fix stats_fetch_consistency value in postgresql.conf.sample

From d06e248ced6a45aa10badae9b223e016605e61c5 Mon Sep 17 00:00:00 2001
From: Kyotaro Horiguchi <horikyota.ntt@gmail.com>
Date: Thu, 26 May 2022 15:55:34 +0900
Subject: [PATCH] Add fileval-bootval consistency check of GUC parameters

We should keep GUC variables consistent between the default values
written in postgresql.conf.sample and defined in guc.c. Add an
automated way to check for the consistency to the TAP test suite. Some
variables are still excluded since they cannot be checked simple way.
---
 src/test/modules/test_misc/t/003_check_guc.pl | 151 +++++++++++++++++-
 1 file changed, 146 insertions(+), 5 deletions(-)

diff --git a/src/test/modules/test_misc/t/003_check_guc.pl b/src/test/modules/test_misc/t/003_check_guc.pl
index 60459ef759..efaa7ec182 100644
--- a/src/test/modules/test_misc/t/003_check_guc.pl
+++ b/src/test/modules/test_misc/t/003_check_guc.pl
@@ -11,18 +11,65 @@ my $node = PostgreSQL::Test::Cluster->new('main');
 $node->init;
 $node->start;
 
+# unit conversion factors
+my %unit_conv_factor =
+  ('b', 1,
+   'kb',  1024,
+   'mb',  1024 * 1024,
+   'gb',  1024 * 1024 * 1024,
+   'tb',  1024 * 1024 * 1024 * 1024,
+   '8kb', 8 * 1024,
+   'us',  1.0 / (1000 / 1000),
+   'ms',  1.0 / 1000,
+   's',   1,
+   'min', 60,
+   'h',   3600,
+   'd',   24 * 3600);
+
+# parameter names that cannot get consistency check performed
+my @ignored_parameters =
+  ('data_directory',
+   'hba_file',
+   'ident_file',
+   'krb_server_keyfile',
+   'max_stack_depth',
+   'bgwriter_flush_after',
+   'wal_sync_method',
+   'checkpoint_flush_after',
+   'timezone_abbreviations',
+   'lc_messages');
+
+# parameter names that requires case-insensitive check
+my @case_insensitive_params =
+  ('ssl_ciphers',
+   'log_filename',
+   'event_source',
+   'log_timezone',
+   'timezone',
+   'lc_monetary',
+   'lc_numeric',
+   'lc_time');
+
 # Grab the names of all the parameters that can be listed in the
 # configuration sample file.  config_file is an exception, it is not
 # in postgresql.conf.sample but is part of the lists from guc.c.
 my $all_params = $node->safe_psql(
 	'postgres',
-	"SELECT name
+	"SELECT name, vartype, unit, boot_val, '!'
      FROM pg_settings
    WHERE NOT 'NOT_IN_SAMPLE' = ANY (pg_settings_get_flags(name)) AND
        name <> 'config_file'
      ORDER BY 1");
 # Note the lower-case conversion, for consistency.
-my @all_params_array = split("\n", lc($all_params));
+my %all_params_hash;
+foreach my $line (split("\n", lc($all_params)))
+{
+	my @f = split('\|', $line);
+	fail("query returned wrong number of columns: $#f : $line") if ($#f != 4);
+	$all_params_hash{$f[0]}->{type} = $f[1];
+	$all_params_hash{$f[0]}->{unit} = $f[2];
+	$all_params_hash{$f[0]}->{bootval} = $f[3];
+}
 
 # Grab the names of all parameters marked as NOT_IN_SAMPLE.
 my $not_in_sample = $node->safe_psql(
@@ -44,6 +91,7 @@ my @gucs_in_file;
 # Read the sample file line-by-line, checking its contents to build a list
 # of everything known as a GUC.
 my $num_tests = 0;
+my $failed = 0;
 open(my $contents, '<', $sample_file)
   || die "Could not open $sample_file: $!";
 while (my $line = <$contents>)
@@ -53,11 +101,16 @@ while (my $line = <$contents>)
 	# file.
 	# - Valid configuration options are followed immediately by " = ",
 	# with one space before and after the equal sign.
-	if ($line =~ m/^#?([_[:alpha:]]+) = .*/)
+	if ($line =~ m/^#?([_[:alpha:]]+) = (.*)$/)
 	{
 		# Lower-case conversion matters for some of the GUCs.
 		my $param_name = lc($1);
 
+		# extract value
+		my $file_value = $2;
+		$file_value =~ s/\s*#.*$//;		# strip trailing comment
+		$file_value =~ s/^'(.*)'$/$1/;	# strip quotes
+
 		# Ignore some exceptions.
 		next if $param_name eq "include";
 		next if $param_name eq "include_dir";
@@ -66,19 +119,28 @@ while (my $line = <$contents>)
 		# Update the list of GUCs found in the sample file, for the
 		# follow-up tests.
 		push @gucs_in_file, $param_name;
+
+		# Check for consistency between bootval and file value.
+		$failed++
+		  if (!check_val($param_name,
+						 $all_params_hash{$param_name}->{type},
+						 $all_params_hash{$param_name}->{bootval},
+						 $all_params_hash{$param_name}->{unit},
+						 $file_value));
 	}
 }
 
 close $contents;
 
+pass("fileval-bootval consistency is fine") if ($failed == 0);
+
 # Cross-check that all the GUCs found in the sample file match the ones
 # fetched above.  This maps the arrays to a hash, making the creation of
 # each exclude and intersection list easier.
 my %gucs_in_file_hash  = map { $_ => 1 } @gucs_in_file;
-my %all_params_hash    = map { $_ => 1 } @all_params_array;
 my %not_in_sample_hash = map { $_ => 1 } @not_in_sample_array;
 
-my @missing_from_file = grep(!$gucs_in_file_hash{$_}, @all_params_array);
+my @missing_from_file = grep(!$gucs_in_file_hash{$_}, keys %all_params_hash);
 is(scalar(@missing_from_file),
 	0, "no parameters missing from postgresql.conf.sample");
 
@@ -108,3 +170,82 @@ foreach my $param (@sample_intersect)
 }
 
 done_testing();
+
+
+# parse $val according to $type.
+# $val may be suffixed by a unit if $optunit is not given.
+sub parse_val
+{
+	my ($type, $val, $optunit) = @_;
+
+	if ($val =~ /^(\d+)([a-zA-Z]*)$/)
+	{
+		$val = $1;
+		my $unit = $2;
+
+		# integer allows octal representaion
+		$val = oct($val) if ($type eq "integer" && $val =~ /^0./);
+
+		# accept $optunit only if $val was not suffixed by a unit
+		if (length $optunit)
+		{
+			fail("check if unit \"$unit\" is known to this script")
+			  if (length $unit);
+			
+			$unit = $optunit;
+		}
+
+
+		if (length($unit))
+		{
+			$unit = lc($unit);
+
+			fail("check if unit \"$unit\" is known to this script")
+			  if (!defined $unit_conv_factor{$unit});
+
+			$val *= $unit_conv_factor{$unit};
+		}
+	}
+
+	return $val;
+}
+
+# check if $bootval and $fileval match according to $type and $unit
+sub check_val
+{
+	my ($param_name, $type, $bootval, $unit, $fileval) = @_;
+
+	my $match = 0;
+	
+	if (grep { $_ eq $param_name } @ignored_parameters)
+	{
+		# this parameter cannot be checked, skip.
+		$match = 1;
+	}
+	elsif ($type eq "integer" || $type eq "real")
+	{
+		# this parameter is numeric, parse with unit conversion
+		my $bootval = parse_val($type, $bootval, $unit);
+		my $fileval = parse_val($type, $fileval);
+	
+		$match = 1 if ($bootval == $fileval);
+	}
+	elsif (($type eq "bool" || $type eq "enum") ||
+		   grep { $_ eq $param_name} @case_insensitive_params)
+	{
+		# this parameter is compared case-insensitively
+		$match = 1 if (lc($bootval) eq lc($fileval));
+	}
+	else
+	{
+		# exact match
+		$match = 1 if ($bootval eq $fileval);
+	}
+
+	if (!$match)
+	{
+		fail("$param_name inconsistent (\"$bootval\" vs \"$fileval\")");
+	}
+
+	return $match;
+}
-- 
2.31.1

From 1e52b23111b5e8860092dcfea0ac9459f1725f0d Mon Sep 17 00:00:00 2001
From: Kyotaro Horiguchi <horikyota.ntt@gmail.com>
Date: Mon, 30 May 2022 16:11:34 +0900
Subject: [PATCH v2] Add fileval-bootval consistency check of GUC parameters

We should keep GUC variables consistent between the default values
written in postgresql.conf.sample and defined in guc.c. Add an
automated way to check for the consistency to the TAP test suite. Some
variables are still excluded since they cannot be checked simple way.
---
 src/backend/utils/misc/guc.c                  | 70 +++++++++++++++++++
 src/backend/utils/misc/postgresql.conf.sample |  6 +-
 src/include/catalog/pg_proc.dat               |  5 ++
 src/test/modules/test_misc/t/003_check_guc.pl | 55 +++++++++++++--
 4 files changed, 127 insertions(+), 9 deletions(-)

diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index 55d41ae7d6..cd47dede1a 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -7514,6 +7514,76 @@ parse_and_validate_value(struct config_generic *record,
 	return true;
 }
 
+/*
+ * Helper function for pg_normalize_config_value().
+ * Makes a palloced copy of src then link val to it.
+ * DO NOT destroy val while dst is in use.
+ */
+static struct config_generic *
+copy_config_and_set_value(struct config_generic *src, union config_var_val *val)
+{
+	struct config_generic *dst;
+
+#define CREATE_CONFIG_COPY(dst, src, t)	\
+	dst = palloc(sizeof(struct t));				\
+	*(struct t *) dst = *(struct t *) src;		\
+	
+	switch (src->vartype)
+	{
+		case PGC_BOOL:
+			CREATE_CONFIG_COPY(dst, src, config_bool);
+			((struct config_bool *)dst)->variable = &val->boolval;
+			break;
+		case PGC_INT:
+			CREATE_CONFIG_COPY(dst, src, config_int);
+			((struct config_int *)dst)->variable = &val->intval;
+			break;
+		case PGC_REAL:
+			CREATE_CONFIG_COPY(dst, src, config_real);
+			((struct config_real *)dst)->variable = &val->realval;
+			break;
+		case PGC_STRING:
+			CREATE_CONFIG_COPY(dst, src, config_string);
+			((struct config_string *)dst)->variable = &val->stringval;
+			break;
+		case PGC_ENUM:
+			CREATE_CONFIG_COPY(dst, src, config_enum);
+			((struct config_enum *)dst)->variable = &val->enumval;
+			break;
+	}
+
+	return dst;
+}
+
+
+/*
+ * Normalize given value according to the specified GUC variable
+ */
+Datum
+pg_normalize_config_value(PG_FUNCTION_ARGS)
+{
+	char   *name = "";
+	char   *value = "";
+	struct config_generic *record;
+	char   *result;
+	void   *extra;
+	union config_var_val altval;
+
+	if (!PG_ARGISNULL(0))
+		name = text_to_cstring(PG_GETARG_TEXT_PP(0));
+	if (!PG_ARGISNULL(1))
+		value = text_to_cstring(PG_GETARG_TEXT_PP(1));
+
+	record = find_option(name, true, false, ERROR);
+
+	parse_and_validate_value(record, name, value, PGC_S_TEST, WARNING,
+							 &altval, &extra);
+	record = copy_config_and_set_value(record, &altval);
+
+	result = _ShowOption(record, true);
+
+	PG_RETURN_TEXT_P(cstring_to_text(result));
+}
 
 /*
  * Sets option `name' to given value.
diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample
index 48ad80cf2e..a6d5e401a9 100644
--- a/src/backend/utils/misc/postgresql.conf.sample
+++ b/src/backend/utils/misc/postgresql.conf.sample
@@ -476,7 +476,7 @@
 					# in all cases.
 
 # These are relevant when logging to syslog:
-#syslog_facility = 'LOCAL0'
+#syslog_facility = 'local0'
 #syslog_ident = 'postgres'
 #syslog_sequence_numbers = on
 #syslog_split_messages = on
@@ -709,7 +709,7 @@
 
 # - Locale and Formatting -
 
-#datestyle = 'iso, mdy'
+#datestyle = 'ISO, MDY'
 #intervalstyle = 'postgres'
 #timezone = 'GMT'
 #timezone_abbreviations = 'Default'     # Select the set of available time zone
@@ -721,7 +721,7 @@
 					# share/timezonesets/.
 #extra_float_digits = 1			# min -15, max 3; any value >0 actually
 					# selects precise output mode
-#client_encoding = sql_ascii		# actually, defaults to database
+#client_encoding = SQL_ASCII		# actually, defaults to database
 					# encoding
 
 # These settings are initialized by initdb, but they can be changed.
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 87aa571a33..c089b351e9 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6118,6 +6118,11 @@
   proname => 'pg_settings_get_flags', provolatile => 's', prorettype => '_text',
   proargtypes => 'text', prosrc => 'pg_settings_get_flags' },
 
+{ oid => '9956', descr => 'normalize value to the unit of specified GUC',
+  proname => 'pg_normalize_config_value', proisstrict => 'f',
+  provolatile => 's', prorettype => 'text', proargtypes => 'text text',
+  proargnames => '{varname,value}', prosrc => 'pg_normalize_config_value' },
+
 { oid => '3329', descr => 'show config file settings',
   proname => 'pg_show_all_file_settings', prorows => '1000', proretset => 't',
   provolatile => 'v', prorettype => 'record', proargtypes => '',
diff --git a/src/test/modules/test_misc/t/003_check_guc.pl b/src/test/modules/test_misc/t/003_check_guc.pl
index 60459ef759..a92206942f 100644
--- a/src/test/modules/test_misc/t/003_check_guc.pl
+++ b/src/test/modules/test_misc/t/003_check_guc.pl
@@ -11,18 +11,40 @@ my $node = PostgreSQL::Test::Cluster->new('main');
 $node->init;
 $node->start;
 
+# parameter names that cannot get consistency check performed
+my @ignored_parameters = (
+	'data_directory',
+	'hba_file',
+	'ident_file',
+	'krb_server_keyfile',
+	'max_stack_depth',
+	'bgwriter_flush_after',
+	'wal_sync_method',
+	'checkpoint_flush_after',
+	'timezone_abbreviations',
+	'lc_messages'
+  );
+
 # Grab the names of all the parameters that can be listed in the
 # configuration sample file.  config_file is an exception, it is not
 # in postgresql.conf.sample but is part of the lists from guc.c.
 my $all_params = $node->safe_psql(
 	'postgres',
-	"SELECT name
+	"SELECT lower(name), vartype, unit, boot_val, '!'
      FROM pg_settings
    WHERE NOT 'NOT_IN_SAMPLE' = ANY (pg_settings_get_flags(name)) AND
        name <> 'config_file'
      ORDER BY 1");
 # Note the lower-case conversion, for consistency.
-my @all_params_array = split("\n", lc($all_params));
+my %all_params_hash;
+foreach my $line (split("\n", $all_params))
+{
+	my @f = split('\|', $line);
+	fail("query returned wrong number of columns: $#f : $line") if ($#f != 4);
+	$all_params_hash{$f[0]}->{type} = $f[1];
+	$all_params_hash{$f[0]}->{unit} = $f[2];
+	$all_params_hash{$f[0]}->{bootval} = $f[3];
+}
 
 # Grab the names of all parameters marked as NOT_IN_SAMPLE.
 my $not_in_sample = $node->safe_psql(
@@ -43,7 +65,7 @@ my @gucs_in_file;
 
 # Read the sample file line-by-line, checking its contents to build a list
 # of everything known as a GUC.
-my $num_tests = 0;
+my @check_elems = ();
 open(my $contents, '<', $sample_file)
   || die "Could not open $sample_file: $!";
 while (my $line = <$contents>)
@@ -53,11 +75,16 @@ while (my $line = <$contents>)
 	# file.
 	# - Valid configuration options are followed immediately by " = ",
 	# with one space before and after the equal sign.
-	if ($line =~ m/^#?([_[:alpha:]]+) = .*/)
+	if ($line =~ m/^#?([_[:alpha:]]+) = (.*)$/)
 	{
 		# Lower-case conversion matters for some of the GUCs.
 		my $param_name = lc($1);
 
+		# extract value
+		my $file_value = $2;
+		$file_value =~ s/\s*#.*$//;		# strip trailing comment
+		$file_value =~ s/^'(.*)'$/$1/;	# strip quotes
+
 		# Ignore some exceptions.
 		next if $param_name eq "include";
 		next if $param_name eq "include_dir";
@@ -66,19 +93,35 @@ while (my $line = <$contents>)
 		# Update the list of GUCs found in the sample file, for the
 		# follow-up tests.
 		push @gucs_in_file, $param_name;
+
+		# Check for consistency between bootval and file value.
+		if (!grep { $_ eq $param_name } @ignored_parameters)
+		{
+			push (@check_elems, "('$param_name','$file_value')");
+		}
 	}
 }
 
 close $contents;
 
+# run consistency check between config-file's default value and boot values.
+my $check_query =
+  'SELECT f.n, f.v, s.boot_val FROM (VALUES '.
+  join(',', @check_elems).
+  ') f(n,v) JOIN pg_settings s ON s.name = f.n '.
+  'WHERE pg_normalize_config_value(f.n, f.v) <> '.
+  'pg_normalize_config_value(f.n, s.boot_val)';
+
+is ($node->safe_psql('postgres', $check_query), '',
+	'check if fileval-bootval consistency is fine');
+
 # Cross-check that all the GUCs found in the sample file match the ones
 # fetched above.  This maps the arrays to a hash, making the creation of
 # each exclude and intersection list easier.
 my %gucs_in_file_hash  = map { $_ => 1 } @gucs_in_file;
-my %all_params_hash    = map { $_ => 1 } @all_params_array;
 my %not_in_sample_hash = map { $_ => 1 } @not_in_sample_array;
 
-my @missing_from_file = grep(!$gucs_in_file_hash{$_}, @all_params_array);
+my @missing_from_file = grep(!$gucs_in_file_hash{$_}, keys %all_params_hash);
 is(scalar(@missing_from_file),
 	0, "no parameters missing from postgresql.conf.sample");
 
-- 
2.31.1

From 7ffa4f5f59564880107ffc3fa0bbd631e020054e Mon Sep 17 00:00:00 2001
From: Kyotaro Horiguchi <horikyota.ntt@gmail.com>
Date: Thu, 16 Jun 2022 17:08:02 +0900
Subject: [PATCH v2] Add fileval-bootval consistency check of GUC parameters

