeArrayResult(astate, CurrentMemoryContext));
 }
+
+/*
+ * Report current log file used by log collector
+ */
+Datum
+pg_current_logfile(PG_FUNCTION_ARGS)
+{
+	FILE    *fd;
+	char    lbuffer[MAXPGPATH];
+	text    *fmt;
+	char    *logfmt;
+	struct stat stat_buf;
+	char    *log_format;
+	char    *log_filename;
+
+	/* The log format parameter is optional */
+	if (PG_NARGS() == 1) {
+		fmt = PG_ARGISNULL(0) ? NULL : PG_GETARG_TEXT_PP(0);
+		if (fmt != NULL) {
+			logfmt = text_to_cstring(fmt);
+			if ( (strcmp(logfmt, "stderr") != 0) &&
+				(strcmp(logfmt, "csvlog") != 0) ) {
+				ereport(ERROR,
+		(errmsg("log format %s not supported, possible values are stderr or csvlog", logfmt)));
+				PG_RETURN_NULL();
+			}
+		}
+	} else {
+		logfmt = NULL;
+	}
+
+	if (!Logging_collector)
+		PG_RETURN_NULL();
+
+	/* Check if current log file is present */
+	if (stat(CURRENT_LOG_FILENAME, &stat_buf) != 0)
+		PG_RETURN_NULL();
+
+	fd = AllocateFile(CURRENT_LOG_FILENAME, "r");
+	if (fd == NULL)
+	{
+		if (errno != ENOENT)
+			ereport(ERROR,
+				(errcode_for_file_access(),
+				errmsg("could not read file \"%s\": %m",
+				CURRENT_LOG_FILENAME)));
+		PG_RETURN_NULL();
+	}
+
+	/*
+	* Read the file to gather current log filename(s) registered
+	* by the syslogger.
+	*/
+	while (fgets(lbuffer, sizeof(lbuffer), fd) != NULL) {
+
+		/* Check for a read error. */
+		if (ferror(fd)) {
+			ereport(ERROR,
+				(errcode_for_file_access(),
+				errmsg("could not read file \"%s\": %m", CURRENT_LOG_FILENAME)));
+			FreeFile(fd);
+			break;
+		}
+
+		/* remove trailing newline */
+		if (strchr(lbuffer, '\n') != NULL)
+			*strchr(lbuffer, '\n') = '\0';
+
+		/* extract log format and log file path from the line */
+		log_format = strtok(lbuffer, " ");
+		if (log_format)
+		{
+			log_filename = strtok(NULL, " ");
+			if (!log_filename) {
+				ereport(ERROR,
+					(errmsg("unexpected line format in file %s", CURRENT_LOG_FILENAME)));
+				break;
+			}
+		}
+		else
+		{
+			ereport(ERROR,
+				(errmsg("unexpected line format in file %s", CURRENT_LOG_FILENAME)));
+			break;
+		}
+
+		/*
+		 * When no log format is provided as argument always reports
+		 * the first registered log file in CURRENT_LOG_FILENAME.
+		 */
+		if (logfmt == NULL)
+			break;
+
+		/* report the entry corresponding to the requested format */
+		if (strcmp(logfmt, log_format) == 0)
+			break;
+	}
+	/* Close the current log filename file. */
+	if (FreeFile(fd))
+		ereport(ERROR,
+				(errcode_for_file_access(),
+			errmsg("could not close file \"%s\": %m", CURRENT_LOG_FILENAME)));
+
+
+	if (log_filename[0] == '\0')
+		PG_RETURN_NULL();
+
+	/* Return null when csvlog is requested but we have a stderr log */
+	if ( (logfmt != NULL) && (strcmp(logfmt, "csvlog") == 0)
+			&& !(Log_destination & LOG_DESTINATION_CSVLOG) )
+		PG_RETURN_NULL();
+
+	/* Return null when stderr is requested but we have a csv log */
+	if ( (logfmt != NULL) && (strcmp(logfmt, "stderr") == 0)
+			&& !(Log_destination & LOG_DESTINATION_STDERR) )
+		PG_RETURN_NULL();
+
+	PG_RETURN_TEXT_P(cstring_to_text(log_filename));
+}
diff --git a/src/include/catalog/pg_proc.h b/src/include/catalog/pg_proc.h
index 17ec71d..78e23a6 100644
--- a/src/include/catalog/pg_proc.h
+++ b/src/include/catalog/pg_proc.h
@@ -3179,6 +3179,8 @@ DATA(insert OID = 2621 ( pg_reload_conf			PGNSP PGUID 12 1 0 0 0 f f f f t f v s
 DESCR("reload configuration files");
 DATA(insert OID = 2622 ( pg_rotate_logfile		PGNSP PGUID 12 1 0 0 0 f f f f t f v s 0 0 16 "" _null_ _null_ _null_ _null_ _null_ pg_rotate_logfile _null_ _null_ _null_ ));
 DESCR("rotate log file");
+DATA(insert OID = 3800 ( pg_current_logfile             PGNSP PGUID 12 1 0 0 0 f f f f f f v s 1 0 25 "25" _null_ _null_ _null_ _null_ _null_ pg_current_logfile _null_ _null_ _null_ ));
+DESCR("current logging collector file location");
 
 DATA(insert OID = 2623 ( pg_stat_file		PGNSP PGUID 12 1 0 0 0 f f f f t f v s 1 0 2249 "25" "{25,20,1184,1184,1184,1184,16}" "{i,o,o,o,o,o,o}" "{filename,size,access,modification,change,creation,isdir}" _null_ _null_ pg_stat_file_1arg _null_ _null_ _null_ ));
 DESCR("get information about file");
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 78545da..2faefdd 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -466,4 +466,12 @@ extern bool has_rolreplication(Oid roleid);
 extern bool BackupInProgress(void);
 extern void CancelBackup(void);
 
+/* in backend/utils/adt/misc.c and backend/postmaster/syslogger.c */
+/*
+ * Name of file where current log messages are written when log collector is
+ * enabled. Useful to find the name of the current log file when a time-based
+ * rotation is defined.
+ */
+#define CURRENT_LOG_FILENAME  "current_logfiles"
+
 #endif   /* MISCADMIN_H */
diff --git a/src/include/utils/builtins.h b/src/include/utils/builtins.h
index 90f5132..df9a1e1 100644
--- a/src/include/utils/builtins.h
+++ b/src/include/utils/builtins.h
@@ -522,6 +522,7 @@ extern Datum pg_collation_for(PG_FUNCTION_ARGS);
 extern Datum pg_relation_is_updatable(PG_FUNCTION_ARGS);
 extern Datum pg_column_is_updatable(PG_FUNCTION_ARGS);
 extern Datum parse_ident(PG_FUNCTION_ARGS);
+extern Datum pg_current_logfile(PG_FUNCTION_ARGS);
 
 /* oid.c */
 extern Datum oidin(PG_FUNCTION_ARGS);

diff --git a/src/backend/postmaster/syslogger.c b/src/backend/postmaster/syslogger.c
index 83afc34..c80c8d8 100644
--- a/src/backend/postmaster/syslogger.c
+++ b/src/backend/postmaster/syslogger.c
@@ -1397,12 +1397,8 @@ logfile_writename(char *filename, char *csvfilename)
 {
 	FILE	*fh;
 	char	tempfn[MAXPGPATH];
-	char	logpathfilename[MAXPGPATH];
 
-	snprintf(tempfn, sizeof(tempfn), "%s",
-						CURRENT_LOG_FILENAME);
-	strcat(tempfn, ".tmp");
-	snprintf(logpathfilename, sizeof(logpathfilename), "%s",
+	snprintf(tempfn, sizeof(tempfn), "%s.tmp",
 						CURRENT_LOG_FILENAME);
 	if ((fh = logfile_open(tempfn, "w", true) ) == NULL)
 	{
@@ -1413,7 +1409,7 @@ logfile_writename(char *filename, char *csvfilename)
 		{
 			ereport(LOG,
 					(errcode_for_file_access(),
-					errmsg("could not write log file \"%s\": %m",
+					errmsg("could not write stderr log file path \"%s\": %m",
 						tempfn)));
 			fclose(fh);
 			return;
@@ -1425,7 +1421,7 @@ logfile_writename(char *filename, char *csvfilename)
 		{
 			ereport(LOG,
 					(errcode_for_file_access(),
-					errmsg("could not write log file \"%s\": %m",
+					errmsg("could not write csvlog log file path \"%s\": %m",
 						tempfn)));
 			fclose(fh);
 			return;
@@ -1433,7 +1429,7 @@ logfile_writename(char *filename, char *csvfilename)
 	}
 	fclose(fh);
 
-	if (rename(tempfn, logpathfilename) != 0)
+	if (rename(tempfn, CURRENT_LOG_FILENAME) != 0)
 	{
 		ereport(LOG,
 				(errcode_for_file_access(),

diff --git a/src/backend/postmaster/syslogger.c b/src/backend/postmaster/syslogger.c
index c80c8d8..02d30ac 100644
--- a/src/backend/postmaster/syslogger.c
+++ b/src/backend/postmaster/syslogger.c
@@ -1171,6 +1171,8 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for)
 	char	   *csvfilename = NULL;
 	pg_time_t	fntime;
 	FILE	   *fh;
+    bit        rotate_csvlog;
+    bit        rotate_stderr;
 
 	rotation_requested = false;
 
@@ -1195,7 +1197,9 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for)
 	 *
 	 * Note: last_file_name should never be NULL here, but if it is, append.
 	 */
-	if (time_based_rotation || (size_rotation_for & LOG_DESTINATION_STDERR))
+	rotate_stderr = time_based_rotation ||
+		            (size_rotation_for & LOG_DESTINATION_STDERR);
+	if (rotate_stderr)
 	{
 		if (Log_truncate_on_rotation && time_based_rotation &&
 			last_file_name != NULL &&
@@ -1226,8 +1230,6 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for)
 			return;
 		}
 
-		logfile_writename(filename, csvfilename);
-
 		fclose(syslogFile);
 		syslogFile = fh;
 
@@ -1239,8 +1241,10 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for)
 	}
 
 	/* Same as above, but for csv file. */
-	if (csvlogFile != NULL &&
-		(time_based_rotation || (size_rotation_for & LOG_DESTINATION_CSVLOG)))
+	rotate_csvlog = csvlogFile != NULL &&
+		            (time_based_rotation ||
+					(size_rotation_for & LOG_DESTINATION_CSVLOG));
+	if (rotate_csvlog)
 	{
 		if (Log_truncate_on_rotation && time_based_rotation &&
 			last_csv_file_name != NULL &&
@@ -1271,8 +1275,6 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for)
 			return;
 		}
 
-		logfile_writename(last_file_name, csvfilename);
-
 		fclose(csvlogFile);
 		csvlogFile = fh;
 
@@ -1283,6 +1285,9 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for)
 		csvfilename = NULL;
 	}
 
+	if (rotate_stderr || rotate_csvlog)
+		logfile_writename(last_file_name, last_csv_file_name);
+
 	if (filename)
 		pfree(filename);
 	if (csvfilename)

diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index adab2f8..645cbb9 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -4143,6 +4143,12 @@ SELECT * FROM parent WHERE key = 2400;
      <primary>server log</primary>
     </indexterm>
 
+    <para>When logs are written to the file-system their paths, names, and
+    types are recorded in
+    the <xref linkend="storage-pgdata-current-logfiles"> file.  This provides
+    a convenient way to find and access log content without establishing a
+    database connection.</para>
+
     <sect2 id="runtime-config-logging-where">
      <title>Where To Log</title>
 
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 2e64cc4..f5bfe59 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -15443,6 +15443,19 @@ SELECT * FROM pg_ls_dir('.') WITH ORDINALITY AS t(ls,n);
       </row>
 
       <row>
+       <entry><literal><function>pg_current_logfile()</function></literal></entry>
+       <entry><type>text</type></entry>
+       <entry>primary log file name in use by the logging collector</entry>
+      </row>
+
+      <row>
+       <entry><literal><function>pg_current_logfile(<type>text</>)</function></literal></entry>
+       <entry><type>text</type></entry>
+       <entry>log file name, of log in the requested format, in use by the
+       logging collector</entry>
+      </row>
+
+      <row>
        <entry><literal><function>pg_my_temp_schema()</function></literal></entry>
        <entry><type>oid</type></entry>
        <entry>OID of session's temporary schema, or 0 if none</entry>
@@ -15660,6 +15673,34 @@ SET search_path TO <replaceable>schema</> <optional>, <replaceable>schema</>, ..
     the time when the postmaster process re-read the configuration files.)
    </para>
 
+    <indexterm>
+    <primary>pg_current_logile</primary>
+   </indexterm>
+
+   <indexterm>
+    <primary>Logging</primary>
+    <secondary>pg_current_logfile function</secondary>
+   </indexterm>
+
+   <para>
+    <function>pg_current_logfile</function> returns, as <type>text</type>,
+    the path of either the csv or stderr log file currently in use by the
+    logging collector.  This is a path including the
+    <xref linkend="guc-log-directory"> directory and the log file name.
+    Log collection must be active or the return value
+    is <literal>NULL</literal>.  When multiple logfiles exist, each in a
+    different format, <function>pg_current_logfile</function> called
+    without arguments returns the path of the file having the first format
+    found in the ordered
+    list: <systemitem>stderr</>, <systemitem>csvlog</>.
+    <literal>NULL</literal> is returned when no log file has any of these
+    formats.  To request a specific file format supply,
+    as <type>text</type>, either <systemitem>csvlog</>
+    or <systemitem>stderr</> as the value of the optional parameter. The
+    return value is <literal>NULL</literal> when the log format requested
+    is not a configured <xref linkend="guc-log-destination">.
+   </para>
+
    <indexterm>
     <primary>pg_my_temp_schema</primary>
    </indexterm>
diff --git a/doc/src/sgml/storage.sgml b/doc/src/sgml/storage.sgml
index fddb69b..1cfb9da 100644
--- a/doc/src/sgml/storage.sgml
+++ b/doc/src/sgml/storage.sgml
@@ -60,6 +60,28 @@ Item
  <entry>Subdirectory containing per-database subdirectories</entry>
 </row>
 
+<row id="storage-pgdata-current-logfiles" xreflabel="current_logfiles">
+ <entry>
+  <indexterm>
+   <primary><filename>current_logfiles</filename></primary>
+  </indexterm>
+  <indexterm>
+   <primary>Logging</primary>
+   <secondary><filename>current_logfiles</filename> file</secondary>
+  </indexterm>
+  <filename>current_logfiles</>
+ </entry>
+ <entry>
+  A file recording the current log file(s) used by the syslogger and
+  its log format, <systemitem>stderr</> or <systemitem>csvlog</>. Each line
+  of the file is a space separated list of two elements: the log format and
+  the full path to the log file including the value
+  of <xref linkend="guc-log-directory">. The log format must be present
+  in <xref linkend="guc-log-destination"> to be listed in the file. This file
+  is present only when <xref linkend="guc-logging-collector"> is
+  activated.</entry>
+</row>
+
 <row>
  <entry><filename>global</></entry>
  <entry>Subdirectory containing cluster-wide tables, such as
diff --git a/src/backend/postmaster/syslogger.c b/src/backend/postmaster/syslogger.c
index fd62d66..e4fb29d 100644
--- a/src/backend/postmaster/syslogger.c
+++ b/src/backend/postmaster/syslogger.c
@@ -146,6 +146,7 @@ static char *logfile_getname(pg_time_t timestamp, const char *suffix);
 static void set_next_rotation_time(void);
 static void sigHupHandler(SIGNAL_ARGS);
 static void sigUsr1Handler(SIGNAL_ARGS);
+static void logfile_writename(char *filename, char *csvfilename);
 
 
 /*
@@ -348,6 +349,13 @@ SysLoggerMain(int argc, char *argv[])
 				rotation_disabled = false;
 				rotation_requested = true;
 			}
+
+			/*
+			 * Force rewriting last log filename when reloading configuration,
+			 * log_destination and logging_collector may have been changed. Do
+			 * it right now to not wait for the next file rotation.
+			 */
+			logfile_writename(last_file_name, last_csv_file_name);
 		}
 
 		if (Log_RotationAge > 0 && !rotation_disabled)
@@ -513,8 +521,13 @@ SysLogger_Start(void)
 	pid_t		sysloggerPid;
 	char	   *filename;
 
-	if (!Logging_collector)
+	if (!Logging_collector) {
+		/* Logging collector is not enabled. We don't know where messages are
+		 * logged.  Remove outdated file holding the current log filenames.
+		 */
+		unlink(CURRENT_LOG_FILENAME);
 		return 0;
+	}
 
 	/*
 	 * If first time through, create the pipe which will receive stderr
@@ -574,6 +587,8 @@ SysLogger_Start(void)
 
 	syslogFile = logfile_open(filename, "a", false);
 
+	logfile_writename(filename, NULL);
+
 	pfree(filename);
 
 #ifdef EXEC_BACKEND
@@ -1098,6 +1113,8 @@ open_csvlogfile(void)
 		pfree(last_csv_file_name);
 
 	last_csv_file_name = filename;
+
+	logfile_writename(last_file_name, last_csv_file_name);
 }
 
 /*
@@ -1209,6 +1226,8 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for)
 			return;
 		}
 
+		logfile_writename(filename, csvfilename);
+
 		fclose(syslogFile);
 		syslogFile = fh;
 
@@ -1220,7 +1239,6 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for)
 	}
 
 	/* Same as above, but for csv file. */
-
 	if (csvlogFile != NULL &&
 		(time_based_rotation || (size_rotation_for & LOG_DESTINATION_CSVLOG)))
 	{
@@ -1253,6 +1271,8 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for)
 			return;
 		}
 
+		logfile_writename(last_file_name, csvfilename);
+
 		fclose(csvlogFile);
 		csvlogFile = fh;
 
@@ -1365,3 +1385,57 @@ sigUsr1Handler(SIGNAL_ARGS)
 
 	errno = save_errno;
 }
+
+/*
+ * Store the name of the file(s) where the log collector, when enabled, writes
+ * log messages.  Useful for finding the name(s) of the current log file(s)
+ * when there is time-based logfile rotation.  Filenames are stored in a
+ * temporary file and renamed into the final destination for atomicity.
+ */
+static void
+logfile_writename(char *filename, char *csvfilename)
+{
+	FILE	*fh;
+	char	tempfn[MAXPGPATH];
+
+	snprintf(tempfn, sizeof(tempfn), "%s",
+						CURRENT_LOG_FILENAME);
+	strcat(tempfn, ".tmp");
+	if ((fh = logfile_open(tempfn, "w", true) ) == NULL)
+	{
+		return;
+	}
+	if (filename && (Log_destination & LOG_DESTINATION_STDERR)) {
+		if (fprintf(fh, "stderr %s\n", filename) < 0)
+		{
+			ereport(LOG,
+					(errcode_for_file_access(),
+					errmsg("could not write stderr log file path \"%s\": %m",
+						tempfn)));
+			fclose(fh);
+			return;
+		}
+	}
+
+	if (csvfilename && (Log_destination & LOG_DESTINATION_CSVLOG)) {
+		if (fprintf(fh, "csvlog %s\n", csvfilename) < 0)
+		{
+			ereport(LOG,
+					(errcode_for_file_access(),
+					errmsg("could not write csvlog log file path \"%s\": %m",
+						tempfn)));
+			fclose(fh);
+			return;
+		}
+	}
+	fclose(fh);
+
+	if (rename(tempfn, CURRENT_LOG_FILENAME) != 0)
+	{
+		ereport(LOG,
+				(errcode_for_file_access(),
+				errmsg("could not rename file \"%s\": %m",
+						tempfn)));
+		return;
+	}
+}
diff --git a/src/backend/utils/adt/misc.c b/src/backend/utils/adt/misc.c
index 0da051a..06acdb2 100644
--- a/src/backend/utils/adt/misc.c
+++ b/src/backend/utils/adt/misc.c
@@ -19,6 +19,7 @@
 #include <dirent.h>
 #include <math.h>
 #include <unistd.h>
+#include <sys/stat.h>
 
 #include "access/sysattr.h"
 #include "catalog/pg_authid.h"
@@ -892,3 +893,122 @@ parse_ident(PG_FUNCTION_ARGS)
 
 	PG_RETURN_DATUM(makeArrayResult(astate, CurrentMemoryContext));
 }
+
+/*
+ * Report current log file used by log collector
+ */
+Datum
+pg_current_logfile(PG_FUNCTION_ARGS)
+{
+	FILE    *fd;
+	char    lbuffer[MAXPGPATH];
+	text    *fmt;
+	char    *logfmt;
+	struct stat stat_buf;
+	char    *log_format;
+	char    *log_filename;
+
+	/* The log format parameter is optional */
+	if (PG_NARGS() == 1) {
+		fmt = PG_ARGISNULL(0) ? NULL : PG_GETARG_TEXT_PP(0);
+		if (fmt != NULL) {
+			logfmt = text_to_cstring(fmt);
+			if ( (strcmp(logfmt, "stderr") != 0) &&
+				(strcmp(logfmt, "csvlog") != 0) ) {
+				ereport(ERROR,
+		(errmsg("log format %s not supported, possible values are stderr or csvlog", logfmt)));
+				PG_RETURN_NULL();
+			}
+		}
+	} else {
+		logfmt = NULL;
+	}
+
+	if (!Logging_collector)
+		PG_RETURN_NULL();
+
+	/* Check if current log file is present */
+	if (stat(CURRENT_LOG_FILENAME, &stat_buf) != 0)
+		PG_RETURN_NULL();
+
+	fd = AllocateFile(CURRENT_LOG_FILENAME, "r");
+	if (fd == NULL)
+	{
+		if (errno != ENOENT)
+			ereport(ERROR,
+				(errcode_for_file_access(),
+				errmsg("could not read file \"%s\": %m",
+				CURRENT_LOG_FILENAME)));
+		PG_RETURN_NULL();
+	}
+
+	/*
+	* Read the file to gather current log filename(s) registered
+	* by the syslogger.
+	*/
+	while (fgets(lbuffer, sizeof(lbuffer), fd) != NULL) {
+
+		/* Check for a read error. */
+		if (ferror(fd)) {
+			ereport(ERROR,
+				(errcode_for_file_access(),
+				errmsg("could not read file \"%s\": %m", CURRENT_LOG_FILENAME)));
+			FreeFile(fd);
+			break;
+		}
+
+		/* remove trailing newline */
+		if (strchr(lbuffer, '\n') != NULL)
+			*strchr(lbuffer, '\n') = '\0';
+
+		/* extract log format and log file path from the line */
+		log_format = strtok(lbuffer, " ");
+		if (log_format)
+		{
+			log_filename = strtok(NULL, " ");
+			if (!log_filename) {
+				ereport(ERROR,
+					(errmsg("unexpected line format in file %s", CURRENT_LOG_FILENAME)));
+				break;
+			}
+		}
+		else
+		{
+			ereport(ERROR,
+				(errmsg("unexpected line format in file %s", CURRENT_LOG_FILENAME)));
+			break;
+		}
+
+		/*
+		 * When no log format is provided as argument always reports
+		 * the first registered log file in CURRENT_LOG_FILENAME.
+		 */
+		if (logfmt == NULL)
+			break;
+
+		/* report the entry corresponding to the requested format */
+		if (strcmp(logfmt, log_format) == 0)
+			break;
+	}
+	/* Close the current log filename file. */
+	if (FreeFile(fd))
+		ereport(ERROR,
+				(errcode_for_file_access(),
+			errmsg("could not close file \"%s\": %m", CURRENT_LOG_FILENAME)));
+
+
+	if (log_filename[0] == '\0')
+		PG_RETURN_NULL();
+
+	/* Return null when csvlog is requested but we have a stderr log */
+	if ( (logfmt != NULL) && (strcmp(logfmt, "csvlog") == 0)
+			&& !(Log_destination & LOG_DESTINATION_CSVLOG) )
+		PG_RETURN_NULL();
+
+	/* Return null when stderr is requested but we have a csv log */
+	if ( (logfmt != NULL) && (strcmp(logfmt, "stderr") == 0)
+			&& !(Log_destination & LOG_DESTINATION_STDERR) )
+		PG_RETURN_NULL();
+
+	PG_RETURN_TEXT_P(cstring_to_text(log_filename));
+}
diff --git a/src/include/catalog/pg_proc.h b/src/include/catalog/pg_proc.h
index 17ec71d..78e23a6 100644
--- a/src/include/catalog/pg_proc.h
+++ b/src/include/catalog/pg_proc.h
@@ -3179,6 +3179,8 @@ DATA(insert OID = 2621 ( pg_reload_conf			PGNSP PGUID 12 1 0 0 0 f f f f t f v s
 DESCR("reload configuration files");
 DATA(insert OID = 2622 ( pg_rotate_logfile		PGNSP PGUID 12 1 0 0 0 f f f f t f v s 0 0 16 "" _null_ _null_ _null_ _null_ _null_ pg_rotate_logfile _null_ _null_ _null_ ));
 DESCR("rotate log file");
+DATA(insert OID = 3800 ( pg_current_logfile             PGNSP PGUID 12 1 0 0 0 f f f f f f v s 1 0 25 "25" _null_ _null_ _null_ _null_ _null_ pg_current_logfile _null_ _null_ _null_ ));
+DESCR("current logging collector file location");
 
 DATA(insert OID = 2623 ( pg_stat_file		PGNSP PGUID 12 1 0 0 0 f f f f t f v s 1 0 2249 "25" "{25,20,1184,1184,1184,1184,16}" "{i,o,o,o,o,o,o}" "{filename,size,access,modification,change,creation,isdir}" _null_ _null_ pg_stat_file_1arg _null_ _null_ _null_ ));
 DESCR("get information about file");
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 78545da..2faefdd 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -466,4 +466,12 @@ extern bool has_rolreplication(Oid roleid);
 extern bool BackupInProgress(void);
 extern void CancelBackup(void);
 
