4 files changed, 28 insertions, 27 deletions

diff --git a/src/backend/utils/error/elog.c b/src/backend/utils/error/elog.c
index 6e8e5aef4e0..f0b3b1feb06 100644
--- a/src/backend/utils/error/elog.c
+++ b/src/backend/utils/error/elog.c
@@ -1805,24 +1805,20 @@ setup_formatted_log_time(void)
 {
 	struct timeval tv;
 	pg_time_t	stamp_time;
-	pg_tz	   *tz;
 	char		msbuf[8];
 
 	gettimeofday(&tv, NULL);
 	stamp_time = (pg_time_t) tv.tv_sec;
 
 	/*
-	 * Normally we print log timestamps in log_timezone, but during startup we
-	 * could get here before that's set. If so, fall back to gmt_timezone
-	 * (which guc.c ensures is set up before Log_line_prefix can become
-	 * nonempty).
+	 * Note: we expect that guc.c will ensure that log_timezone is set up
+	 * (at least with a minimal GMT value) before Log_line_prefix can become
+	 * nonempty or CSV mode can be selected.
 	 */
-	tz = log_timezone ? log_timezone : gmt_timezone;
-
 	pg_strftime(formatted_log_time, FORMATTED_TS_LEN,
 	/* leave room for milliseconds... */
 				"%Y-%m-%d %H:%M:%S     %Z",
-				pg_localtime(&stamp_time, tz));
+				pg_localtime(&stamp_time, log_timezone));
 
 	/* 'paste' milliseconds into place... */
 	sprintf(msbuf, ".%03d", (int) (tv.tv_usec / 1000));
@@ -1836,19 +1832,15 @@ static void
 setup_formatted_start_time(void)
 {
 	pg_time_t	stamp_time = (pg_time_t) MyStartTime;
-	pg_tz	   *tz;
 
 	/*
-	 * Normally we print log timestamps in log_timezone, but during startup we
-	 * could get here before that's set. If so, fall back to gmt_timezone
-	 * (which guc.c ensures is set up before Log_line_prefix can become
-	 * nonempty).
+	 * Note: we expect that guc.c will ensure that log_timezone is set up
+	 * (at least with a minimal GMT value) before Log_line_prefix can become
+	 * nonempty or CSV mode can be selected.
 	 */
-	tz = log_timezone ? log_timezone : gmt_timezone;
-
 	pg_strftime(formatted_start_time, FORMATTED_TS_LEN,
 				"%Y-%m-%d %H:%M:%S %Z",
-				pg_localtime(&stamp_time, tz));
+				pg_localtime(&stamp_time, log_timezone));
 }
 
 /*
@@ -1947,14 +1939,11 @@ log_line_prefix(StringInfo buf, ErrorData *edata)
 			case 't':
 				{
 					pg_time_t	stamp_time = (pg_time_t) time(NULL);
-					pg_tz	   *tz;
 					char		strfbuf[128];
 
-					tz = log_timezone ? log_timezone : gmt_timezone;
-
 					pg_strftime(strfbuf, sizeof(strfbuf),
 								"%Y-%m-%d %H:%M:%S %Z",
-								pg_localtime(&stamp_time, tz));
+								pg_localtime(&stamp_time, log_timezone));
 					appendStringInfoString(buf, strfbuf);
 				}
 				break;
diff --git a/src/backend/utils/misc/guc-file.l b/src/backend/utils/misc/guc-file.l
index 70abf40a28e..809307da8d3 100644
--- a/src/backend/utils/misc/guc-file.l
+++ b/src/backend/utils/misc/guc-file.l
@@ -292,7 +292,6 @@ ProcessConfigFile(GucContext context)
 	if (context == PGC_SIGHUP)
 	{
 		InitializeGUCOptionsFromEnvironment();
-		pg_timezone_initialize();
 		pg_timezone_abbrev_initialize();
 		/* this selects SQL_ASCII in processes not connected to a database */
 		SetConfigOption("client_encoding", GetDatabaseEncodingName(),
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index 6670997acde..a71729c2e70 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -187,6 +187,7 @@ static bool check_log_stats(bool *newval, void **extra, GucSource source);
 static bool check_canonical_path(char **newval, void **extra, GucSource source);
 static bool check_timezone_abbreviations(char **newval, void **extra, GucSource source);
 static void assign_timezone_abbreviations(const char *newval, void *extra);
+static void pg_timezone_abbrev_initialize(void);
 static const char *show_archive_command(void);
 static void assign_tcp_keepalives_idle(int newval, void *extra);
 static void assign_tcp_keepalives_interval(int newval, void *extra);
@@ -2547,7 +2548,7 @@ static struct config_string ConfigureNamesString[] =
 			NULL
 		},
 		&log_timezone_string,
-		NULL,
+		"GMT",
 		check_log_timezone, assign_log_timezone, show_log_timezone
 	},
 
@@ -2827,7 +2828,7 @@ static struct config_string ConfigureNamesString[] =
 			GUC_REPORT
 		},
 		&timezone_string,
-		NULL,
+		"GMT",
 		check_timezone, assign_timezone, show_timezone
 	},
 	{
@@ -3817,7 +3818,7 @@ InitializeGUCOptions(void)
 	 * Before log_line_prefix could possibly receive a nonempty setting, make
 	 * sure that timezone processing is minimally alive (see elog.c).
 	 */
-	pg_timezone_pre_initialize();
+	pg_timezone_initialize();
 
 	/*
 	 * Build sorted array of all GUC variables.
@@ -4115,6 +4116,15 @@ SelectConfigFiles(const char *userDoption, const char *progname)
 	SetConfigOption("data_directory", DataDir, PGC_POSTMASTER, PGC_S_OVERRIDE);
 
 	/*
+	 * If timezone_abbreviations wasn't set in the configuration file, install
+	 * the default value.  We do it this way because we can't safely install
+	 * a "real" value until my_exec_path is set, which may not have happened
+	 * when InitializeGUCOptions runs, so the bootstrap default value cannot
+	 * be the real desired default.
+	 */
+	pg_timezone_abbrev_initialize();
+
+	/*
 	 * Figure out where pg_hba.conf is, and make sure the path is absolute.
 	 */
 	if (HbaFileName)
@@ -8444,8 +8454,11 @@ assign_timezone_abbreviations(const char *newval, void *extra)
  * This is called after initial loading of postgresql.conf.  If no
  * timezone_abbreviations setting was found therein, select default.
  * If a non-default value is already installed, nothing will happen.
+ *
+ * This can also be called from ProcessConfigFile to establish the default
+ * value after a postgresql.conf entry for it is removed.
  */
-void
+static void
 pg_timezone_abbrev_initialize(void)
 {
 	SetConfigOption("timezone_abbreviations", "Default",
diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample
index e713defea2c..a18f14ae253 100644
--- a/src/backend/utils/misc/postgresql.conf.sample
+++ b/src/backend/utils/misc/postgresql.conf.sample
@@ -406,7 +406,7 @@
 #log_temp_files = -1			# log temporary files equal or larger
 					# than the specified size in kilobytes;
 					# -1 disables, 0 logs all temp files
-#log_timezone = '(defaults to server environment setting)'
+#log_timezone = 'GMT'
 
 
 #------------------------------------------------------------------------------
@@ -486,7 +486,7 @@
 
 #datestyle = 'iso, mdy'
 #intervalstyle = 'postgres'
-#timezone = '(defaults to server environment setting)'
+#timezone = 'GMT'
 #timezone_abbreviations = 'Default'     # Select the set of available time zone
 					# abbreviations.  Currently, there are
 					#   Default