We should keep GUC variables consistent between the default values
written in postgresql.conf.sample and defined in guc.c. Add an
automated way to check for the consistency to the TAP test suite. Some
variables are still excluded since they cannot be checked simple way.
---
 src/backend/utils/misc/guc.c                  | 53 ++++++++++++++++
 src/include/catalog/pg_proc.dat               |  5 ++
 src/test/modules/test_misc/t/003_check_guc.pl | 60 +++++++++++++++++--
 3 files changed, 112 insertions(+), 6 deletions(-)

diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index a7cc49898b..7b8b3a4417 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -7520,6 +7520,59 @@ parse_and_validate_value(struct config_generic *record,
 	return true;
 }
 
+/*
+ * Convert value to unitless value according to the specified GUC variable
+ */
+Datum
+pg_config_unitless_value(PG_FUNCTION_ARGS)
+{
+	char   *name = "";
+	char   *value = "";
+	struct config_generic *record;
+	char   *result;
+	void   *extra;
+	union config_var_val val;
+	const char *p;
+	char   buffer[256];
+
+	if (!PG_ARGISNULL(0))
+		name = text_to_cstring(PG_GETARG_TEXT_PP(0));
+	if (!PG_ARGISNULL(1))
+		value = text_to_cstring(PG_GETARG_TEXT_PP(1));
+
+	record = find_option(name, true, false, ERROR);
+
+	parse_and_validate_value(record, name, value, PGC_S_TEST, WARNING,
+							 &val, &extra);
+
+	switch (record->vartype)
+	{
+		case PGC_BOOL:
+			result = (val.boolval ? "on" : "off");
+			break;
+		case PGC_INT:
+			snprintf(buffer, sizeof(buffer), "%d", val.intval);
+			result = pstrdup(buffer);
+			break;
+		case PGC_REAL:
+			snprintf(buffer, sizeof(buffer), "%g", val.realval);
+			result = pstrdup(buffer);
+			break;
+		case PGC_STRING:
+			p = val.stringval;
+			if (p == NULL)
+				p = "";
+			result = pstrdup(p);
+			break;
+		case PGC_ENUM:
+			p = config_enum_lookup_by_value((struct config_enum *)record,
+											val.boolval);
+			result = pstrdup(p);
+			break;
+	}
+
+	PG_RETURN_TEXT_P(cstring_to_text(result));
+}
 
 /*
  * Sets option `name' to given value.
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 87aa571a33..9eb2a584e1 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6118,6 +6118,11 @@
   proname => 'pg_settings_get_flags', provolatile => 's', prorettype => '_text',
   proargtypes => 'text', prosrc => 'pg_settings_get_flags' },
 
+{ oid => '9956', descr => 'normalize value to the unit of specified GUC',
+  proname => 'pg_config_unitless_value', proisstrict => 'f',
+  provolatile => 's', prorettype => 'text', proargtypes => 'text text',
+  proargnames => '{varname,value}', prosrc => 'pg_config_unitless_value' },
+
 { oid => '3329', descr => 'show config file settings',
   proname => 'pg_show_all_file_settings', prorows => '1000', proretset => 't',
   provolatile => 'v', prorettype => 'record', proargtypes => '',
diff --git a/src/test/modules/test_misc/t/003_check_guc.pl b/src/test/modules/test_misc/t/003_check_guc.pl
index 60459ef759..9de6a386de 100644
--- a/src/test/modules/test_misc/t/003_check_guc.pl
+++ b/src/test/modules/test_misc/t/003_check_guc.pl
@@ -11,18 +11,41 @@ my $node = PostgreSQL::Test::Cluster->new('main');
 $node->init;
 $node->start;
 
+# parameter names that cannot get consistency check performed
+my @ignored_parameters = (
+	'data_directory',
+	'hba_file',
+	'ident_file',
+	'krb_server_keyfile',
+	'max_stack_depth',
+	'bgwriter_flush_after',
+	'wal_sync_method',
+	'checkpoint_flush_after',
+	'timezone_abbreviations',
+	'lc_messages',
+	'wal_buffers'
+  );
+
 # Grab the names of all the parameters that can be listed in the
 # configuration sample file.  config_file is an exception, it is not
 # in postgresql.conf.sample but is part of the lists from guc.c.
 my $all_params = $node->safe_psql(
 	'postgres',
-	"SELECT name
+	"SELECT lower(name), vartype, unit, boot_val, '!'
      FROM pg_settings
    WHERE NOT 'NOT_IN_SAMPLE' = ANY (pg_settings_get_flags(name)) AND
        name <> 'config_file'
      ORDER BY 1");
 # Note the lower-case conversion, for consistency.
-my @all_params_array = split("\n", lc($all_params));
+my %all_params_hash;
+foreach my $line (split("\n", $all_params))
+{
+	my @f = split('\|', $line);
+	fail("query returned wrong number of columns: $#f : $line") if ($#f != 4);
+	$all_params_hash{$f[0]}->{type} = $f[1];
+	$all_params_hash{$f[0]}->{unit} = $f[2];
+	$all_params_hash{$f[0]}->{bootval} = $f[3];
+}
 
 # Grab the names of all parameters marked as NOT_IN_SAMPLE.
 my $not_in_sample = $node->safe_psql(
@@ -43,7 +66,7 @@ my @gucs_in_file;
 
 # Read the sample file line-by-line, checking its contents to build a list
 # of everything known as a GUC.
-my $num_tests = 0;
+my @check_elems = ();
 open(my $contents, '<', $sample_file)
   || die "Could not open $sample_file: $!";
 while (my $line = <$contents>)
@@ -53,11 +76,16 @@ while (my $line = <$contents>)
 	# file.
 	# - Valid configuration options are followed immediately by " = ",
 	# with one space before and after the equal sign.
-	if ($line =~ m/^#?([_[:alpha:]]+) = .*/)
+	if ($line =~ m/^#?([_[:alpha:]]+) = (.*)$/)
 	{
 		# Lower-case conversion matters for some of the GUCs.
 		my $param_name = lc($1);
 
+		# extract value
+		my $file_value = $2;
+		$file_value =~ s/\s*#.*$//;		# strip trailing comment
+		$file_value =~ s/^'(.*)'$/$1/;	# strip quotes
+
 		# Ignore some exceptions.
 		next if $param_name eq "include";
 		next if $param_name eq "include_dir";
@@ -66,19 +94,39 @@ while (my $line = <$contents>)
 		# Update the list of GUCs found in the sample file, for the
 		# follow-up tests.
 		push @gucs_in_file, $param_name;
+
+		# Check for consistency between bootval and file value.
+		if (!grep { $_ eq $param_name } @ignored_parameters)
+		{
+			push (@check_elems, "('$param_name','$file_value')");
+		}
 	}
 }
 
 close $contents;
 
+# Run consistency check between config-file's default value and boot
+# values.  To show sample setting that is not found in the view, use
+# LEFT JOIN and make sure pg_settings.name is not NULL.
+my $check_query =
+  'SELECT f.n, f.v, s.boot_val FROM (VALUES '.
+  join(',', @check_elems).
+  ') f(n,v) LEFT JOIN pg_settings s ON lower(s.name) = f.n '.
+  "WHERE pg_config_unitless_value(f.n, f.v) <> COALESCE(s.boot_val, '') ".
+  'OR s.name IS NULL';
+
+print $check_query;
+
+is ($node->safe_psql('postgres', $check_query), '',
+	'check if fileval-bootval consistency is fine');
+
 # Cross-check that all the GUCs found in the sample file match the ones
 # fetched above.  This maps the arrays to a hash, making the creation of
 # each exclude and intersection list easier.
 my %gucs_in_file_hash  = map { $_ => 1 } @gucs_in_file;
-my %all_params_hash    = map { $_ => 1 } @all_params_array;
 my %not_in_sample_hash = map { $_ => 1 } @not_in_sample_array;
 
-my @missing_from_file = grep(!$gucs_in_file_hash{$_}, @all_params_array);
+my @missing_from_file = grep(!$gucs_in_file_hash{$_}, keys %all_params_hash);
 is(scalar(@missing_from_file),
 	0, "no parameters missing from postgresql.conf.sample");
 
-- 
2.31.1

From 4385545514099eb94c1a624d2a082e544ca9c6bc Mon Sep 17 00:00:00 2001
From: Kyotaro Horiguchi <horikyota.ntt@gmail.com>
Date: Thu, 16 Jun 2022 17:00:14 +0900
Subject: [PATCH] Add fileval-bootval consistency check of GUC parameters

We should keep GUC variables consistent between the default values
written in postgresql.conf.sample and defined in guc.c. Add an
automated way to check for the consistency to the TAP test suite.
For simplicity we don't check values that require unit conversion.
Some variables are still excluded since they cannot be checked simple
way.
---
 src/test/modules/test_misc/t/003_check_guc.pl | 76 +++++++++++++++++--
 1 file changed, 70 insertions(+), 6 deletions(-)

diff --git a/src/test/modules/test_misc/t/003_check_guc.pl b/src/test/modules/test_misc/t/003_check_guc.pl
index 60459ef759..a3334fad76 100644
--- a/src/test/modules/test_misc/t/003_check_guc.pl
+++ b/src/test/modules/test_misc/t/003_check_guc.pl
@@ -11,18 +11,39 @@ my $node = PostgreSQL::Test::Cluster->new('main');
 $node->init;
 $node->start;
 
+# parameter names that cannot get consistency check performed
+my @ignored_parameters = (
+	'data_directory',
+	'hba_file',
+	'ident_file',
+	'krb_server_keyfile',
+	'timezone_abbreviations',
+	'lc_messages',
+	'log_file_mode',
+	'unix_socket_permissions',
+	'wal_sync_method'
+  );
+
 # Grab the names of all the parameters that can be listed in the
 # configuration sample file.  config_file is an exception, it is not
 # in postgresql.conf.sample but is part of the lists from guc.c.
 my $all_params = $node->safe_psql(
 	'postgres',
-	"SELECT name
+	"SELECT lower(name), vartype, unit, boot_val, '!'
      FROM pg_settings
    WHERE NOT 'NOT_IN_SAMPLE' = ANY (pg_settings_get_flags(name)) AND
        name <> 'config_file'
      ORDER BY 1");
 # Note the lower-case conversion, for consistency.
-my @all_params_array = split("\n", lc($all_params));
+my %all_params_hash;
+foreach my $line (split("\n", $all_params))
+{
+	my @f = split('\|', $line);
+	fail("query returned wrong number of columns: $#f : $line") if ($#f != 4);
+	$all_params_hash{$f[0]}->{type} = $f[1];
+	$all_params_hash{$f[0]}->{unit} = $f[2];
+	$all_params_hash{$f[0]}->{bootval} = $f[3];
+}
 
 # Grab the names of all parameters marked as NOT_IN_SAMPLE.
 my $not_in_sample = $node->safe_psql(
@@ -43,7 +64,7 @@ my @gucs_in_file;
 
 # Read the sample file line-by-line, checking its contents to build a list
 # of everything known as a GUC.
-my $num_tests = 0;
+my @check_elems = ();
 open(my $contents, '<', $sample_file)
   || die "Could not open $sample_file: $!";
 while (my $line = <$contents>)
@@ -53,11 +74,16 @@ while (my $line = <$contents>)
 	# file.
 	# - Valid configuration options are followed immediately by " = ",
 	# with one space before and after the equal sign.
-	if ($line =~ m/^#?([_[:alpha:]]+) = .*/)
+	if ($line =~ m/^#?([_[:alpha:]]+) = (.*)$/)
 	{
 		# Lower-case conversion matters for some of the GUCs.
 		my $param_name = lc($1);
 
+		# extract value
+		my $file_value = $2;
+		$file_value =~ s/\s*#.*$//;		# strip trailing comment
+		$file_value =~ s/^'(.*)'$/$1/;	# strip quotes
+
 		# Ignore some exceptions.
 		next if $param_name eq "include";
 		next if $param_name eq "include_dir";
@@ -66,19 +92,57 @@ while (my $line = <$contents>)
 		# Update the list of GUCs found in the sample file, for the
 		# follow-up tests.
 		push @gucs_in_file, $param_name;
+
+		# Check for consistency between bootval and file value.
+		if (!grep { $_ eq $param_name } @ignored_parameters)
+		{
+			push (@check_elems, "('$param_name','$file_value')");
+		}
 	}
 }
 
 close $contents;
 
+# Run consistency check between config-file's default value and boot
+# values.  For now we check only variables in string and integers
+# without unit.
+my $check_query =
+  'SELECT f.n, f.v, s.boot_val FROM (VALUES '.
+  join(',', @check_elems).
+  ') f(n,v) LEFT JOIN pg_settings s ON lower(s.name) = f.n '.
+  "WHERE (lower(f.v) <> COALESCE(lower(s.boot_val), '') ".
+  "       AND (s.vartype = 'string' OR s.vartype = 'enum'))".
+  'OR s.name IS NULL';
+
+is ($node->safe_psql('postgres', $check_query), '',
+	'check if fileval-bootval consistency is fine for string variables');
+
+$check_query =
+  'SELECT f.n, f.v, s.boot_val FROM (VALUES '.
+  join(',', @check_elems).
+  ') f(n,v) LEFT JOIN pg_settings s ON lower(s.name) = f.n '.
+  "WHERE ((s.vartype = 'integer' AND s.unit IS NULL) AND f.v <> s.boot_val) ".
+  'OR s.name IS NULL';
+is ($node->safe_psql('postgres', $check_query), '',
+	'check if fileval-bootval consistency is fine for integer variables');
+
+$check_query =
+  'SELECT f.n, f.v, s.boot_val FROM (VALUES '.
+  join(',', @check_elems).
+  ') f(n,v) LEFT JOIN pg_settings s ON lower(s.name) = f.n '.
+  "WHERE ((s.vartype = 'real' AND s.unit IS NULL) ".
+  "        AND (f.v::real <> s.boot_val::real)) ".
+  'OR s.name IS NULL';
+is ($node->safe_psql('postgres', $check_query), '',
+	'check if fileval-bootval consistency is fine for real variables');
+
 # Cross-check that all the GUCs found in the sample file match the ones
 # fetched above.  This maps the arrays to a hash, making the creation of
 # each exclude and intersection list easier.
 my %gucs_in_file_hash  = map { $_ => 1 } @gucs_in_file;
-my %all_params_hash    = map { $_ => 1 } @all_params_array;
 my %not_in_sample_hash = map { $_ => 1 } @not_in_sample_array;
 
-my @missing_from_file = grep(!$gucs_in_file_hash{$_}, @all_params_array);
+my @missing_from_file = grep(!$gucs_in_file_hash{$_}, keys %all_params_hash);
 is(scalar(@missing_from_file),
 	0, "no parameters missing from postgresql.conf.sample");
 
-- 
2.31.1

From d67c13712ab1d47956c1c311d7ed80342fa51e2f Mon Sep 17 00:00:00 2001
From: Kyotaro Horiguchi <horikyota.ntt@gmail.com>
Date: Thu, 16 Jun 2022 17:08:02 +0900
Subject: [PATCH v3] Add fileval-bootval consistency check of GUC parameters

We should keep GUC variables consistent between the default values
written in postgresql.conf.sample and defined in guc.c. Add an
automated way to check for the consistency to the TAP test suite. Some
variables are still excluded since they cannot be checked simple way.
---
 src/backend/utils/misc/guc.c                  | 53 ++++++++++++++++
 src/include/catalog/pg_proc.dat               |  5 ++
 src/test/modules/test_misc/t/003_check_guc.pl | 60 +++++++++++++++++--
 3 files changed, 112 insertions(+), 6 deletions(-)

diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index a7cc49898b..136a21ba88 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -7520,6 +7520,59 @@ parse_and_validate_value(struct config_generic *record,
 	return true;
 }
 
+/*
+ * Convert value to unitless value according to the specified GUC variable
+ */
+Datum
+pg_config_unitless_value(PG_FUNCTION_ARGS)
+{
+	char   *name = "";
+	char   *value = "";
+	struct config_generic *record;
+	char   *result = "";
+	void   *extra;
+	union config_var_val val;
+	const char *p;
+	char   buffer[256];
+
+	if (!PG_ARGISNULL(0))
+		name = text_to_cstring(PG_GETARG_TEXT_PP(0));
+	if (!PG_ARGISNULL(1))
+		value = text_to_cstring(PG_GETARG_TEXT_PP(1));
+
+	record = find_option(name, true, false, ERROR);
+
+	parse_and_validate_value(record, name, value, PGC_S_TEST, WARNING,
+							 &val, &extra);
+
+	switch (record->vartype)
+	{
+		case PGC_BOOL:
+			result = (val.boolval ? "on" : "off");
+			break;
+		case PGC_INT:
+			snprintf(buffer, sizeof(buffer), "%d", val.intval);
+			result = pstrdup(buffer);
+			break;
+		case PGC_REAL:
+			snprintf(buffer, sizeof(buffer), "%g", val.realval);
+			result = pstrdup(buffer);
+			break;
+		case PGC_STRING:
+			p = val.stringval;
+			if (p == NULL)
+				p = "";
+			result = pstrdup(p);
+			break;
+		case PGC_ENUM:
+			p = config_enum_lookup_by_value((struct config_enum *)record,
+											val.boolval);
+			result = pstrdup(p);
+			break;
+	}
+
+	PG_RETURN_TEXT_P(cstring_to_text(result));
+}
 
 /*
  * Sets option `name' to given value.
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 87aa571a33..9eb2a584e1 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6118,6 +6118,11 @@
   proname => 'pg_settings_get_flags', provolatile => 's', prorettype => '_text',
   proargtypes => 'text', prosrc => 'pg_settings_get_flags' },
 
+{ oid => '9956', descr => 'normalize value to the unit of specified GUC',
+  proname => 'pg_config_unitless_value', proisstrict => 'f',
+  provolatile => 's', prorettype => 'text', proargtypes => 'text text',
+  proargnames => '{varname,value}', prosrc => 'pg_config_unitless_value' },
+
 { oid => '3329', descr => 'show config file settings',
   proname => 'pg_show_all_file_settings', prorows => '1000', proretset => 't',
   provolatile => 'v', prorettype => 'record', proargtypes => '',
diff --git a/src/test/modules/test_misc/t/003_check_guc.pl b/src/test/modules/test_misc/t/003_check_guc.pl
index 60459ef759..9de6a386de 100644
--- a/src/test/modules/test_misc/t/003_check_guc.pl
+++ b/src/test/modules/test_misc/t/003_check_guc.pl
@@ -11,18 +11,41 @@ my $node = PostgreSQL::Test::Cluster->new('main');
 $node->init;
 $node->start;
 