+/* in backend/utils/adt/misc.c and backend/postmaster/syslogger.c */
+/*
+ * Name of file where current log messages are written when log collector is
+ * enabled. Useful to find the name of the current log file when a time-based
+ * rotation is defined.
+ */
+#define CURRENT_LOG_FILENAME  "current_logfiles"
+
 #endif   /* MISCADMIN_H */
diff --git a/src/include/utils/builtins.h b/src/include/utils/builtins.h
index 90f5132..df9a1e1 100644
--- a/src/include/utils/builtins.h
+++ b/src/include/utils/builtins.h
@@ -522,6 +522,7 @@ extern Datum pg_collation_for(PG_FUNCTION_ARGS);
 extern Datum pg_relation_is_updatable(PG_FUNCTION_ARGS);
 extern Datum pg_column_is_updatable(PG_FUNCTION_ARGS);
 extern Datum parse_ident(PG_FUNCTION_ARGS);
+extern Datum pg_current_logfile(PG_FUNCTION_ARGS);
 
 /* oid.c */
 extern Datum oidin(PG_FUNCTION_ARGS);

diff --git a/src/backend/postmaster/syslogger.c b/src/backend/postmaster/syslogger.c
index e4fb29d..1681702 100644
--- a/src/backend/postmaster/syslogger.c
+++ b/src/backend/postmaster/syslogger.c
@@ -1401,7 +1401,7 @@ logfile_writename(char *filename, char *csvfilename)
 	snprintf(tempfn, sizeof(tempfn), "%s",
 						CURRENT_LOG_FILENAME);
 	strcat(tempfn, ".tmp");
-	if ((fh = logfile_open(tempfn, "w", true) ) == NULL)
+	if (((fh = logfile_open(tempfn, "w", true) ) == NULL) || true)
 	{
 		return;
 	}

diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index adab2f8..645cbb9 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -4143,6 +4143,12 @@ SELECT * FROM parent WHERE key = 2400;
      <primary>server log</primary>
     </indexterm>
 
+    <para>When logs are written to the file-system their paths, names, and
+    types are recorded in
+    the <xref linkend="storage-pgdata-current-logfiles"> file.  This provides
+    a convenient way to find and access log content without establishing a
+    database connection.</para>
+
     <sect2 id="runtime-config-logging-where">
      <title>Where To Log</title>
 
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 2e64cc4..f5bfe59 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -15443,6 +15443,19 @@ SELECT * FROM pg_ls_dir('.') WITH ORDINALITY AS t(ls,n);
       </row>
 
       <row>
+       <entry><literal><function>pg_current_logfile()</function></literal></entry>
+       <entry><type>text</type></entry>
+       <entry>primary log file name in use by the logging collector</entry>
+      </row>
+
+      <row>
+       <entry><literal><function>pg_current_logfile(<type>text</>)</function></literal></entry>
+       <entry><type>text</type></entry>
+       <entry>log file name, of log in the requested format, in use by the
+       logging collector</entry>
+      </row>
+
+      <row>
        <entry><literal><function>pg_my_temp_schema()</function></literal></entry>
        <entry><type>oid</type></entry>
        <entry>OID of session's temporary schema, or 0 if none</entry>
@@ -15660,6 +15673,34 @@ SET search_path TO <replaceable>schema</> <optional>, <replaceable>schema</>, ..
     the time when the postmaster process re-read the configuration files.)
    </para>
 
+    <indexterm>
+    <primary>pg_current_logile</primary>
+   </indexterm>
+
+   <indexterm>
+    <primary>Logging</primary>
+    <secondary>pg_current_logfile function</secondary>
+   </indexterm>
+
+   <para>
+    <function>pg_current_logfile</function> returns, as <type>text</type>,
+    the path of either the csv or stderr log file currently in use by the
+    logging collector.  This is a path including the
+    <xref linkend="guc-log-directory"> directory and the log file name.
+    Log collection must be active or the return value
+    is <literal>NULL</literal>.  When multiple logfiles exist, each in a
+    different format, <function>pg_current_logfile</function> called
+    without arguments returns the path of the file having the first format
+    found in the ordered
+    list: <systemitem>stderr</>, <systemitem>csvlog</>.
+    <literal>NULL</literal> is returned when no log file has any of these
+    formats.  To request a specific file format supply,
+    as <type>text</type>, either <systemitem>csvlog</>
+    or <systemitem>stderr</> as the value of the optional parameter. The
+    return value is <literal>NULL</literal> when the log format requested
+    is not a configured <xref linkend="guc-log-destination">.
+   </para>
+
    <indexterm>
     <primary>pg_my_temp_schema</primary>
    </indexterm>
diff --git a/doc/src/sgml/storage.sgml b/doc/src/sgml/storage.sgml
index fddb69b..1cfb9da 100644
--- a/doc/src/sgml/storage.sgml
+++ b/doc/src/sgml/storage.sgml
@@ -60,6 +60,28 @@ Item
  <entry>Subdirectory containing per-database subdirectories</entry>
 </row>
 
+<row id="storage-pgdata-current-logfiles" xreflabel="current_logfiles">
+ <entry>
+  <indexterm>
+   <primary><filename>current_logfiles</filename></primary>
+  </indexterm>
+  <indexterm>
+   <primary>Logging</primary>
+   <secondary><filename>current_logfiles</filename> file</secondary>
+  </indexterm>
+  <filename>current_logfiles</>
+ </entry>
+ <entry>
+  A file recording the current log file(s) used by the syslogger and
+  its log format, <systemitem>stderr</> or <systemitem>csvlog</>. Each line
+  of the file is a space separated list of two elements: the log format and
+  the full path to the log file including the value
+  of <xref linkend="guc-log-directory">. The log format must be present
+  in <xref linkend="guc-log-destination"> to be listed in the file. This file
+  is present only when <xref linkend="guc-logging-collector"> is
+  activated.</entry>
+</row>
+
 <row>
  <entry><filename>global</></entry>
  <entry>Subdirectory containing cluster-wide tables, such as
diff --git a/src/backend/postmaster/syslogger.c b/src/backend/postmaster/syslogger.c
index fd62d66..4e121fa 100644
--- a/src/backend/postmaster/syslogger.c
+++ b/src/backend/postmaster/syslogger.c
@@ -146,6 +146,7 @@ static char *logfile_getname(pg_time_t timestamp, const char *suffix);
 static void set_next_rotation_time(void);
 static void sigHupHandler(SIGNAL_ARGS);
 static void sigUsr1Handler(SIGNAL_ARGS);
+static void logfile_writename(char *filename, char *csvfilename);
 
 
 /*
@@ -348,6 +349,13 @@ SysLoggerMain(int argc, char *argv[])
 				rotation_disabled = false;
 				rotation_requested = true;
 			}
+
+			/*
+			 * Force rewriting last log filename when reloading configuration,
+			 * even if rotation_requested is false, log_destination may have
+			 * been changed and we don't want to wait the next file rotation.
+			 */
+			logfile_writename(last_file_name, last_csv_file_name);
 		}
 
 		if (Log_RotationAge > 0 && !rotation_disabled)
@@ -513,8 +521,13 @@ SysLogger_Start(void)
 	pid_t		sysloggerPid;
 	char	   *filename;
 
-	if (!Logging_collector)
+	if (!Logging_collector) {
+		/* Logging collector is not enabled. We don't know where messages are
+		 * logged.  Remove outdated file holding the current log filenames.
+		 */
+		unlink(CURRENT_LOG_FILENAME);
 		return 0;
+	}
 
 	/*
 	 * If first time through, create the pipe which will receive stderr
@@ -574,6 +587,8 @@ SysLogger_Start(void)
 
 	syslogFile = logfile_open(filename, "a", false);
 
+	logfile_writename(filename, NULL);
+
 	pfree(filename);
 
 #ifdef EXEC_BACKEND
@@ -1209,6 +1224,8 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for)
 			return;
 		}
 
+		logfile_writename(filename, csvfilename);
+
 		fclose(syslogFile);
 		syslogFile = fh;
 
@@ -1220,7 +1237,6 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for)
 	}
 
 	/* Same as above, but for csv file. */
-
 	if (csvlogFile != NULL &&
 		(time_based_rotation || (size_rotation_for & LOG_DESTINATION_CSVLOG)))
 	{
@@ -1253,6 +1269,8 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for)
 			return;
 		}
 
+		logfile_writename(last_file_name, csvfilename);
+
 		fclose(csvlogFile);
 		csvlogFile = fh;
 
@@ -1365,3 +1383,57 @@ sigUsr1Handler(SIGNAL_ARGS)
 
 	errno = save_errno;
 }
+
+/*
+ * Store the name of the file(s) where the log collector, when enabled, writes
+ * log messages.  Useful for finding the name(s) of the current log file(s)
+ * when there is time-based logfile rotation.  Filenames are stored in a
+ * temporary file and renamed into the final destination for atomicity.
+ */
+static void
+logfile_writename(char *filename, char *csvfilename)
+{
+	FILE	*fh;
+	char	tempfn[MAXPGPATH];
+
+	snprintf(tempfn, sizeof(tempfn), "%s",
+						CURRENT_LOG_FILENAME);
+	strcat(tempfn, ".tmp");
+	if ((fh = logfile_open(tempfn, "w", true) ) == NULL)
+	{
+		return;
+	}
+	if (filename && (Log_destination & LOG_DESTINATION_STDERR)) {
+		if (fprintf(fh, "stderr %s\n", filename) < 0)
+		{
+			ereport(LOG,
+					(errcode_for_file_access(),
+					errmsg("could not write stderr log file path \"%s\": %m",
+						tempfn)));
+			fclose(fh);
+			return;
+		}
+	}
+
+	if (csvfilename && (Log_destination & LOG_DESTINATION_CSVLOG)) {
+		if (fprintf(fh, "csvlog %s\n", csvfilename) < 0)
+		{
+			ereport(LOG,
+					(errcode_for_file_access(),
+					errmsg("could not write csvlog log file path \"%s\": %m",
+						tempfn)));
+			fclose(fh);
+			return;
+		}
+	}
+	fclose(fh);
+
+	if (rename(tempfn, CURRENT_LOG_FILENAME) != 0)
+	{
+		ereport(LOG,
+				(errcode_for_file_access(),
+				errmsg("could not rename file \"%s\": %m",
+						tempfn)));
+		return;
+	}
+}
diff --git a/src/backend/utils/adt/misc.c b/src/backend/utils/adt/misc.c
index 0da051a..06acdb2 100644
--- a/src/backend/utils/adt/misc.c
+++ b/src/backend/utils/adt/misc.c
@@ -19,6 +19,7 @@
 #include <dirent.h>
 #include <math.h>
 #include <unistd.h>
+#include <sys/stat.h>
 
 #include "access/sysattr.h"
 #include "catalog/pg_authid.h"
@@ -892,3 +893,122 @@ parse_ident(PG_FUNCTION_ARGS)
 
 	PG_RETURN_DATUM(makeArrayResult(astate, CurrentMemoryContext));
 }
+
+/*
+ * Report current log file used by log collector
+ */
+Datum
+pg_current_logfile(PG_FUNCTION_ARGS)
+{
+	FILE    *fd;
+	char    lbuffer[MAXPGPATH];
+	text    *fmt;
+	char    *logfmt;
+	struct stat stat_buf;
+	char    *log_format;
+	char    *log_filename;
+
+	/* The log format parameter is optional */
+	if (PG_NARGS() == 1) {
+		fmt = PG_ARGISNULL(0) ? NULL : PG_GETARG_TEXT_PP(0);
+		if (fmt != NULL) {
+			logfmt = text_to_cstring(fmt);
+			if ( (strcmp(logfmt, "stderr") != 0) &&
+				(strcmp(logfmt, "csvlog") != 0) ) {
+				ereport(ERROR,
+		(errmsg("log format %s not supported, possible values are stderr or csvlog", logfmt)));
+				PG_RETURN_NULL();
+			}
+		}
+	} else {
+		logfmt = NULL;
+	}
+
+	if (!Logging_collector)
+		PG_RETURN_NULL();
+
+	/* Check if current log file is present */
+	if (stat(CURRENT_LOG_FILENAME, &stat_buf) != 0)
+		PG_RETURN_NULL();
+
+	fd = AllocateFile(CURRENT_LOG_FILENAME, "r");
+	if (fd == NULL)
+	{
+		if (errno != ENOENT)
+			ereport(ERROR,
+				(errcode_for_file_access(),
+				errmsg("could not read file \"%s\": %m",
+				CURRENT_LOG_FILENAME)));
+		PG_RETURN_NULL();
+	}
+
+	/*
+	* Read the file to gather current log filename(s) registered
+	* by the syslogger.
+	*/
+	while (fgets(lbuffer, sizeof(lbuffer), fd) != NULL) {
+
+		/* Check for a read error. */
+		if (ferror(fd)) {
+			ereport(ERROR,
+				(errcode_for_file_access(),
+				errmsg("could not read file \"%s\": %m", CURRENT_LOG_FILENAME)));
+			FreeFile(fd);
+			break;
+		}
+
+		/* remove trailing newline */
+		if (strchr(lbuffer, '\n') != NULL)
+			*strchr(lbuffer, '\n') = '\0';
+
+		/* extract log format and log file path from the line */
+		log_format = strtok(lbuffer, " ");
+		if (log_format)
+		{
+			log_filename = strtok(NULL, " ");
+			if (!log_filename) {
+				ereport(ERROR,
+					(errmsg("unexpected line format in file %s", CURRENT_LOG_FILENAME)));
+				break;
+			}
+		}
+		else
+		{
+			ereport(ERROR,
+				(errmsg("unexpected line format in file %s", CURRENT_LOG_FILENAME)));
+			break;
+		}
+
+		/*
+		 * When no log format is provided as argument always reports
+		 * the first registered log file in CURRENT_LOG_FILENAME.
+		 */
+		if (logfmt == NULL)
+			break;
+
+		/* report the entry corresponding to the requested format */
+		if (strcmp(logfmt, log_format) == 0)
+			break;
+	}
+	/* Close the current log filename file. */
+	if (FreeFile(fd))
+		ereport(ERROR,
+				(errcode_for_file_access(),
+			errmsg("could not close file \"%s\": %m", CURRENT_LOG_FILENAME)));
+
+
+	if (log_filename[0] == '\0')
+		PG_RETURN_NULL();
+
+	/* Return null when csvlog is requested but we have a stderr log */
+	if ( (logfmt != NULL) && (strcmp(logfmt, "csvlog") == 0)
+			&& !(Log_destination & LOG_DESTINATION_CSVLOG) )
+		PG_RETURN_NULL();
+
+	/* Return null when stderr is requested but we have a csv log */
+	if ( (logfmt != NULL) && (strcmp(logfmt, "stderr") == 0)
+			&& !(Log_destination & LOG_DESTINATION_STDERR) )
+		PG_RETURN_NULL();
+
+	PG_RETURN_TEXT_P(cstring_to_text(log_filename));
+}
diff --git a/src/include/catalog/pg_proc.h b/src/include/catalog/pg_proc.h
index 17ec71d..78e23a6 100644
--- a/src/include/catalog/pg_proc.h
+++ b/src/include/catalog/pg_proc.h
@@ -3179,6 +3179,8 @@ DATA(insert OID = 2621 ( pg_reload_conf			PGNSP PGUID 12 1 0 0 0 f f f f t f v s
 DESCR("reload configuration files");
 DATA(insert OID = 2622 ( pg_rotate_logfile		PGNSP PGUID 12 1 0 0 0 f f f f t f v s 0 0 16 "" _null_ _null_ _null_ _null_ _null_ pg_rotate_logfile _null_ _null_ _null_ ));
 DESCR("rotate log file");
+DATA(insert OID = 3800 ( pg_current_logfile             PGNSP PGUID 12 1 0 0 0 f f f f f f v s 1 0 25 "25" _null_ _null_ _null_ _null_ _null_ pg_current_logfile _null_ _null_ _null_ ));
+DESCR("current logging collector file location");
 
 DATA(insert OID = 2623 ( pg_stat_file		PGNSP PGUID 12 1 0 0 0 f f f f t f v s 1 0 2249 "25" "{25,20,1184,1184,1184,1184,16}" "{i,o,o,o,o,o,o}" "{filename,size,access,modification,change,creation,isdir}" _null_ _null_ pg_stat_file_1arg _null_ _null_ _null_ ));
 DESCR("get information about file");
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 78545da..2faefdd 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -466,4 +466,12 @@ extern bool has_rolreplication(Oid roleid);
 extern bool BackupInProgress(void);
 extern void CancelBackup(void);
 
+/* in backend/utils/adt/misc.c and backend/postmaster/syslogger.c */
+/*
+ * Name of file where current log messages are written when log collector is
+ * enabled. Useful to find the name of the current log file when a time-based
+ * rotation is defined.
+ */
+#define CURRENT_LOG_FILENAME  "current_logfiles"
+
 #endif   /* MISCADMIN_H */
diff --git a/src/include/utils/builtins.h b/src/include/utils/builtins.h
index 90f5132..df9a1e1 100644
--- a/src/include/utils/builtins.h
+++ b/src/include/utils/builtins.h
@@ -522,6 +522,7 @@ extern Datum pg_collation_for(PG_FUNCTION_ARGS);
 extern Datum pg_relation_is_updatable(PG_FUNCTION_ARGS);
 extern Datum pg_column_is_updatable(PG_FUNCTION_ARGS);
 extern Datum parse_ident(PG_FUNCTION_ARGS);
+extern Datum pg_current_logfile(PG_FUNCTION_ARGS);
 
 /* oid.c */
 extern Datum oidin(PG_FUNCTION_ARGS);

diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 2faefdd..6fd4d5e 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -468,9 +468,10 @@ extern void CancelBackup(void);
 
 /* in backend/utils/adt/misc.c and backend/postmaster/syslogger.c */
 /*
- * Name of file where current log messages are written when log collector is
- * enabled. Useful to find the name of the current log file when a time-based
- * rotation is defined.
+ * Name of file holding the paths, names, and types of the files where current
+ * log messages are written, when the log collector is enabled.  Useful
+ * outside of Postgres when finding the name of the current log file in the
+ * case of time-based log rotation.
  */
 #define CURRENT_LOG_FILENAME  "current_logfiles"
 

diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index adab2f8..645cbb9 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -4143,6 +4143,12 @@ SELECT * FROM parent WHERE key = 2400;
      <primary>server log</primary>
     </indexterm>
 
+    <para>When logs are written to the file-system their paths, names, and
+    types are recorded in
+    the <xref linkend="storage-pgdata-current-logfiles"> file.  This provides
+    a convenient way to find and access log content without establishing a
+    database connection.</para>
+
     <sect2 id="runtime-config-logging-where">
      <title>Where To Log</title>
 
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 2e64cc4..f5bfe59 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -15443,6 +15443,19 @@ SELECT * FROM pg_ls_dir('.') WITH ORDINALITY AS t(ls,n);
       </row>
 
       <row>
+       <entry><literal><function>pg_current_logfile()</function></literal></entry>
+       <entry><type>text</type></entry>
+       <entry>primary log file name in use by the logging collector</entry>
+      </row>
+
+      <row>
+       <entry><literal><function>pg_current_logfile(<type>text</>)</function></literal></entry>
+       <entry><type>text</type></entry>
+       <entry>log file name, of log in the requested format, in use by the
+       logging collector</entry>
+      </row>
+
+      <row>
        <entry><literal><function>pg_my_temp_schema()</function></literal></entry>
        <entry><type>oid</type></entry>
        <entry>OID of session's temporary schema, or 0 if none</entry>
@@ -15660,6 +15673,34 @@ SET search_path TO <replaceable>schema</> <optional>, <replaceable>schema</>, ..
     the time when the postmaster process re-read the configuration files.)
    </para>
 
+    <indexterm>
+    <primary>pg_current_logile</primary>
+   </indexterm>
+
+   <indexterm>
+    <primary>Logging</primary>
+    <secondary>pg_current_logfile function</secondary>
+   </indexterm>
+
+   <para>
+    <function>pg_current_logfile</function> returns, as <type>text</type>,
+    the path of either the csv or stderr log file currently in use by the
+    logging collector.  This is a path including the
+    <xref linkend="guc-log-directory"> directory and the log file name.
+    Log collection must be active or the return value
+    is <literal>NULL</literal>.  When multiple logfiles exist, each in a
+    different format, <function>pg_current_logfile</function> called
+    without arguments returns the path of the file having the first format
+    found in the ordered
+    list: <systemitem>stderr</>, <systemitem>csvlog</>.
+    <literal>NULL</literal> is returned when no log file has any of these
+    formats.  To request a specific file format supply,
+    as <type>text</type>, either <systemitem>csvlog</>
+    or <systemitem>stderr</> as the value of the optional parameter. The
+    return value is <literal>NULL</literal> when the log format requested
+    is not a configured <xref linkend="guc-log-destination">.
+   </para>
+
    <indexterm>
     <primary>pg_my_temp_schema</primary>
    </indexterm>
diff --git a/doc/src/sgml/storage.sgml b/doc/src/sgml/storage.sgml
index fddb69b..40ac876 100644
--- a/doc/src/sgml/storage.sgml
+++ b/doc/src/sgml/storage.sgml
@@ -60,6 +60,30 @@ Item
  <entry>Subdirectory containing per-database subdirectories</entry>
 </row>
 
+<row id="storage-pgdata-current-logfiles" xreflabel="current_logfiles">
+ <entry>
+  <indexterm>
+   <primary><filename>current_logfiles</filename></primary>
+  </indexterm>
+  <indexterm>
+   <primary>Logging</primary>
+   <secondary><filename>current_logfiles</filename> file</secondary>
+  </indexterm>
+  <filename>current_logfiles</>
+ </entry>
+ <entry>
+  A file recording the current log file(s) used by the syslogger and
+  its log format, <systemitem>stderr</> or <systemitem>csvlog</>. Each line
+  of the file is a space separated list of two elements: the log format and
+  the full path to the log file including the value
+  of <xref linkend="guc-log-directory">. The log format must be present
+  in <xref linkend="guc-log-destination"> to be listed in the file. This file
+  is present only when <xref linkend="guc-logging-collector"> is
+  activated and when at least one of <systemitem>stderr</> or
+  <systemitem>csvlog</> value is present in
+<xref linkend="guc-log-destination">.</entry>
+</row>
+
 <row>
  <entry><filename>global</></entry>
  <entry>Subdirectory containing cluster-wide tables, such as
diff --git a/src/backend/postmaster/syslogger.c b/src/backend/postmaster/syslogger.c
index fd62d66..6e7bdce 100644
--- a/src/backend/postmaster/syslogger.c
+++ b/src/backend/postmaster/syslogger.c
@@ -146,6 +146,7 @@ static char *logfile_getname(pg_time_t timestamp, const char *suffix);
 static void set_next_rotation_time(void);
 static void sigHupHandler(SIGNAL_ARGS);
 static void sigUsr1Handler(SIGNAL_ARGS);
+static void logfile_writename(char *filename, char *csvfilename);
 
 
 /*
@@ -348,6 +349,13 @@ SysLoggerMain(int argc, char *argv[])
 				rotation_disabled = false;
 				rotation_requested = true;
 			}
+
+			/*
+			 * Force rewriting last log filename when reloading configuration,
+			 * even if rotation_requested is false, log_destination may have
+			 * been changed and we don't want to wait the next file rotation.
+			 */
+			logfile_writename(last_file_name, last_csv_file_name);
 		}
 
 		if (Log_RotationAge > 0 && !rotation_disabled)
@@ -513,8 +521,13 @@ SysLogger_Start(void)
 	pid_t		sysloggerPid;
 	char	   *filename;
 
-	if (!Logging_collector)
+	if (!Logging_collector) {
+		/* Logging collector is not enabled. We don't know where messages are
+		 * logged.  Remove outdated file holding the current log filenames.
+		 */
+		unlink(CURRENT_LOG_FILENAME);
 		return 0;
+	}
 
 	/*
 	 * If first time through, create the pipe which will receive stderr
@@ -574,6 +587,8 @@ SysLogger_Start(void)
 
 	syslogFile = logfile_open(filename, "a", false);
 
+	logfile_writename(filename, NULL);
+
 	pfree(filename);
 
 #ifdef EXEC_BACKEND
@@ -1098,6 +1113,8 @@ open_csvlogfile(void)
 		pfree(last_csv_file_name);
 
 	last_csv_file_name = filename;
+
+	logfile_writename(last_file_name, last_csv_file_name);
 }
 
 /*
@@ -1209,6 +1226,9 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for)
 			return;
 		}
 
+		if (csvlogFile == NULL)
+			logfile_writename(filename, csvfilename);
+
 		fclose(syslogFile);
 		syslogFile = fh;
 
@@ -1220,7 +1240,6 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for)
 	}
 
 	/* Same as above, but for csv file. */
-
 	if (csvlogFile != NULL &&
 		(time_based_rotation || (size_rotation_for & LOG_DESTINATION_CSVLOG)))
 	{
@@ -1261,6 +1280,9 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for)
 			pfree(last_csv_file_name);
 		last_csv_file_name = csvfilename;
 		csvfilename = NULL;
+
+		logfile_writename(last_file_name, last_csv_file_name);
+
 	}
 
 	if (filename)
@@ -1365,3 +1387,62 @@ sigUsr1Handler(SIGNAL_ARGS)
 
 	errno = save_errno;
 }
+
+/*
+ * Store the name of the file(s) where the log collector, when enabled, writes
+ * log messages.  Useful for finding the name(s) of the current log file(s)
+ * when there is time-based logfile rotation.  Filenames are stored in a
+ * temporary file and renamed into the final destination for atomicity.
+ */
+static void
+logfile_writename(char *filename, char *csvfilename)
+{
+	FILE	*fh;
+	char	tempfn[MAXPGPATH];
+
+	if (!(Log_destination & LOG_DESTINATION_STDERR) && !(Log_destination & LOG_DESTINATION_CSVLOG)) {
+		unlink(CURRENT_LOG_FILENAME);
+		return;
+	}
+
+	snprintf(tempfn, sizeof(tempfn), "%s",
+						CURRENT_LOG_FILENAME);
+	strcat(tempfn, ".tmp");
+	if ((fh = logfile_open(tempfn, "w", true) ) == NULL)
+	{
+		return;
+	}
+	if (filename && (Log_destination & LOG_DESTINATION_STDERR)) {
+		if (fprintf(fh, "stderr %s\n", filename) < 0)
+		{
+			ereport(LOG,
+					(errcode_for_file_access(),
+					errmsg("could not write stderr log file path \"%s\": %m",
+						tempfn)));
+			fclose(fh);
+			return;
+		}
+	}
+
+	if (csvfilename && (Log_destination & LOG_DESTINATION_CSVLOG)) {
+		if (fprintf(fh, "csvlog %s\n", csvfilename) < 0)
+		{
+			ereport(LOG,
+					(errcode_for_file_access(),
+					errmsg("could not write csvlog log file path \"%s\": %m",
+						tempfn)));
+			fclose(fh);
+			return;
+		}
+	}
+	fclose(fh);
+
+	if (rename(tempfn, CURRENT_LOG_FILENAME) != 0)
+	{
+		ereport(LOG,
+				(errcode_for_file_access(),
+				errmsg("could not rename file \"%s\": %m",
+						tempfn)));
+		return;
+	}
+}
diff --git a/src/backend/utils/adt/misc.c b/src/backend/utils/adt/misc.c
index 0da051a..73fa708 100644
--- a/src/backend/utils/adt/misc.c
+++ b/src/backend/utils/adt/misc.c
@@ -19,6 +19,7 @@
 #include <dirent.h>
 #include <math.h>
 #include <unistd.h>
+#include <sys/stat.h>
 
 #include "access/sysattr.h"
 #include "catalog/pg_authid.h"
@@ -892,3 +893,135 @@ parse_ident(PG_FUNCTION_ARGS)
 
 	PG_RETURN_DATUM(makeArrayResult(astate, CurrentMemoryContext));
 }
+
+/*
+ * Report current log file used by log collector
+ */
+Datum
+pg_current_logfile(PG_FUNCTION_ARGS)
+{
+	FILE    *fd;
+	char    lbuffer[MAXPGPATH];
+	text    *fmt;
+	char    *logfmt;
+	struct stat stat_buf;
+	char    *log_format;
+	char    *log_filename;
+
+	/* The log format parameter is optional */
+	if (PG_NARGS() == 1) {
+		fmt = PG_ARGISNULL(0) ? NULL : PG_GETARG_TEXT_PP(0);
+		if (fmt != NULL) {
+			logfmt = text_to_cstring(fmt);
+			if ( (strcmp(logfmt, "stderr") != 0) &&
+				(strcmp(logfmt, "csvlog") != 0) ) {
+				ereport(ERROR,
+		(errmsg("log format %s not supported, possible values are stderr or csvlog", logfmt)));
+				PG_RETURN_NULL();
+			}
+		}
+	} else {
+		logfmt = NULL;
+	}
+
+	if (!Logging_collector)
+		PG_RETURN_NULL();
+
+	/* Check if current log file is present */
+	if (stat(CURRENT_LOG_FILENAME, &stat_buf) != 0)
+		PG_RETURN_NULL();
+
+	fd = AllocateFile(CURRENT_LOG_FILENAME, "r");
+	if (fd == NULL)
+	{
+		if (errno != ENOENT)
+			ereport(ERROR,
+				(errcode_for_file_access(),
+				errmsg("could not read file \"%s\": %m",
+				CURRENT_LOG_FILENAME)));
+		PG_RETURN_NULL();
+	}
+
+	/*
+	* Read the file to gather current log filename(s) registered
+	* by the syslogger.
+	*/
+	while (fgets(lbuffer, sizeof(lbuffer), fd) != NULL) {
+
+		/* Check for a read error. */
+		if (ferror(fd)) {
+			ereport(ERROR,
+				(errcode_for_file_access(),
+				errmsg("could not read file \"%s\": %m", CURRENT_LOG_FILENAME)));
+			FreeFile(fd);
+			break;
+		}
+
+		/* remove trailing newline */
+		if (strchr(lbuffer, '\n') != NULL)
+			*strchr(lbuffer, '\n') = '\0';
+
+		/* extract log format and log file path from the line */
+		log_format = strtok(lbuffer, " ");
+		if (log_format)
+		{
+			log_filename = strtok(NULL, " ");
+			if (!log_filename) {
+				ereport(ERROR,
+					(errmsg("unexpected line format in file %s", CURRENT_LOG_FILENAME)));
+				break;
+			}
+		}
+		else
+		{
+			ereport(ERROR,
+				(errmsg("unexpected line format in file %s", CURRENT_LOG_FILENAME)));
+			break;
+		}
+
+		/*
+		 * When no log format is provided as argument always reports
+		 * the first registered log file in CURRENT_LOG_FILENAME.
+		 */
+		if (logfmt == NULL)
+			break;
+
+		/* report the entry corresponding to the requested format */
+		if (strcmp(logfmt, log_format) == 0)
+			break;
+	}
+	/* Close the current log filename file. */
+	if (FreeFile(fd))
+		ereport(ERROR,
+				(errcode_for_file_access(),
+			errmsg("could not close file \"%s\": %m", CURRENT_LOG_FILENAME)));
+
+
+	if (log_filename[0] == '\0')
+		PG_RETURN_NULL();
+
+	/* Return null when csvlog is requested but we have a stderr log */
+	if ( (logfmt != NULL) && (strcmp(logfmt, "csvlog") == 0)
+			&& !(Log_destination & LOG_DESTINATION_CSVLOG) )
+		PG_RETURN_NULL();
+
+	/* Return null when stderr is requested but we have a csv log */
+	if ( (logfmt != NULL) && (strcmp(logfmt, "stderr") == 0)
+			&& !(Log_destination & LOG_DESTINATION_STDERR) )
+		PG_RETURN_NULL();
+
+	PG_RETURN_TEXT_P(cstring_to_text(log_filename));
+}
+
+/*
+ * Report current log file used by log collector (1 argument version)
+ *
+ * note: this wrapper is necessary to pass the sanity check in opr_sanity,
+ * which checks that all built-in functions that share the implementing C
+ * function take the same number of arguments
+ */
+Datum
+pg_current_logfile_1arg(PG_FUNCTION_ARGS)
+{
+        return pg_current_logfile(fcinfo);
+}
diff --git a/src/include/catalog/pg_proc.h b/src/include/catalog/pg_proc.h
index 17ec71d..98b5acf 100644
--- a/src/include/catalog/pg_proc.h
+++ b/src/include/catalog/pg_proc.h
@@ -3179,6 +3179,10 @@ DATA(insert OID = 2621 ( pg_reload_conf			PGNSP PGUID 12 1 0 0 0 f f f f t f v s
 DESCR("reload configuration files");
 DATA(insert OID = 2622 ( pg_rotate_logfile		PGNSP PGUID 12 1 0 0 0 f f f f t f v s 0 0 16 "" _null_ _null_ _null_ _null_ _null_ pg_rotate_logfile _null_ _null_ _null_ ));
 DESCR("rotate log file");
+DATA(insert OID = 3800 ( pg_current_logfile             PGNSP PGUID 12 1 0 0 0 f f f f f f v s 0 0 25 "" _null_ _null_ _null_ _null_ _null_ pg_current_logfile _null_ _null_ _null_ ));
+DESCR("current logging collector file location");
+DATA(insert OID = 3801 ( pg_current_logfile             PGNSP PGUID 12 1 0 0 0 f f f f f f v s 1 0 25 "25" _null_ _null_ _null_ _null_ _null_ pg_current_logfile_1arg _null_ _null_ _null_ ));
+DESCR("current logging collector file location");
 
 DATA(insert OID = 2623 ( pg_stat_file		PGNSP PGUID 12 1 0 0 0 f f f f t f v s 1 0 2249 "25" "{25,20,1184,1184,1184,1184,16}" "{i,o,o,o,o,o,o}" "{filename,size,access,modification,change,creation,isdir}" _null_ _null_ pg_stat_file_1arg _null_ _null_ _null_ ));
 DESCR("get information about file");
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 78545da..6fd4d5e 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -466,4 +466,13 @@ extern bool has_rolreplication(Oid roleid);
 extern bool BackupInProgress(void);
 extern void CancelBackup(void);
 
+/* in backend/utils/adt/misc.c and backend/postmaster/syslogger.c */
+/*
+ * Name of file holding the paths, names, and types of the files where current
+ * log messages are written, when the log collector is enabled.  Useful
+ * outside of Postgres when finding the name of the current log file in the
+ * case of time-based log rotation.
+ */
+#define CURRENT_LOG_FILENAME  "current_logfiles"
+
 #endif   /* MISCADMIN_H */
diff --git a/src/include/utils/builtins.h b/src/include/utils/builtins.h
index 90f5132..e532022 100644
--- a/src/include/utils/builtins.h
+++ b/src/include/utils/builtins.h
@@ -522,6 +522,8 @@ extern Datum pg_collation_for(PG_FUNCTION_ARGS);
 extern Datum pg_relation_is_updatable(PG_FUNCTION_ARGS);
 extern Datum pg_column_is_updatable(PG_FUNCTION_ARGS);
 extern Datum parse_ident(PG_FUNCTION_ARGS);
+extern Datum pg_current_logfile(PG_FUNCTION_ARGS);
+extern Datum pg_current_logfile_1arg(PG_FUNCTION_ARGS);
 
 /* oid.c */
 extern Datum oidin(PG_FUNCTION_ARGS);

diff --git a/src/backend/postmaster/syslogger.c b/src/backend/postmaster/syslogger.c
index 6e7bdce..7d6ddce 100644
--- a/src/backend/postmaster/syslogger.c
+++ b/src/backend/postmaster/syslogger.c
@@ -1400,7 +1400,9 @@ logfile_writename(char *filename, char *csvfilename)
 	FILE	*fh;
 	char	tempfn[MAXPGPATH];
 
-	if (!(Log_destination & LOG_DESTINATION_STDERR) && !(Log_destination & LOG_DESTINATION_CSVLOG)) {
+	if (!(Log_destination & LOG_DESTINATION_STDERR)
+		&& !(Log_destination & LOG_DESTINATION_CSVLOG))
+	{
 		unlink(CURRENT_LOG_FILENAME);
 		return;
 	}

diff --git a/src/backend/postmaster/syslogger.c b/src/backend/postmaster/syslogger.c
index 6e7bdce..8569cea 100644
--- a/src/backend/postmaster/syslogger.c
+++ b/src/backend/postmaster/syslogger.c
@@ -1171,6 +1171,8 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for)
 	char	   *csvfilename = NULL;
 	pg_time_t	fntime;
 	FILE	   *fh;
+    bool       rotate_csvlog;
+    bool       rotate_stderr;
 
 	rotation_requested = false;
 
@@ -1195,7 +1197,9 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for)
 	 *
 	 * Note: last_file_name should never be NULL here, but if it is, append.
 	 */
-	if (time_based_rotation || (size_rotation_for & LOG_DESTINATION_STDERR))
+	rotate_stderr = time_based_rotation ||
+		            (size_rotation_for & LOG_DESTINATION_STDERR);
+	if (rotate_stderr)
 	{
 		if (Log_truncate_on_rotation && time_based_rotation &&
 			last_file_name != NULL &&
@@ -1226,9 +1230,6 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for)
 			return;
 		}
 
-		if (csvlogFile == NULL)
-			logfile_writename(filename, csvfilename);
-
 		fclose(syslogFile);
 		syslogFile = fh;
 
@@ -1240,8 +1241,10 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for)
 	}
 
 	/* Same as above, but for csv file. */
-	if (csvlogFile != NULL &&
-		(time_based_rotation || (size_rotation_for & LOG_DESTINATION_CSVLOG)))
+	rotate_csvlog = csvlogFile != NULL &&
+		            (time_based_rotation ||
+					(size_rotation_for & LOG_DESTINATION_CSVLOG));
+	if (rotate_csvlog)
 	{
 		if (Log_truncate_on_rotation && time_based_rotation &&
 			last_csv_file_name != NULL &&
@@ -1280,11 +1283,11 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for)
 			pfree(last_csv_file_name);
 		last_csv_file_name = csvfilename;
 		csvfilename = NULL;
+	}
 
+	if (rotate_stderr || rotate_csvlog)
 		logfile_writename(last_file_name, last_csv_file_name);
 
-	}
-
 	if (filename)
 		pfree(filename);
 	if (csvfilename)

diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index 65660c1..eb77a3c 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -75,6 +75,7 @@
 #include "utils/builtins.h"
 #include "utils/bytea.h"
 #include "utils/guc_tables.h"
+#include "utils/guc_values.h"
 #include "utils/memutils.h"
 #include "utils/pg_locale.h"
 #include "utils/plancache.h"
@@ -3256,13 +3257,13 @@ static struct config_string ConfigureNamesString[] =
 	{
 		{"log_destination", PGC_SIGHUP, LOGGING_WHERE,
 			gettext_noop("Sets the destination for server log output."),
-			gettext_noop("Valid values are combinations of \"stderr\", "
-						 "\"syslog\", \"csvlog\", and \"eventlog\", "
-						 "depending on the platform."),
+			gettext_noop("Valid values are combinations of \"" GUCV_STDERR
+						  "\", \"" GUCV_SYSLOG "\", \"" GUCV_CSVLOG "\", and "
+						 "\"" GUCV_EVENTLOG "\", depending on the platform."),
 			GUC_LIST_INPUT
 		},
 		&Log_destination_string,
-		"stderr",
+		GUCV_STDERR,
 		check_log_destination, assign_log_destination, NULL
 	},
 	{
@@ -9892,16 +9893,16 @@ check_log_destination(char **newval, void **extra, GucSource source)
 	{
 		char	   *tok = (char *) lfirst(l);
 
-		if (pg_strcasecmp(tok, "stderr") == 0)
+		if (pg_strcasecmp(tok, GUCV_STDERR) == 0)
 			newlogdest |= LOG_DESTINATION_STDERR;
-		else if (pg_strcasecmp(tok, "csvlog") == 0)
+		else if (pg_strcasecmp(tok, GUCV_CSVLOG) == 0)
 			newlogdest |= LOG_DESTINATION_CSVLOG;
 #ifdef HAVE_SYSLOG
-		else if (pg_strcasecmp(tok, "syslog") == 0)
+		else if (pg_strcasecmp(tok, GUCV_SYSLOG) == 0)
 			newlogdest |= LOG_DESTINATION_SYSLOG;
 #endif
 #ifdef WIN32
-		else if (pg_strcasecmp(tok, "eventlog") == 0)
+		else if (pg_strcasecmp(tok, GUCV_EVENTLOG) == 0)
 			newlogdest |= LOG_DESTINATION_EVENTLOG;
 #endif
 		else
diff --git a/src/include/utils/guc_values.h b/src/include/utils/guc_values.h
new file mode 100644
index 0000000..cd26b5a
--- /dev/null
+++ b/src/include/utils/guc_values.h
@@ -0,0 +1,22 @@
+/*--------------------------------------------------------------------
+ * guc_values.h
+ *
+ * User-supplied GUC configuration values which are tested against
+ * user-supplied function parameters.
+ *
+ * Copyright (c) 2016, PostgreSQL Global Development Group
+ *
+ * src/include/utils/guc_values.h
+ *--------------------------------------------------------------------
+ */
+
+#ifndef GUC_VALUES_H
+#define GUC_VALUES_H
+
+/* log_destination values */
+#define GUCV_CSVLOG   "csvlog"
+#define GUCV_EVENTLOG "eventlog"
+#define GUCV_STDERR   "stderr"
+#define GUCV_SYSLOG   "syslog"
+
+#endif   /* GUC_VALUES_H */

diff --git a/src/backend/postmaster/syslogger.c b/src/backend/postmaster/syslogger.c
index 83afc34..9aa5247 100644
--- a/src/backend/postmaster/syslogger.c
+++ b/src/backend/postmaster/syslogger.c
@@ -45,6 +45,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "utils/guc.h"
+#include "utils/guc_values.h"
 #include "utils/ps_status.h"
 #include "utils/timestamp.h"
 
@@ -1409,7 +1410,7 @@ logfile_writename(char *filename, char *csvfilename)
 		return;
 	}
 	if (filename && (Log_destination & LOG_DESTINATION_STDERR)) {
-		if (fprintf(fh, "stderr %s\n", filename) < 0)
+		if (fprintf(fh, GUCV_STDERR " %s\n", filename) < 0)
 		{
 			ereport(LOG,
 					(errcode_for_file_access(),
@@ -1421,7 +1422,7 @@ logfile_writename(char *filename, char *csvfilename)
 	}
 
 	if (csvfilename && (Log_destination & LOG_DESTINATION_CSVLOG)) {
-		if (fprintf(fh, "csvlog %s\n", csvfilename) < 0)
+		if (fprintf(fh, GUCV_CSVLOG " %s\n", csvfilename) < 0)
 		{
 			ereport(LOG,
 					(errcode_for_file_access(),
diff --git a/src/backend/utils/adt/misc.c b/src/backend/utils/adt/misc.c
index 06acdb2..e2d1939 100644
--- a/src/backend/utils/adt/misc.c
+++ b/src/backend/utils/adt/misc.c
@@ -43,6 +43,7 @@
 #include "tcop/tcopprot.h"
 #include "utils/acl.h"
 #include "utils/builtins.h"
+#include "utils/guc_values.h"
 #include "utils/timestamp.h"
 
 #define atooid(x)  ((Oid) strtoul((x), NULL, 10))
@@ -913,10 +914,11 @@ pg_current_logfile(PG_FUNCTION_ARGS)
 		fmt = PG_ARGISNULL(0) ? NULL : PG_GETARG_TEXT_PP(0);
 		if (fmt != NULL) {
 			logfmt = text_to_cstring(fmt);
-			if ( (strcmp(logfmt, "stderr") != 0) &&
-				(strcmp(logfmt, "csvlog") != 0) ) {
+			if ( (strcmp(logfmt, GUCV_STDERR) != 0) &&
+				(strcmp(logfmt, GUCV_CSVLOG) != 0) ) {
 				ereport(ERROR,
-		(errmsg("log format %s not supported, possible values are stderr or csvlog", logfmt)));
+		(errmsg("log format %s not supported, possible values are "
+				GUCV_STDERR " or " GUCV_CSVLOG, logfmt)));
 				PG_RETURN_NULL();
 			}
 		}
@@ -1001,12 +1003,12 @@ pg_current_logfile(PG_FUNCTION_ARGS)
 		PG_RETURN_NULL();
 
 	/* Return null when csvlog is requested but we have a stderr log */
-	if ( (logfmt != NULL) && (strcmp(logfmt, "csvlog") == 0)
+	if ( (logfmt != NULL) && (strcmp(logfmt, GUCV_CSVLOG) == 0)
 			&& !(Log_destination & LOG_DESTINATION_CSVLOG) )
 		PG_RETURN_NULL();
 
 	/* Return null when stderr is requested but we have a csv log */
-	if ( (logfmt != NULL) && (strcmp(logfmt, "stderr") == 0)
+	if ( (logfmt != NULL) && (strcmp(logfmt, GUCV_STDERR) == 0)
 			&& !(Log_destination & LOG_DESTINATION_STDERR) )
 		PG_RETURN_NULL();
 

diff --git a/doc/src/sgml/storage.sgml b/doc/src/sgml/storage.sgml
index cf20d99..256a14f 100644
--- a/doc/src/sgml/storage.sgml
+++ b/doc/src/sgml/storage.sgml
@@ -72,16 +72,34 @@ Item
   <filename>current_logfiles</>
  </entry>
  <entry>
-  A file recording the current log file(s) used by the syslogger and
-  its log format, <systemitem>stderr</> or <systemitem>csvlog</>. Each line
-  of the file is a space separated list of two elements: the log format and
-  the full path to the log file including the value
-  of <xref linkend="guc-log-directory">. The log format must be present
-  in <xref linkend="guc-log-destination"> to be listed in the file. This file
+  <para>A file recording the log file(s) currently written to by the syslogger
+  and the file's log formats, <systemitem>stderr</>
+  or <systemitem>csvlog</>. Each line of the file is a space separated list of
+  two elements: the log format and the full path to the log file including the
+  value of <xref linkend="guc-log-directory">.</para>
+
+  <para>During server startup <filename>current_logfiles</filename> reports
+  the default server log destination.  After server startup the log format
+  must be present in <xref linkend="guc-log-destination"> to be listed in
+  <filename>current_logfiles</filename>.</para>
+
+  <note>
+    <para>Non-<productname>PostgreSQL</productname> log sources, such as 3rd
+    party libraries, which deliver error messages directly to stderr are
+    always logged by <productname>PostgreSQL</productname> to stderr.  Stderr
+    is also the destination for any incomplete log messages produced by
+    <productname>PostgreSQL</productname>.  When
+    <systemitem>stderr</systemitem> is not in
+    <xref linkend="guc-log-destination">,
+    <filename>current_logfiles</filename> does not not contain the name of the
+    file where these sorts of log messages are written.</para>
+  </note>
+  
+  <para>The <filename>current_logfiles</filename> file
   is present only when <xref linkend="guc-logging-collector"> is
   activated and when at least one of <systemitem>stderr</> or
   <systemitem>csvlog</> value is present in
-<xref linkend="guc-log-destination">.</entry>
+  <xref linkend="guc-log-destination">.</para></entry>
 </row>
 
 <row>

diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index adab2f8..645cbb9 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -4143,6 +4143,12 @@ SELECT * FROM parent WHERE key = 2400;
      <primary>server log</primary>
     </indexterm>
 
+    <para>When logs are written to the file-system their paths, names, and
+    types are recorded in
+    the <xref linkend="storage-pgdata-current-logfiles"> file.  This provides
+    a convenient way to find and access log content without establishing a
+    database connection.</para>
+
     <sect2 id="runtime-config-logging-where">
      <title>Where To Log</title>
 
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 2e64cc4..f5bfe59 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -15443,6 +15443,19 @@ SELECT * FROM pg_ls_dir('.') WITH ORDINALITY AS t(ls,n);
       </row>
 
       <row>
+       <entry><literal><function>pg_current_logfile()</function></literal></entry>
+       <entry><type>text</type></entry>
+       <entry>primary log file name in use by the logging collector</entry>
+      </row>
+
+      <row>
+       <entry><literal><function>pg_current_logfile(<type>text</>)</function></literal></entry>
+       <entry><type>text</type></entry>
+       <entry>log file name, of log in the requested format, in use by the
+       logging collector</entry>
+      </row>
+
+      <row>
        <entry><literal><function>pg_my_temp_schema()</function></literal></entry>
        <entry><type>oid</type></entry>
        <entry>OID of session's temporary schema, or 0 if none</entry>
@@ -15660,6 +15673,34 @@ SET search_path TO <replaceable>schema</> <optional>, <replaceable>schema</>, ..
     the time when the postmaster process re-read the configuration files.)
    </para>
 
+    <indexterm>
+    <primary>pg_current_logile</primary>
+   </indexterm>
+
+   <indexterm>
+    <primary>Logging</primary>
+    <secondary>pg_current_logfile function</secondary>
+   </indexterm>
+
+   <para>
+    <function>pg_current_logfile</function> returns, as <type>text</type>,
+    the path of either the csv or stderr log file currently in use by the
+    logging collector.  This is a path including the
+    <xref linkend="guc-log-directory"> directory and the log file name.
+    Log collection must be active or the return value
+    is <literal>NULL</literal>.  When multiple logfiles exist, each in a
+    different format, <function>pg_current_logfile</function> called
+    without arguments returns the path of the file having the first format
+    found in the ordered
+    list: <systemitem>stderr</>, <systemitem>csvlog</>.
+    <literal>NULL</literal> is returned when no log file has any of these
+    formats.  To request a specific file format supply,
+    as <type>text</type>, either <systemitem>csvlog</>
+    or <systemitem>stderr</> as the value of the optional parameter. The
+    return value is <literal>NULL</literal> when the log format requested
+    is not a configured <xref linkend="guc-log-destination">.
+   </para>
+
    <indexterm>
     <primary>pg_my_temp_schema</primary>
    </indexterm>
diff --git a/doc/src/sgml/storage.sgml b/doc/src/sgml/storage.sgml
index 5c52824..256a14f 100644
--- a/doc/src/sgml/storage.sgml
+++ b/doc/src/sgml/storage.sgml
@@ -60,6 +60,48 @@ Item
  <entry>Subdirectory containing per-database subdirectories</entry>
 </row>
 
+<row id="storage-pgdata-current-logfiles" xreflabel="current_logfiles">
+ <entry>
+  <indexterm>
+   <primary><filename>current_logfiles</filename></primary>
+  </indexterm>
+  <indexterm>
+   <primary>Logging</primary>
+   <secondary><filename>current_logfiles</filename> file</secondary>
+  </indexterm>
+  <filename>current_logfiles</>
+ </entry>
+ <entry>
+  <para>A file recording the log file(s) currently written to by the syslogger
+  and the file's log formats, <systemitem>stderr</>
+  or <systemitem>csvlog</>. Each line of the file is a space separated list of
+  two elements: the log format and the full path to the log file including the
+  value of <xref linkend="guc-log-directory">.</para>
+
+  <para>During server startup <filename>current_logfiles</filename> reports
+  the default server log destination.  After server startup the log format
+  must be present in <xref linkend="guc-log-destination"> to be listed in
+  <filename>current_logfiles</filename>.</para>
+
+  <note>
+    <para>Non-<productname>PostgreSQL</productname> log sources, such as 3rd
+    party libraries, which deliver error messages directly to stderr are
+    always logged by <productname>PostgreSQL</productname> to stderr.  Stderr
+    is also the destination for any incomplete log messages produced by
+    <productname>PostgreSQL</productname>.  When
+    <systemitem>stderr</systemitem> is not in
+    <xref linkend="guc-log-destination">,
+    <filename>current_logfiles</filename> does not not contain the name of the
+    file where these sorts of log messages are written.</para>
+  </note>
+  
+  <para>The <filename>current_logfiles</filename> file
+  is present only when <xref linkend="guc-logging-collector"> is
+  activated and when at least one of <systemitem>stderr</> or
+  <systemitem>csvlog</> value is present in
+  <xref linkend="guc-log-destination">.</para></entry>
+</row>
+
 <row>
  <entry><filename>global</></entry>
  <entry>Subdirectory containing cluster-wide tables, such as
diff --git a/src/backend/postmaster/syslogger.c b/src/backend/postmaster/syslogger.c
index fd62d66..fa11fa0 100644
--- a/src/backend/postmaster/syslogger.c
+++ b/src/backend/postmaster/syslogger.c
@@ -146,6 +146,7 @@ static char *logfile_getname(pg_time_t timestamp, const char *suffix);
 static void set_next_rotation_time(void);
 static void sigHupHandler(SIGNAL_ARGS);
 static void sigUsr1Handler(SIGNAL_ARGS);
+static void logfile_writename(char *filename, char *csvfilename);
 