+# parameter names that cannot get consistency check performed
+my @ignored_parameters = (
+	'data_directory',
+	'hba_file',
+	'ident_file',
+	'krb_server_keyfile',
+	'max_stack_depth',
+	'bgwriter_flush_after',
+	'wal_sync_method',
+	'checkpoint_flush_after',
+	'timezone_abbreviations',
+	'lc_messages',
+	'wal_buffers'
+  );
+
 # Grab the names of all the parameters that can be listed in the
 # configuration sample file.  config_file is an exception, it is not
 # in postgresql.conf.sample but is part of the lists from guc.c.
 my $all_params = $node->safe_psql(
 	'postgres',
-	"SELECT name
+	"SELECT lower(name), vartype, unit, boot_val, '!'
      FROM pg_settings
    WHERE NOT 'NOT_IN_SAMPLE' = ANY (pg_settings_get_flags(name)) AND
        name <> 'config_file'
      ORDER BY 1");
 # Note the lower-case conversion, for consistency.
-my @all_params_array = split("\n", lc($all_params));
+my %all_params_hash;
+foreach my $line (split("\n", $all_params))
+{
+	my @f = split('\|', $line);
+	fail("query returned wrong number of columns: $#f : $line") if ($#f != 4);
+	$all_params_hash{$f[0]}->{type} = $f[1];
+	$all_params_hash{$f[0]}->{unit} = $f[2];
+	$all_params_hash{$f[0]}->{bootval} = $f[3];
+}
 
 # Grab the names of all parameters marked as NOT_IN_SAMPLE.
 my $not_in_sample = $node->safe_psql(
@@ -43,7 +66,7 @@ my @gucs_in_file;
 
 # Read the sample file line-by-line, checking its contents to build a list
 # of everything known as a GUC.
-my $num_tests = 0;
+my @check_elems = ();
 open(my $contents, '<', $sample_file)
   || die "Could not open $sample_file: $!";
 while (my $line = <$contents>)
@@ -53,11 +76,16 @@ while (my $line = <$contents>)
 	# file.
 	# - Valid configuration options are followed immediately by " = ",
 	# with one space before and after the equal sign.
-	if ($line =~ m/^#?([_[:alpha:]]+) = .*/)
+	if ($line =~ m/^#?([_[:alpha:]]+) = (.*)$/)
 	{
 		# Lower-case conversion matters for some of the GUCs.
 		my $param_name = lc($1);
 
+		# extract value
+		my $file_value = $2;
+		$file_value =~ s/\s*#.*$//;		# strip trailing comment
+		$file_value =~ s/^'(.*)'$/$1/;	# strip quotes
+
 		# Ignore some exceptions.
 		next if $param_name eq "include";
 		next if $param_name eq "include_dir";
@@ -66,19 +94,39 @@ while (my $line = <$contents>)
 		# Update the list of GUCs found in the sample file, for the
 		# follow-up tests.
 		push @gucs_in_file, $param_name;
+
+		# Check for consistency between bootval and file value.
+		if (!grep { $_ eq $param_name } @ignored_parameters)
+		{
+			push (@check_elems, "('$param_name','$file_value')");
+		}
 	}
 }
 
 close $contents;
 
+# Run consistency check between config-file's default value and boot
+# values.  To show sample setting that is not found in the view, use
+# LEFT JOIN and make sure pg_settings.name is not NULL.
+my $check_query =
+  'SELECT f.n, f.v, s.boot_val FROM (VALUES '.
+  join(',', @check_elems).
+  ') f(n,v) LEFT JOIN pg_settings s ON lower(s.name) = f.n '.
+  "WHERE pg_config_unitless_value(f.n, f.v) <> COALESCE(s.boot_val, '') ".
+  'OR s.name IS NULL';
+
+print $check_query;
+
+is ($node->safe_psql('postgres', $check_query), '',
+	'check if fileval-bootval consistency is fine');
+
 # Cross-check that all the GUCs found in the sample file match the ones
 # fetched above.  This maps the arrays to a hash, making the creation of
 # each exclude and intersection list easier.
 my %gucs_in_file_hash  = map { $_ => 1 } @gucs_in_file;
-my %all_params_hash    = map { $_ => 1 } @all_params_array;
 my %not_in_sample_hash = map { $_ => 1 } @not_in_sample_array;
 
-my @missing_from_file = grep(!$gucs_in_file_hash{$_}, @all_params_array);
+my @missing_from_file = grep(!$gucs_in_file_hash{$_}, keys %all_params_hash);
 is(scalar(@missing_from_file),
 	0, "no parameters missing from postgresql.conf.sample");
 
-- 
2.31.1

From 8ab61286529f819a08e0e70d0b5522cabf4592b1 Mon Sep 17 00:00:00 2001
From: Kyotaro Horiguchi <horikyota.ntt@gmail.com>
Date: Thu, 16 Jun 2022 17:08:02 +0900
Subject: [PATCH v4] Add fileval-bootval consistency check of GUC parameters

We should keep GUC variables consistent between the default values
written in postgresql.conf.sample and defined in guc.c. Add an
automated way to check for the consistency to the TAP test suite. Some
variables are still excluded since they cannot be checked simple way.
---
 src/backend/utils/misc/guc.c                  | 57 ++++++++++++++++
 src/include/catalog/pg_proc.dat               |  5 ++
 src/test/modules/test_misc/t/003_check_guc.pl | 67 +++++++++++++++++--
 .../unsafe_tests/expected/rolenames.out       | 13 ++++
 .../modules/unsafe_tests/sql/rolenames.sql    |  7 ++
 5 files changed, 143 insertions(+), 6 deletions(-)

diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index a7cc49898b..1e7a0a2edc 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -7520,6 +7520,63 @@ parse_and_validate_value(struct config_generic *record,
 	return true;
 }
 
+/*
+ * Convert value to unitless value according to the specified GUC variable
+ */
+Datum
+pg_config_unitless_value(PG_FUNCTION_ARGS)
+{
+	char   *name;
+	char   *value;
+	struct config_generic *record;
+	const char *result = "";
+	void   *extra;
+	union config_var_val val;
+	char   buffer[256];
+
+	name = text_to_cstring(PG_GETARG_TEXT_PP(0));
+	value = text_to_cstring(PG_GETARG_TEXT_PP(1));
+
+	record = find_option(name, true, false, ERROR);
+
+	/*
+	 * This function doesn't reveal values of the variables, but be consistent
+	 * with similar functions.
+	 */
+	if ((record->flags & GUC_SUPERUSER_ONLY) &&
+		!has_privs_of_role(GetUserId(), ROLE_PG_READ_ALL_SETTINGS))
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("must be superuser or have privileges of pg_read_all_settings to convert value for \"%s\"",
+						name)));
+
+	parse_and_validate_value(record, name, value, PGC_S_TEST, WARNING,
+							 &val, &extra);
+
+	switch (record->vartype)
+	{
+		case PGC_BOOL:
+			result = (val.boolval ? "on" : "off");
+			break;
+		case PGC_INT:
+			snprintf(buffer, sizeof(buffer), "%d", val.intval);
+			result = buffer;
+			break;
+		case PGC_REAL:
+			snprintf(buffer, sizeof(buffer), "%g", val.realval);
+			result = buffer;
+			break;
+		case PGC_STRING:
+			result = val.stringval;
+			break;
+		case PGC_ENUM:
+			result = config_enum_lookup_by_value((struct config_enum *)record,
+												 val.boolval);
+			break;
+	}
+
+	PG_RETURN_TEXT_P(cstring_to_text(result));
+}
 
 /*
  * Sets option `name' to given value.
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 87aa571a33..794ba12dae 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6118,6 +6118,11 @@
   proname => 'pg_settings_get_flags', provolatile => 's', prorettype => '_text',
   proargtypes => 'text', prosrc => 'pg_settings_get_flags' },
 
+{ oid => '9956', descr => 'normalize value to the unit of specified GUC',
+  proname => 'pg_config_unitless_value', provolatile => 's',
+  prorettype => 'text', proargtypes => 'text text',
+  proargnames => '{varname,value}', prosrc => 'pg_config_unitless_value' },
+
 { oid => '3329', descr => 'show config file settings',
   proname => 'pg_show_all_file_settings', prorows => '1000', proretset => 't',
   provolatile => 'v', prorettype => 'record', proargtypes => '',
diff --git a/src/test/modules/test_misc/t/003_check_guc.pl b/src/test/modules/test_misc/t/003_check_guc.pl
index 60459ef759..d213b3b2bc 100644
--- a/src/test/modules/test_misc/t/003_check_guc.pl
+++ b/src/test/modules/test_misc/t/003_check_guc.pl
@@ -11,6 +11,28 @@ my $node = PostgreSQL::Test::Cluster->new('main');
 $node->init;
 $node->start;
 
+# These are non-variables but that are mistakenly parsed as variable
+# settings in the loop below.
+my %skip_names =
+  map { $_ => 1 } ('include', 'include_dir', 'include_if_exists');
+
+# The following parameters are defaultly set with
+# environment-dependent values at run-time which may not match the
+# default values written in the sample config file.
+my %ignore_parameters = 
+  map { $_ => 1 } (
+	  'data_directory',
+	  'hba_file',
+	  'ident_file',
+	  'krb_server_keyfile',
+	  'max_stack_depth',
+	  'bgwriter_flush_after',
+	  'wal_sync_method',
+	  'checkpoint_flush_after',
+	  'timezone_abbreviations',
+	  'lc_messages',
+	  'wal_buffers');
+
 # Grab the names of all the parameters that can be listed in the
 # configuration sample file.  config_file is an exception, it is not
 # in postgresql.conf.sample but is part of the lists from guc.c.
@@ -43,7 +65,7 @@ my @gucs_in_file;
 
 # Read the sample file line-by-line, checking its contents to build a list
 # of everything known as a GUC.
-my $num_tests = 0;
+my @file_vals = ();
 open(my $contents, '<', $sample_file)
   || die "Could not open $sample_file: $!";
 while (my $line = <$contents>)
@@ -53,19 +75,29 @@ while (my $line = <$contents>)
 	# file.
 	# - Valid configuration options are followed immediately by " = ",
 	# with one space before and after the equal sign.
-	if ($line =~ m/^#?([_[:alpha:]]+) = .*/)
+	if ($line =~ m/^#?([_[:alpha:]]+) = (.*)$/)
 	{
 		# Lower-case conversion matters for some of the GUCs.
 		my $param_name = lc($1);
 
-		# Ignore some exceptions.
-		next if $param_name eq "include";
-		next if $param_name eq "include_dir";
-		next if $param_name eq "include_if_exists";
+		# extract value
+		my $file_value = $2;
+		$file_value =~ s/\s*#.*$//;		# strip trailing comment
+		$file_value =~ s/^'(.*)'$/$1/;	# strip quotes
+
+		next if (defined $skip_names{$param_name});
 
 		# Update the list of GUCs found in the sample file, for the
 		# follow-up tests.
 		push @gucs_in_file, $param_name;
+
+		# Update the list of GUCs that value check between the sample
+		# file and pg_setting.boot_val will be performed.
+		if (!defined $ignore_parameters{$param_name})
+		{
+			push(@file_vals, [$param_name, $file_value]);
+		}
+		  
 	}
 }
 
@@ -107,4 +139,27 @@ foreach my $param (@sample_intersect)
 	);
 }
 
+# Check if GUC values in config-file and boot value match
+my $values = $node->safe_psql(
+	'postgres',
+	'SELECT f.n, pg_config_unitless_value(f.n, f.v), s.boot_val, \'!\' '.
+	'FROM (VALUES '.
+	join(',', map { "('${$_}[0]','${$_}[1]')" } @file_vals).
+	') f(n,v) '.
+	'JOIN pg_settings s ON (s.name = f.n)');
+
+my $fails = "";
+foreach my $l (split("\n", $values))
+{
+	# $l: <varname>|<fileval>|<boot_val>|!
+	my @t = split("\\|", $l);
+	if ($t[1] ne $t[2])
+	{
+		$fails .= "\n" if ($fails ne "");
+		$fails .= "$t[0]: file \"$t[1]\" != boot_val \"$t[2]\"";
+	}
+}
+
+is($fails, "", "check if GUC values in .sample and boot value match");
+
 done_testing();
diff --git a/src/test/modules/unsafe_tests/expected/rolenames.out b/src/test/modules/unsafe_tests/expected/rolenames.out
index 88b1ff843b..17983005d8 100644
--- a/src/test/modules/unsafe_tests/expected/rolenames.out
+++ b/src/test/modules/unsafe_tests/expected/rolenames.out
@@ -1081,6 +1081,19 @@ ERROR:  must be superuser or have privileges of pg_read_all_settings to examine
 RESET SESSION AUTHORIZATION;
 ERROR:  current transaction is aborted, commands ignored until end of transaction block
 ROLLBACK;
+BEGIN;
+SET SESSION AUTHORIZATION regress_role_haspriv;
+-- passes with role member of pg_read_all_settings
+SELECT pg_config_unitless_value('session_preload_libraries', 'val');
+ pg_config_unitless_value 
+--------------------------
+ val
+(1 row)
+
+SET SESSION AUTHORIZATION regress_role_nopriv;
+SELECT pg_config_unitless_value('session_preload_libraries', 'val');
+ERROR:  must be superuser or have privileges of pg_read_all_settings to convert value for "session_preload_libraries"
+ROLLBACK;
 REVOKE pg_read_all_settings FROM regress_role_haspriv;
 -- clean up
 \c
diff --git a/src/test/modules/unsafe_tests/sql/rolenames.sql b/src/test/modules/unsafe_tests/sql/rolenames.sql
index adac36536d..355aa32c2a 100644
--- a/src/test/modules/unsafe_tests/sql/rolenames.sql
+++ b/src/test/modules/unsafe_tests/sql/rolenames.sql
@@ -492,6 +492,13 @@ SET SESSION AUTHORIZATION regress_role_nopriv;
 SHOW session_preload_libraries;
 RESET SESSION AUTHORIZATION;
 ROLLBACK;
+BEGIN;
+SET SESSION AUTHORIZATION regress_role_haspriv;
+-- passes with role member of pg_read_all_settings
+SELECT pg_config_unitless_value('session_preload_libraries', 'val');
+SET SESSION AUTHORIZATION regress_role_nopriv;
+SELECT pg_config_unitless_value('session_preload_libraries', 'val');
+ROLLBACK;
 REVOKE pg_read_all_settings FROM regress_role_haspriv;
 
 -- clean up
-- 
2.31.1

From 5f9a56a9c0d73a221e55b2c02e006d3104f4937b Mon Sep 17 00:00:00 2001
From: Justin Pryzby <pryzbyj@telsasoft.com>
Date: Tue, 19 Jul 2022 08:31:56 -0500
Subject: [PATCH 1/2] wip: add DYNAMIC_DEFAULT for settings which are vary by
 configure flags or platform or initdb

---
 doc/src/sgml/func.sgml       |  4 ++++
 src/backend/utils/misc/guc.c | 36 +++++++++++++++++++++++-------------
 src/include/utils/guc.h      |  6 ++++--
 3 files changed, 31 insertions(+), 15 deletions(-)

diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index e3e24e185a4..0fd6234eaf2 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -24977,6 +24977,10 @@ SELECT currval(pg_get_serial_sequence('sometable', 'id'));
         an empty array if the GUC exists but there are no flags to show.
         Only the most useful flags are exposed, as of the following:
         <simplelist>
+         <member>
+          <literal>DYNAMIC_DEFAULT</literal>: parameters whose default varies by
+          platform, or compile-time options, or initdb.
+         </member>
          <member>
           <literal>EXPLAIN</literal>: parameters included in
           <command>EXPLAIN (SETTINGS)</command> commands.
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index 0328029d430..dbbadc5a475 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -1435,7 +1435,7 @@ static struct config_bool ConfigureNamesBool[] =
 		{"debug_assertions", PGC_INTERNAL, PRESET_OPTIONS,
 			gettext_noop("Shows whether the running server has assertion checks enabled."),
 			NULL,
-			GUC_NOT_IN_SAMPLE | GUC_DISALLOW_IN_FILE
+			GUC_NOT_IN_SAMPLE | GUC_DISALLOW_IN_FILE | GUC_DYNAMIC_DEFAULT
 		},
 		&assert_enabled,
 #ifdef USE_ASSERT_CHECKING
@@ -1611,7 +1611,8 @@ static struct config_bool ConfigureNamesBool[] =
 	{
 		{"update_process_title", PGC_SUSET, PROCESS_TITLE,
 			gettext_noop("Updates the process title to show the active SQL command."),
-			gettext_noop("Enables updating of the process title every time a new SQL command is received by the server.")
+			gettext_noop("Enables updating of the process title every time a new SQL command is received by the server."),
+			GUC_DYNAMIC_DEFAULT
 		},
 		&update_process_title,
 #ifdef WIN32
@@ -2362,6 +2363,7 @@ static struct config_int ConfigureNamesInt[] =
 			gettext_noop("Sets the maximum number of concurrent connections."),
 			NULL
 		},
+
 		&MaxConnections,
 		100, 1, MAX_BACKENDS,
 		check_maxconnections, NULL, NULL
@@ -2397,7 +2399,7 @@ static struct config_int ConfigureNamesInt[] =
 		{"shared_buffers", PGC_POSTMASTER, RESOURCES_MEM,
 			gettext_noop("Sets the number of shared memory buffers used by the server."),
 			NULL,
-			GUC_UNIT_BLOCKS
+			GUC_UNIT_BLOCKS | GUC_DYNAMIC_DEFAULT
 		},
 		&NBuffers,
 		16384, 16, INT_MAX / 2,
@@ -3142,7 +3144,7 @@ static struct config_int ConfigureNamesInt[] =
 			RESOURCES_ASYNCHRONOUS,
 			gettext_noop("Number of simultaneous requests that can be handled efficiently by the disk subsystem."),
 			NULL,
-			GUC_EXPLAIN
+			GUC_EXPLAIN|GUC_DYNAMIC_DEFAULT
 		},
 		&effective_io_concurrency,
 #ifdef USE_PREFETCH
@@ -3160,7 +3162,7 @@ static struct config_int ConfigureNamesInt[] =
 			RESOURCES_ASYNCHRONOUS,
 			gettext_noop("A variant of effective_io_concurrency that is used for maintenance work."),
 			NULL,
-			GUC_EXPLAIN
+			GUC_EXPLAIN|GUC_DYNAMIC_DEFAULT
 		},
 		&maintenance_io_concurrency,
 #ifdef USE_PREFETCH
@@ -3327,9 +3329,11 @@ static struct config_int ConfigureNamesInt[] =
 			gettext_noop("Shows the size of write ahead log segments."),
 			NULL,
 			GUC_UNIT_BYTE | GUC_NOT_IN_SAMPLE | GUC_DISALLOW_IN_FILE | GUC_RUNTIME_COMPUTED
+
 		},
 		&wal_segment_size,
 		DEFAULT_XLOG_SEG_SIZE,
+
 		WalSegMinSize,
 		WalSegMaxSize,
 		NULL, NULL, NULL
@@ -3523,6 +3527,7 @@ static struct config_int ConfigureNamesInt[] =
 			GUC_UNIT_BLOCKS | GUC_EXPLAIN,
 		},
 		&effective_cache_size,
+
 		DEFAULT_EFFECTIVE_CACHE_SIZE, 1, INT_MAX,
 		NULL, NULL, NULL
 	},
@@ -3620,7 +3625,7 @@ static struct config_int ConfigureNamesInt[] =
 		{"debug_discard_caches", PGC_SUSET, DEVELOPER_OPTIONS,
 			gettext_noop("Aggressively flush system caches for debugging purposes."),
 			NULL,
-			GUC_NOT_IN_SAMPLE
+			GUC_NOT_IN_SAMPLE | GUC_DYNAMIC_DEFAULT
 		},
 		&debug_discard_caches,
 #ifdef DISCARD_CACHES_ENABLED
@@ -4447,7 +4452,7 @@ static struct config_string ConfigureNamesString[] =
 		{"unix_socket_directories", PGC_POSTMASTER, CONN_AUTH_SETTINGS,
 			gettext_noop("Sets the directories where Unix-domain sockets will be created."),
 			NULL,
-			GUC_LIST_INPUT | GUC_LIST_QUOTE | GUC_SUPERUSER_ONLY
+			GUC_LIST_INPUT | GUC_LIST_QUOTE | GUC_SUPERUSER_ONLY | GUC_DYNAMIC_DEFAULT
 		},
 		&Unix_socket_directories,
 #ifdef HAVE_UNIX_SOCKETS
@@ -4532,7 +4537,7 @@ static struct config_string ConfigureNamesString[] =
 		{"ssl_library", PGC_INTERNAL, PRESET_OPTIONS,
 			gettext_noop("Shows the name of the SSL library."),
 			NULL,
-			GUC_NOT_IN_SAMPLE | GUC_DISALLOW_IN_FILE
+			GUC_NOT_IN_SAMPLE | GUC_DISALLOW_IN_FILE | GUC_DYNAMIC_DEFAULT
 		},
 		&ssl_library,
 #ifdef USE_SSL
@@ -4618,7 +4623,7 @@ static struct config_string ConfigureNamesString[] =
 		{"ssl_ciphers", PGC_SIGHUP, CONN_AUTH_SSL,
 			gettext_noop("Sets the list of allowed SSL ciphers."),
 			NULL,
-			GUC_SUPERUSER_ONLY
+			GUC_SUPERUSER_ONLY | GUC_DYNAMIC_DEFAULT
 		},
 		&SSLCipherSuites,
 #ifdef USE_OPENSSL
@@ -4633,7 +4638,7 @@ static struct config_string ConfigureNamesString[] =
 		{"ssl_ecdh_curve", PGC_SIGHUP, CONN_AUTH_SSL,
 			gettext_noop("Sets the curve to use for ECDH."),
 			NULL,
-			GUC_SUPERUSER_ONLY
+			GUC_SUPERUSER_ONLY | GUC_DYNAMIC_DEFAULT
 		},
 		&SSLECDHCurve,
 #ifdef USE_SSL
@@ -4871,7 +4876,8 @@ static struct config_enum ConfigureNamesEnum[] =
 	{
 		{"syslog_facility", PGC_SIGHUP, LOGGING_WHERE,
 			gettext_noop("Sets the syslog \"facility\" to be used when syslog enabled."),
-			NULL
+			NULL,
+			GUC_DYNAMIC_DEFAULT
 		},
 		&syslog_facility,
 #ifdef HAVE_SYSLOG
@@ -4984,7 +4990,8 @@ static struct config_enum ConfigureNamesEnum[] =
 	{
 		{"dynamic_shared_memory_type", PGC_POSTMASTER, RESOURCES_MEM,
 			gettext_noop("Selects the dynamic shared memory implementation used."),
-			NULL
+			NULL,
+			GUC_DYNAMIC_DEFAULT
 		},
 		&dynamic_shared_memory_type,
 		DEFAULT_DYNAMIC_SHARED_MEMORY_TYPE, dynamic_shared_memory_options,
@@ -5008,6 +5015,7 @@ static struct config_enum ConfigureNamesEnum[] =
 		},
 		&sync_method,
 		DEFAULT_SYNC_METHOD, sync_method_options,
+
 		NULL, assign_xlog_sync_method, NULL
 	},
 
@@ -9943,7 +9951,7 @@ GetConfigOptionByName(const char *name, const char **varname, bool missing_ok)
 Datum
 pg_settings_get_flags(PG_FUNCTION_ARGS)
 {
-#define MAX_GUC_FLAGS	5
+#define MAX_GUC_FLAGS	6
 	char	   *varname = TextDatumGetCString(PG_GETARG_DATUM(0));
 	struct config_generic *record;
 	int			cnt = 0;
@@ -9956,6 +9964,8 @@ pg_settings_get_flags(PG_FUNCTION_ARGS)
 	if (record == NULL)
 		PG_RETURN_NULL();
 
+	if (record->flags & GUC_DYNAMIC_DEFAULT)
+		flags[cnt++] = CStringGetTextDatum("DYNAMIC_DEFAULT");
 	if (record->flags & GUC_EXPLAIN)
 		flags[cnt++] = CStringGetTextDatum("EXPLAIN");
 	if (record->flags & GUC_NO_RESET_ALL)
diff --git a/src/include/utils/guc.h b/src/include/utils/guc.h
index 4d0920c42e2..bb09c507f81 100644
--- a/src/include/utils/guc.h
+++ b/src/include/utils/guc.h
@@ -221,14 +221,14 @@ typedef enum
 
 #define GUC_UNIT_KB				0x1000	/* value is in kilobytes */
 #define GUC_UNIT_BLOCKS			0x2000	/* value is in blocks */
-#define GUC_UNIT_XBLOCKS		0x3000	/* value is in xlog blocks */
+#define GUC_UNIT_XBLOCKS		0x3000	/* value is in xlog blocks */ //
 #define GUC_UNIT_MB				0x4000	/* value is in megabytes */
 #define GUC_UNIT_BYTE			0x8000	/* value is in bytes */
 #define GUC_UNIT_MEMORY			0xF000	/* mask for size-related units */
 
 #define GUC_UNIT_MS			   0x10000	/* value is in milliseconds */
 #define GUC_UNIT_S			   0x20000	/* value is in seconds */
-#define GUC_UNIT_MIN		   0x30000	/* value is in minutes */
+#define GUC_UNIT_MIN		   0x30000	/* value is in minutes */ //
 #define GUC_UNIT_TIME		   0xF0000	/* mask for time-related units */
 
 #define GUC_EXPLAIN			  0x100000	/* include in explain */
@@ -239,6 +239,8 @@ typedef enum
  */
 #define GUC_RUNTIME_COMPUTED  0x200000
 
+#define GUC_DYNAMIC_DEFAULT		  0x400000	/* default value is dynamic */
+
 #define GUC_UNIT				(GUC_UNIT_MEMORY | GUC_UNIT_TIME)
 
 
-- 
2.17.1

From fabe483dc806294eab85fb1dd0690344c5bd1e06 Mon Sep 17 00:00:00 2001
From: Kyotaro Horiguchi <horikyota.ntt@gmail.com>
Date: Mon, 30 May 2022 16:11:34 +0900
Subject: [PATCH 2/2] Add fileval-bootval consistency check of GUC parameters

We should keep GUC variables consistent between the default values
written in postgresql.conf.sample and defined in guc.c. Add an
automated way to check for the consistency to the TAP test suite. Some
variables are still excluded since they cannot be checked simple way.
---
 src/backend/utils/misc/guc.c                  | 70 +++++++++++++++++++
 src/backend/utils/misc/postgresql.conf.sample |  6 +-
 src/include/catalog/pg_proc.dat               |  5 ++
 src/test/modules/test_misc/t/003_check_guc.pl | 57 +++++++++++++--
 4 files changed, 129 insertions(+), 9 deletions(-)

diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index dbbadc5a475..a700cbbf4bc 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -7526,6 +7526,76 @@ parse_and_validate_value(struct config_generic *record,
 	return true;
 }
 
+/*
+ * Helper function for pg_normalize_config_value().
+ * Makes a palloced copy of src then link val to it.
+ * DO NOT destroy val while dst is in use.
+ */
+static struct config_generic *
+copy_config_and_set_value(struct config_generic *src, union config_var_val *val)
+{
+	struct config_generic *dst;
+
+#define CREATE_CONFIG_COPY(dst, src, t)	\
+	dst = palloc(sizeof(struct t));				\
+	*(struct t *) dst = *(struct t *) src;		\
+	
+	switch (src->vartype)
+	{
+		case PGC_BOOL:
+			CREATE_CONFIG_COPY(dst, src, config_bool);
+			((struct config_bool *)dst)->variable = &val->boolval;
+			break;
+		case PGC_INT:
+			CREATE_CONFIG_COPY(dst, src, config_int);
+			((struct config_int *)dst)->variable = &val->intval;
+			break;
+		case PGC_REAL:
+			CREATE_CONFIG_COPY(dst, src, config_real);
+			((struct config_real *)dst)->variable = &val->realval;
+			break;
+		case PGC_STRING:
+			CREATE_CONFIG_COPY(dst, src, config_string);
+			((struct config_string *)dst)->variable = &val->stringval;
+			break;
+		case PGC_ENUM:
+			CREATE_CONFIG_COPY(dst, src, config_enum);
+			((struct config_enum *)dst)->variable = &val->enumval;
+			break;
+	}
+
+	return dst;
+}
+
+
+/*
+ * Normalize given value according to the specified GUC variable
+ */
+Datum
+pg_normalize_config_value(PG_FUNCTION_ARGS)
+{
+	char   *name = "";
+	char   *value = "";
+	struct config_generic *record;
+	char   *result;
+	void   *extra;
+	union config_var_val altval;
+
+	if (!PG_ARGISNULL(0))
+		name = text_to_cstring(PG_GETARG_TEXT_PP(0));
+	if (!PG_ARGISNULL(1))
+		value = text_to_cstring(PG_GETARG_TEXT_PP(1));
+
+	record = find_option(name, true, false, ERROR);
+
+	parse_and_validate_value(record, name, value, PGC_S_TEST, WARNING,
+							 &altval, &extra);
+	record = copy_config_and_set_value(record, &altval);
+
+	result = _ShowOption(record, true);
+
+	PG_RETURN_TEXT_P(cstring_to_text(result));
+}
 
 /*
  * Sets option `name' to given value.
diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample
index b4bc06e5f5a..b6403a14496 100644
--- a/src/backend/utils/misc/postgresql.conf.sample
+++ b/src/backend/utils/misc/postgresql.conf.sample
@@ -476,7 +476,7 @@
 					# in all cases.
 
 # These are relevant when logging to syslog:
-#syslog_facility = 'LOCAL0'
+#syslog_facility = 'local0'
 #syslog_ident = 'postgres'
 #syslog_sequence_numbers = on
 #syslog_split_messages = on
@@ -709,7 +709,7 @@
 
 # - Locale and Formatting -
 
-#datestyle = 'iso, mdy'
+#datestyle = 'ISO, MDY'
 #intervalstyle = 'postgres'
 #timezone = 'GMT'
 #timezone_abbreviations = 'Default'     # Select the set of available time zone
@@ -721,7 +721,7 @@
 					# share/timezonesets/.
 #extra_float_digits = 1			# min -15, max 3; any value >0 actually
 					# selects precise output mode
-#client_encoding = sql_ascii		# actually, defaults to database
+#client_encoding = SQL_ASCII		# actually, defaults to database
 					# encoding
 
 # These settings are initialized by initdb, but they can be changed.
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 8873078c160..a92630d768b 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6118,6 +6118,11 @@
   proname => 'pg_settings_get_flags', provolatile => 's', prorettype => '_text',
   proargtypes => 'text', prosrc => 'pg_settings_get_flags' },
 
+{ oid => '9956', descr => 'normalize value to the unit of specified GUC',
+  proname => 'pg_normalize_config_value', proisstrict => 'f',
+  provolatile => 's', prorettype => 'text', proargtypes => 'text text',
+  proargnames => '{varname,value}', prosrc => 'pg_normalize_config_value' },
+
 { oid => '3329', descr => 'show config file settings',
   proname => 'pg_show_all_file_settings', prorows => '1000', proretset => 't',
   provolatile => 'v', prorettype => 'record', proargtypes => '',
diff --git a/src/test/modules/test_misc/t/003_check_guc.pl b/src/test/modules/test_misc/t/003_check_guc.pl
index 60459ef759e..dfb2d203247 100644
--- a/src/test/modules/test_misc/t/003_check_guc.pl
+++ b/src/test/modules/test_misc/t/003_check_guc.pl
@@ -11,18 +11,40 @@ my $node = PostgreSQL::Test::Cluster->new('main');
 $node->init;
 $node->start;
 
+# parameter names that cannot get consistency check performed
+my @ignored_parameters = (
+	'data_directory',
+	'hba_file',
+	'ident_file',
+	'krb_server_keyfile',
+	'max_stack_depth',
+	'bgwriter_flush_after',
+	'wal_sync_method',
+	'checkpoint_flush_after',
+	'timezone_abbreviations',
+	'lc_messages'
+  );
+
 # Grab the names of all the parameters that can be listed in the
 # configuration sample file.  config_file is an exception, it is not
 # in postgresql.conf.sample but is part of the lists from guc.c.
 my $all_params = $node->safe_psql(
 	'postgres',
-	"SELECT name
+	"SELECT lower(name), vartype, unit, boot_val, '!'
      FROM pg_settings
    WHERE NOT 'NOT_IN_SAMPLE' = ANY (pg_settings_get_flags(name)) AND
        name <> 'config_file'
      ORDER BY 1");
 # Note the lower-case conversion, for consistency.
-my @all_params_array = split("\n", lc($all_params));
+my %all_params_hash;
+foreach my $line (split("\n", $all_params))
+{
+	my @f = split('\|', $line);
+	fail("query returned wrong number of columns: $#f : $line") if ($#f != 4);
+	$all_params_hash{$f[0]}->{type} = $f[1];
+	$all_params_hash{$f[0]}->{unit} = $f[2];
+	$all_params_hash{$f[0]}->{bootval} = $f[3];
+}
 
 # Grab the names of all parameters marked as NOT_IN_SAMPLE.
 my $not_in_sample = $node->safe_psql(
@@ -43,7 +65,7 @@ my @gucs_in_file;
 
 # Read the sample file line-by-line, checking its contents to build a list
 # of everything known as a GUC.
-my $num_tests = 0;
+my @check_elems = ();
 open(my $contents, '<', $sample_file)
   || die "Could not open $sample_file: $!";
 while (my $line = <$contents>)
@@ -53,11 +75,16 @@ while (my $line = <$contents>)
 	# file.
 	# - Valid configuration options are followed immediately by " = ",
 	# with one space before and after the equal sign.
-	if ($line =~ m/^#?([_[:alpha:]]+) = .*/)
+	if ($line =~ m/^#?([_[:alpha:]]+) = (.*)$/)
 	{
 		# Lower-case conversion matters for some of the GUCs.
 		my $param_name = lc($1);
 
+		# extract value
+		my $file_value = $2;
+		$file_value =~ s/\s*#.*$//;		# strip trailing comment
+		$file_value =~ s/^'(.*)'$/$1/;	# strip quotes
+
 		# Ignore some exceptions.
 		next if $param_name eq "include";
 		next if $param_name eq "include_dir";
@@ -66,19 +93,37 @@ while (my $line = <$contents>)
 		# Update the list of GUCs found in the sample file, for the
 		# follow-up tests.
 		push @gucs_in_file, $param_name;
+
+		# Check for consistency between bootval and file value.
+		if (!grep { $_ eq $param_name } @ignored_parameters)
+		{
+			push (@check_elems, "('$param_name','$file_value')");
+		}
 	}
 }
 
 close $contents;
 
+# run consistency check between config-file's default value and boot values.
+my $check_query =
+  'SELECT f.n, f.v, s.boot_val FROM (VALUES '.
+  join(',', @check_elems).
+  ') f(n,v) JOIN pg_settings s ON s.name = f.n '.
+  'JOIN pg_settings_get_flags(s.name) flags ON true '.
+  "WHERE 'DYNAMIC_DEFAULT' <> ALL(flags) AND " .
+  'pg_normalize_config_value(f.n, f.v) <> '.
+  'pg_normalize_config_value(f.n, s.boot_val)';
+
+is ($node->safe_psql('postgres', $check_query), '',
+	'check if fileval-bootval consistency is fine');
+
 # Cross-check that all the GUCs found in the sample file match the ones
 # fetched above.  This maps the arrays to a hash, making the creation of
 # each exclude and intersection list easier.
 my %gucs_in_file_hash  = map { $_ => 1 } @gucs_in_file;
-my %all_params_hash    = map { $_ => 1 } @all_params_array;
 my %not_in_sample_hash = map { $_ => 1 } @not_in_sample_array;
 
-my @missing_from_file = grep(!$gucs_in_file_hash{$_}, @all_params_array);
+my @missing_from_file = grep(!$gucs_in_file_hash{$_}, keys %all_params_hash);
 is(scalar(@missing_from_file),
 	0, "no parameters missing from postgresql.conf.sample");
 
-- 
2.17.1

From 25ee6d6ed23ff273e622551fd033c8d086953fe5 Mon Sep 17 00:00:00 2001
From: Justin Pryzby <pryzbyj@telsasoft.com>
Date: Tue, 19 Jul 2022 08:31:56 -0500
Subject: [PATCH 1/2] add DYNAMIC_DEFAULT for settings which vary by
 ./configure or platform or initdb