 
 /*
@@ -348,6 +349,13 @@ SysLoggerMain(int argc, char *argv[])
 				rotation_disabled = false;
 				rotation_requested = true;
 			}
+
+			/*
+			 * Force rewriting last log filename when reloading configuration,
+			 * even if rotation_requested is false, log_destination may have
+			 * been changed and we don't want to wait the next file rotation.
+			 */
+			logfile_writename(last_file_name, last_csv_file_name);
 		}
 
 		if (Log_RotationAge > 0 && !rotation_disabled)
@@ -513,8 +521,13 @@ SysLogger_Start(void)
 	pid_t		sysloggerPid;
 	char	   *filename;
 
-	if (!Logging_collector)
+	if (!Logging_collector) {
+		/* Logging collector is not enabled. We don't know where messages are
+		 * logged.  Remove outdated file holding the current log filenames.
+		 */
+		unlink(LOG_METAINFO_DATAFILE);
 		return 0;
+	}
 
 	/*
 	 * If first time through, create the pipe which will receive stderr
@@ -574,6 +587,8 @@ SysLogger_Start(void)
 
 	syslogFile = logfile_open(filename, "a", false);
 
+	logfile_writename(filename, NULL);
+
 	pfree(filename);
 
 #ifdef EXEC_BACKEND
@@ -1098,6 +1113,8 @@ open_csvlogfile(void)
 		pfree(last_csv_file_name);
 
 	last_csv_file_name = filename;
+
+	logfile_writename(last_file_name, last_csv_file_name);
 }
 
 /*
@@ -1154,6 +1171,8 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for)
 	char	   *csvfilename = NULL;
 	pg_time_t	fntime;
 	FILE	   *fh;
+	bool       rotate_csvlog;
+	bool       rotate_stderr;
 
 	rotation_requested = false;
 
@@ -1178,7 +1197,9 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for)
 	 *
 	 * Note: last_file_name should never be NULL here, but if it is, append.
 	 */
-	if (time_based_rotation || (size_rotation_for & LOG_DESTINATION_STDERR))
+	rotate_stderr = time_based_rotation ||
+		(size_rotation_for & LOG_DESTINATION_STDERR);
+	if (rotate_stderr)
 	{
 		if (Log_truncate_on_rotation && time_based_rotation &&
 			last_file_name != NULL &&
@@ -1220,9 +1241,9 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for)
 	}
 
 	/* Same as above, but for csv file. */
-
-	if (csvlogFile != NULL &&
-		(time_based_rotation || (size_rotation_for & LOG_DESTINATION_CSVLOG)))
+	rotate_csvlog = csvlogFile != NULL &&
+		(time_based_rotation || (size_rotation_for & LOG_DESTINATION_CSVLOG));
+	if (rotate_csvlog)
 	{
 		if (Log_truncate_on_rotation && time_based_rotation &&
 			last_csv_file_name != NULL &&
@@ -1263,6 +1284,8 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for)
 		csvfilename = NULL;
 	}
 
+	if (rotate_stderr || rotate_csvlog)
+		logfile_writename(last_file_name, last_csv_file_name);
 	if (filename)
 		pfree(filename);
 	if (csvfilename)
@@ -1365,3 +1388,65 @@ sigUsr1Handler(SIGNAL_ARGS)
 
 	errno = save_errno;
 }
+
+/*
+ * Store the name of the file(s) where the log collector, when enabled, writes
+ * log messages.  Useful for finding the name(s) of the current log file(s)
+ * when there is time-based logfile rotation.  Filenames are stored in a
+ * temporary file and renamed into the final destination for atomicity.
+ */
+static void
+logfile_writename(char *filename, char *csvfilename)
+{
+	FILE	*fh;
+	char	tempfn[MAXPGPATH];
+
+	if (!(Log_destination & LOG_DESTINATION_STDERR)
+		&& !(Log_destination & LOG_DESTINATION_CSVLOG))
+	{
+		unlink(LOG_METAINFO_DATAFILE);
+		return;
+	}
+
+	snprintf(tempfn, sizeof(tempfn), "%s.tmp", LOG_METAINFO_DATAFILE);
+
+	if ((fh = logfile_open(tempfn, "w", true) ) == NULL)
+	{
+		return;
+	}
+	if (filename && (Log_destination & LOG_DESTINATION_STDERR))
+	{
+		if (fprintf(fh, "stderr %s\n", filename) < 0)
+		{
+			ereport(LOG,
+					(errcode_for_file_access(),
+					errmsg("could not write stderr log file path \"%s\": %m",
+						tempfn)));
+			fclose(fh);
+			return;
+		}
+	}
+
+	if (csvfilename && (Log_destination & LOG_DESTINATION_CSVLOG))
+	{
+		if (fprintf(fh, "csvlog %s\n", csvfilename) < 0)
+		{
+			ereport(LOG,
+					(errcode_for_file_access(),
+					errmsg("could not write csvlog log file path \"%s\": %m",
+						tempfn)));
+			fclose(fh);
+			return;
+		}
+	}
+	fclose(fh);
+
+	if (rename(tempfn, LOG_METAINFO_DATAFILE) != 0)
+	{
+		ereport(LOG,
+				(errcode_for_file_access(),
+				errmsg("could not rename file \"%s\": %m",
+						tempfn)));
+		return;
+	}
+}
diff --git a/src/backend/utils/adt/misc.c b/src/backend/utils/adt/misc.c
index 0da051a..53185e5 100644
--- a/src/backend/utils/adt/misc.c
+++ b/src/backend/utils/adt/misc.c
@@ -19,6 +19,7 @@
 #include <dirent.h>
 #include <math.h>
 #include <unistd.h>
+#include <sys/stat.h>
 
 #include "access/sysattr.h"
 #include "catalog/pg_authid.h"
@@ -892,3 +893,135 @@ parse_ident(PG_FUNCTION_ARGS)
 
 	PG_RETURN_DATUM(makeArrayResult(astate, CurrentMemoryContext));
 }
+
+/*
+ * Report current log file used by log collector
+ */
+Datum
+pg_current_logfile(PG_FUNCTION_ARGS)
+{
+	FILE    *fd;
+	char    lbuffer[MAXPGPATH];
+	text    *fmt;
+	char    *logfmt;
+	struct stat stat_buf;
+	char    *log_format;
+	char    *log_filename;
+
+	/* The log format parameter is optional */
+	if (PG_NARGS() == 1) {
+		fmt = PG_ARGISNULL(0) ? NULL : PG_GETARG_TEXT_PP(0);
+		if (fmt != NULL) {
+			logfmt = text_to_cstring(fmt);
+			if ( (strcmp(logfmt, "stderr") != 0) &&
+				(strcmp(logfmt, "csvlog") != 0) ) {
+				ereport(ERROR,
+		(errmsg("log format %s not supported, possible values are stderr or csvlog", logfmt)));
+				PG_RETURN_NULL();
+			}
+		}
+	} else {
+		logfmt = NULL;
+	}
+
+	if (!Logging_collector)
+		PG_RETURN_NULL();
+
+	/* Check if current log file is present */
+	if (stat(LOG_METAINFO_DATAFILE, &stat_buf) != 0)
+		PG_RETURN_NULL();
+
+	fd = AllocateFile(LOG_METAINFO_DATAFILE, "r");
+	if (fd == NULL)
+	{
+		if (errno != ENOENT)
+			ereport(ERROR,
+				(errcode_for_file_access(),
+				errmsg("could not read file \"%s\": %m",
+				LOG_METAINFO_DATAFILE)));
+		PG_RETURN_NULL();
+	}
+
+	/*
+	* Read the file to gather current log filename(s) registered
+	* by the syslogger.
+	*/
+	while (fgets(lbuffer, sizeof(lbuffer), fd) != NULL) {
+
+		/* Check for a read error. */
+		if (ferror(fd)) {
+			ereport(ERROR,
+				(errcode_for_file_access(),
+				errmsg("could not read file \"%s\": %m", LOG_METAINFO_DATAFILE)));
+			FreeFile(fd);
+			break;
+		}
+
+		/* remove trailing newline */
+		if (strchr(lbuffer, '\n') != NULL)
+			*strchr(lbuffer, '\n') = '\0';
+
+		/* extract log format and log file path from the line */
+		log_format = strtok(lbuffer, " ");
+		if (log_format)
+		{
+			log_filename = strtok(NULL, " ");
+			if (!log_filename) {
+				ereport(ERROR,
+					(errmsg("unexpected line format in file %s", LOG_METAINFO_DATAFILE)));
+				break;
+			}
+		}
+		else
+		{
+			ereport(ERROR,
+				(errmsg("unexpected line format in file %s", LOG_METAINFO_DATAFILE)));
+			break;
+		}
+
+		/*
+		 * When no log format is provided as argument always reports
+		 * the first registered log file in LOG_METAINFO_DATAFILE.
+		 */
+		if (logfmt == NULL)
+			break;
+
+		/* report the entry corresponding to the requested format */
+		if (strcmp(logfmt, log_format) == 0)
+			break;
+	}
+	/* Close the current log filename file. */
+	if (FreeFile(fd))
+		ereport(ERROR,
+				(errcode_for_file_access(),
+			errmsg("could not close file \"%s\": %m", LOG_METAINFO_DATAFILE)));
+
+
+	if (log_filename[0] == '\0')
+		PG_RETURN_NULL();
+
+	/* Return null when csvlog is requested but we have a stderr log */
+	if ( (logfmt != NULL) && (strcmp(logfmt, "csvlog") == 0)
+			&& !(Log_destination & LOG_DESTINATION_CSVLOG) )
+		PG_RETURN_NULL();
+
+	/* Return null when stderr is requested but we have a csv log */
+	if ( (logfmt != NULL) && (strcmp(logfmt, "stderr") == 0)
+			&& !(Log_destination & LOG_DESTINATION_STDERR) )
+		PG_RETURN_NULL();
+
+	PG_RETURN_TEXT_P(cstring_to_text(log_filename));
+}
+
+/*
+ * Report current log file used by log collector (1 argument version)
+ *
+ * note: this wrapper is necessary to pass the sanity check in opr_sanity,
+ * which checks that all built-in functions that share the implementing C
+ * function take the same number of arguments
+ */
+Datum
+pg_current_logfile_1arg(PG_FUNCTION_ARGS)
+{
+	return pg_current_logfile(fcinfo);
+}
diff --git a/src/include/catalog/pg_proc.h b/src/include/catalog/pg_proc.h
index 047a1ce..26db448 100644
--- a/src/include/catalog/pg_proc.h
+++ b/src/include/catalog/pg_proc.h
@@ -3181,6 +3181,10 @@ DATA(insert OID = 2621 ( pg_reload_conf			PGNSP PGUID 12 1 0 0 0 f f f f t f v s
 DESCR("reload configuration files");
 DATA(insert OID = 2622 ( pg_rotate_logfile		PGNSP PGUID 12 1 0 0 0 f f f f t f v s 0 0 16 "" _null_ _null_ _null_ _null_ _null_ pg_rotate_logfile _null_ _null_ _null_ ));
 DESCR("rotate log file");
+DATA(insert OID = 3800 ( pg_current_logfile             PGNSP PGUID 12 1 0 0 0 f f f f f f v s 0 0 25 "" _null_ _null_ _null_ _null_ _null_ pg_current_logfile _null_ _null_ _null_ ));
+DESCR("current logging collector file location");
+DATA(insert OID = 3801 ( pg_current_logfile             PGNSP PGUID 12 1 0 0 0 f f f f f f v s 1 0 25 "25" _null_ _null_ _null_ _null_ _null_ pg_current_logfile_1arg _null_ _null_ _null_ ));
+DESCR("current logging collector file location");
 
 DATA(insert OID = 2623 ( pg_stat_file		PGNSP PGUID 12 1 0 0 0 f f f f t f v s 1 0 2249 "25" "{25,20,1184,1184,1184,1184,16}" "{i,o,o,o,o,o,o}" "{filename,size,access,modification,change,creation,isdir}" _null_ _null_ pg_stat_file_1arg _null_ _null_ _null_ ));
 DESCR("get information about file");
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 78545da..646cadb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -466,4 +466,13 @@ extern bool has_rolreplication(Oid roleid);
 extern bool BackupInProgress(void);
 extern void CancelBackup(void);
 
+/* in backend/utils/adt/misc.c and backend/postmaster/syslogger.c */
+/*
+ * Name of file holding the paths, names, and types of the files where current
+ * log messages are written, when the log collector is enabled.  Useful
+ * outside of Postgres when finding the name of the current log file in the
+ * case of time-based log rotation.
+ */
+#define LOG_METAINFO_DATAFILE  "current_logfiles"
+
 #endif   /* MISCADMIN_H */
diff --git a/src/include/utils/builtins.h b/src/include/utils/builtins.h
index 90f5132..e532022 100644
--- a/src/include/utils/builtins.h
+++ b/src/include/utils/builtins.h
@@ -522,6 +522,8 @@ extern Datum pg_collation_for(PG_FUNCTION_ARGS);
 extern Datum pg_relation_is_updatable(PG_FUNCTION_ARGS);
 extern Datum pg_column_is_updatable(PG_FUNCTION_ARGS);
 extern Datum parse_ident(PG_FUNCTION_ARGS);
+extern Datum pg_current_logfile(PG_FUNCTION_ARGS);
+extern Datum pg_current_logfile_1arg(PG_FUNCTION_ARGS);
 
 /* oid.c */
 extern Datum oidin(PG_FUNCTION_ARGS);

diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index adab2f8..645cbb9 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -4143,6 +4143,12 @@ SELECT * FROM parent WHERE key = 2400;
      <primary>server log</primary>
     </indexterm>
 
+    <para>When logs are written to the file-system their paths, names, and
+    types are recorded in
+    the <xref linkend="storage-pgdata-current-logfiles"> file.  This provides
+    a convenient way to find and access log content without establishing a
+    database connection.</para>
+
     <sect2 id="runtime-config-logging-where">
      <title>Where To Log</title>
 
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 2e64cc4..f5bfe59 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -15443,6 +15443,19 @@ SELECT * FROM pg_ls_dir('.') WITH ORDINALITY AS t(ls,n);
       </row>
 
       <row>
+       <entry><literal><function>pg_current_logfile()</function></literal></entry>
+       <entry><type>text</type></entry>
+       <entry>primary log file name in use by the logging collector</entry>
+      </row>
+
+      <row>
+       <entry><literal><function>pg_current_logfile(<type>text</>)</function></literal></entry>
+       <entry><type>text</type></entry>
+       <entry>log file name, of log in the requested format, in use by the
+       logging collector</entry>
+      </row>
+
+      <row>
        <entry><literal><function>pg_my_temp_schema()</function></literal></entry>
        <entry><type>oid</type></entry>
        <entry>OID of session's temporary schema, or 0 if none</entry>
@@ -15660,6 +15673,34 @@ SET search_path TO <replaceable>schema</> <optional>, <replaceable>schema</>, ..
     the time when the postmaster process re-read the configuration files.)
    </para>
 
+    <indexterm>
+    <primary>pg_current_logile</primary>
+   </indexterm>
+
+   <indexterm>
+    <primary>Logging</primary>
+    <secondary>pg_current_logfile function</secondary>
+   </indexterm>
+
+   <para>
+    <function>pg_current_logfile</function> returns, as <type>text</type>,
+    the path of either the csv or stderr log file currently in use by the
+    logging collector.  This is a path including the
+    <xref linkend="guc-log-directory"> directory and the log file name.
+    Log collection must be active or the return value
+    is <literal>NULL</literal>.  When multiple logfiles exist, each in a
+    different format, <function>pg_current_logfile</function> called
+    without arguments returns the path of the file having the first format
+    found in the ordered
+    list: <systemitem>stderr</>, <systemitem>csvlog</>.
+    <literal>NULL</literal> is returned when no log file has any of these
+    formats.  To request a specific file format supply,
+    as <type>text</type>, either <systemitem>csvlog</>
+    or <systemitem>stderr</> as the value of the optional parameter. The
+    return value is <literal>NULL</literal> when the log format requested
+    is not a configured <xref linkend="guc-log-destination">.
+   </para>
+
    <indexterm>
     <primary>pg_my_temp_schema</primary>
    </indexterm>
diff --git a/doc/src/sgml/storage.sgml b/doc/src/sgml/storage.sgml
index 5c52824..256a14f 100644
--- a/doc/src/sgml/storage.sgml
+++ b/doc/src/sgml/storage.sgml
@@ -60,6 +60,48 @@ Item
  <entry>Subdirectory containing per-database subdirectories</entry>
 </row>
 
+<row id="storage-pgdata-current-logfiles" xreflabel="current_logfiles">
+ <entry>
+  <indexterm>
+   <primary><filename>current_logfiles</filename></primary>
+  </indexterm>
+  <indexterm>
+   <primary>Logging</primary>
+   <secondary><filename>current_logfiles</filename> file</secondary>
+  </indexterm>
+  <filename>current_logfiles</>
+ </entry>
+ <entry>
+  <para>A file recording the log file(s) currently written to by the syslogger
+  and the file's log formats, <systemitem>stderr</>
+  or <systemitem>csvlog</>. Each line of the file is a space separated list of
+  two elements: the log format and the full path to the log file including the
+  value of <xref linkend="guc-log-directory">.</para>
+
+  <para>During server startup <filename>current_logfiles</filename> reports
+  the default server log destination.  After server startup the log format
+  must be present in <xref linkend="guc-log-destination"> to be listed in
+  <filename>current_logfiles</filename>.</para>
+
+  <note>
+    <para>Non-<productname>PostgreSQL</productname> log sources, such as 3rd
+    party libraries, which deliver error messages directly to stderr are
+    always logged by <productname>PostgreSQL</productname> to stderr.  Stderr
+    is also the destination for any incomplete log messages produced by
+    <productname>PostgreSQL</productname>.  When
+    <systemitem>stderr</systemitem> is not in
+    <xref linkend="guc-log-destination">,
+    <filename>current_logfiles</filename> does not not contain the name of the
+    file where these sorts of log messages are written.</para>
+  </note>
+  
+  <para>The <filename>current_logfiles</filename> file
+  is present only when <xref linkend="guc-logging-collector"> is
+  activated and when at least one of <systemitem>stderr</> or
+  <systemitem>csvlog</> value is present in
+  <xref linkend="guc-log-destination">.</para></entry>
+</row>
+
 <row>
  <entry><filename>global</></entry>
  <entry>Subdirectory containing cluster-wide tables, such as
diff --git a/src/backend/postmaster/syslogger.c b/src/backend/postmaster/syslogger.c
index fd62d66..fa11fa0 100644
--- a/src/backend/postmaster/syslogger.c
+++ b/src/backend/postmaster/syslogger.c
@@ -146,6 +146,7 @@ static char *logfile_getname(pg_time_t timestamp, const char *suffix);
 static void set_next_rotation_time(void);
 static void sigHupHandler(SIGNAL_ARGS);
 static void sigUsr1Handler(SIGNAL_ARGS);
+static void logfile_writename(char *filename, char *csvfilename);
 
 
 /*
@@ -348,6 +349,13 @@ SysLoggerMain(int argc, char *argv[])
 				rotation_disabled = false;
 				rotation_requested = true;
 			}
+
+			/*
+			 * Force rewriting last log filename when reloading configuration,
+			 * even if rotation_requested is false, log_destination may have
+			 * been changed and we don't want to wait the next file rotation.
+			 */
+			logfile_writename(last_file_name, last_csv_file_name);
 		}
 
 		if (Log_RotationAge > 0 && !rotation_disabled)
@@ -513,8 +521,13 @@ SysLogger_Start(void)
 	pid_t		sysloggerPid;
 	char	   *filename;
 
-	if (!Logging_collector)
+	if (!Logging_collector) {
+		/* Logging collector is not enabled. We don't know where messages are
+		 * logged.  Remove outdated file holding the current log filenames.
+		 */
+		unlink(LOG_METAINFO_DATAFILE);
 		return 0;
+	}
 
 	/*
 	 * If first time through, create the pipe which will receive stderr
@@ -574,6 +587,8 @@ SysLogger_Start(void)
 
 	syslogFile = logfile_open(filename, "a", false);
 
+	logfile_writename(filename, NULL);
+
 	pfree(filename);
 
 #ifdef EXEC_BACKEND
@@ -1098,6 +1113,8 @@ open_csvlogfile(void)
 		pfree(last_csv_file_name);
 
 	last_csv_file_name = filename;
+
+	logfile_writename(last_file_name, last_csv_file_name);
 }
 
 /*
@@ -1154,6 +1171,8 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for)
 	char	   *csvfilename = NULL;
 	pg_time_t	fntime;
 	FILE	   *fh;
+	bool       rotate_csvlog;
+	bool       rotate_stderr;
 
 	rotation_requested = false;
 
@@ -1178,7 +1197,9 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for)
 	 *
 	 * Note: last_file_name should never be NULL here, but if it is, append.
 	 */
-	if (time_based_rotation || (size_rotation_for & LOG_DESTINATION_STDERR))
+	rotate_stderr = time_based_rotation ||
+		(size_rotation_for & LOG_DESTINATION_STDERR);
+	if (rotate_stderr)
 	{
 		if (Log_truncate_on_rotation && time_based_rotation &&
 			last_file_name != NULL &&
@@ -1220,9 +1241,9 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for)
 	}
 
 	/* Same as above, but for csv file. */
-
-	if (csvlogFile != NULL &&
-		(time_based_rotation || (size_rotation_for & LOG_DESTINATION_CSVLOG)))
+	rotate_csvlog = csvlogFile != NULL &&
+		(time_based_rotation || (size_rotation_for & LOG_DESTINATION_CSVLOG));
+	if (rotate_csvlog)
 	{
 		if (Log_truncate_on_rotation && time_based_rotation &&
 			last_csv_file_name != NULL &&
@@ -1263,6 +1284,8 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for)
 		csvfilename = NULL;
 	}
 
+	if (rotate_stderr || rotate_csvlog)
+		logfile_writename(last_file_name, last_csv_file_name);
 	if (filename)
 		pfree(filename);
 	if (csvfilename)
@@ -1365,3 +1388,65 @@ sigUsr1Handler(SIGNAL_ARGS)
 
 	errno = save_errno;
 }
+
+/*
+ * Store the name of the file(s) where the log collector, when enabled, writes
+ * log messages.  Useful for finding the name(s) of the current log file(s)
+ * when there is time-based logfile rotation.  Filenames are stored in a
+ * temporary file and renamed into the final destination for atomicity.
+ */
+static void
+logfile_writename(char *filename, char *csvfilename)
+{
+	FILE	*fh;
+	char	tempfn[MAXPGPATH];
+
+	if (!(Log_destination & LOG_DESTINATION_STDERR)
+		&& !(Log_destination & LOG_DESTINATION_CSVLOG))
+	{
+		unlink(LOG_METAINFO_DATAFILE);
+		return;
+	}
+
+	snprintf(tempfn, sizeof(tempfn), "%s.tmp", LOG_METAINFO_DATAFILE);
+
+	if ((fh = logfile_open(tempfn, "w", true) ) == NULL)
+	{
+		return;
+	}
+	if (filename && (Log_destination & LOG_DESTINATION_STDERR))
+	{
+		if (fprintf(fh, "stderr %s\n", filename) < 0)
+		{
+			ereport(LOG,
+					(errcode_for_file_access(),
+					errmsg("could not write stderr log file path \"%s\": %m",
+						tempfn)));
+			fclose(fh);
+			return;
+		}
+	}
+
+	if (csvfilename && (Log_destination & LOG_DESTINATION_CSVLOG))
+	{
+		if (fprintf(fh, "csvlog %s\n", csvfilename) < 0)
+		{
+			ereport(LOG,
+					(errcode_for_file_access(),
+					errmsg("could not write csvlog log file path \"%s\": %m",
+						tempfn)));
+			fclose(fh);
+			return;
+		}
+	}
+	fclose(fh);
+
+	if (rename(tempfn, LOG_METAINFO_DATAFILE) != 0)
+	{
+		ereport(LOG,
+				(errcode_for_file_access(),
+				errmsg("could not rename file \"%s\": %m",
+						tempfn)));
+		return;
+	}
+}
diff --git a/src/backend/utils/adt/misc.c b/src/backend/utils/adt/misc.c
index 0da051a..53185e5 100644
--- a/src/backend/utils/adt/misc.c
+++ b/src/backend/utils/adt/misc.c
@@ -19,6 +19,7 @@
 #include <dirent.h>
 #include <math.h>
 #include <unistd.h>
+#include <sys/stat.h>
 
 #include "access/sysattr.h"
 #include "catalog/pg_authid.h"
@@ -892,3 +893,135 @@ parse_ident(PG_FUNCTION_ARGS)
 