---
 doc/src/sgml/func.sgml              |  8 ++++++
 src/backend/utils/misc/guc_funcs.c  |  4 ++-
 src/backend/utils/misc/guc_tables.c | 39 ++++++++++++++++-------------
 src/include/utils/guc.h             |  2 ++
 4 files changed, 35 insertions(+), 18 deletions(-)

diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 67eb3806326..63063d054c5 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -24341,6 +24341,14 @@ SELECT collation for ('foo' COLLATE "de_DE");
      <row><entry>Flag</entry><entry>Description</entry></row>
     </thead>
     <tbody>
+
+     <row>
+      <entry><literal>DYNAMIC_DEFAULT</literal></entry>
+      <entry>Parameters with this flag have default values which vary by
+      platform, or compile-time options, or are set dynamically during initdb.
+      </entry>
+     </row>
+
      <row>
       <entry><literal>EXPLAIN</literal></entry>
       <entry>Parameters with this flag are included in
diff --git a/src/backend/utils/misc/guc_funcs.c b/src/backend/utils/misc/guc_funcs.c
index 3d2df18659b..3376f23e076 100644
--- a/src/backend/utils/misc/guc_funcs.c
+++ b/src/backend/utils/misc/guc_funcs.c
@@ -539,7 +539,7 @@ ShowAllGUCConfig(DestReceiver *dest)
 Datum
 pg_settings_get_flags(PG_FUNCTION_ARGS)
 {
-#define MAX_GUC_FLAGS	5
+#define MAX_GUC_FLAGS	6
 	char	   *varname = TextDatumGetCString(PG_GETARG_DATUM(0));
 	struct config_generic *record;
 	int			cnt = 0;
@@ -552,6 +552,8 @@ pg_settings_get_flags(PG_FUNCTION_ARGS)
 	if (record == NULL)
 		PG_RETURN_NULL();
 
+	if (record->flags & GUC_DYNAMIC_DEFAULT)
+		flags[cnt++] = CStringGetTextDatum("DYNAMIC_DEFAULT");
 	if (record->flags & GUC_EXPLAIN)
 		flags[cnt++] = CStringGetTextDatum("EXPLAIN");
 	if (record->flags & GUC_NO_RESET_ALL)
diff --git a/src/backend/utils/misc/guc_tables.c b/src/backend/utils/misc/guc_tables.c
index 7bff45e10d6..bd3c84bc7b8 100644
--- a/src/backend/utils/misc/guc_tables.c
+++ b/src/backend/utils/misc/guc_tables.c
@@ -1201,7 +1201,7 @@ struct config_bool ConfigureNamesBool[] =
 		{"debug_assertions", PGC_INTERNAL, PRESET_OPTIONS,
 			gettext_noop("Shows whether the running server has assertion checks enabled."),
 			NULL,
-			GUC_NOT_IN_SAMPLE | GUC_DISALLOW_IN_FILE
+			GUC_NOT_IN_SAMPLE | GUC_DISALLOW_IN_FILE | GUC_DYNAMIC_DEFAULT
 		},
 		&assert_enabled,
 #ifdef USE_ASSERT_CHECKING
@@ -1377,7 +1377,8 @@ struct config_bool ConfigureNamesBool[] =
 	{
 		{"update_process_title", PGC_SUSET, PROCESS_TITLE,
 			gettext_noop("Updates the process title to show the active SQL command."),
-			gettext_noop("Enables updating of the process title every time a new SQL command is received by the server.")
+			gettext_noop("Enables updating of the process title every time a new SQL command is received by the server."),
+			GUC_DYNAMIC_DEFAULT
 		},
 		&update_process_title,
 #ifdef WIN32
@@ -2126,7 +2127,8 @@ struct config_int ConfigureNamesInt[] =
 	{
 		{"max_connections", PGC_POSTMASTER, CONN_AUTH_SETTINGS,
 			gettext_noop("Sets the maximum number of concurrent connections."),
-			NULL
+			NULL,
+			GUC_DYNAMIC_DEFAULT
 		},
 		&MaxConnections,
 		100, 1, MAX_BACKENDS,
@@ -2163,7 +2165,7 @@ struct config_int ConfigureNamesInt[] =
 		{"shared_buffers", PGC_POSTMASTER, RESOURCES_MEM,
 			gettext_noop("Sets the number of shared memory buffers used by the server."),
 			NULL,
-			GUC_UNIT_BLOCKS
+			GUC_UNIT_BLOCKS | GUC_DYNAMIC_DEFAULT
 		},
 		&NBuffers,
 		16384, 16, INT_MAX / 2,
@@ -2677,7 +2679,7 @@ struct config_int ConfigureNamesInt[] =
 		{"checkpoint_flush_after", PGC_SIGHUP, WAL_CHECKPOINTS,
 			gettext_noop("Number of pages after which previously performed writes are flushed to disk."),
 			NULL,
-			GUC_UNIT_BLOCKS
+			GUC_UNIT_BLOCKS | GUC_DYNAMIC_DEFAULT
 		},
 		&checkpoint_flush_after,
 		DEFAULT_CHECKPOINT_FLUSH_AFTER, 0, WRITEBACK_MAX_PENDING_FLUSHES,
@@ -2895,7 +2897,7 @@ struct config_int ConfigureNamesInt[] =
 		{"bgwriter_flush_after", PGC_SIGHUP, RESOURCES_BGWRITER,
 			gettext_noop("Number of pages after which previously performed writes are flushed to disk."),
 			NULL,
-			GUC_UNIT_BLOCKS
+			GUC_UNIT_BLOCKS | GUC_DYNAMIC_DEFAULT
 		},
 		&bgwriter_flush_after,
 		DEFAULT_BGWRITER_FLUSH_AFTER, 0, WRITEBACK_MAX_PENDING_FLUSHES,
@@ -2908,7 +2910,7 @@ struct config_int ConfigureNamesInt[] =
 			RESOURCES_ASYNCHRONOUS,
 			gettext_noop("Number of simultaneous requests that can be handled efficiently by the disk subsystem."),
 			NULL,
-			GUC_EXPLAIN
+			GUC_EXPLAIN | GUC_DYNAMIC_DEFAULT
 		},
 		&effective_io_concurrency,
 #ifdef USE_PREFETCH
@@ -2926,7 +2928,7 @@ struct config_int ConfigureNamesInt[] =
 			RESOURCES_ASYNCHRONOUS,
 			gettext_noop("A variant of effective_io_concurrency that is used for maintenance work."),
 			NULL,
-			GUC_EXPLAIN
+			GUC_EXPLAIN | GUC_DYNAMIC_DEFAULT
 		},
 		&maintenance_io_concurrency,
 #ifdef USE_PREFETCH
@@ -2943,7 +2945,7 @@ struct config_int ConfigureNamesInt[] =
 		{"backend_flush_after", PGC_USERSET, RESOURCES_ASYNCHRONOUS,
 			gettext_noop("Number of pages after which previously performed writes are flushed to disk."),
 			NULL,
-			GUC_UNIT_BLOCKS
+			GUC_UNIT_BLOCKS | GUC_DYNAMIC_DEFAULT
 		},
 		&backend_flush_after,
 		DEFAULT_BACKEND_FLUSH_AFTER, 0, WRITEBACK_MAX_PENDING_FLUSHES,
@@ -3397,7 +3399,7 @@ struct config_int ConfigureNamesInt[] =
 		{"debug_discard_caches", PGC_SUSET, DEVELOPER_OPTIONS,
 			gettext_noop("Aggressively flush system caches for debugging purposes."),
 			NULL,
-			GUC_NOT_IN_SAMPLE
+			GUC_NOT_IN_SAMPLE | GUC_DYNAMIC_DEFAULT
 		},
 		&debug_discard_caches,
 #ifdef DISCARD_CACHES_ENABLED
@@ -4224,7 +4226,7 @@ struct config_string ConfigureNamesString[] =
 		{"unix_socket_directories", PGC_POSTMASTER, CONN_AUTH_SETTINGS,
 			gettext_noop("Sets the directories where Unix-domain sockets will be created."),
 			NULL,
-			GUC_LIST_INPUT | GUC_LIST_QUOTE | GUC_SUPERUSER_ONLY
+			GUC_LIST_INPUT | GUC_LIST_QUOTE | GUC_SUPERUSER_ONLY | GUC_DYNAMIC_DEFAULT
 		},
 		&Unix_socket_directories,
 		DEFAULT_PGSOCKET_DIR,
@@ -4305,7 +4307,7 @@ struct config_string ConfigureNamesString[] =
 		{"ssl_library", PGC_INTERNAL, PRESET_OPTIONS,
 			gettext_noop("Shows the name of the SSL library."),
 			NULL,
-			GUC_NOT_IN_SAMPLE | GUC_DISALLOW_IN_FILE
+			GUC_NOT_IN_SAMPLE | GUC_DISALLOW_IN_FILE | GUC_DYNAMIC_DEFAULT
 		},
 		&ssl_library,
 #ifdef USE_SSL
@@ -4391,7 +4393,7 @@ struct config_string ConfigureNamesString[] =
 		{"ssl_ciphers", PGC_SIGHUP, CONN_AUTH_SSL,
 			gettext_noop("Sets the list of allowed SSL ciphers."),
 			NULL,
-			GUC_SUPERUSER_ONLY
+			GUC_SUPERUSER_ONLY | GUC_DYNAMIC_DEFAULT
 		},
 		&SSLCipherSuites,
 #ifdef USE_OPENSSL
@@ -4406,7 +4408,7 @@ struct config_string ConfigureNamesString[] =
 		{"ssl_ecdh_curve", PGC_SIGHUP, CONN_AUTH_SSL,
 			gettext_noop("Sets the curve to use for ECDH."),
 			NULL,
-			GUC_SUPERUSER_ONLY
+			GUC_SUPERUSER_ONLY | GUC_DYNAMIC_DEFAULT
 		},
 		&SSLECDHCurve,
 #ifdef USE_SSL
@@ -4644,7 +4646,8 @@ struct config_enum ConfigureNamesEnum[] =
 	{
 		{"syslog_facility", PGC_SIGHUP, LOGGING_WHERE,
 			gettext_noop("Sets the syslog \"facility\" to be used when syslog enabled."),
-			NULL
+			NULL,
+			GUC_DYNAMIC_DEFAULT
 		},
 		&syslog_facility,
 #ifdef HAVE_SYSLOG
@@ -4757,7 +4760,8 @@ struct config_enum ConfigureNamesEnum[] =
 	{
 		{"dynamic_shared_memory_type", PGC_POSTMASTER, RESOURCES_MEM,
 			gettext_noop("Selects the dynamic shared memory implementation used."),
-			NULL
+			NULL,
+			GUC_DYNAMIC_DEFAULT
 		},
 		&dynamic_shared_memory_type,
 		DEFAULT_DYNAMIC_SHARED_MEMORY_TYPE, dynamic_shared_memory_options,
@@ -4777,7 +4781,8 @@ struct config_enum ConfigureNamesEnum[] =
 	{
 		{"wal_sync_method", PGC_SIGHUP, WAL_SETTINGS,
 			gettext_noop("Selects the method used for forcing WAL updates to disk."),
-			NULL
+			NULL,
+			GUC_DYNAMIC_DEFAULT
 		},
 		&sync_method,
 		DEFAULT_SYNC_METHOD, sync_method_options,
diff --git a/src/include/utils/guc.h b/src/include/utils/guc.h
index e426dd757d9..0447d3eb56a 100644
--- a/src/include/utils/guc.h
+++ b/src/include/utils/guc.h
@@ -238,6 +238,8 @@ typedef enum
  */
 #define GUC_RUNTIME_COMPUTED  0x200000
 
+#define GUC_DYNAMIC_DEFAULT		  0x400000	/* default value is dynamic */
+
 #define GUC_UNIT				(GUC_UNIT_MEMORY | GUC_UNIT_TIME)
 
 
-- 
2.25.1

From d7940be9ac7f1e4d29b6651a315c8dbfc54f84e2 Mon Sep 17 00:00:00 2001
From: Justin Pryzby <pryzbyj@telsasoft.com>
Date: Wed, 25 May 2022 05:14:43 -0500
Subject: [PATCH 2/2] WIP: test guc default values

---
 src/backend/utils/misc/postgresql.conf.sample |  2 +-
 src/test/modules/test_misc/t/003_check_guc.pl | 32 +++++++++++++++++++
 2 files changed, 33 insertions(+), 1 deletion(-)

diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample
index 8a0b383eb71..88a033103d1 100644
--- a/src/backend/utils/misc/postgresql.conf.sample
+++ b/src/backend/utils/misc/postgresql.conf.sample
@@ -721,7 +721,7 @@
 					# share/timezonesets/.
 #extra_float_digits = 1			# min -15, max 3; any value >0 actually
 					# selects precise output mode
-#client_encoding = sql_ascii		# actually, defaults to database
+#client_encoding = SQL_ASCII		# actually, defaults to database
 					# encoding
 
 # These settings are initialized by initdb, but they can be changed.
diff --git a/src/test/modules/test_misc/t/003_check_guc.pl b/src/test/modules/test_misc/t/003_check_guc.pl
index 60459ef759e..dd5ac2c8bc4 100644
--- a/src/test/modules/test_misc/t/003_check_guc.pl
+++ b/src/test/modules/test_misc/t/003_check_guc.pl
@@ -107,4 +107,36 @@ foreach my $param (@sample_intersect)
 	);
 }
 
+# Test that GUCs in postgresql.conf.sample show the correct default values
+my $check_defaults = $node->safe_psql(
+	'postgres',
+	"
+	CREATE TABLE sample_conf AS
+	SELECT m[1] AS name, COALESCE(m[3], m[5]) AS sample_value
+	FROM (SELECT regexp_split_to_table(pg_read_file('../../../$sample_file'), '\n') AS ln) conf,
+	regexp_match(ln, '^#?([_[:alpha:]]+) (= ''([^'']*)''|(= ([^[:space:]]*))).*') AS m
+	WHERE ln ~ '^#?[[:alpha:]]'
+	");
+
+$check_defaults = $node->safe_psql(
+	'postgres',
+	"
+	SELECT name, current_setting(name), sc.sample_value, boot_val
+	FROM pg_show_all_settings() psas
+	JOIN sample_conf sc USING(name)
+	WHERE sc.sample_value != boot_val -- same value
+	AND sc.sample_value != current_setting(name) -- same value, with human units
+	AND sc.sample_value != current_setting(name)||'.0' -- same value with .0 suffix
+	AND 'DYNAMIC_DEFAULT' != ALL(pg_settings_get_flags(psas.name)) -- dynamically-set defaults
+	AND NOT (sc.sample_value ~ '^0' AND current_setting(name) ~ '^0') -- zeros may be written differently
+	AND NOT (sc.sample_value='60s' AND current_setting(name) = '1min') -- two ways to write 1min
+	AND name NOT IN ('krb_server_keyfile', 'wal_retrieve_retry_interval', 'log_autovacuum_min_duration'); -- exceptions
+	");
+
+my @check_defaults_array = split("\n", lc($check_defaults));
+print(STDERR "$check_defaults\n");
+
+is (@check_defaults_array, 0,
+	'check for consistency of defaults in postgresql.conf.sample');
+
 done_testing();
-- 
2.25.1

From c3ac7bd40d26eb692f939d58935415ceb1cf308e Mon Sep 17 00:00:00 2001
From: Justin Pryzby <pryzbyj@telsasoft.com>
Date: Tue, 19 Jul 2022 08:31:56 -0500
Subject: [PATCH 1/2] add DYNAMIC_DEFAULT for settings which vary by
 ./configure or platform or initdb

---
 doc/src/sgml/func.sgml              | 15 ++++++
 src/backend/utils/misc/guc_funcs.c  |  6 ++-
 src/backend/utils/misc/guc_tables.c | 78 ++++++++++++++++++-----------
 src/include/utils/guc.h             |  2 +
 4 files changed, 70 insertions(+), 31 deletions(-)

diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 6e0425cb3dc..b8e05073d1a 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -24374,6 +24374,21 @@ SELECT collation for ('foo' COLLATE "de_DE");
      <row><entry>Flag</entry><entry>Description</entry></row>
     </thead>
     <tbody>
+
+     <row>
+      <entry><literal>DEFAULT_COMPILE</literal></entry>
+      <entry>Parameters with this flag have default values which vary by
+      platform, or compile-time options.
+      </entry>
+     </row>
+
+     <row>
+      <entry><literal>DEFAULT_INITDB</literal></entry>
+      <entry>Parameters with this flag have default values which are
+      determined dynamically during initdb.
+      </entry>
+     </row>
+
      <row>
       <entry><literal>EXPLAIN</literal></entry>
       <entry>Parameters with this flag are included in
diff --git a/src/backend/utils/misc/guc_funcs.c b/src/backend/utils/misc/guc_funcs.c
index 108b3bd1290..2b666e8d014 100644
--- a/src/backend/utils/misc/guc_funcs.c
+++ b/src/backend/utils/misc/guc_funcs.c
@@ -538,7 +538,7 @@ ShowAllGUCConfig(DestReceiver *dest)
 Datum
 pg_settings_get_flags(PG_FUNCTION_ARGS)
 {
-#define MAX_GUC_FLAGS	6
+#define MAX_GUC_FLAGS	8
 	char	   *varname = TextDatumGetCString(PG_GETARG_DATUM(0));
 	struct config_generic *record;
 	int			cnt = 0;
@@ -551,6 +551,10 @@ pg_settings_get_flags(PG_FUNCTION_ARGS)
 	if (record == NULL)
 		PG_RETURN_NULL();
 
+	if (record->flags & GUC_DEFAULT_COMPILE)
+		flags[cnt++] = CStringGetTextDatum("DEFAULT_COMPILE");
+	if (record->flags & GUC_DEFAULT_INITDB)
+		flags[cnt++] = CStringGetTextDatum("DEFAULT_INITDB");
 	if (record->flags & GUC_EXPLAIN)
 		flags[cnt++] = CStringGetTextDatum("EXPLAIN");
 	if (record->flags & GUC_NO_RESET)
diff --git a/src/backend/utils/misc/guc_tables.c b/src/backend/utils/misc/guc_tables.c
index 6454d034e7e..885d3dd8b81 100644
--- a/src/backend/utils/misc/guc_tables.c
+++ b/src/backend/utils/misc/guc_tables.c
@@ -601,7 +601,7 @@ StaticAssertDecl(lengthof(GucContext_Names) == (PGC_USERSET + 1),
 const char *const GucSource_Names[] =
 {
 	 /* PGC_S_DEFAULT */ "default",
-	 /* PGC_S_DYNAMIC_DEFAULT */ "default",
+	 /* PGC_S_DYNAMIC_DEFAULT */ "default", //
 	 /* PGC_S_ENV_VAR */ "environment variable",
 	 /* PGC_S_FILE */ "configuration file",
 	 /* PGC_S_ARGV */ "command line",
@@ -1191,7 +1191,7 @@ struct config_bool ConfigureNamesBool[] =
 		{"debug_assertions", PGC_INTERNAL, PRESET_OPTIONS,
 			gettext_noop("Shows whether the running server has assertion checks enabled."),
 			NULL,
-			GUC_NOT_IN_SAMPLE | GUC_DISALLOW_IN_FILE
+			GUC_NOT_IN_SAMPLE | GUC_DISALLOW_IN_FILE | GUC_DEFAULT_COMPILE
 		},
 		&assert_enabled,
 #ifdef USE_ASSERT_CHECKING
@@ -1367,7 +1367,8 @@ struct config_bool ConfigureNamesBool[] =
 	{
 		{"update_process_title", PGC_SUSET, PROCESS_TITLE,
 			gettext_noop("Updates the process title to show the active SQL command."),
-			gettext_noop("Enables updating of the process title every time a new SQL command is received by the server.")
+			gettext_noop("Enables updating of the process title every time a new SQL command is received by the server."),
+			GUC_DEFAULT_COMPILE
 		},
 		&update_process_title,
 #ifdef WIN32
@@ -2116,7 +2117,8 @@ struct config_int ConfigureNamesInt[] =
 	{
 		{"max_connections", PGC_POSTMASTER, CONN_AUTH_SETTINGS,
 			gettext_noop("Sets the maximum number of concurrent connections."),
-			NULL
+			NULL,
+			GUC_DEFAULT_INITDB
 		},
 		&MaxConnections,
 		100, 1, MAX_BACKENDS,
@@ -2153,7 +2155,7 @@ struct config_int ConfigureNamesInt[] =
 		{"shared_buffers", PGC_POSTMASTER, RESOURCES_MEM,
 			gettext_noop("Sets the number of shared memory buffers used by the server."),
 			NULL,
-			GUC_UNIT_BLOCKS
+			GUC_UNIT_BLOCKS | GUC_DEFAULT_INITDB
 		},
 		&NBuffers,
 		16384, 16, INT_MAX / 2,
@@ -2196,7 +2198,8 @@ struct config_int ConfigureNamesInt[] =
 	{
 		{"port", PGC_POSTMASTER, CONN_AUTH_SETTINGS,
 			gettext_noop("Sets the TCP port the server listens on."),
-			NULL
+			NULL,
+			GUC_DEFAULT_COMPILE
 		},
 		&PostPortNumber,
 		DEF_PGPORT, 1, 65535,
@@ -2225,7 +2228,8 @@ struct config_int ConfigureNamesInt[] =
 						 "to be a numeric mode specification in the form "
 						 "accepted by the chmod and umask system calls. "
 						 "(To use the customary octal format the number must "
-						 "start with a 0 (zero).)")
+						 "start with a 0 (zero).)"),
+			GUC_DEFAULT_INITDB
 		},
 		&Log_file_mode,
 		0600, 0000, 0777,
@@ -2667,7 +2671,7 @@ struct config_int ConfigureNamesInt[] =
 		{"checkpoint_flush_after", PGC_SIGHUP, WAL_CHECKPOINTS,
 			gettext_noop("Number of pages after which previously performed writes are flushed to disk."),
 			NULL,
-			GUC_UNIT_BLOCKS
+			GUC_UNIT_BLOCKS | GUC_DEFAULT_COMPILE
 		},
 		&checkpoint_flush_after,
 		DEFAULT_CHECKPOINT_FLUSH_AFTER, 0, WRITEBACK_MAX_PENDING_FLUSHES,
@@ -2885,7 +2889,7 @@ struct config_int ConfigureNamesInt[] =
 		{"bgwriter_flush_after", PGC_SIGHUP, RESOURCES_BGWRITER,
 			gettext_noop("Number of pages after which previously performed writes are flushed to disk."),
 			NULL,
-			GUC_UNIT_BLOCKS
+			GUC_UNIT_BLOCKS | GUC_DEFAULT_COMPILE
 		},
 		&bgwriter_flush_after,
 		DEFAULT_BGWRITER_FLUSH_AFTER, 0, WRITEBACK_MAX_PENDING_FLUSHES,
@@ -2898,7 +2902,7 @@ struct config_int ConfigureNamesInt[] =
 			RESOURCES_ASYNCHRONOUS,
 			gettext_noop("Number of simultaneous requests that can be handled efficiently by the disk subsystem."),
 			NULL,
-			GUC_EXPLAIN
+			GUC_EXPLAIN | GUC_DEFAULT_COMPILE
 		},
 		&effective_io_concurrency,
 #ifdef USE_PREFETCH
@@ -2916,7 +2920,7 @@ struct config_int ConfigureNamesInt[] =
 			RESOURCES_ASYNCHRONOUS,
 			gettext_noop("A variant of effective_io_concurrency that is used for maintenance work."),
 			NULL,
-			GUC_EXPLAIN
+			GUC_EXPLAIN | GUC_DEFAULT_COMPILE
 		},
 		&maintenance_io_concurrency,
 #ifdef USE_PREFETCH
@@ -2933,7 +2937,7 @@ struct config_int ConfigureNamesInt[] =
 		{"backend_flush_after", PGC_USERSET, RESOURCES_ASYNCHRONOUS,
 			gettext_noop("Number of pages after which previously performed writes are flushed to disk."),
 			NULL,
-			GUC_UNIT_BLOCKS
+			GUC_UNIT_BLOCKS | GUC_DEFAULT_COMPILE
 		},
 		&backend_flush_after,
 		DEFAULT_BACKEND_FLUSH_AFTER, 0, WRITEBACK_MAX_PENDING_FLUSHES,
@@ -3387,7 +3391,7 @@ struct config_int ConfigureNamesInt[] =
 		{"debug_discard_caches", PGC_SUSET, DEVELOPER_OPTIONS,
 			gettext_noop("Aggressively flush system caches for debugging purposes."),
 			NULL,
-			GUC_NOT_IN_SAMPLE
+			GUC_NOT_IN_SAMPLE | GUC_DEFAULT_COMPILE
 		},
 		&debug_discard_caches,
 #ifdef DISCARD_CACHES_ENABLED
@@ -3880,7 +3884,8 @@ struct config_string ConfigureNamesString[] =
 	{
 		{"log_timezone", PGC_SIGHUP, LOGGING_WHAT,
 			gettext_noop("Sets the time zone to use in log messages."),
-			NULL
+			NULL,
+			GUC_DEFAULT_INITDB
 		},
 		&log_timezone_string,
 		"GMT",
@@ -3892,7 +3897,7 @@ struct config_string ConfigureNamesString[] =
 			gettext_noop("Sets the display format for date and time values."),
 			gettext_noop("Also controls interpretation of ambiguous "
 						 "date inputs."),
-			GUC_LIST_INPUT | GUC_REPORT
+			GUC_LIST_INPUT | GUC_REPORT | GUC_DEFAULT_INITDB
 		},
 		&datestyle_string,
 		"ISO, MDY",
@@ -3994,7 +3999,8 @@ struct config_string ConfigureNamesString[] =
 	{
 		{"lc_messages", PGC_SUSET, CLIENT_CONN_LOCALE,
 			gettext_noop("Sets the language in which messages are displayed."),
-			NULL
+			NULL,
+			GUC_DEFAULT_INITDB
 		},
 		&locale_messages,
 		"",
@@ -4004,7 +4010,8 @@ struct config_string ConfigureNamesString[] =
 	{
 		{"lc_monetary", PGC_USERSET, CLIENT_CONN_LOCALE,
 			gettext_noop("Sets the locale for formatting monetary amounts."),
-			NULL
+			NULL,
+			GUC_DEFAULT_INITDB
 		},
 		&locale_monetary,
 		"C",
@@ -4014,7 +4021,8 @@ struct config_string ConfigureNamesString[] =
 	{
 		{"lc_numeric", PGC_USERSET, CLIENT_CONN_LOCALE,
 			gettext_noop("Sets the locale for formatting numbers."),
-			NULL
+			NULL,
+			GUC_DEFAULT_INITDB
 		},
 		&locale_numeric,
 		"C",
@@ -4024,7 +4032,8 @@ struct config_string ConfigureNamesString[] =
 	{
 		{"lc_time", PGC_USERSET, CLIENT_CONN_LOCALE,
 			gettext_noop("Sets the locale for formatting date and time values."),
-			NULL
+			NULL,
+			GUC_DEFAULT_INITDB
 		},
 		&locale_time,
 		"C",
@@ -4183,7 +4192,8 @@ struct config_string ConfigureNamesString[] =
 		{"TimeZone", PGC_USERSET, CLIENT_CONN_LOCALE,
 			gettext_noop("Sets the time zone for displaying and interpreting time stamps."),
 			NULL,
-			GUC_REPORT
+			GUC_REPORT | GUC_DEFAULT_INITDB
+
 		},
 		&timezone_string,
 		"GMT",
@@ -4214,7 +4224,7 @@ struct config_string ConfigureNamesString[] =
 		{"unix_socket_directories", PGC_POSTMASTER, CONN_AUTH_SETTINGS,
 			gettext_noop("Sets the directories where Unix-domain sockets will be created."),
 			NULL,
-			GUC_LIST_INPUT | GUC_LIST_QUOTE | GUC_SUPERUSER_ONLY
+			GUC_LIST_INPUT | GUC_LIST_QUOTE | GUC_SUPERUSER_ONLY | GUC_DEFAULT_COMPILE
 		},
 		&Unix_socket_directories,
 		DEFAULT_PGSOCKET_DIR,
@@ -4295,7 +4305,7 @@ struct config_string ConfigureNamesString[] =
 		{"ssl_library", PGC_INTERNAL, PRESET_OPTIONS,
 			gettext_noop("Shows the name of the SSL library."),
 			NULL,
-			GUC_NOT_IN_SAMPLE | GUC_DISALLOW_IN_FILE
+			GUC_NOT_IN_SAMPLE | GUC_DISALLOW_IN_FILE | GUC_DEFAULT_COMPILE
 		},
 		&ssl_library,
 #ifdef USE_SSL
@@ -4370,7 +4380,9 @@ struct config_string ConfigureNamesString[] =
 	{
 		{"default_text_search_config", PGC_USERSET, CLIENT_CONN_LOCALE,
 			gettext_noop("Sets default text search configuration."),
-			NULL
+			NULL,
+			GUC_DEFAULT_INITDB
+
 		},
 		&TSCurrentConfig,
 		"pg_catalog.simple",
@@ -4381,7 +4393,7 @@ struct config_string ConfigureNamesString[] =
 		{"ssl_ciphers", PGC_SIGHUP, CONN_AUTH_SSL,
 			gettext_noop("Sets the list of allowed SSL ciphers."),
 			NULL,
-			GUC_SUPERUSER_ONLY
+			GUC_SUPERUSER_ONLY | GUC_DEFAULT_COMPILE
 		},
 		&SSLCipherSuites,
 #ifdef USE_OPENSSL
@@ -4396,7 +4408,7 @@ struct config_string ConfigureNamesString[] =
 		{"ssl_ecdh_curve", PGC_SIGHUP, CONN_AUTH_SSL,
 			gettext_noop("Sets the curve to use for ECDH."),
 			NULL,
-			GUC_SUPERUSER_ONLY
+			GUC_SUPERUSER_ONLY | GUC_DEFAULT_COMPILE
 		},
 		&SSLECDHCurve,
 #ifdef USE_SSL
@@ -4634,7 +4646,8 @@ struct config_enum ConfigureNamesEnum[] =
 	{
 		{"syslog_facility", PGC_SIGHUP, LOGGING_WHERE,
 			gettext_noop("Sets the syslog \"facility\" to be used when syslog enabled."),
-			NULL
+			NULL,
+			GUC_DEFAULT_COMPILE
 		},
 		&syslog_facility,
 #ifdef HAVE_SYSLOG
@@ -4747,7 +4760,9 @@ struct config_enum ConfigureNamesEnum[] =
 	{
 		{"dynamic_shared_memory_type", PGC_POSTMASTER, RESOURCES_MEM,
 			gettext_noop("Selects the dynamic shared memory implementation used."),
-			NULL
+			NULL,
+			/* platform-specific default, which is also overriden during initdb */
+			GUC_DEFAULT_COMPILE | GUC_DEFAULT_INITDB
 		},
 		&dynamic_shared_memory_type,
 		DEFAULT_DYNAMIC_SHARED_MEMORY_TYPE, dynamic_shared_memory_options,
@@ -4757,7 +4772,8 @@ struct config_enum ConfigureNamesEnum[] =
 	{
 		{"shared_memory_type", PGC_POSTMASTER, RESOURCES_MEM,
 			gettext_noop("Selects the shared memory implementation used for the main shared memory region."),
-			NULL
+			NULL,
+			GUC_DEFAULT_COMPILE
 		},
 		&shared_memory_type,
 		DEFAULT_SHARED_MEMORY_TYPE, shared_memory_options,
@@ -4767,7 +4783,8 @@ struct config_enum ConfigureNamesEnum[] =
 	{
 		{"wal_sync_method", PGC_SIGHUP, WAL_SETTINGS,
 			gettext_noop("Selects the method used for forcing WAL updates to disk."),
-			NULL
+			NULL,
+			GUC_DEFAULT_COMPILE
 		},
 		&sync_method,
 		DEFAULT_SYNC_METHOD, sync_method_options,
@@ -4829,7 +4846,8 @@ struct config_enum ConfigureNamesEnum[] =
 	{
 		{"password_encryption", PGC_USERSET, CONN_AUTH_AUTH,
 			gettext_noop("Chooses the algorithm for encrypting passwords."),
-			NULL
+			NULL,
+			GUC_DEFAULT_INITDB
 		},
 		&Password_encryption,
 		PASSWORD_TYPE_SCRAM_SHA_256, password_encryption_options,
diff --git a/src/include/utils/guc.h b/src/include/utils/guc.h
index b3aaff9665b..79053583a03 100644
--- a/src/include/utils/guc.h
+++ b/src/include/utils/guc.h
@@ -221,6 +221,8 @@ typedef enum
 #define GUC_DISALLOW_IN_AUTO_FILE \
 							   0x002000 /* can't set in PG_AUTOCONF_FILENAME */
 #define GUC_RUNTIME_COMPUTED   0x004000 /* delay processing in 'postgres -C' */
+#define GUC_DEFAULT_COMPILE	   0x008000	/* default is determined at compile time */
+#define GUC_DEFAULT_INITDB	   0x010000	/* default is determined at during initdb */
 
 #define GUC_UNIT_KB			 0x01000000 /* value is in kilobytes */
 #define GUC_UNIT_BLOCKS		 0x02000000 /* value is in blocks */
-- 
2.25.1

From 862586ef48b35071393c858c01419144d09c8400 Mon Sep 17 00:00:00 2001
From: Justin Pryzby <pryzbyj@telsasoft.com>
Date: Wed, 25 May 2022 05:14:43 -0500
Subject: [PATCH 2/2] WIP: test guc default values

---
 src/backend/utils/misc/postgresql.conf.sample |  2 +-
 src/test/modules/test_misc/t/003_check_guc.pl | 33 +++++++++++++++++++
 2 files changed, 34 insertions(+), 1 deletion(-)

diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample
index 1ce0dee6d04..21bfbef3291 100644
--- a/src/backend/utils/misc/postgresql.conf.sample
+++ b/src/backend/utils/misc/postgresql.conf.sample
@@ -720,7 +720,7 @@
 					# share/timezonesets/.
 #extra_float_digits = 1			# min -15, max 3; any value >0 actually
 					# selects precise output mode
-#client_encoding = sql_ascii		# actually, defaults to database
+#client_encoding = SQL_ASCII		# actually, defaults to database
 					# encoding
 
 # These settings are initialized by initdb, but they can be changed.
diff --git a/src/test/modules/test_misc/t/003_check_guc.pl b/src/test/modules/test_misc/t/003_check_guc.pl
index 60459ef759e..a660e85db58 100644
--- a/src/test/modules/test_misc/t/003_check_guc.pl
+++ b/src/test/modules/test_misc/t/003_check_guc.pl
@@ -107,4 +107,37 @@ foreach my $param (@sample_intersect)
 	);
 }
 
+# Test that GUCs in postgresql.conf.sample show the correct default values
+my $check_defaults = $node->safe_psql(
+	'postgres',
+	"
+	CREATE TABLE sample_conf AS
+	SELECT m[1] AS name, COALESCE(m[3], m[5]) AS sample_value
+	FROM (SELECT regexp_split_to_table(pg_read_file('../../../$sample_file'), '\n') AS ln) conf,
+	regexp_match(ln, '^#?([_[:alpha:]]+) (= ''([^'']*)''|(= ([^[:space:]]*))).*') AS m
+	WHERE ln ~ '^#?[[:alpha:]]'
+	");
+
+$check_defaults = $node->safe_psql(
+	'postgres',
+	"
+	SELECT name, current_setting(name), sc.sample_value, boot_val
+	FROM pg_show_all_settings() psas
+	JOIN sample_conf sc USING(name)
+	WHERE sc.sample_value != boot_val -- same value (specified by Cluster.pm)
+	AND sc.sample_value != current_setting(name) -- same value, with human units
+	AND sc.sample_value != current_setting(name)||'.0' -- same value with .0 suffix
+	AND 'DEFAULT_COMPILE' != ALL(pg_settings_get_flags(psas.name)) -- dynamically-set defaults
+	AND 'DEFAULT_INITDB' != ALL(pg_settings_get_flags(psas.name)) -- dynamically-set defaults
+	AND NOT (sc.sample_value ~ '^0' AND current_setting(name) ~ '^0') -- zeros may be written differently
+	AND NOT (sc.sample_value='60s' AND current_setting(name) = '1min') -- two ways to write 1min
+	AND name NOT IN ('krb_server_keyfile', 'wal_retrieve_retry_interval', 'log_autovacuum_min_duration'); -- exceptions
+	");
+
+my @check_defaults_array = split("\n", lc($check_defaults));
+print(STDERR "$check_defaults\n");
+
+is (@check_defaults_array, 0,
+	'check for consistency of defaults in postgresql.conf.sample');
+
 done_testing();
-- 
2.25.1

From e1f0940e7682052b2ec9d58c361f56630aa1742e Mon Sep 17 00:00:00 2001
From: Justin Pryzby <pryzbyj@telsasoft.com>
Date: Tue, 19 Jul 2022 08:31:56 -0500
Subject: [PATCH 1/2] pg_settings_get_flags(): add DEFAULT_COMPILE and
 DEFAULT_INITDB ..