 	PG_RETURN_DATUM(makeArrayResult(astate, CurrentMemoryContext));
 }
+
+/*
+ * Report current log file used by log collector
+ */
+Datum
+pg_current_logfile(PG_FUNCTION_ARGS)
+{
+	FILE    *fd;
+	char    lbuffer[MAXPGPATH];
+	text    *fmt;
+	char    *logfmt;
+	struct stat stat_buf;
+	char    *log_format;
+	char    *log_filename;
+
+	/* The log format parameter is optional */
+	if (PG_NARGS() == 1) {
+		fmt = PG_ARGISNULL(0) ? NULL : PG_GETARG_TEXT_PP(0);
+		if (fmt != NULL) {
+			logfmt = text_to_cstring(fmt);
+			if ( (strcmp(logfmt, "stderr") != 0) &&
+				(strcmp(logfmt, "csvlog") != 0) ) {
+				ereport(ERROR,
+		(errmsg("log format %s not supported, possible values are stderr or csvlog", logfmt)));
+				PG_RETURN_NULL();
+			}
+		}
+	} else {
+		logfmt = NULL;
+	}
+
+	if (!Logging_collector)
+		PG_RETURN_NULL();
+
+	/* Check if current log file is present */
+	if (stat(LOG_METAINFO_DATAFILE, &stat_buf) != 0)
+		PG_RETURN_NULL();
+
+	fd = AllocateFile(LOG_METAINFO_DATAFILE, "r");
+	if (fd == NULL)
+	{
+		if (errno != ENOENT)
+			ereport(ERROR,
+				(errcode_for_file_access(),
+				errmsg("could not read file \"%s\": %m",
+				LOG_METAINFO_DATAFILE)));
+		PG_RETURN_NULL();
+	}
+
+	/*
+	* Read the file to gather current log filename(s) registered
+	* by the syslogger.
+	*/
+	while (fgets(lbuffer, sizeof(lbuffer), fd) != NULL) {
+
+		/* Check for a read error. */
+		if (ferror(fd)) {
+			ereport(ERROR,
+				(errcode_for_file_access(),
+				errmsg("could not read file \"%s\": %m", LOG_METAINFO_DATAFILE)));
+			FreeFile(fd);
+			break;
+		}
+
+		/* remove trailing newline */
+		if (strchr(lbuffer, '\n') != NULL)
+			*strchr(lbuffer, '\n') = '\0';
+
+		/* extract log format and log file path from the line */
+		log_format = strtok(lbuffer, " ");
+		if (log_format)
+		{
+			log_filename = strtok(NULL, " ");
+			if (!log_filename) {
+				ereport(ERROR,
+					(errmsg("unexpected line format in file %s", LOG_METAINFO_DATAFILE)));
+				break;
+			}
+		}
+		else
+		{
+			ereport(ERROR,
+				(errmsg("unexpected line format in file %s", LOG_METAINFO_DATAFILE)));
+			break;
+		}
+
+		/*
+		 * When no log format is provided as argument always reports
+		 * the first registered log file in LOG_METAINFO_DATAFILE.
+		 */
+		if (logfmt == NULL)
+			break;
+
+		/* report the entry corresponding to the requested format */
+		if (strcmp(logfmt, log_format) == 0)
+			break;
+	}
+	/* Close the current log filename file. */
+	if (FreeFile(fd))
+		ereport(ERROR,
+				(errcode_for_file_access(),
+			errmsg("could not close file \"%s\": %m", LOG_METAINFO_DATAFILE)));
+
+
+	if (log_filename[0] == '\0')
+		PG_RETURN_NULL();
+
+	/* Return null when csvlog is requested but we have a stderr log */
+	if ( (logfmt != NULL) && (strcmp(logfmt, "csvlog") == 0)
+			&& !(Log_destination & LOG_DESTINATION_CSVLOG) )
+		PG_RETURN_NULL();
+
+	/* Return null when stderr is requested but we have a csv log */
+	if ( (logfmt != NULL) && (strcmp(logfmt, "stderr") == 0)
+			&& !(Log_destination & LOG_DESTINATION_STDERR) )
+		PG_RETURN_NULL();
+
+	PG_RETURN_TEXT_P(cstring_to_text(log_filename));
+}
+
+/*
+ * Report current log file used by log collector (1 argument version)
+ *
+ * note: this wrapper is necessary to pass the sanity check in opr_sanity,
+ * which checks that all built-in functions that share the implementing C
+ * function take the same number of arguments
+ */
+Datum
+pg_current_logfile_1arg(PG_FUNCTION_ARGS)
+{
+	return pg_current_logfile(fcinfo);
+}
diff --git a/src/include/catalog/pg_proc.h b/src/include/catalog/pg_proc.h
index 047a1ce..26db448 100644
--- a/src/include/catalog/pg_proc.h
+++ b/src/include/catalog/pg_proc.h
@@ -3181,6 +3181,10 @@ DATA(insert OID = 2621 ( pg_reload_conf			PGNSP PGUID 12 1 0 0 0 f f f f t f v s
 DESCR("reload configuration files");
 DATA(insert OID = 2622 ( pg_rotate_logfile		PGNSP PGUID 12 1 0 0 0 f f f f t f v s 0 0 16 "" _null_ _null_ _null_ _null_ _null_ pg_rotate_logfile _null_ _null_ _null_ ));
 DESCR("rotate log file");
+DATA(insert OID = 3800 ( pg_current_logfile             PGNSP PGUID 12 1 0 0 0 f f f f f f v s 0 0 25 "" _null_ _null_ _null_ _null_ _null_ pg_current_logfile _null_ _null_ _null_ ));
+DESCR("current logging collector file location");
+DATA(insert OID = 3801 ( pg_current_logfile             PGNSP PGUID 12 1 0 0 0 f f f f f f v s 1 0 25 "25" _null_ _null_ _null_ _null_ _null_ pg_current_logfile_1arg _null_ _null_ _null_ ));
+DESCR("current logging collector file location");
 
 DATA(insert OID = 2623 ( pg_stat_file		PGNSP PGUID 12 1 0 0 0 f f f f t f v s 1 0 2249 "25" "{25,20,1184,1184,1184,1184,16}" "{i,o,o,o,o,o,o}" "{filename,size,access,modification,change,creation,isdir}" _null_ _null_ pg_stat_file_1arg _null_ _null_ _null_ ));
 DESCR("get information about file");
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 78545da..646cadb 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -466,4 +466,13 @@ extern bool has_rolreplication(Oid roleid);
 extern bool BackupInProgress(void);
 extern void CancelBackup(void);
 
+/* in backend/utils/adt/misc.c and backend/postmaster/syslogger.c */
+/*
+ * Name of file holding the paths, names, and types of the files where current
+ * log messages are written, when the log collector is enabled.  Useful
+ * outside of Postgres when finding the name of the current log file in the
+ * case of time-based log rotation.
+ */
+#define LOG_METAINFO_DATAFILE  "current_logfiles"
+
 #endif   /* MISCADMIN_H */
diff --git a/src/include/utils/builtins.h b/src/include/utils/builtins.h
index 90f5132..e532022 100644
--- a/src/include/utils/builtins.h
+++ b/src/include/utils/builtins.h
@@ -522,6 +522,8 @@ extern Datum pg_collation_for(PG_FUNCTION_ARGS);
 extern Datum pg_relation_is_updatable(PG_FUNCTION_ARGS);
 extern Datum pg_column_is_updatable(PG_FUNCTION_ARGS);
 extern Datum parse_ident(PG_FUNCTION_ARGS);
+extern Datum pg_current_logfile(PG_FUNCTION_ARGS);
+extern Datum pg_current_logfile_1arg(PG_FUNCTION_ARGS);
 
 /* oid.c */
 extern Datum oidin(PG_FUNCTION_ARGS);

diff --git a/doc/src/sgml/storage.sgml b/doc/src/sgml/storage.sgml
index 256a14f..61b180f 100644
--- a/doc/src/sgml/storage.sgml
+++ b/doc/src/sgml/storage.sgml
@@ -76,11 +76,8 @@ Item
   and the file's log formats, <systemitem>stderr</>
   or <systemitem>csvlog</>. Each line of the file is a space separated list of
   two elements: the log format and the full path to the log file including the
-  value of <xref linkend="guc-log-directory">.</para>
-
-  <para>During server startup <filename>current_logfiles</filename> reports
-  the default server log destination.  After server startup the log format
-  must be present in <xref linkend="guc-log-destination"> to be listed in
+  value of <xref linkend="guc-log-directory">.  The log format must be present
+  in <xref linkend="guc-log-destination"> to be listed in
   <filename>current_logfiles</filename>.</para>
 
   <note>

diff --git a/src/backend/postmaster/syslogger.c b/src/backend/postmaster/syslogger.c
index fa11fa0..8a9a776 100644
--- a/src/backend/postmaster/syslogger.c
+++ b/src/backend/postmaster/syslogger.c
@@ -1171,8 +1171,8 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for)
 	char	   *csvfilename = NULL;
 	pg_time_t	fntime;
 	FILE	   *fh;
-	bool       rotate_csvlog;
-	bool       rotate_stderr;
+	int         rotate_csvlog;
+	int         rotate_stderr;
 
 	rotation_requested = false;
 

diff --git a/src/backend/postmaster/syslogger.c b/src/backend/postmaster/syslogger.c
index fa11fa0..3d8d9cd 100644
--- a/src/backend/postmaster/syslogger.c
+++ b/src/backend/postmaster/syslogger.c
@@ -304,10 +304,38 @@ SysLoggerMain(int argc, char *argv[])
 		 */
 		if (got_SIGHUP)
 		{
+			int			old_log_destination;
+
 			got_SIGHUP = false;
+			old_log_destination = Log_destination;
 			ProcessConfigFile(PGC_SIGHUP);
 
 			/*
+			 * Ensure that additions to log_destination do not result in
+			 * writing out-of-date data to LOG_METAINFO_DATAFILE.
+			 */
+			if (!(old_log_destination && LOG_DESTINATION_STDERR) &&
+				(Log_destination && LOG_DESTINATION_STDERR))
+			{
+				last_file_name = NULL;
+			}
+
+			if (!(old_log_destination && LOG_DESTINATION_CSVLOG) &&
+				(Log_destination && LOG_DESTINATION_CSVLOG))
+			{
+				last_csv_file_name = NULL;
+			}
+
+			/*
+			 * When log_destination changes and stops writing to a logfile
+			 * immediately remove the logfile from the LOG_METAINFO_DATAFILE
+			 * file.  (Or delete the LOG_METAINFO_DATAFILE entirely.)  Do not
+			 * wait until the next logfile rotation, which could be some while
+			 * in the future.
+			 */
+			logfile_writename(last_file_name, last_csv_file_name);
+
+			/*
 			 * Check if the log directory or filename pattern changed in
 			 * postgresql.conf. If so, force rotation to make sure we're
 			 * writing the logfiles in the right place.
@@ -349,13 +377,6 @@ SysLoggerMain(int argc, char *argv[])
 				rotation_disabled = false;
 				rotation_requested = true;
 			}
-
-			/*
-			 * Force rewriting last log filename when reloading configuration,
-			 * even if rotation_requested is false, log_destination may have
-			 * been changed and we don't want to wait the next file rotation.
-			 */
-			logfile_writename(last_file_name, last_csv_file_name);
 		}
 
 		if (Log_RotationAge > 0 && !rotation_disabled)

diff --git a/src/backend/postmaster/syslogger.c b/src/backend/postmaster/syslogger.c
index faa0b11..f71114d 100644
--- a/src/backend/postmaster/syslogger.c
+++ b/src/backend/postmaster/syslogger.c
@@ -304,7 +304,7 @@ SysLoggerMain(int argc, char *argv[])
 		 */
 		if (got_SIGHUP)
 		{
-			int			old_log_destination;
+			PGLogDestination	old_log_destination;
 
 			got_SIGHUP = false;
 			old_log_destination = Log_destination;
diff --git a/src/include/utils/elog.h b/src/include/utils/elog.h
index 70dc365..34d4926 100644
--- a/src/include/utils/elog.h
+++ b/src/include/utils/elog.h
@@ -386,7 +386,8 @@ typedef enum
 
 extern int	Log_error_verbosity;
 extern char *Log_line_prefix;
-extern int	Log_destination;
+typedef int PGLogDestination;
+extern PGLogDestination	Log_destination;
 extern char *Log_destination_string;
 extern bool syslog_sequence_numbers;
 extern bool syslog_split_messages;

diff --git a/doc/src/sgml/storage.sgml b/doc/src/sgml/storage.sgml
index 61b180f..3b8f5fd 100644
--- a/doc/src/sgml/storage.sgml
+++ b/doc/src/sgml/storage.sgml
@@ -96,7 +96,14 @@ Item
   is present only when <xref linkend="guc-logging-collector"> is
   activated and when at least one of <systemitem>stderr</> or
   <systemitem>csvlog</> value is present in
-  <xref linkend="guc-log-destination">.</para></entry>
+  <xref linkend="guc-log-destination">.</para>
+
+  <para>On a busy system <filename>current_logfiles</filename> might not be
+  updated immediately upon logfile rotation.  On an extremely busy system it
+  is possible, although highly unlikely, for a logfile to be "skipped" and
+  never appear in <filename>current_logfiles</filename>.</para>
+ </entry>
+
 </row>
 
 <row>

diff --git a/src/backend/postmaster/syslogger.c b/src/backend/postmaster/syslogger.c
index 3d8d9cd..691e6eb 100644
--- a/src/backend/postmaster/syslogger.c
+++ b/src/backend/postmaster/syslogger.c
@@ -146,7 +146,7 @@ static char *logfile_getname(pg_time_t timestamp, const char *suffix);
 static void set_next_rotation_time(void);
 static void sigHupHandler(SIGNAL_ARGS);
 static void sigUsr1Handler(SIGNAL_ARGS);
-static void logfile_writename(char *filename, char *csvfilename);
+static void logfile_writename(void);
 
 
 /*
@@ -333,7 +333,7 @@ SysLoggerMain(int argc, char *argv[])
 			 * wait until the next logfile rotation, which could be some while
 			 * in the future.
 			 */
-			logfile_writename(last_file_name, last_csv_file_name);
+			logfile_writename();
 
 			/*
 			 * Check if the log directory or filename pattern changed in
@@ -540,7 +540,6 @@ int
 SysLogger_Start(void)
 {
 	pid_t		sysloggerPid;
-	char	   *filename;
 
 	if (!Logging_collector) {
 		/* Logging collector is not enabled. We don't know where messages are
@@ -604,13 +603,12 @@ SysLogger_Start(void)
 	 * a time-based rotation.
 	 */
 	first_syslogger_file_time = time(NULL);
-	filename = logfile_getname(first_syslogger_file_time, NULL);
-
-	syslogFile = logfile_open(filename, "a", false);
+	last_file_name = logfile_getname(first_syslogger_file_time, NULL);
 
-	logfile_writename(filename, NULL);
+	syslogFile = logfile_open(last_file_name, "a", false);
 
-	pfree(filename);
+	logfile_writename();
+	pfree(last_file_name);
 
 #ifdef EXEC_BACKEND
 	switch ((sysloggerPid = syslogger_forkexec()))
@@ -1135,7 +1133,7 @@ open_csvlogfile(void)
 
 	last_csv_file_name = filename;
 
-	logfile_writename(last_file_name, last_csv_file_name);
+	logfile_writename();
 }
 
 /*
@@ -1306,7 +1304,7 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for)
 	}
 
 	if (rotate_stderr || rotate_csvlog)
-		logfile_writename(last_file_name, last_csv_file_name);
+		logfile_writename();
 	if (filename)
 		pfree(filename);
 	if (csvfilename)
@@ -1417,7 +1415,7 @@ sigUsr1Handler(SIGNAL_ARGS)
  * temporary file and renamed into the final destination for atomicity.
  */
 static void
-logfile_writename(char *filename, char *csvfilename)
+logfile_writename(void)
 {
 	FILE	*fh;
 	char	tempfn[MAXPGPATH];
@@ -1435,9 +1433,10 @@ logfile_writename(char *filename, char *csvfilename)
 	{
 		return;
 	}
-	if (filename && (Log_destination & LOG_DESTINATION_STDERR))
+
+	if (last_file_name && (Log_destination & LOG_DESTINATION_STDERR))
 	{
-		if (fprintf(fh, "stderr %s\n", filename) < 0)
+		if (fprintf(fh, "stderr %s\n", last_file_name) < 0)
 		{
 			ereport(LOG,
 					(errcode_for_file_access(),
@@ -1448,9 +1447,9 @@ logfile_writename(char *filename, char *csvfilename)
 		}
 	}
 
-	if (csvfilename && (Log_destination & LOG_DESTINATION_CSVLOG))
+	if (last_csv_file_name && (Log_destination & LOG_DESTINATION_CSVLOG))
 	{
-		if (fprintf(fh, "csvlog %s\n", csvfilename) < 0)
+		if (fprintf(fh, "csvlog %s\n", last_csv_file_name) < 0)
 		{
 			ereport(LOG,
 					(errcode_for_file_access(),

diff --git a/src/backend/postmaster/syslogger.c b/src/backend/postmaster/syslogger.c
index 691e6eb..5434826 100644
--- a/src/backend/postmaster/syslogger.c
+++ b/src/backend/postmaster/syslogger.c
@@ -86,6 +86,7 @@ static FILE *csvlogFile = NULL;
 NON_EXEC_STATIC pg_time_t first_syslogger_file_time = 0;
 static char *last_file_name = NULL;
 static char *last_csv_file_name = NULL;
+static bool log_metainfo_stale = false;
 
 /*
  * Buffers for saving partial messages from different backends.
@@ -299,6 +300,15 @@ SysLoggerMain(int argc, char *argv[])
 		/* Clear any already-pending wakeups */
 		ResetLatch(MyLatch);
 
+		/* On a busy system the logfile meta information may not have been
+		 * written so retry.  (The cost of this is doing extra I/O on an
+		 * already busy system.)  Write the info before SIGHUP config file
+		 * re-read in an attempt to not ever "skip" writing a logfile
+		 * filename.
+		 */
+		if (log_metainfo_stale)
+			logfile_writename();
+
 		/*
 		 * Process any requests or signals received recently.
 		 */
@@ -1431,6 +1441,11 @@ logfile_writename(void)
 
 	if ((fh = logfile_open(tempfn, "w", true) ) == NULL)
 	{
+		if (errno == ENFILE || errno == EMFILE)
+			/* The system is too busy to write logfile meta info.
+			 * This is not too suprising on a busy system.
+			 * Try again when logs are next written. */
+			log_metainfo_stale = true;
 		return;
 	}
 
@@ -1469,4 +1484,6 @@ logfile_writename(void)
 						tempfn)));
 		return;
 	}
+
+	log_metainfo_stale = false;
 }

diff --git a/src/backend/postmaster/syslogger.c b/src/backend/postmaster/syslogger.c
index 5434826..7335659 100644
--- a/src/backend/postmaster/syslogger.c
+++ b/src/backend/postmaster/syslogger.c
@@ -55,6 +55,16 @@
  */
 #define READ_BUF_SIZE (2 * PIPE_CHUNK_SIZE)
 
+/*
+ * Retries of writing LOG_METAINFO_DATAFILE are backed off on failure, but we
+ * don't want to backoff forever.  The backoff is Fibonacci so takes 2 storage
+ * locations (last, the n-1 value, and next, the n value).  Plus a counter for
+ * how many occasions for retry have been skipped.
+ */
+#define MAX_METAINFO_BACKOFF           250
+#define INITIAL_LAST_METAINFO_BACKOFF    0    /* fibnocci n-1 value */
+#define INITIAL_NEXT_METAINFO_BACKOFF    1    /* fibnocci n value */
+#define INITIAL_METAINFO_BACKOFF_CNTR    0    /* first retry is immediate */
 
 /*
  * GUC parameters.  Logging_collector cannot be changed after postmaster
@@ -87,6 +97,9 @@ NON_EXEC_STATIC pg_time_t first_syslogger_file_time = 0;
 static char *last_file_name = NULL;
 static char *last_csv_file_name = NULL;
 static bool log_metainfo_stale = false;
+static int  last_metainfo_backoff = 1;  /* fibnocci n-1 value */
+static int  next_metainfo_backoff = 1;  /* fibnocci n value */
+static int  metainfo_backoff_cntr = 0;  /* first retry is immediate */
 
 /*
  * Buffers for saving partial messages from different backends.
@@ -148,6 +161,7 @@ static void set_next_rotation_time(void);
 static void sigHupHandler(SIGNAL_ARGS);
 static void sigUsr1Handler(SIGNAL_ARGS);
 static void logfile_writename(void);
+static void logfile_rewritename(void);
 
 
 /*
@@ -307,7 +321,7 @@ SysLoggerMain(int argc, char *argv[])
 		 * filename.
 		 */
 		if (log_metainfo_stale)
-			logfile_writename();
+			logfile_rewritename();
 
 		/*
 		 * Process any requests or signals received recently.
@@ -1487,3 +1501,40 @@ logfile_writename(void)
 
 	log_metainfo_stale = false;
 }
+
+/*
+ * Increasingly backoff from retrying to write LOG_METAINFO_DATAFILE
+ * to prevent a busy system from becoming even more busy.
+ * The Fibonacci sequence is used because it's slope steadily increases
+ * without being exponential.
+ */
+static void
+logfile_rewritename(void)
+{
+	if (metainfo_backoff_cntr <= 0)
+	{	/* Done backing off, retry. */
+
+		logfile_writename();
+
+		if (log_metainfo_stale)
+		{
+			/* Retry failed.  Compute next backoff interval. */
+			if (next_metainfo_backoff >= MAX_METAINFO_BACKOFF)
+			{
+				metainfo_backoff_cntr = MAX_METAINFO_BACKOFF;
+			} else {
+				metainfo_backoff_cntr = next_metainfo_backoff;
+				next_metainfo_backoff =
+					last_metainfo_backoff + last_metainfo_backoff;
+				last_metainfo_backoff = metainfo_backoff_cntr;
+			}
+		} else {
+			/* Retry succeeded.  Re-initialize backoff counters. */
+			last_metainfo_backoff = INITIAL_LAST_METAINFO_BACKOFF;
+			next_metainfo_backoff = INITIAL_NEXT_METAINFO_BACKOFF;
+			metainfo_backoff_cntr = INITIAL_METAINFO_BACKOFF_CNTR;
+		}
+	} else {
+		metainfo_backoff_cntr -= 1;
+	}
+}

diff --git a/src/backend/postmaster/syslogger.c b/src/backend/postmaster/syslogger.c
index 5434826..918bce6 100644
--- a/src/backend/postmaster/syslogger.c
+++ b/src/backend/postmaster/syslogger.c
@@ -147,6 +147,7 @@ static char *logfile_getname(pg_time_t timestamp, const char *suffix);
 static void set_next_rotation_time(void);
 static void sigHupHandler(SIGNAL_ARGS);
 static void sigUsr1Handler(SIGNAL_ARGS);
+static int  rm_log_metainfo(void);
 static void logfile_writename(void);
 
 
@@ -343,7 +344,8 @@ SysLoggerMain(int argc, char *argv[])
 			 * wait until the next logfile rotation, which could be some while
 			 * in the future.
 			 */
-			logfile_writename();
+			if (!rm_log_metainfo())
+				logfile_writename();
 
 			/*
 			 * Check if the log directory or filename pattern changed in
@@ -617,7 +619,8 @@ SysLogger_Start(void)
 
 	syslogFile = logfile_open(last_file_name, "a", false);
 
-	logfile_writename();
+	if (!rm_log_metainfo())
+		logfile_writename();
 	pfree(last_file_name);
 
 #ifdef EXEC_BACKEND
@@ -1417,6 +1420,22 @@ sigUsr1Handler(SIGNAL_ARGS)
 
 	errno = save_errno;
 }
+ 
+ /*
+ * Delete the LOG_METAINFO_DATAFILE if it's not going to be used.
+ */
+static int
+rm_log_metainfo(void)
+{
+	if (!(Log_destination & LOG_DESTINATION_STDERR)
+		&& !(Log_destination & LOG_DESTINATION_CSVLOG))
+	{
+		unlink(LOG_METAINFO_DATAFILE);
+		return true;
+	}
+	return false;
+}
+
 
 /*
  * Store the name of the file(s) where the log collector, when enabled, writes
@@ -1430,13 +1449,6 @@ logfile_writename(void)
 	FILE	*fh;
 	char	tempfn[MAXPGPATH];
 
-	if (!(Log_destination & LOG_DESTINATION_STDERR)
-		&& !(Log_destination & LOG_DESTINATION_CSVLOG))
-	{
-		unlink(LOG_METAINFO_DATAFILE);
-		return;
-	}
-
 	snprintf(tempfn, sizeof(tempfn), "%s.tmp", LOG_METAINFO_DATAFILE);
 
 	if ((fh = logfile_open(tempfn, "w", true) ) == NULL)

diff --git a/src/backend/postmaster/syslogger.c b/src/backend/postmaster/syslogger.c
index 918bce6..e8905c1 100644
--- a/src/backend/postmaster/syslogger.c
+++ b/src/backend/postmaster/syslogger.c
@@ -324,6 +324,11 @@ SysLoggerMain(int argc, char *argv[])
 			/*
 			 * Ensure that additions to log_destination do not result in
 			 * writing out-of-date data to LOG_METAINFO_DATAFILE.
+			 * While it is tempting to do this only when we conditionally
+			 * call logfile_writename() immediately below, writing a new
+			 * csv logfile causes a logfile_writename() call so we must
+			 * test for the csv case unconditionally.  May as well do
+			 * stderr the same way.
 			 */
 			if (!(old_log_destination && LOG_DESTINATION_STDERR) &&
 				(Log_destination && LOG_DESTINATION_STDERR))
@@ -344,8 +349,14 @@ SysLoggerMain(int argc, char *argv[])
 			 * wait until the next logfile rotation, which could be some while
 			 * in the future.
 			 */
-			if (!rm_log_metainfo())
-				logfile_writename();
+			if (((old_log_destination && LOG_DESTINATION_STDERR) &&
+				 ! (Log_destination && LOG_DESTINATION_STDERR))
+				|| ((old_log_destination && LOG_DESTINATION_CSVLOG) &&
+					! (Log_destination && LOG_DESTINATION_CSVLOG)))
+			{
+				if (!rm_log_metainfo())
+					logfile_writename();
+			}
 
 			/*
 			 * Check if the log directory or filename pattern changed in

diff --git a/src/backend/postmaster/syslogger.c b/src/backend/postmaster/syslogger.c
index 5434826..e58d6e6 100644
--- a/src/backend/postmaster/syslogger.c
+++ b/src/backend/postmaster/syslogger.c
@@ -1225,6 +1225,8 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for)
 	 * different from what we were previously logging into.
 	 *
 	 * Note: last_file_name should never be NULL here, but if it is, append.
+	 * (last_file_name is NULL if logfile_getname() runs out of RAM on
+	 * syslogger startup.)
 	 */
 	rotate_stderr = time_based_rotation ||
 		(size_rotation_for & LOG_DESTINATION_STDERR);

diff --git a/src/backend/postmaster/syslogger.c b/src/backend/postmaster/syslogger.c
index 5434826..59d8a83 100644
--- a/src/backend/postmaster/syslogger.c
+++ b/src/backend/postmaster/syslogger.c
@@ -1197,7 +1197,7 @@ static void
 logfile_rotate(bool time_based_rotation, int size_rotation_for)
 {
 	char	   *filename;
-	char	   *csvfilename = NULL;
+	char	   *csvfilename;
 	pg_time_t	fntime;
 	FILE	   *fh;
 	bool       rotate_csvlog;
@@ -1214,9 +1214,6 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for)
 		fntime = next_rotation_time;
 	else
 		fntime = time(NULL);
-	filename = logfile_getname(fntime, NULL);
-	if (csvlogFile != NULL)
-		csvfilename = logfile_getname(fntime, ".csv");
 