for settings which vary by ./configure or platform or initdb

Note that this is independent from PGC_S_DYNAMIC_DEFAULT.
---
 doc/src/sgml/func.sgml              | 15 ++++++
 src/backend/utils/misc/guc_funcs.c  |  6 ++-
 src/backend/utils/misc/guc_tables.c | 76 ++++++++++++++++++-----------
 src/include/utils/guc.h             |  2 +
 4 files changed, 69 insertions(+), 30 deletions(-)

diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 82fba48d5f7..67c68fc9292 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -24377,6 +24377,21 @@ SELECT collation for ('foo' COLLATE "de_DE");
      <row><entry>Flag</entry><entry>Description</entry></row>
     </thead>
     <tbody>
+
+     <row>
+      <entry><literal>DEFAULT_COMPILE</literal></entry>
+      <entry>Parameters with this flag have default values which vary by
+      platform, or compile-time options.
+      </entry>
+     </row>
+
+     <row>
+      <entry><literal>DEFAULT_INITDB</literal></entry>
+      <entry>Parameters with this flag have default values which are
+      determined dynamically during initdb.
+      </entry>
+     </row>
+
      <row>
       <entry><literal>EXPLAIN</literal></entry>
       <entry>Parameters with this flag are included in
diff --git a/src/backend/utils/misc/guc_funcs.c b/src/backend/utils/misc/guc_funcs.c
index 108b3bd1290..2b666e8d014 100644
--- a/src/backend/utils/misc/guc_funcs.c
+++ b/src/backend/utils/misc/guc_funcs.c
@@ -538,7 +538,7 @@ ShowAllGUCConfig(DestReceiver *dest)
 Datum
 pg_settings_get_flags(PG_FUNCTION_ARGS)
 {
-#define MAX_GUC_FLAGS	6
+#define MAX_GUC_FLAGS	8
 	char	   *varname = TextDatumGetCString(PG_GETARG_DATUM(0));
 	struct config_generic *record;
 	int			cnt = 0;
@@ -551,6 +551,10 @@ pg_settings_get_flags(PG_FUNCTION_ARGS)
 	if (record == NULL)
 		PG_RETURN_NULL();
 
+	if (record->flags & GUC_DEFAULT_COMPILE)
+		flags[cnt++] = CStringGetTextDatum("DEFAULT_COMPILE");
+	if (record->flags & GUC_DEFAULT_INITDB)
+		flags[cnt++] = CStringGetTextDatum("DEFAULT_INITDB");
 	if (record->flags & GUC_EXPLAIN)
 		flags[cnt++] = CStringGetTextDatum("EXPLAIN");
 	if (record->flags & GUC_NO_RESET)
diff --git a/src/backend/utils/misc/guc_tables.c b/src/backend/utils/misc/guc_tables.c
index e5cc4e3205a..6bd206c164a 100644
--- a/src/backend/utils/misc/guc_tables.c
+++ b/src/backend/utils/misc/guc_tables.c
@@ -1205,7 +1205,7 @@ struct config_bool ConfigureNamesBool[] =
 		{"debug_assertions", PGC_INTERNAL, PRESET_OPTIONS,
 			gettext_noop("Shows whether the running server has assertion checks enabled."),
 			NULL,
-			GUC_NOT_IN_SAMPLE | GUC_DISALLOW_IN_FILE
+			GUC_NOT_IN_SAMPLE | GUC_DISALLOW_IN_FILE | GUC_DEFAULT_COMPILE
 		},
 		&assert_enabled,
 		DEFAULT_ASSERT_ENABLED,
@@ -1377,7 +1377,8 @@ struct config_bool ConfigureNamesBool[] =
 	{
 		{"update_process_title", PGC_SUSET, PROCESS_TITLE,
 			gettext_noop("Updates the process title to show the active SQL command."),
-			gettext_noop("Enables updating of the process title every time a new SQL command is received by the server.")
+			gettext_noop("Enables updating of the process title every time a new SQL command is received by the server."),
+			GUC_DEFAULT_COMPILE
 		},
 		&update_process_title,
 		DEFAULT_UPDATE_PROCESS_TITLE,
@@ -2122,7 +2123,8 @@ struct config_int ConfigureNamesInt[] =
 	{
 		{"max_connections", PGC_POSTMASTER, CONN_AUTH_SETTINGS,
 			gettext_noop("Sets the maximum number of concurrent connections."),
-			NULL
+			NULL,
+			GUC_DEFAULT_INITDB
 		},
 		&MaxConnections,
 		100, 1, MAX_BACKENDS,
@@ -2159,7 +2161,7 @@ struct config_int ConfigureNamesInt[] =
 		{"shared_buffers", PGC_POSTMASTER, RESOURCES_MEM,
 			gettext_noop("Sets the number of shared memory buffers used by the server."),
 			NULL,
-			GUC_UNIT_BLOCKS
+			GUC_UNIT_BLOCKS | GUC_DEFAULT_INITDB
 		},
 		&NBuffers,
 		16384, 16, INT_MAX / 2,
@@ -2202,7 +2204,8 @@ struct config_int ConfigureNamesInt[] =
 	{
 		{"port", PGC_POSTMASTER, CONN_AUTH_SETTINGS,
 			gettext_noop("Sets the TCP port the server listens on."),
-			NULL
+			NULL,
+			GUC_DEFAULT_COMPILE
 		},
 		&PostPortNumber,
 		DEF_PGPORT, 1, 65535,
@@ -2231,7 +2234,8 @@ struct config_int ConfigureNamesInt[] =
 						 "to be a numeric mode specification in the form "
 						 "accepted by the chmod and umask system calls. "
 						 "(To use the customary octal format the number must "
-						 "start with a 0 (zero).)")
+						 "start with a 0 (zero).)"),
+			GUC_DEFAULT_INITDB
 		},
 		&Log_file_mode,
 		0600, 0000, 0777,
@@ -2673,7 +2677,7 @@ struct config_int ConfigureNamesInt[] =
 		{"checkpoint_flush_after", PGC_SIGHUP, WAL_CHECKPOINTS,
 			gettext_noop("Number of pages after which previously performed writes are flushed to disk."),
 			NULL,
-			GUC_UNIT_BLOCKS
+			GUC_UNIT_BLOCKS | GUC_DEFAULT_COMPILE
 		},
 		&checkpoint_flush_after,
 		DEFAULT_CHECKPOINT_FLUSH_AFTER, 0, WRITEBACK_MAX_PENDING_FLUSHES,
@@ -2891,7 +2895,7 @@ struct config_int ConfigureNamesInt[] =
 		{"bgwriter_flush_after", PGC_SIGHUP, RESOURCES_BGWRITER,
 			gettext_noop("Number of pages after which previously performed writes are flushed to disk."),
 			NULL,
-			GUC_UNIT_BLOCKS
+			GUC_UNIT_BLOCKS | GUC_DEFAULT_COMPILE
 		},
 		&bgwriter_flush_after,
 		DEFAULT_BGWRITER_FLUSH_AFTER, 0, WRITEBACK_MAX_PENDING_FLUSHES,
@@ -2904,7 +2908,7 @@ struct config_int ConfigureNamesInt[] =
 			RESOURCES_ASYNCHRONOUS,
 			gettext_noop("Number of simultaneous requests that can be handled efficiently by the disk subsystem."),
 			NULL,
-			GUC_EXPLAIN
+			GUC_EXPLAIN | GUC_DEFAULT_COMPILE
 		},
 		&effective_io_concurrency,
 		DEFAULT_EFFECTIVE_IO_CONCURRENCY,
@@ -2918,7 +2922,7 @@ struct config_int ConfigureNamesInt[] =
 			RESOURCES_ASYNCHRONOUS,
 			gettext_noop("A variant of effective_io_concurrency that is used for maintenance work."),
 			NULL,
-			GUC_EXPLAIN
+			GUC_EXPLAIN | GUC_DEFAULT_COMPILE
 		},
 		&maintenance_io_concurrency,
 		DEFAULT_MAINTENANCE_IO_CONCURRENCY,
@@ -2931,7 +2935,7 @@ struct config_int ConfigureNamesInt[] =
 		{"backend_flush_after", PGC_USERSET, RESOURCES_ASYNCHRONOUS,
 			gettext_noop("Number of pages after which previously performed writes are flushed to disk."),
 			NULL,
-			GUC_UNIT_BLOCKS
+			GUC_UNIT_BLOCKS | GUC_DEFAULT_COMPILE
 		},
 		&backend_flush_after,
 		DEFAULT_BACKEND_FLUSH_AFTER, 0, WRITEBACK_MAX_PENDING_FLUSHES,
@@ -3385,7 +3389,7 @@ struct config_int ConfigureNamesInt[] =
 		{"debug_discard_caches", PGC_SUSET, DEVELOPER_OPTIONS,
 			gettext_noop("Aggressively flush system caches for debugging purposes."),
 			NULL,
-			GUC_NOT_IN_SAMPLE
+			GUC_NOT_IN_SAMPLE | GUC_DEFAULT_COMPILE
 		},
 		&debug_discard_caches,
 #ifdef DISCARD_CACHES_ENABLED
@@ -3878,7 +3882,8 @@ struct config_string ConfigureNamesString[] =
 	{
 		{"log_timezone", PGC_SIGHUP, LOGGING_WHAT,
 			gettext_noop("Sets the time zone to use in log messages."),
-			NULL
+			NULL,
+			GUC_DEFAULT_INITDB
 		},
 		&log_timezone_string,
 		"GMT",
@@ -3890,7 +3895,7 @@ struct config_string ConfigureNamesString[] =
 			gettext_noop("Sets the display format for date and time values."),
 			gettext_noop("Also controls interpretation of ambiguous "
 						 "date inputs."),
-			GUC_LIST_INPUT | GUC_REPORT
+			GUC_LIST_INPUT | GUC_REPORT | GUC_DEFAULT_INITDB
 		},
 		&datestyle_string,
 		"ISO, MDY",
@@ -3992,7 +3997,8 @@ struct config_string ConfigureNamesString[] =
 	{
 		{"lc_messages", PGC_SUSET, CLIENT_CONN_LOCALE,
 			gettext_noop("Sets the language in which messages are displayed."),
-			NULL
+			NULL,
+			GUC_DEFAULT_INITDB
 		},
 		&locale_messages,
 		"",
@@ -4002,7 +4008,8 @@ struct config_string ConfigureNamesString[] =
 	{
 		{"lc_monetary", PGC_USERSET, CLIENT_CONN_LOCALE,
 			gettext_noop("Sets the locale for formatting monetary amounts."),
-			NULL
+			NULL,
+			GUC_DEFAULT_INITDB
 		},
 		&locale_monetary,
 		"C",
@@ -4012,7 +4019,8 @@ struct config_string ConfigureNamesString[] =
 	{
 		{"lc_numeric", PGC_USERSET, CLIENT_CONN_LOCALE,
 			gettext_noop("Sets the locale for formatting numbers."),
-			NULL
+			NULL,
+			GUC_DEFAULT_INITDB
 		},
 		&locale_numeric,
 		"C",
@@ -4022,7 +4030,8 @@ struct config_string ConfigureNamesString[] =
 	{
 		{"lc_time", PGC_USERSET, CLIENT_CONN_LOCALE,
 			gettext_noop("Sets the locale for formatting date and time values."),
-			NULL
+			NULL,
+			GUC_DEFAULT_INITDB
 		},
 		&locale_time,
 		"C",
@@ -4181,7 +4190,8 @@ struct config_string ConfigureNamesString[] =
 		{"TimeZone", PGC_USERSET, CLIENT_CONN_LOCALE,
 			gettext_noop("Sets the time zone for displaying and interpreting time stamps."),
 			NULL,
-			GUC_REPORT
+			GUC_REPORT | GUC_DEFAULT_INITDB
+
 		},
 		&timezone_string,
 		"GMT",
@@ -4212,7 +4222,7 @@ struct config_string ConfigureNamesString[] =
 		{"unix_socket_directories", PGC_POSTMASTER, CONN_AUTH_SETTINGS,
 			gettext_noop("Sets the directories where Unix-domain sockets will be created."),
 			NULL,
-			GUC_LIST_INPUT | GUC_LIST_QUOTE | GUC_SUPERUSER_ONLY
+			GUC_LIST_INPUT | GUC_LIST_QUOTE | GUC_SUPERUSER_ONLY | GUC_DEFAULT_COMPILE
 		},
 		&Unix_socket_directories,
 		DEFAULT_PGSOCKET_DIR,
@@ -4293,7 +4303,7 @@ struct config_string ConfigureNamesString[] =
 		{"ssl_library", PGC_INTERNAL, PRESET_OPTIONS,
 			gettext_noop("Shows the name of the SSL library."),
 			NULL,
-			GUC_NOT_IN_SAMPLE | GUC_DISALLOW_IN_FILE
+			GUC_NOT_IN_SAMPLE | GUC_DISALLOW_IN_FILE | GUC_DEFAULT_COMPILE
 		},
 		&ssl_library,
 #ifdef USE_SSL
@@ -4368,7 +4378,9 @@ struct config_string ConfigureNamesString[] =
 	{
 		{"default_text_search_config", PGC_USERSET, CLIENT_CONN_LOCALE,
 			gettext_noop("Sets default text search configuration."),
-			NULL
+			NULL,
+			GUC_DEFAULT_INITDB
+
 		},
 		&TSCurrentConfig,
 		"pg_catalog.simple",
@@ -4379,7 +4391,7 @@ struct config_string ConfigureNamesString[] =
 		{"ssl_ciphers", PGC_SIGHUP, CONN_AUTH_SSL,
 			gettext_noop("Sets the list of allowed SSL ciphers."),
 			NULL,
-			GUC_SUPERUSER_ONLY
+			GUC_SUPERUSER_ONLY | GUC_DEFAULT_COMPILE
 		},
 		&SSLCipherSuites,
 #ifdef USE_OPENSSL
@@ -4394,7 +4406,7 @@ struct config_string ConfigureNamesString[] =
 		{"ssl_ecdh_curve", PGC_SIGHUP, CONN_AUTH_SSL,
 			gettext_noop("Sets the curve to use for ECDH."),
 			NULL,
-			GUC_SUPERUSER_ONLY
+			GUC_SUPERUSER_ONLY | GUC_DEFAULT_COMPILE
 		},
 		&SSLECDHCurve,
 #ifdef USE_SSL
@@ -4632,7 +4644,8 @@ struct config_enum ConfigureNamesEnum[] =
 	{
 		{"syslog_facility", PGC_SIGHUP, LOGGING_WHERE,
 			gettext_noop("Sets the syslog \"facility\" to be used when syslog enabled."),
-			NULL
+			NULL,
+			GUC_DEFAULT_COMPILE
 		},
 		&syslog_facility,
 		DEFAULT_SYSLOG_FACILITY,
@@ -4741,7 +4754,9 @@ struct config_enum ConfigureNamesEnum[] =
 	{
 		{"dynamic_shared_memory_type", PGC_POSTMASTER, RESOURCES_MEM,
 			gettext_noop("Selects the dynamic shared memory implementation used."),
-			NULL
+			NULL,
+			/* platform-specific default, which is also overriden during initdb */
+			GUC_DEFAULT_COMPILE | GUC_DEFAULT_INITDB
 		},
 		&dynamic_shared_memory_type,
 		DEFAULT_DYNAMIC_SHARED_MEMORY_TYPE, dynamic_shared_memory_options,
@@ -4751,7 +4766,8 @@ struct config_enum ConfigureNamesEnum[] =
 	{
 		{"shared_memory_type", PGC_POSTMASTER, RESOURCES_MEM,
 			gettext_noop("Selects the shared memory implementation used for the main shared memory region."),
-			NULL
+			NULL,
+			GUC_DEFAULT_COMPILE
 		},
 		&shared_memory_type,
 		DEFAULT_SHARED_MEMORY_TYPE, shared_memory_options,
@@ -4761,7 +4777,8 @@ struct config_enum ConfigureNamesEnum[] =
 	{
 		{"wal_sync_method", PGC_SIGHUP, WAL_SETTINGS,
 			gettext_noop("Selects the method used for forcing WAL updates to disk."),
-			NULL
+			NULL,
+			GUC_DEFAULT_COMPILE
 		},
 		&sync_method,
 		DEFAULT_SYNC_METHOD, sync_method_options,
@@ -4823,7 +4840,8 @@ struct config_enum ConfigureNamesEnum[] =
 	{
 		{"password_encryption", PGC_USERSET, CONN_AUTH_AUTH,
 			gettext_noop("Chooses the algorithm for encrypting passwords."),
-			NULL
+			NULL,
+			GUC_DEFAULT_INITDB
 		},
 		&Password_encryption,
 		PASSWORD_TYPE_SCRAM_SHA_256, password_encryption_options,
diff --git a/src/include/utils/guc.h b/src/include/utils/guc.h
index b3aaff9665b..79053583a03 100644
--- a/src/include/utils/guc.h
+++ b/src/include/utils/guc.h
@@ -221,6 +221,8 @@ typedef enum
 #define GUC_DISALLOW_IN_AUTO_FILE \
 							   0x002000 /* can't set in PG_AUTOCONF_FILENAME */
 #define GUC_RUNTIME_COMPUTED   0x004000 /* delay processing in 'postgres -C' */
+#define GUC_DEFAULT_COMPILE	   0x008000	/* default is determined at compile time */
+#define GUC_DEFAULT_INITDB	   0x010000	/* default is determined at during initdb */
 
 #define GUC_UNIT_KB			 0x01000000 /* value is in kilobytes */
 #define GUC_UNIT_BLOCKS		 0x02000000 /* value is in blocks */
-- 
2.25.1

From 8ba199da40fc44c851224d6b088a15e4464c2419 Mon Sep 17 00:00:00 2001
From: Justin Pryzby <pryzbyj@telsasoft.com>
Date: Wed, 25 May 2022 05:14:43 -0500
Subject: [PATCH 2/2] WIP: test GUC default values

---
 src/backend/utils/misc/postgresql.conf.sample |  2 +-
 src/test/modules/test_misc/t/003_check_guc.pl | 33 +++++++++++++++++++
 2 files changed, 34 insertions(+), 1 deletion(-)

diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample
index 1ce0dee6d04..21bfbef3291 100644
--- a/src/backend/utils/misc/postgresql.conf.sample
+++ b/src/backend/utils/misc/postgresql.conf.sample
@@ -720,7 +720,7 @@
 					# share/timezonesets/.
 #extra_float_digits = 1			# min -15, max 3; any value >0 actually
 					# selects precise output mode
-#client_encoding = sql_ascii		# actually, defaults to database
+#client_encoding = SQL_ASCII		# actually, defaults to database
 					# encoding
 
 # These settings are initialized by initdb, but they can be changed.
diff --git a/src/test/modules/test_misc/t/003_check_guc.pl b/src/test/modules/test_misc/t/003_check_guc.pl
index 1786cd19299..22e8612350c 100644
--- a/src/test/modules/test_misc/t/003_check_guc.pl
+++ b/src/test/modules/test_misc/t/003_check_guc.pl
@@ -106,4 +106,37 @@ foreach my $param (@sample_intersect)
 	);
 }
 