 	/*
 	 * Decide whether to overwrite or append.  We can overwrite if (a)
@@ -1230,6 +1227,8 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for)
 		(size_rotation_for & LOG_DESTINATION_STDERR);
 	if (rotate_stderr)
 	{
+		filename = logfile_getname(fntime, NULL);
+
 		if (Log_truncate_on_rotation && time_based_rotation &&
 			last_file_name != NULL &&
 			strcmp(filename, last_file_name) != 0)
@@ -1252,10 +1251,7 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for)
 				rotation_disabled = true;
 			}
 
-			if (filename)
-				pfree(filename);
-			if (csvfilename)
-				pfree(csvfilename);
+			pfree(filename);
 			return;
 		}
 
@@ -1266,7 +1262,6 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for)
 		if (last_file_name != NULL)
 			pfree(last_file_name);
 		last_file_name = filename;
-		filename = NULL;
 	}
 
 	/* Same as above, but for csv file. */
@@ -1274,6 +1269,9 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for)
 		(time_based_rotation || (size_rotation_for & LOG_DESTINATION_CSVLOG));
 	if (rotate_csvlog)
 	{
+		if (csvlogFile != NULL)
+			csvfilename = logfile_getname(fntime, ".csv");
+
 		if (Log_truncate_on_rotation && time_based_rotation &&
 			last_csv_file_name != NULL &&
 			strcmp(csvfilename, last_csv_file_name) != 0)
@@ -1296,10 +1294,7 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for)
 				rotation_disabled = true;
 			}
 
-			if (filename)
-				pfree(filename);
-			if (csvfilename)
-				pfree(csvfilename);
+			pfree(csvfilename);
 			return;
 		}
 
@@ -1310,15 +1305,10 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for)
 		if (last_csv_file_name != NULL)
 			pfree(last_csv_file_name);
 		last_csv_file_name = csvfilename;
-		csvfilename = NULL;
 	}
 
 	if (rotate_stderr || rotate_csvlog)
 		logfile_writename();
-	if (filename)
-		pfree(filename);
-	if (csvfilename)
-		pfree(csvfilename);
 
 	set_next_rotation_time();
 }

diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index da74f00..9979019 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -75,6 +75,7 @@
 #include "utils/builtins.h"
 #include "utils/bytea.h"
 #include "utils/guc_tables.h"
+#include "utils/guc_values.h"
 #include "utils/memutils.h"
 #include "utils/pg_locale.h"
 #include "utils/plancache.h"
@@ -3256,13 +3257,13 @@ static struct config_string ConfigureNamesString[] =
 	{
 		{"log_destination", PGC_SIGHUP, LOGGING_WHERE,
 			gettext_noop("Sets the destination for server log output."),
-			gettext_noop("Valid values are combinations of \"stderr\", "
-						 "\"syslog\", \"csvlog\", and \"eventlog\", "
-						 "depending on the platform."),
+			gettext_noop("Valid values are combinations of \"" GUCV_STDERR
+						  "\", \"" GUCV_SYSLOG "\", \"" GUCV_CSVLOG "\", and "
+						 "\"" GUCV_EVENTLOG "\", depending on the platform."),
 			GUC_LIST_INPUT
 		},
 		&Log_destination_string,
-		"stderr",
+		GUCV_STDERR,
 		check_log_destination, assign_log_destination, NULL
 	},
 	{
@@ -9902,16 +9903,16 @@ check_log_destination(char **newval, void **extra, GucSource source)
 	{
 		char	   *tok = (char *) lfirst(l);
 
-		if (pg_strcasecmp(tok, "stderr") == 0)
+		if (pg_strcasecmp(tok, GUCV_STDERR) == 0)
 			newlogdest |= LOG_DESTINATION_STDERR;
-		else if (pg_strcasecmp(tok, "csvlog") == 0)
+		else if (pg_strcasecmp(tok, GUCV_CSVLOG) == 0)
 			newlogdest |= LOG_DESTINATION_CSVLOG;
 #ifdef HAVE_SYSLOG
-		else if (pg_strcasecmp(tok, "syslog") == 0)
+		else if (pg_strcasecmp(tok, GUCV_SYSLOG) == 0)
 			newlogdest |= LOG_DESTINATION_SYSLOG;
 #endif
 #ifdef WIN32
-		else if (pg_strcasecmp(tok, "eventlog") == 0)
+		else if (pg_strcasecmp(tok, GUCV_EVENTLOG) == 0)
 			newlogdest |= LOG_DESTINATION_EVENTLOG;
 #endif
 		else
diff --git a/src/include/utils/guc_values.h b/src/include/utils/guc_values.h
new file mode 100644
index 0000000..cd26b5a
--- /dev/null
+++ b/src/include/utils/guc_values.h
@@ -0,0 +1,22 @@
+/*--------------------------------------------------------------------
+ * guc_values.h
+ *
+ * User-supplied GUC configuration values which are tested against
+ * user-supplied function parameters.
+ *
+ * Copyright (c) 2016, PostgreSQL Global Development Group
+ *
+ * src/include/utils/guc_values.h
+ *--------------------------------------------------------------------
+ */
+
+#ifndef GUC_VALUES_H
+#define GUC_VALUES_H
+
+/* log_destination values */
+#define GUCV_CSVLOG   "csvlog"
+#define GUCV_EVENTLOG "eventlog"
+#define GUCV_STDERR   "stderr"
+#define GUCV_SYSLOG   "syslog"
+
+#endif   /* GUC_VALUES_H */

diff --git a/src/backend/postmaster/syslogger.c b/src/backend/postmaster/syslogger.c
index 5434826..77772be 100644
--- a/src/backend/postmaster/syslogger.c
+++ b/src/backend/postmaster/syslogger.c
@@ -45,6 +45,7 @@
 #include "storage/latch.h"
 #include "storage/pg_shmem.h"
 #include "utils/guc.h"
+#include "utils/guc_values.h"
 #include "utils/ps_status.h"
 #include "utils/timestamp.h"
 
@@ -1451,7 +1452,7 @@ logfile_writename(void)
 
 	if (last_file_name && (Log_destination & LOG_DESTINATION_STDERR))
 	{
-		if (fprintf(fh, "stderr %s\n", last_file_name) < 0)
+		if (fprintf(fh, GUCV_STDERR " %s\n", last_file_name) < 0)
 		{
 			ereport(LOG,
 					(errcode_for_file_access(),
@@ -1464,7 +1465,7 @@ logfile_writename(void)
 
 	if (last_csv_file_name && (Log_destination & LOG_DESTINATION_CSVLOG))
 	{
-		if (fprintf(fh, "csvlog %s\n", last_csv_file_name) < 0)
+		if (fprintf(fh, GUCV_CSVLOG " %s\n", last_csv_file_name) < 0)
 		{
 			ereport(LOG,
 					(errcode_for_file_access(),
diff --git a/src/backend/utils/adt/misc.c b/src/backend/utils/adt/misc.c
index 53185e5..49c6da3 100644
--- a/src/backend/utils/adt/misc.c
+++ b/src/backend/utils/adt/misc.c
@@ -43,6 +43,7 @@
 #include "tcop/tcopprot.h"
 #include "utils/acl.h"
 #include "utils/builtins.h"
+#include "utils/guc_values.h"
 #include "utils/timestamp.h"
 
 #define atooid(x)  ((Oid) strtoul((x), NULL, 10))
@@ -913,10 +914,11 @@ pg_current_logfile(PG_FUNCTION_ARGS)
 		fmt = PG_ARGISNULL(0) ? NULL : PG_GETARG_TEXT_PP(0);
 		if (fmt != NULL) {
 			logfmt = text_to_cstring(fmt);
-			if ( (strcmp(logfmt, "stderr") != 0) &&
-				(strcmp(logfmt, "csvlog") != 0) ) {
+			if ( (strcmp(logfmt, GUCV_STDERR) != 0) &&
+				(strcmp(logfmt, GUCV_CSVLOG) != 0) ) {
 				ereport(ERROR,
-		(errmsg("log format %s not supported, possible values are stderr or csvlog", logfmt)));
+		(errmsg("log format %s not supported, possible values are "
+				GUCV_STDERR " or " GUCV_CSVLOG, logfmt)));
 				PG_RETURN_NULL();
 			}
 		}
@@ -1001,12 +1003,12 @@ pg_current_logfile(PG_FUNCTION_ARGS)
 		PG_RETURN_NULL();
 
 	/* Return null when csvlog is requested but we have a stderr log */
-	if ( (logfmt != NULL) && (strcmp(logfmt, "csvlog") == 0)
+	if ( (logfmt != NULL) && (strcmp(logfmt, GUCV_CSVLOG) == 0)
 			&& !(Log_destination & LOG_DESTINATION_CSVLOG) )
 		PG_RETURN_NULL();
 
 	/* Return null when stderr is requested but we have a csv log */
-	if ( (logfmt != NULL) && (strcmp(logfmt, "stderr") == 0)
+	if ( (logfmt != NULL) && (strcmp(logfmt, GUCV_STDERR) == 0)
 			&& !(Log_destination & LOG_DESTINATION_STDERR) )
 		PG_RETURN_NULL();
 

diff --git a/src/backend/postmaster/syslogger.c b/src/backend/postmaster/syslogger.c
index 5434826..6c3b632 100644
--- a/src/backend/postmaster/syslogger.c
+++ b/src/backend/postmaster/syslogger.c
@@ -147,6 +147,7 @@ static char *logfile_getname(pg_time_t timestamp, const char *suffix);
 static void set_next_rotation_time(void);
 static void sigHupHandler(SIGNAL_ARGS);
 static void sigUsr1Handler(SIGNAL_ARGS);
+static bool rm_log_metainfo(void);
 static void logfile_writename(void);
 
 
@@ -343,7 +344,8 @@ SysLoggerMain(int argc, char *argv[])
 			 * wait until the next logfile rotation, which could be some while
 			 * in the future.
 			 */
-			logfile_writename();
+			if (!rm_log_metainfo())
+				logfile_writename();
 
 			/*
 			 * Check if the log directory or filename pattern changed in
@@ -617,7 +619,8 @@ SysLogger_Start(void)
 
 	syslogFile = logfile_open(last_file_name, "a", false);
 
-	logfile_writename();
+	if (!rm_log_metainfo())
+		logfile_writename();
 	pfree(last_file_name);
 
 #ifdef EXEC_BACKEND
@@ -1417,6 +1420,22 @@ sigUsr1Handler(SIGNAL_ARGS)
 
 	errno = save_errno;
 }
+ 
+ /*
+ * Delete the LOG_METAINFO_DATAFILE if it's not going to be used.
+ */
+static bool
+rm_log_metainfo(void)
+{
+	if (!(Log_destination & LOG_DESTINATION_STDERR)
+		&& !(Log_destination & LOG_DESTINATION_CSVLOG))
+	{
+		unlink(LOG_METAINFO_DATAFILE);
+		return true;
+	}
+	return false;
+}
+
 
 /*
  * Store the name of the file(s) where the log collector, when enabled, writes
@@ -1430,13 +1449,6 @@ logfile_writename(void)
 	FILE	*fh;
 	char	tempfn[MAXPGPATH];
 
-	if (!(Log_destination & LOG_DESTINATION_STDERR)
-		&& !(Log_destination & LOG_DESTINATION_CSVLOG))
-	{
-		unlink(LOG_METAINFO_DATAFILE);
-		return;
-	}
-
 	snprintf(tempfn, sizeof(tempfn), "%s.tmp", LOG_METAINFO_DATAFILE);
 
 	if ((fh = logfile_open(tempfn, "w", true) ) == NULL)

diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index f5bfe59..5e0a088 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -15699,7 +15699,10 @@ SET search_path TO <replaceable>schema</> <optional>, <replaceable>schema</>, ..
     or <systemitem>stderr</> as the value of the optional parameter. The
     return value is <literal>NULL</literal> when the log format requested
     is not a configured <xref linkend="guc-log-destination">.
-   </para>
+    <function>pg_current_logfiles</function> reflects the content of the
+    <xref linkend="storage-pgdata-current-logfiles"> file.  All caveats
+    regards <filename>current_logfiles</filename> content are applicable
+    to <function>pg_current_logfiles</function>' return value.</para>
 
    <indexterm>
     <primary>pg_my_temp_schema</primary>
diff --git a/doc/src/sgml/storage.sgml b/doc/src/sgml/storage.sgml
index 3b8f5fd..928133c 100644
--- a/doc/src/sgml/storage.sgml
+++ b/doc/src/sgml/storage.sgml
@@ -81,10 +81,37 @@ Item
   <filename>current_logfiles</filename>.</para>
 
   <note>
-    <para>Non-<productname>PostgreSQL</productname> log sources, such as 3rd
-    party libraries, which deliver error messages directly to stderr are
-    always logged by <productname>PostgreSQL</productname> to stderr.  Stderr
-    is also the destination for any incomplete log messages produced by
+    <indexterm>
+      <primary><application>pg_ctl</application></primary>
+      <secondary>and <filename>current_logfiles</filename></secondary>
+    </indexterm>
+    <indexterm>
+      <primary><filename>stderr</filename></primary>
+      <secondary>and <filename>current_logfiles</filename></secondary>
+    </indexterm>
+    <indexterm>
+      <primary>log_destination configuration parameter</primary>
+      <secondary>and <filename>current_logfiles</filename></secondary>
+    </indexterm>
+
+    <para>Although logs directed to <filename>stderr</filename> may be written
+    to the filesystem, when the writing of <filename>stderr</filename> is
+    managed outside of the <productname>PostgreSQL</productname> database
+    server the location of such files in the filesystem is not reflected in
+    the content of <filename>current_logfiles</filename>.  One such case is
+    when the <application>pg_ctl</application> command is used to start
+    the <command>postgres</command> database server, capture
+    the <filename>stderr</filename> output of the server, and direct it to a
+    file.</para>
+
+    <para>There are other notable situations related
+    to <filename>stderr</filename> logging.
+    Non-<productname>PostgreSQL</productname> log sources, such as 3rd party
+    libraries, which deliver error messages directly
+    to <filename>stderr</filename> are always logged
+    by <productname>PostgreSQL</productname>
+    to <filename>stderr</filename>.  <Filename>Stderr</Filename> is also the
+    destination for any incomplete log messages produced by
     <productname>PostgreSQL</productname>.  When
     <systemitem>stderr</systemitem> is not in
     <xref linkend="guc-log-destination">,

diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index 645cbb9..edbf1d7 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -4149,6 +4149,28 @@ SELECT * FROM parent WHERE key = 2400;
     a convenient way to find and access log content without establishing a
     database connection.</para>
 
+    <note>
+      <indexterm>
+        <primary><filename>current_logfiles</filename></primary>
+        <secondary>in relation to <application>systemd</application></secondary>
+      </indexterm>
+      <indexterm>
+        <primary><function>pg_current_logfile</function></primary>
+        <secondary>in relation to <application>systemd</application></secondary>
+      </indexterm>
+
+      <para><filename>current_logfiles</filename> exists only
+      when <xref linkend="guc-logging-collector"> is <literal>on</literal>.
+      The <varname>logging_collector</varname> default,
+      in <productname>PostgreSQL</productname> and in many binary
+      distributions, is <literal>off</literal>.
+      Many <productname>Linux</productname> distributions' default is to leave
+      the logging collector off and rely on <application>systemd</application>
+      to collect <filename>stderr</filename> and manage logging.  This default
+      affects the <xref linkend="functions-info-pg-current-logfile"> function
+      as well.</para>
+    </note>
+
     <sect2 id="runtime-config-logging-where">
      <title>Where To Log</title>
 
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 5e0a088..bbd3ecd 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -15682,7 +15682,8 @@ SET search_path TO <replaceable>schema</> <optional>, <replaceable>schema</>, ..
     <secondary>pg_current_logfile function</secondary>
    </indexterm>
 
-   <para>
+   <para id="functions-info-pg-current-logfile"
+         xreflabel="pg_current_logfile">
     <function>pg_current_logfile</function> returns, as <type>text</type>,
     the path of either the csv or stderr log file currently in use by the
     logging collector.  This is a path including the

diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index 645cbb9..ba635f4 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -4149,6 +4149,32 @@ SELECT * FROM parent WHERE key = 2400;
     a convenient way to find and access log content without establishing a
     database connection.</para>
 
+    <note>
+      <indexterm>
+        <primary><filename>current_logfiles</filename></primary>
+        <secondary>in relation to <application>systemd</application></secondary>
+      </indexterm>
+      <indexterm>
+        <primary><function>pg_current_logfile</function></primary>
+        <secondary>in relation to <application>systemd</application></secondary>
+      </indexterm>
+      <indexterm>
+        <primary>systemd</primary>
+        <secondary>Logging and logfiles</secondary>
+      </indexterm>
+
+      <para><filename>current_logfiles</filename> exists only
+      when <xref linkend="guc-logging-collector"> is <literal>on</literal>.
+      The <varname>logging_collector</varname> default,
+      in <productname>PostgreSQL</productname> and in many binary
+      distributions, is <literal>off</literal>.
+      Many <productname>Linux</productname> distributions' default is to leave
+      the logging collector off and rely on <application>systemd</application>
+      to collect <filename>stderr</filename> and manage logging.  This default
+      affects the <xref linkend="functions-info-pg-current-logfile"> function
+      as well.</para>
+    </note>
+
     <sect2 id="runtime-config-logging-where">
      <title>Where To Log</title>
 
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 5e0a088..bbd3ecd 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -15682,7 +15682,8 @@ SET search_path TO <replaceable>schema</> <optional>, <replaceable>schema</>, ..
     <secondary>pg_current_logfile function</secondary>
    </indexterm>
 
-   <para>
+   <para id="functions-info-pg-current-logfile"
+         xreflabel="pg_current_logfile">
     <function>pg_current_logfile</function> returns, as <type>text</type>,
     the path of either the csv or stderr log file currently in use by the
     logging collector.  This is a path including the

diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index dcd0663..cd60268 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -4144,6 +4144,12 @@ SELECT * FROM parent WHERE key = 2400;
      <primary>server log</primary>
     </indexterm>
 
+    <para>When logs are written to the file-system their paths, names, and
+    types are recorded in
+    the <xref linkend="storage-pgdata-current-logfiles"> file.  This provides
+    a convenient way to find and access log content without establishing a
+    database connection.</para>
+
     <sect2 id="runtime-config-logging-where">
      <title>Where To Log</title>
 
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 2e64cc4..08d9f46 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -15443,6 +15443,19 @@ SELECT * FROM pg_ls_dir('.') WITH ORDINALITY AS t(ls,n);
       </row>
 
       <row>
+       <entry><literal><function>pg_current_logfile()</function></literal></entry>
+       <entry><type>text</type></entry>
+       <entry>primary log file name in use by the logging collector</entry>
+      </row>
+
+      <row>
+       <entry><literal><function>pg_current_logfile(<type>text</>)</function></literal></entry>
+       <entry><type>text</type></entry>
+       <entry>log file name, of log in the requested format, in use by the
+       logging collector</entry>
+      </row>
+
+      <row>
        <entry><literal><function>pg_my_temp_schema()</function></literal></entry>
        <entry><type>oid</type></entry>
        <entry>OID of session's temporary schema, or 0 if none</entry>
@@ -15660,6 +15673,39 @@ SET search_path TO <replaceable>schema</> <optional>, <replaceable>schema</>, ..
     the time when the postmaster process re-read the configuration files.)
    </para>
 
+    <indexterm>
+    <primary>pg_current_logile</primary>
+   </indexterm>
+
+   <indexterm>
+    <primary>Logging</primary>
+    <secondary>pg_current_logfile function</secondary>
+   </indexterm>
+
+   <para>
+    <function>pg_current_logfile</function> returns, as <type>text</type>,
+    the path of either the csv or stderr log file currently in use by the
+    logging collector.  This is a path including the
+    <xref linkend="guc-log-directory"> directory and the log file name.
+    Log collection must be active or the return value
+    is <literal>NULL</literal>.  When multiple logfiles exist, each in a
+    different format, <function>pg_current_logfile</function> called
+    without arguments returns the path of the file having the first format
+    found in the ordered
+    list: <systemitem>stderr</>, <systemitem>csvlog</>.
+    <literal>NULL</literal> is returned when no log file has any of these
+    formats.  To request a specific file format supply,
+    as <type>text</type>, either <systemitem>csvlog</>
+    or <systemitem>stderr</> as the value of the optional parameter. The
+    return value is <literal>NULL</literal> when the log format requested
+    is not a configured <xref linkend="guc-log-destination">.
+
+   <function>pg_current_logfiles</function> reflects the content of the
+    <xref linkend="storage-pgdata-current-logfiles"> file.  All caveats
+    regards <filename>current_logfiles</filename> content are applicable
+    to <function>pg_current_logfiles</function>' return value.
+   </para>
+
    <indexterm>
     <primary>pg_my_temp_schema</primary>
    </indexterm>
diff --git a/doc/src/sgml/storage.sgml b/doc/src/sgml/storage.sgml
index 5c52824..928133c 100644
--- a/doc/src/sgml/storage.sgml
+++ b/doc/src/sgml/storage.sgml
@@ -60,6 +60,79 @@ Item
  <entry>Subdirectory containing per-database subdirectories</entry>
 </row>
 
+<row id="storage-pgdata-current-logfiles" xreflabel="current_logfiles">
+ <entry>
+  <indexterm>
+   <primary><filename>current_logfiles</filename></primary>
+  </indexterm>
+  <indexterm>
+   <primary>Logging</primary>
+   <secondary><filename>current_logfiles</filename> file</secondary>
+  </indexterm>
+  <filename>current_logfiles</>
+ </entry>
+ <entry>
+  <para>A file recording the log file(s) currently written to by the syslogger
+  and the file's log formats, <systemitem>stderr</>
+  or <systemitem>csvlog</>. Each line of the file is a space separated list of
+  two elements: the log format and the full path to the log file including the
+  value of <xref linkend="guc-log-directory">.  The log format must be present
+  in <xref linkend="guc-log-destination"> to be listed in
+  <filename>current_logfiles</filename>.</para>
+
+  <note>
+    <indexterm>
+      <primary><application>pg_ctl</application></primary>
+      <secondary>and <filename>current_logfiles</filename></secondary>
+    </indexterm>
+    <indexterm>
+      <primary><filename>stderr</filename></primary>
+      <secondary>and <filename>current_logfiles</filename></secondary>
+    </indexterm>
+    <indexterm>
+      <primary>log_destination configuration parameter</primary>
+      <secondary>and <filename>current_logfiles</filename></secondary>
+    </indexterm>
+
+    <para>Although logs directed to <filename>stderr</filename> may be written
+    to the filesystem, when the writing of <filename>stderr</filename> is
+    managed outside of the <productname>PostgreSQL</productname> database
+    server the location of such files in the filesystem is not reflected in
+    the content of <filename>current_logfiles</filename>.  One such case is
+    when the <application>pg_ctl</application> command is used to start
+    the <command>postgres</command> database server, capture
+    the <filename>stderr</filename> output of the server, and direct it to a
+    file.</para>
+
+    <para>There are other notable situations related
+    to <filename>stderr</filename> logging.
+    Non-<productname>PostgreSQL</productname> log sources, such as 3rd party
+    libraries, which deliver error messages directly
+    to <filename>stderr</filename> are always logged
+    by <productname>PostgreSQL</productname>
+    to <filename>stderr</filename>.  <Filename>Stderr</Filename> is also the
+    destination for any incomplete log messages produced by
+    <productname>PostgreSQL</productname>.  When
+    <systemitem>stderr</systemitem> is not in
+    <xref linkend="guc-log-destination">,
+    <filename>current_logfiles</filename> does not not contain the name of the
+    file where these sorts of log messages are written.</para>
+  </note>
+  
+  <para>The <filename>current_logfiles</filename> file
+  is present only when <xref linkend="guc-logging-collector"> is
+  activated and when at least one of <systemitem>stderr</> or
+  <systemitem>csvlog</> value is present in
+  <xref linkend="guc-log-destination">.</para>
+
+  <para>On a busy system <filename>current_logfiles</filename> might not be
+  updated immediately upon logfile rotation.  On an extremely busy system it
+  is possible, although highly unlikely, for a logfile to be "skipped" and
+  never appear in <filename>current_logfiles</filename>.</para>
+ </entry>
+
+</row>
+
 <row>
  <entry><filename>global</></entry>
  <entry>Subdirectory containing cluster-wide tables, such as
diff --git a/src/backend/postmaster/syslogger.c b/src/backend/postmaster/syslogger.c
index fd62d66..2092576 100644
--- a/src/backend/postmaster/syslogger.c
+++ b/src/backend/postmaster/syslogger.c
@@ -86,6 +86,7 @@ static FILE *csvlogFile = NULL;
 NON_EXEC_STATIC pg_time_t first_syslogger_file_time = 0;
 static char *last_file_name = NULL;
 static char *last_csv_file_name = NULL;
+static bool log_metainfo_stale = false;
 
 /*
  * Buffers for saving partial messages from different backends.
@@ -146,6 +147,8 @@ static char *logfile_getname(pg_time_t timestamp, const char *suffix);
 static void set_next_rotation_time(void);
 static void sigHupHandler(SIGNAL_ARGS);
 static void sigUsr1Handler(SIGNAL_ARGS);
+static bool rm_log_metainfo(void);
+static void logfile_writename(void);
 
 
 /*
@@ -298,6 +301,16 @@ SysLoggerMain(int argc, char *argv[])
 		/* Clear any already-pending wakeups */
 		ResetLatch(MyLatch);
 
+		/* On a busy system the logfile meta information may not have been
+		* written so retry.  (The cost of this is doing extra I/O on an
+		* already busy system.)  Write the info before SIGHUP config file
+		* re-read in an attempt to not ever "skip" writing a logfile
+		* filename.
+		*/
+		if (log_metainfo_stale && !rotation_disabled)
+			logfile_writename();
+
+
 		/*
 		 * Process any requests or signals received recently.
 		 */
@@ -348,6 +361,14 @@ SysLoggerMain(int argc, char *argv[])
 				rotation_disabled = false;
 				rotation_requested = true;
 			}
+
+			/*
+			 * Force rewriting last log filename when reloading configuration,
+			 * even if rotation_requested is false, log_destination may have
+			 * been changed and we don't want to wait the next file rotation.
+			 */
+			if (!rm_log_metainfo())
+				logfile_writename();
 		}
 
 		if (Log_RotationAge > 0 && !rotation_disabled)
@@ -511,10 +532,14 @@ int
 SysLogger_Start(void)
 {
 	pid_t		sysloggerPid;
-	char	   *filename;
 
-	if (!Logging_collector)
+	if (!Logging_collector) {
+		/* Logging collector is not enabled. We don't know where messages are
+		 * logged.  Remove outdated file holding the current log filenames.
+		 */
+		unlink(LOG_METAINFO_DATAFILE);
 		return 0;
+	}
 
 	/*
 	 * If first time through, create the pipe which will receive stderr
@@ -570,11 +595,13 @@ SysLogger_Start(void)
 	 * a time-based rotation.
 	 */
 	first_syslogger_file_time = time(NULL);
-	filename = logfile_getname(first_syslogger_file_time, NULL);
+	last_file_name = logfile_getname(first_syslogger_file_time, NULL);
 
-	syslogFile = logfile_open(filename, "a", false);
+	syslogFile = logfile_open(last_file_name, "a", false);
 
-	pfree(filename);
+	if (!rm_log_metainfo())
+		logfile_writename();
+	pfree(last_file_name);
 
 #ifdef EXEC_BACKEND
 	switch ((sysloggerPid = syslogger_forkexec()))
@@ -1098,6 +1125,8 @@ open_csvlogfile(void)
 		pfree(last_csv_file_name);
 
 	last_csv_file_name = filename;
+
+	logfile_writename();
 }
 
 /*
@@ -1151,9 +1180,11 @@ static void
 logfile_rotate(bool time_based_rotation, int size_rotation_for)
 {
 	char	   *filename;
-	char	   *csvfilename = NULL;
+	char	   *csvfilename;
 	pg_time_t	fntime;
 	FILE	   *fh;
+	bool       rotate_csvlog;
+	bool       rotate_stderr;
 
 	rotation_requested = false;
 
@@ -1166,9 +1197,6 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for)
 		fntime = next_rotation_time;
 	else
 		fntime = time(NULL);
-	filename = logfile_getname(fntime, NULL);
-	if (csvlogFile != NULL)
-		csvfilename = logfile_getname(fntime, ".csv");
 
 	/*
 	 * Decide whether to overwrite or append.  We can overwrite if (a)
@@ -1178,8 +1206,12 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for)
 	 *
 	 * Note: last_file_name should never be NULL here, but if it is, append.
 	 */
-	if (time_based_rotation || (size_rotation_for & LOG_DESTINATION_STDERR))
+	rotate_stderr = time_based_rotation ||
+		(size_rotation_for & LOG_DESTINATION_STDERR);
+	if (rotate_stderr)
 	{
+		filename = logfile_getname(fntime, NULL);
+
 		if (Log_truncate_on_rotation && time_based_rotation &&
 			last_file_name != NULL &&
 			strcmp(filename, last_file_name) != 0)
@@ -1202,10 +1234,7 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for)
 				rotation_disabled = true;
 			}
 
-			if (filename)
-				pfree(filename);
-			if (csvfilename)
-				pfree(csvfilename);
+			pfree(filename);
 			return;
 		}
 
@@ -1216,14 +1245,16 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for)
 		if (last_file_name != NULL)
 			pfree(last_file_name);
 		last_file_name = filename;
-		filename = NULL;
 	}
 
 	/* Same as above, but for csv file. */
-
-	if (csvlogFile != NULL &&
-		(time_based_rotation || (size_rotation_for & LOG_DESTINATION_CSVLOG)))
+	rotate_csvlog = csvlogFile != NULL &&
+		(time_based_rotation || (size_rotation_for & LOG_DESTINATION_CSVLOG));
+	if (rotate_csvlog)
 	{
+		if (csvlogFile != NULL)
+			csvfilename = logfile_getname(fntime, ".csv");
+
 		if (Log_truncate_on_rotation && time_based_rotation &&
 			last_csv_file_name != NULL &&
 			strcmp(csvfilename, last_csv_file_name) != 0)
@@ -1246,10 +1277,7 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for)
 				rotation_disabled = true;
 			}
 
-			if (filename)
-				pfree(filename);
-			if (csvfilename)
-				pfree(csvfilename);
+			pfree(csvfilename);
 			return;
 		}
 
@@ -1260,13 +1288,10 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for)
 		if (last_csv_file_name != NULL)
 			pfree(last_csv_file_name);
 		last_csv_file_name = csvfilename;
-		csvfilename = NULL;
 	}
 
-	if (filename)
-		pfree(filename);
-	if (csvfilename)
-		pfree(csvfilename);
+	if (rotate_stderr || rotate_csvlog)
+		logfile_writename();
 
 	set_next_rotation_time();
 }
@@ -1365,3 +1390,81 @@ sigUsr1Handler(SIGNAL_ARGS)
 
 	errno = save_errno;
 }
+
+/*
+ * Store the name of the file(s) where the log collector, when enabled, writes
+ * log messages.  Useful for finding the name(s) of the current log file(s)
+ * when there is time-based logfile rotation.  Filenames are stored in a
+ * temporary file and renamed into the final destination for atomicity.
+ */
+static void
+logfile_writename()
+{
+	FILE	*fh;
+	char	tempfn[MAXPGPATH];
+
+	snprintf(tempfn, sizeof(tempfn), "%s.tmp", LOG_METAINFO_DATAFILE);
+
+	if ((fh = logfile_open(tempfn, "w", true) ) == NULL)
+	{
+		if (errno == ENFILE || errno == EMFILE)
+			/* The system is too busy to write logfile meta info.
+			* This is not too suprising on a busy system.
+			* Try again when logs are next written. */
+			log_metainfo_stale = true;
+		return;
+	}
+	if (last_file_name && (Log_destination & LOG_DESTINATION_STDERR))
+	{
+		if (fprintf(fh, "stderr %s\n", last_file_name) < 0)
+		{
+			ereport(LOG,
+					(errcode_for_file_access(),
+					errmsg("could not write stderr log file path \"%s\": %m",
+						tempfn)));
+			fclose(fh);
+			return;
+		}
+	}
+
+	if (last_csv_file_name && (Log_destination & LOG_DESTINATION_CSVLOG))
+	{
+		if (fprintf(fh, "csvlog %s\n", last_csv_file_name) < 0)
+		{
+			ereport(LOG,
+					(errcode_for_file_access(),
+					errmsg("could not write csvlog log file path \"%s\": %m",
+						tempfn)));
+			fclose(fh);
+			return;
+		}
+	}
+	fclose(fh);
+
+	if (rename(tempfn, LOG_METAINFO_DATAFILE) != 0)
+	{
+		ereport(LOG,
+				(errcode_for_file_access(),
+				errmsg("could not rename file \"%s\": %m",
+						tempfn)));
+		return;
+	}
+
+	log_metainfo_stale = false;
+}
+
+/*
+ * Delete the LOG_METAINFO_DATAFILE if it's not going to be used.
+ */
+static bool
+rm_log_metainfo(void)
+{
+	if (!(Log_destination & LOG_DESTINATION_STDERR)
+		&& !(Log_destination & LOG_DESTINATION_CSVLOG))
+	{
+		unlink(LOG_METAINFO_DATAFILE);
+		return true;
+	}
+	return false;
+}
+
diff --git a/src/backend/utils/adt/misc.c b/src/backend/utils/adt/misc.c
index 0da051a..dd75acc 100644
--- a/src/backend/utils/adt/misc.c
+++ b/src/backend/utils/adt/misc.c
@@ -19,6 +19,7 @@
 #include <dirent.h>
 #include <math.h>
 #include <unistd.h>
+#include <sys/stat.h>
 
 #include "access/sysattr.h"
 #include "catalog/pg_authid.h"
@@ -892,3 +893,125 @@ parse_ident(PG_FUNCTION_ARGS)
 
 	PG_RETURN_DATUM(makeArrayResult(astate, CurrentMemoryContext));
 }
+
+/*
+ * Report current log file used by log collector
+ */
+Datum
+pg_current_logfile(PG_FUNCTION_ARGS)
+{
+	FILE    *fd;
+	char    lbuffer[MAXPGPATH];
+	text    *fmt;
+	char    *logfmt;
+	struct stat stat_buf;
+	char    log_format[15];
+	char    log_filename[MAXPGPATH];
+
+	/* The log format parameter is optional */
+	if (PG_NARGS() == 1) {
+		fmt = PG_ARGISNULL(0) ? NULL : PG_GETARG_TEXT_PP(0);
+		if (fmt != NULL) {
+			logfmt = text_to_cstring(fmt);
+			if ( (strcmp(logfmt, "stderr") != 0) &&
+				(strcmp(logfmt, "csvlog") != 0) ) {
+				ereport(ERROR,
+		(errmsg("log format %s not supported, possible values are stderr or csvlog", logfmt)));
+				PG_RETURN_NULL();
+			}
+		}
+	} else {
+		logfmt = NULL;
+	}
+
+	if (!Logging_collector)
+		PG_RETURN_NULL();
+
+	/* Check if current log file is present */
+	if (stat(LOG_METAINFO_DATAFILE, &stat_buf) != 0)
+		PG_RETURN_NULL();
+
+	fd = AllocateFile(LOG_METAINFO_DATAFILE, "r");
+	if (fd == NULL)
+	{
+		if (errno != ENOENT)
+			ereport(ERROR,
+				(errcode_for_file_access(),
+				errmsg("could not read file \"%s\": %m",
+				LOG_METAINFO_DATAFILE)));
+		PG_RETURN_NULL();
+	}
+
+	/*
+	* Read the file to gather current log filename(s) registered
+	* by the syslogger.
+	*/
+	while (fgets(lbuffer, sizeof(lbuffer), fd) != NULL) {
+
+		/* Check for a read error. */
+		if (ferror(fd)) {
+			ereport(ERROR,
+				(errcode_for_file_access(),
+				errmsg("could not read file \"%s\": %m", LOG_METAINFO_DATAFILE)));
+			FreeFile(fd);
+			break;
+		}
+
+		/* remove trailing newline */
+		if (strchr(lbuffer, '\n') != NULL)
+			*strchr(lbuffer, '\n') = '\0';
+
+		/* extract log format and log file path from the line */
+		if (sscanf(lbuffer, "%s %s", log_format, log_filename) != 2)
+		{
+			ereport(ERROR,
+				(errmsg("unexpected line format in file %s", LOG_METAINFO_DATAFILE)));
+			break;
+		}
+
+		/*
+		 * When no log format is provided as argument always reports
+		 * the first registered log file in LOG_METAINFO_DATAFILE.
+		 */
+		if (logfmt == NULL)
+			break;
+
+		/* report the entry corresponding to the requested format */
+		if (strcmp(logfmt, log_format) == 0)
+			break;
+	}
+	/* Close the current log filename file. */
+	if (FreeFile(fd))
+		ereport(ERROR,
+				(errcode_for_file_access(),
+			errmsg("could not close file \"%s\": %m", LOG_METAINFO_DATAFILE)));
+
+
+	if (log_filename[0] == '\0')
+		PG_RETURN_NULL();
+
+	/* Return null when csvlog is requested but we have a stderr log */
+	if ( (logfmt != NULL) && (strcmp(logfmt, "csvlog") == 0)
+			&& !(Log_destination & LOG_DESTINATION_CSVLOG) )
+		PG_RETURN_NULL();
+
+	/* Return null when stderr is requested but we have a csv log */
+	if ( (logfmt != NULL) && (strcmp(logfmt, "stderr") == 0)
+			&& !(Log_destination & LOG_DESTINATION_STDERR) )
+		PG_RETURN_NULL();
+
+	PG_RETURN_TEXT_P(cstring_to_text(log_filename));
+}
+
+/*
+ * Report current log file used by log collector (1 argument version)
+ *
+ * note: this wrapper is necessary to pass the sanity check in opr_sanity,
+ * which checks that all built-in functions that share the implementing C
+ * function take the same number of arguments
+ */
+Datum
+pg_current_logfile_1arg(PG_FUNCTION_ARGS)
+{
+	return pg_current_logfile(fcinfo);
+}
diff --git a/src/include/catalog/pg_proc.h b/src/include/catalog/pg_proc.h
index 047a1ce..26db448 100644
--- a/src/include/catalog/pg_proc.h
+++ b/src/include/catalog/pg_proc.h
@@ -3181,6 +3181,10 @@ DATA(insert OID = 2621 ( pg_reload_conf			PGNSP PGUID 12 1 0 0 0 f f f f t f v s
 DESCR("reload configuration files");
 DATA(insert OID = 2622 ( pg_rotate_logfile		PGNSP PGUID 12 1 0 0 0 f f f f t f v s 0 0 16 "" _null_ _null_ _null_ _null_ _null_ pg_rotate_logfile _null_ _null_ _null_ ));
 DESCR("rotate log file");
+DATA(insert OID = 3800 ( pg_current_logfile             PGNSP PGUID 12 1 0 0 0 f f f f f f v s 0 0 25 "" _null_ _null_ _null_ _null_ _null_ pg_current_logfile _null_ _null_ _null_ ));
+DESCR("current logging collector file location");
+DATA(insert OID = 3801 ( pg_current_logfile             PGNSP PGUID 12 1 0 0 0 f f f f f f v s 1 0 25 "25" _null_ _null_ _null_ _null_ _null_ pg_current_logfile_1arg _null_ _null_ _null_ ));
+DESCR("current logging collector file location");
 
 DATA(insert OID = 2623 ( pg_stat_file		PGNSP PGUID 12 1 0 0 0 f f f f t f v s 1 0 2249 "25" "{25,20,1184,1184,1184,1184,16}" "{i,o,o,o,o,o,o}" "{filename,size,access,modification,change,creation,isdir}" _null_ _null_ pg_stat_file_1arg _null_ _null_ _null_ ));
 DESCR("get information about file");
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 78c9954..36a5b58 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -466,4 +466,13 @@ extern bool has_rolreplication(Oid roleid);
 extern bool BackupInProgress(void);
 extern void CancelBackup(void);
 
+/* in backend/utils/adt/misc.c and backend/postmaster/syslogger.c */
+/*
+ * Name of file holding the paths, names, and types of the files where current
+ * log messages are written, when the log collector is enabled.  Useful
+ * outside of Postgres when finding the name of the current log file in the
+ * case of time-based log rotation.
+ */
+#define LOG_METAINFO_DATAFILE  "current_logfiles"
+
 #endif   /* MISCADMIN_H */
diff --git a/src/include/utils/builtins.h b/src/include/utils/builtins.h
index 90f5132..e532022 100644
--- a/src/include/utils/builtins.h
+++ b/src/include/utils/builtins.h
@@ -522,6 +522,8 @@ extern Datum pg_collation_for(PG_FUNCTION_ARGS);
 extern Datum pg_relation_is_updatable(PG_FUNCTION_ARGS);
 extern Datum pg_column_is_updatable(PG_FUNCTION_ARGS);
 extern Datum parse_ident(PG_FUNCTION_ARGS);
+extern Datum pg_current_logfile(PG_FUNCTION_ARGS);
+extern Datum pg_current_logfile_1arg(PG_FUNCTION_ARGS);
 
 /* oid.c */
 extern Datum oidin(PG_FUNCTION_ARGS);

diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index 0fc4e57..41144cb 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -4169,6 +4169,12 @@ SELECT * FROM parent WHERE key = 2400;
      <primary>server log</primary>
     </indexterm>
 
+    <para>When logs are written to the file-system their paths, names, and
+    types are recorded in
+    the <xref linkend="storage-pgdata-current-logfiles"> file.  This provides
+    a convenient way to find and access log content without establishing a
+    database connection.</para>
+
     <sect2 id="runtime-config-logging-where">
      <title>Where To Log</title>
 
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index eca98df..47ca846 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -15444,6 +15444,19 @@ SELECT * FROM pg_ls_dir('.') WITH ORDINALITY AS t(ls,n);
       </row>
 
       <row>
+       <entry><literal><function>pg_current_logfile()</function></literal></entry>
+       <entry><type>text</type></entry>
+       <entry>primary log file name in use by the logging collector</entry>
+      </row>
+
+      <row>
+       <entry><literal><function>pg_current_logfile(<type>text</>)</function></literal></entry>
+       <entry><type>text</type></entry>
+       <entry>log file name, of log in the requested format, in use by the
+       logging collector</entry>
+      </row>
+
+      <row>
        <entry><literal><function>pg_my_temp_schema()</function></literal></entry>
        <entry><type>oid</type></entry>
        <entry>OID of session's temporary schema, or 0 if none</entry>
@@ -15661,6 +15674,39 @@ SET search_path TO <replaceable>schema</> <optional>, <replaceable>schema</>, ..
     the time when the postmaster process re-read the configuration files.)
    </para>
 
+    <indexterm>
+    <primary>pg_current_logile</primary>
+   </indexterm>
+
+   <indexterm>
+    <primary>Logging</primary>
+    <secondary>pg_current_logfile function</secondary>
+   </indexterm>
+
+   <para>
+    <function>pg_current_logfile</function> returns, as <type>text</type>,
+    the path of either the csv or stderr log file currently in use by the
+    logging collector.  This is a path including the
+    <xref linkend="guc-log-directory"> directory and the log file name.
+    Log collection must be active or the return value
+    is <literal>NULL</literal>.  When multiple logfiles exist, each in a
+    different format, <function>pg_current_logfile</function> called
+    without arguments returns the path of the file having the first format
+    found in the ordered
+    list: <systemitem>stderr</>, <systemitem>csvlog</>.
+    <literal>NULL</literal> is returned when no log file has any of these
+    formats.  To request a specific file format supply,
+    as <type>text</type>, either <systemitem>csvlog</>
+    or <systemitem>stderr</> as the value of the optional parameter. The
+    return value is <literal>NULL</literal> when the log format requested
+    is not a configured <xref linkend="guc-log-destination">.
+
+   <function>pg_current_logfiles</function> reflects the content of the
+    <xref linkend="storage-pgdata-current-logfiles"> file.  All caveats
+    regards <filename>current_logfiles</filename> content are applicable
+    to <function>pg_current_logfiles</function>' return value.
+   </para>
+
    <indexterm>
     <primary>pg_my_temp_schema</primary>
    </indexterm>
diff --git a/doc/src/sgml/storage.sgml b/doc/src/sgml/storage.sgml
index 5c52824..928133c 100644
--- a/doc/src/sgml/storage.sgml
+++ b/doc/src/sgml/storage.sgml
@@ -60,6 +60,79 @@ Item
  <entry>Subdirectory containing per-database subdirectories</entry>
 </row>
 
+<row id="storage-pgdata-current-logfiles" xreflabel="current_logfiles">
+ <entry>
+  <indexterm>
+   <primary><filename>current_logfiles</filename></primary>
+  </indexterm>
+  <indexterm>
+   <primary>Logging</primary>
+   <secondary><filename>current_logfiles</filename> file</secondary>
+  </indexterm>
+  <filename>current_logfiles</>
+ </entry>
+ <entry>
+  <para>A file recording the log file(s) currently written to by the syslogger
+  and the file's log formats, <systemitem>stderr</>
+  or <systemitem>csvlog</>. Each line of the file is a space separated list of
+  two elements: the log format and the full path to the log file including the
+  value of <xref linkend="guc-log-directory">.  The log format must be present
+  in <xref linkend="guc-log-destination"> to be listed in
+  <filename>current_logfiles</filename>.</para>
+
+  <note>
+    <indexterm>
+      <primary><application>pg_ctl</application></primary>
+      <secondary>and <filename>current_logfiles</filename></secondary>
+    </indexterm>
+    <indexterm>
+      <primary><filename>stderr</filename></primary>
+      <secondary>and <filename>current_logfiles</filename></secondary>
+    </indexterm>
+    <indexterm>
+      <primary>log_destination configuration parameter</primary>
+      <secondary>and <filename>current_logfiles</filename></secondary>
+    </indexterm>
+
+    <para>Although logs directed to <filename>stderr</filename> may be written
+    to the filesystem, when the writing of <filename>stderr</filename> is
+    managed outside of the <productname>PostgreSQL</productname> database
+    server the location of such files in the filesystem is not reflected in
+    the content of <filename>current_logfiles</filename>.  One such case is
+    when the <application>pg_ctl</application> command is used to start
+    the <command>postgres</command> database server, capture
+    the <filename>stderr</filename> output of the server, and direct it to a
+    file.</para>
+
+    <para>There are other notable situations related
+    to <filename>stderr</filename> logging.
+    Non-<productname>PostgreSQL</productname> log sources, such as 3rd party
+    libraries, which deliver error messages directly
+    to <filename>stderr</filename> are always logged
+    by <productname>PostgreSQL</productname>
+    to <filename>stderr</filename>.  <Filename>Stderr</Filename> is also the
+    destination for any incomplete log messages produced by
+    <productname>PostgreSQL</productname>.  When
+    <systemitem>stderr</systemitem> is not in
+    <xref linkend="guc-log-destination">,
+    <filename>current_logfiles</filename> does not not contain the name of the
+    file where these sorts of log messages are written.</para>
+  </note>
+  
+  <para>The <filename>current_logfiles</filename> file
+  is present only when <xref linkend="guc-logging-collector"> is
+  activated and when at least one of <systemitem>stderr</> or
+  <systemitem>csvlog</> value is present in
+  <xref linkend="guc-log-destination">.</para>
+
+  <para>On a busy system <filename>current_logfiles</filename> might not be
+  updated immediately upon logfile rotation.  On an extremely busy system it
+  is possible, although highly unlikely, for a logfile to be "skipped" and
+  never appear in <filename>current_logfiles</filename>.</para>
+ </entry>
+
+</row>
+
 <row>
  <entry><filename>global</></entry>
  <entry>Subdirectory containing cluster-wide tables, such as
diff --git a/src/backend/postmaster/syslogger.c b/src/backend/postmaster/syslogger.c
index fd62d66..ea812e0 100644
--- a/src/backend/postmaster/syslogger.c
+++ b/src/backend/postmaster/syslogger.c
@@ -146,6 +146,8 @@ static char *logfile_getname(pg_time_t timestamp, const char *suffix);
 static void set_next_rotation_time(void);
 static void sigHupHandler(SIGNAL_ARGS);
 static void sigUsr1Handler(SIGNAL_ARGS);
+static bool rm_log_metainfo(void);
+static void logfile_writename(void);
 
 
 /*
@@ -348,6 +350,14 @@ SysLoggerMain(int argc, char *argv[])
 				rotation_disabled = false;
 				rotation_requested = true;
 			}
+
+			/*
+			 * Force rewriting last log filename when reloading configuration,
+			 * even if rotation_requested is false, log_destination may have
+			 * been changed and we don't want to wait the next file rotation.
+			 */
+			if (!rm_log_metainfo())
+				logfile_writename();
 		}
 
 		if (Log_RotationAge > 0 && !rotation_disabled)
@@ -511,10 +521,14 @@ int
 SysLogger_Start(void)
 {
 	pid_t		sysloggerPid;
-	char	   *filename;
 
-	if (!Logging_collector)
+	if (!Logging_collector) {
+		/* Logging collector is not enabled. We don't know where messages are
+		 * logged.  Remove outdated file holding the current log filenames.
+		 */
+		unlink(LOG_METAINFO_DATAFILE);
 		return 0;
+	}
 
 	/*
 	 * If first time through, create the pipe which will receive stderr
@@ -570,11 +584,13 @@ SysLogger_Start(void)
 	 * a time-based rotation.
 	 */
 	first_syslogger_file_time = time(NULL);
-	filename = logfile_getname(first_syslogger_file_time, NULL);
+	last_file_name = logfile_getname(first_syslogger_file_time, NULL);
 
-	syslogFile = logfile_open(filename, "a", false);
+	syslogFile = logfile_open(last_file_name, "a", false);
 
-	pfree(filename);
+	if (!rm_log_metainfo())
+		logfile_writename();
+	pfree(last_file_name);
 
 #ifdef EXEC_BACKEND
 	switch ((sysloggerPid = syslogger_forkexec()))
@@ -1098,6 +1114,8 @@ open_csvlogfile(void)
 		pfree(last_csv_file_name);
 
 	last_csv_file_name = filename;
+
+	logfile_writename();
 }
 
 /*
@@ -1151,9 +1169,11 @@ static void
 logfile_rotate(bool time_based_rotation, int size_rotation_for)
 {
 	char	   *filename;
-	char	   *csvfilename = NULL;
+	char	   *csvfilename;
 	pg_time_t	fntime;
 	FILE	   *fh;
+	bool       rotate_csvlog;
+	bool       rotate_stderr;
 
 	rotation_requested = false;
 
@@ -1166,9 +1186,6 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for)
 		fntime = next_rotation_time;
 	else
 		fntime = time(NULL);
-	filename = logfile_getname(fntime, NULL);
-	if (csvlogFile != NULL)
-		csvfilename = logfile_getname(fntime, ".csv");
 
 	/*
 	 * Decide whether to overwrite or append.  We can overwrite if (a)
@@ -1178,8 +1195,12 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for)
 	 *
 	 * Note: last_file_name should never be NULL here, but if it is, append.
 	 */
-	if (time_based_rotation || (size_rotation_for & LOG_DESTINATION_STDERR))
+	rotate_stderr = time_based_rotation ||
+		(size_rotation_for & LOG_DESTINATION_STDERR);
+	if (rotate_stderr)
 	{
+		filename = logfile_getname(fntime, NULL);
+
 		if (Log_truncate_on_rotation && time_based_rotation &&
 			last_file_name != NULL &&
 			strcmp(filename, last_file_name) != 0)
@@ -1202,10 +1223,7 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for)
 				rotation_disabled = true;
 			}
 
-			if (filename)
-				pfree(filename);
-			if (csvfilename)
-				pfree(csvfilename);
+			pfree(filename);
 			return;
 		}
 
@@ -1216,14 +1234,16 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for)
 		if (last_file_name != NULL)
 			pfree(last_file_name);
 		last_file_name = filename;
-		filename = NULL;
 	}
 
 	/* Same as above, but for csv file. */
-
-	if (csvlogFile != NULL &&
-		(time_based_rotation || (size_rotation_for & LOG_DESTINATION_CSVLOG)))
+	rotate_csvlog = csvlogFile != NULL &&
+		(time_based_rotation || (size_rotation_for & LOG_DESTINATION_CSVLOG));
+	if (rotate_csvlog)
 	{
+		if (csvlogFile != NULL)
+			csvfilename = logfile_getname(fntime, ".csv");
+
 		if (Log_truncate_on_rotation && time_based_rotation &&
 			last_csv_file_name != NULL &&
 			strcmp(csvfilename, last_csv_file_name) != 0)
@@ -1246,10 +1266,7 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for)
 				rotation_disabled = true;
 			}
 
-			if (filename)
-				pfree(filename);
-			if (csvfilename)
-				pfree(csvfilename);
+			pfree(csvfilename);
 			return;
 		}
 
@@ -1260,13 +1277,10 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for)
 		if (last_csv_file_name != NULL)
 			pfree(last_csv_file_name);
 		last_csv_file_name = csvfilename;
-		csvfilename = NULL;
 	}
 
-	if (filename)
-		pfree(filename);
-	if (csvfilename)
-		pfree(csvfilename);
+	if (rotate_stderr || rotate_csvlog)
+		logfile_writename();
 
 	set_next_rotation_time();
 }
@@ -1365,3 +1379,77 @@ sigUsr1Handler(SIGNAL_ARGS)
 
 	errno = save_errno;
 }
+
+/*
+ * Store the name of the file(s) where the log collector, when enabled, writes
+ * log messages.  Useful for finding the name(s) of the current log file(s)
+ * when there is time-based logfile rotation.  Filenames are stored in a
+ * temporary file and renamed into the final destination for atomicity.
+ */
+static void
+logfile_writename()
+{
+	FILE	*fh;
+	char	tempfn[MAXPGPATH];
+
+	snprintf(tempfn, sizeof(tempfn), "%s.tmp", LOG_METAINFO_DATAFILE);
+
+	if ((fh = logfile_open(tempfn, "w", true) ) == NULL)
+	{
+		if (errno == ENFILE || errno == EMFILE)
+			ereport(LOG,
+				(errmsg("system is too busy to write logfile meta info, %s will be updated on next rotation (or use SIGHUP to retry)", LOG_METAINFO_DATAFILE)));
+		return;
+	}
+	if (last_file_name && (Log_destination & LOG_DESTINATION_STDERR))
+	{
+		if (fprintf(fh, "stderr %s\n", last_file_name) < 0)
+		{
+			ereport(LOG,
+					(errcode_for_file_access(),
+					errmsg("could not write stderr log file path \"%s\": %m",
+						tempfn)));
+			fclose(fh);
+			return;
+		}
+	}
+
+	if (last_csv_file_name && (Log_destination & LOG_DESTINATION_CSVLOG))
+	{
+		if (fprintf(fh, "csvlog %s\n", last_csv_file_name) < 0)
+		{
+			ereport(LOG,
+					(errcode_for_file_access(),
+					errmsg("could not write csvlog log file path \"%s\": %m",
+						tempfn)));
+			fclose(fh);
+			return;
+		}
+	}
+	fclose(fh);
+
+	if (rename(tempfn, LOG_METAINFO_DATAFILE) != 0)
+	{
+		ereport(LOG,
+				(errcode_for_file_access(),
+				errmsg("could not rename file \"%s\": %m",
+						tempfn)));
+		return;
+	}
+
+}
+
+/*
+ * Delete the LOG_METAINFO_DATAFILE if it's not going to be used.
+ */
+static bool
+rm_log_metainfo(void)
+{
+	if (!(Log_destination & LOG_DESTINATION_STDERR)
+		&& !(Log_destination & LOG_DESTINATION_CSVLOG))
+	{
+		unlink(LOG_METAINFO_DATAFILE);
+		return true;
+	}
+	return false;
+}
diff --git a/src/backend/utils/adt/misc.c b/src/backend/utils/adt/misc.c
index 0da051a..2da40b2 100644
--- a/src/backend/utils/adt/misc.c
+++ b/src/backend/utils/adt/misc.c
@@ -19,6 +19,7 @@
 #include <dirent.h>
 #include <math.h>
 #include <unistd.h>
+#include <sys/stat.h>
 
 #include "access/sysattr.h"
 #include "catalog/pg_authid.h"
@@ -892,3 +893,141 @@ parse_ident(PG_FUNCTION_ARGS)
 
 	PG_RETURN_DATUM(makeArrayResult(astate, CurrentMemoryContext));
 }
+
+/*
+ * Report current log file used by log collector
+ */
+Datum
+pg_current_logfile(PG_FUNCTION_ARGS)
+{
+	FILE    *fd;
+	char    lbuffer[MAXPGPATH];
+	char    log_filepath[MAXPGPATH];
+	text    *fmt;
+	char    *logfmt;
+	struct  stat stat_buf;
+
+	/* The log format parameter is optional */
+	if (PG_NARGS() == 1) {
+		fmt = PG_ARGISNULL(0) ? NULL : PG_GETARG_TEXT_PP(0);
+		if (fmt != NULL) {
+			logfmt = text_to_cstring(fmt);
+			if ( (strcmp(logfmt, "stderr") != 0) &&
+				(strcmp(logfmt, "csvlog") != 0) ) {
+				ereport(ERROR,
+		(errmsg("log format %s not supported, possible values are stderr or csvlog", logfmt)));
+				PG_RETURN_NULL();
+			}
+		}
+	} else {
+		logfmt = NULL;
+	}
+
+	if (!Logging_collector)
+		PG_RETURN_NULL();
+
+	/* Check if current log file is present */
+	if (stat(LOG_METAINFO_DATAFILE, &stat_buf) != 0)
+		PG_RETURN_NULL();
+
+	fd = AllocateFile(LOG_METAINFO_DATAFILE, "r");
+	if (fd == NULL)
+	{
+		if (errno != ENOENT)
+			ereport(ERROR,
+				(errcode_for_file_access(),
+				errmsg("could not read file \"%s\": %m",
+				LOG_METAINFO_DATAFILE)));
+		PG_RETURN_NULL();
+	}
+
+	/*
+	* Read the file to gather current log filename(s) registered
+	* by the syslogger.
+	*/
+	while (fgets(lbuffer, sizeof(lbuffer), fd) != NULL) {
+		char    log_format[10];
+		int     i = 0, space_pos = 0;
+
+		/* Check for a read error. */
+		if (ferror(fd)) {
+			ereport(ERROR,
+				(errcode_for_file_access(),
+				errmsg("could not read file \"%s\": %m", LOG_METAINFO_DATAFILE)));
+			FreeFile(fd);
+			break;
+		}
+
+		/* remove trailing newline */
+		if (strchr(lbuffer, '\n') != NULL)
+			*strchr(lbuffer, '\n') = '\0';
+
+		/* extract log format and log file path from the line */
+		for (i = 0; lbuffer[i] != '\0'; i++)
+		{
+			if ((space_pos == 0) && (isspace(lbuffer[i]) != 0))
+			{
+				log_format[i] = '\0';
+				space_pos = i;
+			}
+			else if (space_pos > 0)
+				log_filepath[i-space_pos-1] = lbuffer[i];
+			else
+				log_format[i] = lbuffer[i];
+		}
+		log_filepath[i] = '\0';
+		if ((space_pos != (int)strlen("stderr")) &&
+			(space_pos != (int)strlen("csvlog")))
+		{
+			ereport(ERROR,
+				(errmsg("unexpected line format in file %s", LOG_METAINFO_DATAFILE)));
+			break;
+		}
+
+		/*
+		 * When no log format is provided as argument always reports
+		 * the first registered log file in LOG_METAINFO_DATAFILE.
+		 */
+		if (logfmt == NULL)
+			break;
+
+		/* report the entry corresponding to the requested format */
+		if (strcmp(logfmt, log_format) == 0)
+			break;
+	}
+	/* Close the current log filename file. */
+	if (FreeFile(fd))
+		ereport(ERROR,
+				(errcode_for_file_access(),
+			errmsg("could not close file \"%s\": %m", LOG_METAINFO_DATAFILE)));
+
+
+
+	if (lbuffer[0] == '\0')
+		PG_RETURN_NULL();
+
+	/* Return null when csvlog is requested but we have a stderr log */
+	if ( (logfmt != NULL) && (strcmp(logfmt, "csvlog") == 0)
+			&& !(Log_destination & LOG_DESTINATION_CSVLOG) )
+		PG_RETURN_NULL();
+
+	/* Return null when stderr is requested but we have a csv log */
+	if ( (logfmt != NULL) && (strcmp(logfmt, "stderr") == 0)
+			&& !(Log_destination & LOG_DESTINATION_STDERR) )
+		PG_RETURN_NULL();
+
+	PG_RETURN_TEXT_P(cstring_to_text(log_filepath));
+}
+
+/*
+ * Report current log file used by log collector (1 argument version)
+ *
+ * note: this wrapper is necessary to pass the sanity check in opr_sanity,
+ * which checks that all built-in functions that share the implementing C
+ * function take the same number of arguments
+ */
+Datum
+pg_current_logfile_1arg(PG_FUNCTION_ARGS)
+{
+	return pg_current_logfile(fcinfo);
+}
diff --git a/src/include/catalog/pg_proc.h b/src/include/catalog/pg_proc.h
index 047a1ce..26db448 100644
--- a/src/include/catalog/pg_proc.h
+++ b/src/include/catalog/pg_proc.h
@@ -3181,6 +3181,10 @@ DATA(insert OID = 2621 ( pg_reload_conf			PGNSP PGUID 12 1 0 0 0 f f f f t f v s
 DESCR("reload configuration files");
 DATA(insert OID = 2622 ( pg_rotate_logfile		PGNSP PGUID 12 1 0 0 0 f f f f t f v s 0 0 16 "" _null_ _null_ _null_ _null_ _null_ pg_rotate_logfile _null_ _null_ _null_ ));
 DESCR("rotate log file");
+DATA(insert OID = 3800 ( pg_current_logfile             PGNSP PGUID 12 1 0 0 0 f f f f f f v s 0 0 25 "" _null_ _null_ _null_ _null_ _null_ pg_current_logfile _null_ _null_ _null_ ));
+DESCR("current logging collector file location");
+DATA(insert OID = 3801 ( pg_current_logfile             PGNSP PGUID 12 1 0 0 0 f f f f f f v s 1 0 25 "25" _null_ _null_ _null_ _null_ _null_ pg_current_logfile_1arg _null_ _null_ _null_ ));
+DESCR("current logging collector file location");
 
 DATA(insert OID = 2623 ( pg_stat_file		PGNSP PGUID 12 1 0 0 0 f f f f t f v s 1 0 2249 "25" "{25,20,1184,1184,1184,1184,16}" "{i,o,o,o,o,o,o}" "{filename,size,access,modification,change,creation,isdir}" _null_ _null_ pg_stat_file_1arg _null_ _null_ _null_ ));
 DESCR("get information about file");
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 999440f..afc636f 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -467,4 +467,13 @@ extern bool has_rolreplication(Oid roleid);
 extern bool BackupInProgress(void);
 extern void CancelBackup(void);
 
+/* in backend/utils/adt/misc.c and backend/postmaster/syslogger.c */
+/*
+ * Name of file holding the paths, names, and types of the files where current
+ * log messages are written, when the log collector is enabled.  Useful
+ * outside of Postgres when finding the name of the current log file in the
+ * case of time-based log rotation.
+ */
+#define LOG_METAINFO_DATAFILE  "current_logfiles"
+
 #endif   /* MISCADMIN_H */
diff --git a/src/include/utils/builtins.h b/src/include/utils/builtins.h
index 90f5132..e532022 100644
--- a/src/include/utils/builtins.h
+++ b/src/include/utils/builtins.h
@@ -522,6 +522,8 @@ extern Datum pg_collation_for(PG_FUNCTION_ARGS);
 extern Datum pg_relation_is_updatable(PG_FUNCTION_ARGS);
 extern Datum pg_column_is_updatable(PG_FUNCTION_ARGS);
 extern Datum parse_ident(PG_FUNCTION_ARGS);
+extern Datum pg_current_logfile(PG_FUNCTION_ARGS);
+extern Datum pg_current_logfile_1arg(PG_FUNCTION_ARGS);
 
 /* oid.c */
 extern Datum oidin(PG_FUNCTION_ARGS);

diff --git a/doc/src/sgml/storage.sgml b/doc/src/sgml/storage.sgml
index 61b180f..3b8f5fd 100644
--- a/doc/src/sgml/storage.sgml
+++ b/doc/src/sgml/storage.sgml
@@ -96,7 +96,14 @@ Item
   is present only when <xref linkend="guc-logging-collector"> is
   activated and when at least one of <systemitem>stderr</> or
   <systemitem>csvlog</> value is present in
-  <xref linkend="guc-log-destination">.</para></entry>
+  <xref linkend="guc-log-destination">.</para>
+
+  <para>On a busy system <filename>current_logfiles</filename> might not be
+  updated immediately upon logfile rotation.  On an extremely busy system it
+  is possible, although highly unlikely, for a logfile to be "skipped" and
+  never appear in <filename>current_logfiles</filename>.</para>
+ </entry>
+
 </row>
 
 <row>

diff --git a/src/backend/postmaster/syslogger.c b/src/backend/postmaster/syslogger.c
index 3d8d9cd..691e6eb 100644
--- a/src/backend/postmaster/syslogger.c
+++ b/src/backend/postmaster/syslogger.c
@@ -146,7 +146,7 @@ static char *logfile_getname(pg_time_t timestamp, const char *suffix);
 static void set_next_rotation_time(void);
 static void sigHupHandler(SIGNAL_ARGS);
 static void sigUsr1Handler(SIGNAL_ARGS);
-static void logfile_writename(char *filename, char *csvfilename);
+static void logfile_writename(void);
 
 
 /*
@@ -333,7 +333,7 @@ SysLoggerMain(int argc, char *argv[])
 			 * wait until the next logfile rotation, which could be some while
 			 * in the future.
 			 */
-			logfile_writename(last_file_name, last_csv_file_name);
+			logfile_writename();
 
 			/*
 			 * Check if the log directory or filename pattern changed in
@@ -540,7 +540,6 @@ int
 SysLogger_Start(void)
 {
 	pid_t		sysloggerPid;
-	char	   *filename;
 
 	if (!Logging_collector) {
 		/* Logging collector is not enabled. We don't know where messages are
@@ -604,13 +603,12 @@ SysLogger_Start(void)
 	 * a time-based rotation.
 	 */
 	first_syslogger_file_time = time(NULL);
-	filename = logfile_getname(first_syslogger_file_time, NULL);
-
-	syslogFile = logfile_open(filename, "a", false);
+	last_file_name = logfile_getname(first_syslogger_file_time, NULL);
 
-	logfile_writename(filename, NULL);
+	syslogFile = logfile_open(last_file_name, "a", false);
 
-	pfree(filename);
+	logfile_writename();
+	pfree(last_file_name);
 
 #ifdef EXEC_BACKEND
 	switch ((sysloggerPid = syslogger_forkexec()))
@@ -1135,7 +1133,7 @@ open_csvlogfile(void)
 
 	last_csv_file_name = filename;
 
-	logfile_writename(last_file_name, last_csv_file_name);
+	logfile_writename();
 }
 
 /*
@@ -1306,7 +1304,7 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for)
 	}
 
 	if (rotate_stderr || rotate_csvlog)
-		logfile_writename(last_file_name, last_csv_file_name);
+		logfile_writename();
 	if (filename)
 		pfree(filename);
 	if (csvfilename)
@@ -1417,7 +1415,7 @@ sigUsr1Handler(SIGNAL_ARGS)
  * temporary file and renamed into the final destination for atomicity.
  */
 static void
-logfile_writename(char *filename, char *csvfilename)
+logfile_writename(void)
 {
 	FILE	*fh;
 	char	tempfn[MAXPGPATH];
@@ -1435,9 +1433,10 @@ logfile_writename(char *filename, char *csvfilename)
 	{
 		return;
 	}
-	if (filename && (Log_destination & LOG_DESTINATION_STDERR))
+
+	if (last_file_name && (Log_destination & LOG_DESTINATION_STDERR))
 	{
-		if (fprintf(fh, "stderr %s\n", filename) < 0)
+		if (fprintf(fh, "stderr %s\n", last_file_name) < 0)
 		{
 			ereport(LOG,
 					(errcode_for_file_access(),
@@ -1448,9 +1447,9 @@ logfile_writename(char *filename, char *csvfilename)
 		}
 	}
 
-	if (csvfilename && (Log_destination & LOG_DESTINATION_CSVLOG))
+	if (last_csv_file_name && (Log_destination & LOG_DESTINATION_CSVLOG))
 	{
-		if (fprintf(fh, "csvlog %s\n", csvfilename) < 0)
+		if (fprintf(fh, "csvlog %s\n", last_csv_file_name) < 0)
 		{
 			ereport(LOG,
 					(errcode_for_file_access(),

diff --git a/src/backend/postmaster/syslogger.c b/src/backend/postmaster/syslogger.c
index 691e6eb..5434826 100644
--- a/src/backend/postmaster/syslogger.c
+++ b/src/backend/postmaster/syslogger.c
@@ -86,6 +86,7 @@ static FILE *csvlogFile = NULL;
 NON_EXEC_STATIC pg_time_t first_syslogger_file_time = 0;
 static char *last_file_name = NULL;
 static char *last_csv_file_name = NULL;
+static bool log_metainfo_stale = false;
 
 /*
  * Buffers for saving partial messages from different backends.
@@ -299,6 +300,15 @@ SysLoggerMain(int argc, char *argv[])
 		/* Clear any already-pending wakeups */
 		ResetLatch(MyLatch);
 
+		/* On a busy system the logfile meta information may not have been
+		 * written so retry.  (The cost of this is doing extra I/O on an
+		 * already busy system.)  Write the info before SIGHUP config file
+		 * re-read in an attempt to not ever "skip" writing a logfile
+		 * filename.
+		 */
+		if (log_metainfo_stale)
+			logfile_writename();
+
 		/*
 		 * Process any requests or signals received recently.
 		 */
@@ -1431,6 +1441,11 @@ logfile_writename(void)
 
 	if ((fh = logfile_open(tempfn, "w", true) ) == NULL)
 	{
+		if (errno == ENFILE || errno == EMFILE)
+			/* The system is too busy to write logfile meta info.
+			 * This is not too suprising on a busy system.
+			 * Try again when logs are next written. */
+			log_metainfo_stale = true;
 		return;
 	}
 
@@ -1469,4 +1484,6 @@ logfile_writename(void)
 						tempfn)));
 		return;
 	}
+
+	log_metainfo_stale = false;
 }

diff --git a/src/backend/postmaster/syslogger.c b/src/backend/postmaster/syslogger.c
index 5434826..7335659 100644
--- a/src/backend/postmaster/syslogger.c
+++ b/src/backend/postmaster/syslogger.c
@@ -55,6 +55,16 @@
  */
 #define READ_BUF_SIZE (2 * PIPE_CHUNK_SIZE)
 
+/*
+ * Retries of writing LOG_METAINFO_DATAFILE are backed off on failure, but we
+ * don't want to backoff forever.  The backoff is Fibonacci so takes 2 storage
+ * locations (last, the n-1 value, and next, the n value).  Plus a counter for
+ * how many occasions for retry have been skipped.
+ */
+#define MAX_METAINFO_BACKOFF           250
+#define INITIAL_LAST_METAINFO_BACKOFF    0    /* fibnocci n-1 value */
+#define INITIAL_NEXT_METAINFO_BACKOFF    1    /* fibnocci n value */
+#define INITIAL_METAINFO_BACKOFF_CNTR    0    /* first retry is immediate */
 
 /*
  * GUC parameters.  Logging_collector cannot be changed after postmaster
@@ -87,6 +97,9 @@ NON_EXEC_STATIC pg_time_t first_syslogger_file_time = 0;
 static char *last_file_name = NULL;
 static char *last_csv_file_name = NULL;
 static bool log_metainfo_stale = false;
+static int  last_metainfo_backoff = 1;  /* fibnocci n-1 value */
+static int  next_metainfo_backoff = 1;  /* fibnocci n value */
+static int  metainfo_backoff_cntr = 0;  /* first retry is immediate */
 
 /*
  * Buffers for saving partial messages from different backends.
@@ -148,6 +161,7 @@ static void set_next_rotation_time(void);
 static void sigHupHandler(SIGNAL_ARGS);
 static void sigUsr1Handler(SIGNAL_ARGS);
 static void logfile_writename(void);
+static void logfile_rewritename(void);
 
 
 /*
@@ -307,7 +321,7 @@ SysLoggerMain(int argc, char *argv[])
 		 * filename.
 		 */
 		if (log_metainfo_stale)
-			logfile_writename();
+			logfile_rewritename();
 
 		/*
 		 * Process any requests or signals received recently.
@@ -1487,3 +1501,40 @@ logfile_writename(void)
 
 	log_metainfo_stale = false;
 }
+
+/*
+ * Increasingly backoff from retrying to write LOG_METAINFO_DATAFILE
+ * to prevent a busy system from becoming even more busy.
+ * The Fibonacci sequence is used because it's slope steadily increases
+ * without being exponential.
+ */
+static void
+logfile_rewritename(void)
+{
+	if (metainfo_backoff_cntr <= 0)
+	{	/* Done backing off, retry. */
+
+		logfile_writename();
+
+		if (log_metainfo_stale)
+		{
+			/* Retry failed.  Compute next backoff interval. */
+			if (next_metainfo_backoff >= MAX_METAINFO_BACKOFF)
+			{
+				metainfo_backoff_cntr = MAX_METAINFO_BACKOFF;
+			} else {
+				metainfo_backoff_cntr = next_metainfo_backoff;
+				next_metainfo_backoff =
+					last_metainfo_backoff + last_metainfo_backoff;
+				last_metainfo_backoff = metainfo_backoff_cntr;
+			}
+		} else {
+			/* Retry succeeded.  Re-initialize backoff counters. */
+			last_metainfo_backoff = INITIAL_LAST_METAINFO_BACKOFF;
+			next_metainfo_backoff = INITIAL_NEXT_METAINFO_BACKOFF;
+			metainfo_backoff_cntr = INITIAL_METAINFO_BACKOFF_CNTR;
+		}
+	} else {
+		metainfo_backoff_cntr -= 1;
+	}
+}

diff --git a/src/backend/postmaster/syslogger.c b/src/backend/postmaster/syslogger.c
index 5434826..59d8a83 100644
--- a/src/backend/postmaster/syslogger.c
+++ b/src/backend/postmaster/syslogger.c
@@ -1197,7 +1197,7 @@ static void
 logfile_rotate(bool time_based_rotation, int size_rotation_for)
 {
 	char	   *filename;
-	char	   *csvfilename = NULL;
+	char	   *csvfilename;
 	pg_time_t	fntime;
 	FILE	   *fh;
 	bool       rotate_csvlog;
@@ -1214,9 +1214,6 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for)
 		fntime = next_rotation_time;
 	else
 		fntime = time(NULL);
-	filename = logfile_getname(fntime, NULL);
-	if (csvlogFile != NULL)
-		csvfilename = logfile_getname(fntime, ".csv");
 
 	/*
 	 * Decide whether to overwrite or append.  We can overwrite if (a)
@@ -1230,6 +1227,8 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for)
 		(size_rotation_for & LOG_DESTINATION_STDERR);
 	if (rotate_stderr)
 	{
+		filename = logfile_getname(fntime, NULL);
+
 		if (Log_truncate_on_rotation && time_based_rotation &&
 			last_file_name != NULL &&
 			strcmp(filename, last_file_name) != 0)
@@ -1252,10 +1251,7 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for)
 				rotation_disabled = true;
 			}
 
-			if (filename)
-				pfree(filename);
-			if (csvfilename)
-				pfree(csvfilename);
+			pfree(filename);
 			return;
 		}
 
@@ -1266,7 +1262,6 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for)
 		if (last_file_name != NULL)
 			pfree(last_file_name);
 		last_file_name = filename;
-		filename = NULL;
 	}
 
 	/* Same as above, but for csv file. */
@@ -1274,6 +1269,9 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for)
 		(time_based_rotation || (size_rotation_for & LOG_DESTINATION_CSVLOG));
 	if (rotate_csvlog)
 	{
+		if (csvlogFile != NULL)
+			csvfilename = logfile_getname(fntime, ".csv");
+
 		if (Log_truncate_on_rotation && time_based_rotation &&
 			last_csv_file_name != NULL &&
 			strcmp(csvfilename, last_csv_file_name) != 0)
@@ -1296,10 +1294,7 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for)
 				rotation_disabled = true;
 			}
 
-			if (filename)
-				pfree(filename);
-			if (csvfilename)
-				pfree(csvfilename);
+			pfree(csvfilename);
 			return;
 		}
 
@@ -1310,15 +1305,10 @@ logfile_rotate(bool time_based_rotation, int size_rotation_for)
 		if (last_csv_file_name != NULL)
 			pfree(last_csv_file_name);
 		last_csv_file_name = csvfilename;
-		csvfilename = NULL;
 	}
 
 	if (rotate_stderr || rotate_csvlog)
 		logfile_writename();
-	if (filename)
-		pfree(filename);
-	if (csvfilename)
-		pfree(csvfilename);
 
 	set_next_rotation_time();
 }