+# Test that GUCs in postgresql.conf.sample show the correct default values
+my $check_defaults = $node->safe_psql(
+	'postgres',
+	"
+	CREATE TABLE sample_conf AS
+	SELECT m[1] AS name, COALESCE(m[3], m[5]) AS sample_value
+	FROM (SELECT regexp_split_to_table(pg_read_file('$sample_file'), '\n') AS ln) conf,
+	regexp_match(ln, '^#?([_[:alpha:]]+) (= ''([^'']*)''|(= ([^[:space:]]*))).*') AS m
+	WHERE ln ~ '^#?[[:alpha:]]'
+	");
+
+$check_defaults = $node->safe_psql(
+	'postgres',
+	"
+	SELECT name, current_setting(name), sc.sample_value, boot_val
+	FROM pg_show_all_settings() psas
+	JOIN sample_conf sc USING(name)
+	WHERE sc.sample_value != boot_val -- same value (specified by Cluster.pm)
+	AND sc.sample_value != current_setting(name) -- same value, with human units
+	AND sc.sample_value != current_setting(name)||'.0' -- same value with .0 suffix
+	AND 'DEFAULT_COMPILE' != ALL(pg_settings_get_flags(psas.name)) -- dynamically-set defaults
+	AND 'DEFAULT_INITDB' != ALL(pg_settings_get_flags(psas.name)) -- dynamically-set defaults
+	AND NOT (sc.sample_value ~ '^0' AND current_setting(name) ~ '^0') -- zeros may be written differently
+	AND NOT (sc.sample_value='60s' AND current_setting(name) = '1min') -- two ways to write 1min
+	AND name NOT IN ('krb_server_keyfile', 'wal_retrieve_retry_interval', 'log_autovacuum_min_duration'); -- exceptions
+	");
+
+my @check_defaults_array = split("\n", lc($check_defaults));
+print(STDERR "$check_defaults\n");
+
+is (@check_defaults_array, 0,
+	'check for consistency of defaults in postgresql.conf.sample');
+
 done_testing();
-- 
2.25.1

From b38dce442fa20439c6b75b9f4bac20d52d3dd94b Mon Sep 17 00:00:00 2001
From: Justin Pryzby <pryzbyj@telsasoft.com>
Date: Tue, 19 Jul 2022 08:31:56 -0500
Subject: [PATCH 1/2] pg_settings_get_flags(): add DEFAULT_COMPILE and
 DEFAULT_INITDB ..

for settings which vary by ./configure or platform or initdb

Note that this is independent from PGC_S_DYNAMIC_DEFAULT.
---
 doc/src/sgml/func.sgml              | 15 ++++++
 src/backend/utils/misc/guc_funcs.c  |  6 ++-
 src/backend/utils/misc/guc_tables.c | 76 ++++++++++++++++++-----------
 src/include/utils/guc.h             |  2 +
 4 files changed, 69 insertions(+), 30 deletions(-)

diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index d599b243b10..66451a6c759 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -24825,6 +24825,21 @@ SELECT collation for ('foo' COLLATE "de_DE");
      <row><entry>Flag</entry><entry>Description</entry></row>
     </thead>
     <tbody>
+
+     <row>
+      <entry><literal>DEFAULT_COMPILE</literal></entry>
+      <entry>Parameters with this flag have default values which vary by
+      platform, or compile-time options.
+      </entry>
+     </row>
+
+     <row>
+      <entry><literal>DEFAULT_INITDB</literal></entry>
+      <entry>Parameters with this flag have default values which are
+      determined dynamically during initdb.
+      </entry>
+     </row>
+
      <row>
       <entry><literal>EXPLAIN</literal></entry>
       <entry>Parameters with this flag are included in
diff --git a/src/backend/utils/misc/guc_funcs.c b/src/backend/utils/misc/guc_funcs.c
index 2ce1e53ec54..70fdce3868d 100644
--- a/src/backend/utils/misc/guc_funcs.c
+++ b/src/backend/utils/misc/guc_funcs.c
@@ -577,7 +577,7 @@ ShowAllGUCConfig(DestReceiver *dest)
 Datum
 pg_settings_get_flags(PG_FUNCTION_ARGS)
 {
-#define MAX_GUC_FLAGS	6
+#define MAX_GUC_FLAGS	8
 	char	   *varname = TextDatumGetCString(PG_GETARG_DATUM(0));
 	struct config_generic *record;
 	int			cnt = 0;
@@ -590,6 +590,10 @@ pg_settings_get_flags(PG_FUNCTION_ARGS)
 	if (record == NULL)
 		PG_RETURN_NULL();
 
+	if (record->flags & GUC_DEFAULT_COMPILE)
+		flags[cnt++] = CStringGetTextDatum("DEFAULT_COMPILE");
+	if (record->flags & GUC_DEFAULT_INITDB)
+		flags[cnt++] = CStringGetTextDatum("DEFAULT_INITDB");
 	if (record->flags & GUC_EXPLAIN)
 		flags[cnt++] = CStringGetTextDatum("EXPLAIN");
 	if (record->flags & GUC_NO_RESET)
diff --git a/src/backend/utils/misc/guc_tables.c b/src/backend/utils/misc/guc_tables.c
index 2c3061b7359..0d6c782a1df 100644
--- a/src/backend/utils/misc/guc_tables.c
+++ b/src/backend/utils/misc/guc_tables.c
@@ -1233,7 +1233,7 @@ struct config_bool ConfigureNamesBool[] =
 		{"debug_assertions", PGC_INTERNAL, PRESET_OPTIONS,
 			gettext_noop("Shows whether the running server has assertion checks enabled."),
 			NULL,
-			GUC_NOT_IN_SAMPLE | GUC_DISALLOW_IN_FILE
+			GUC_NOT_IN_SAMPLE | GUC_DISALLOW_IN_FILE | GUC_DEFAULT_COMPILE
 		},
 		&assert_enabled,
 		DEFAULT_ASSERT_ENABLED,
@@ -1425,7 +1425,8 @@ struct config_bool ConfigureNamesBool[] =
 	{
 		{"update_process_title", PGC_SUSET, PROCESS_TITLE,
 			gettext_noop("Updates the process title to show the active SQL command."),
-			gettext_noop("Enables updating of the process title every time a new SQL command is received by the server.")
+			gettext_noop("Enables updating of the process title every time a new SQL command is received by the server."),
+			GUC_DEFAULT_COMPILE
 		},
 		&update_process_title,
 		DEFAULT_UPDATE_PROCESS_TITLE,
@@ -2170,7 +2171,8 @@ struct config_int ConfigureNamesInt[] =
 	{
 		{"max_connections", PGC_POSTMASTER, CONN_AUTH_SETTINGS,
 			gettext_noop("Sets the maximum number of concurrent connections."),
-			NULL
+			NULL,
+			GUC_DEFAULT_INITDB
 		},
 		&MaxConnections,
 		100, 1, MAX_BACKENDS,
@@ -2218,7 +2220,7 @@ struct config_int ConfigureNamesInt[] =
 		{"shared_buffers", PGC_POSTMASTER, RESOURCES_MEM,
 			gettext_noop("Sets the number of shared memory buffers used by the server."),
 			NULL,
-			GUC_UNIT_BLOCKS
+			GUC_UNIT_BLOCKS | GUC_DEFAULT_INITDB
 		},
 		&NBuffers,
 		16384, 16, INT_MAX / 2,
@@ -2261,7 +2263,8 @@ struct config_int ConfigureNamesInt[] =
 	{
 		{"port", PGC_POSTMASTER, CONN_AUTH_SETTINGS,
 			gettext_noop("Sets the TCP port the server listens on."),
-			NULL
+			NULL,
+			GUC_DEFAULT_COMPILE
 		},
 		&PostPortNumber,
 		DEF_PGPORT, 1, 65535,
@@ -2290,7 +2293,8 @@ struct config_int ConfigureNamesInt[] =
 						 "to be a numeric mode specification in the form "
 						 "accepted by the chmod and umask system calls. "
 						 "(To use the customary octal format the number must "
-						 "start with a 0 (zero).)")
+						 "start with a 0 (zero).)"),
+			GUC_DEFAULT_INITDB
 		},
 		&Log_file_mode,
 		0600, 0000, 0777,
@@ -2723,7 +2727,7 @@ struct config_int ConfigureNamesInt[] =
 		{"checkpoint_flush_after", PGC_SIGHUP, WAL_CHECKPOINTS,
 			gettext_noop("Number of pages after which previously performed writes are flushed to disk."),
 			NULL,
-			GUC_UNIT_BLOCKS
+			GUC_UNIT_BLOCKS | GUC_DEFAULT_COMPILE
 		},
 		&checkpoint_flush_after,
 		DEFAULT_CHECKPOINT_FLUSH_AFTER, 0, WRITEBACK_MAX_PENDING_FLUSHES,
@@ -2941,7 +2945,7 @@ struct config_int ConfigureNamesInt[] =
 		{"bgwriter_flush_after", PGC_SIGHUP, RESOURCES_BGWRITER,
 			gettext_noop("Number of pages after which previously performed writes are flushed to disk."),
 			NULL,
-			GUC_UNIT_BLOCKS
+			GUC_UNIT_BLOCKS | GUC_DEFAULT_COMPILE
 		},
 		&bgwriter_flush_after,
 		DEFAULT_BGWRITER_FLUSH_AFTER, 0, WRITEBACK_MAX_PENDING_FLUSHES,
@@ -2954,7 +2958,7 @@ struct config_int ConfigureNamesInt[] =
 			RESOURCES_ASYNCHRONOUS,
 			gettext_noop("Number of simultaneous requests that can be handled efficiently by the disk subsystem."),
 			NULL,
-			GUC_EXPLAIN
+			GUC_EXPLAIN | GUC_DEFAULT_COMPILE
 		},
 		&effective_io_concurrency,
 		DEFAULT_EFFECTIVE_IO_CONCURRENCY,
@@ -2968,7 +2972,7 @@ struct config_int ConfigureNamesInt[] =
 			RESOURCES_ASYNCHRONOUS,
 			gettext_noop("A variant of effective_io_concurrency that is used for maintenance work."),
 			NULL,
-			GUC_EXPLAIN
+			GUC_EXPLAIN | GUC_DEFAULT_COMPILE
 		},
 		&maintenance_io_concurrency,
 		DEFAULT_MAINTENANCE_IO_CONCURRENCY,
@@ -2981,7 +2985,7 @@ struct config_int ConfigureNamesInt[] =
 		{"backend_flush_after", PGC_USERSET, RESOURCES_ASYNCHRONOUS,
 			gettext_noop("Number of pages after which previously performed writes are flushed to disk."),
 			NULL,
-			GUC_UNIT_BLOCKS
+			GUC_UNIT_BLOCKS | GUC_DEFAULT_COMPILE
 		},
 		&backend_flush_after,
 		DEFAULT_BACKEND_FLUSH_AFTER, 0, WRITEBACK_MAX_PENDING_FLUSHES,
@@ -3436,7 +3440,7 @@ struct config_int ConfigureNamesInt[] =
 		{"debug_discard_caches", PGC_SUSET, DEVELOPER_OPTIONS,
 			gettext_noop("Aggressively flush system caches for debugging purposes."),
 			NULL,
-			GUC_NOT_IN_SAMPLE
+			GUC_NOT_IN_SAMPLE | GUC_DEFAULT_COMPILE
 		},
 		&debug_discard_caches,
 #ifdef DISCARD_CACHES_ENABLED
@@ -3930,7 +3934,8 @@ struct config_string ConfigureNamesString[] =
 	{
 		{"log_timezone", PGC_SIGHUP, LOGGING_WHAT,
 			gettext_noop("Sets the time zone to use in log messages."),
-			NULL
+			NULL,
+			GUC_DEFAULT_INITDB
 		},
 		&log_timezone_string,
 		"GMT",
@@ -3942,7 +3947,7 @@ struct config_string ConfigureNamesString[] =
 			gettext_noop("Sets the display format for date and time values."),
 			gettext_noop("Also controls interpretation of ambiguous "
 						 "date inputs."),
-			GUC_LIST_INPUT | GUC_REPORT
+			GUC_LIST_INPUT | GUC_REPORT | GUC_DEFAULT_INITDB
 		},
 		&datestyle_string,
 		"ISO, MDY",
@@ -4056,7 +4061,8 @@ struct config_string ConfigureNamesString[] =
 	{
 		{"lc_messages", PGC_SUSET, CLIENT_CONN_LOCALE,
 			gettext_noop("Sets the language in which messages are displayed."),
-			NULL
+			NULL,
+			GUC_DEFAULT_INITDB
 		},
 		&locale_messages,
 		"",
@@ -4066,7 +4072,8 @@ struct config_string ConfigureNamesString[] =
 	{
 		{"lc_monetary", PGC_USERSET, CLIENT_CONN_LOCALE,
 			gettext_noop("Sets the locale for formatting monetary amounts."),
-			NULL
+			NULL,
+			GUC_DEFAULT_INITDB
 		},
 		&locale_monetary,
 		"C",
@@ -4076,7 +4083,8 @@ struct config_string ConfigureNamesString[] =
 	{
 		{"lc_numeric", PGC_USERSET, CLIENT_CONN_LOCALE,
 			gettext_noop("Sets the locale for formatting numbers."),
-			NULL
+			NULL,
+			GUC_DEFAULT_INITDB
 		},
 		&locale_numeric,
 		"C",
@@ -4086,7 +4094,8 @@ struct config_string ConfigureNamesString[] =
 	{
 		{"lc_time", PGC_USERSET, CLIENT_CONN_LOCALE,
 			gettext_noop("Sets the locale for formatting date and time values."),
-			NULL
+			NULL,
+			GUC_DEFAULT_INITDB
 		},
 		&locale_time,
 		"C",
@@ -4245,7 +4254,8 @@ struct config_string ConfigureNamesString[] =
 		{"TimeZone", PGC_USERSET, CLIENT_CONN_LOCALE,
 			gettext_noop("Sets the time zone for displaying and interpreting time stamps."),
 			NULL,
-			GUC_REPORT
+			GUC_REPORT | GUC_DEFAULT_INITDB
+
 		},
 		&timezone_string,
 		"GMT",
@@ -4276,7 +4286,7 @@ struct config_string ConfigureNamesString[] =
 		{"unix_socket_directories", PGC_POSTMASTER, CONN_AUTH_SETTINGS,
 			gettext_noop("Sets the directories where Unix-domain sockets will be created."),
 			NULL,
-			GUC_LIST_INPUT | GUC_LIST_QUOTE | GUC_SUPERUSER_ONLY
+			GUC_LIST_INPUT | GUC_LIST_QUOTE | GUC_SUPERUSER_ONLY | GUC_DEFAULT_COMPILE
 		},
 		&Unix_socket_directories,
 		DEFAULT_PGSOCKET_DIR,
@@ -4357,7 +4367,7 @@ struct config_string ConfigureNamesString[] =
 		{"ssl_library", PGC_INTERNAL, PRESET_OPTIONS,
 			gettext_noop("Shows the name of the SSL library."),
 			NULL,
-			GUC_NOT_IN_SAMPLE | GUC_DISALLOW_IN_FILE
+			GUC_NOT_IN_SAMPLE | GUC_DISALLOW_IN_FILE | GUC_DEFAULT_COMPILE
 		},
 		&ssl_library,
 #ifdef USE_SSL
@@ -4432,7 +4442,9 @@ struct config_string ConfigureNamesString[] =
 	{
 		{"default_text_search_config", PGC_USERSET, CLIENT_CONN_LOCALE,
 			gettext_noop("Sets default text search configuration."),
-			NULL
+			NULL,
+			GUC_DEFAULT_INITDB
+
 		},
 		&TSCurrentConfig,
 		"pg_catalog.simple",
@@ -4443,7 +4455,7 @@ struct config_string ConfigureNamesString[] =
 		{"ssl_ciphers", PGC_SIGHUP, CONN_AUTH_SSL,
 			gettext_noop("Sets the list of allowed SSL ciphers."),
 			NULL,
-			GUC_SUPERUSER_ONLY
+			GUC_SUPERUSER_ONLY | GUC_DEFAULT_COMPILE
 		},
 		&SSLCipherSuites,
 #ifdef USE_OPENSSL
@@ -4458,7 +4470,7 @@ struct config_string ConfigureNamesString[] =
 		{"ssl_ecdh_curve", PGC_SIGHUP, CONN_AUTH_SSL,
 			gettext_noop("Sets the curve to use for ECDH."),
 			NULL,
-			GUC_SUPERUSER_ONLY
+			GUC_SUPERUSER_ONLY | GUC_DEFAULT_COMPILE
 		},
 		&SSLECDHCurve,
 #ifdef USE_SSL
@@ -4717,7 +4729,8 @@ struct config_enum ConfigureNamesEnum[] =
 	{
 		{"syslog_facility", PGC_SIGHUP, LOGGING_WHERE,
 			gettext_noop("Sets the syslog \"facility\" to be used when syslog enabled."),
-			NULL
+			NULL,
+			GUC_DEFAULT_COMPILE
 		},
 		&syslog_facility,
 		DEFAULT_SYSLOG_FACILITY,
@@ -4826,7 +4839,9 @@ struct config_enum ConfigureNamesEnum[] =
 	{
 		{"dynamic_shared_memory_type", PGC_POSTMASTER, RESOURCES_MEM,
 			gettext_noop("Selects the dynamic shared memory implementation used."),
-			NULL
+			NULL,
+			/* platform-specific default, which is also overriden during initdb */
+			GUC_DEFAULT_COMPILE | GUC_DEFAULT_INITDB
 		},
 		&dynamic_shared_memory_type,
 		DEFAULT_DYNAMIC_SHARED_MEMORY_TYPE, dynamic_shared_memory_options,
@@ -4836,7 +4851,8 @@ struct config_enum ConfigureNamesEnum[] =
 	{
 		{"shared_memory_type", PGC_POSTMASTER, RESOURCES_MEM,
 			gettext_noop("Selects the shared memory implementation used for the main shared memory region."),
-			NULL
+			NULL,
+			GUC_DEFAULT_COMPILE
 		},
 		&shared_memory_type,
 		DEFAULT_SHARED_MEMORY_TYPE, shared_memory_options,
@@ -4846,7 +4862,8 @@ struct config_enum ConfigureNamesEnum[] =
 	{
 		{"wal_sync_method", PGC_SIGHUP, WAL_SETTINGS,
 			gettext_noop("Selects the method used for forcing WAL updates to disk."),
-			NULL
+			NULL,
+			GUC_DEFAULT_COMPILE
 		},
 		&sync_method,
 		DEFAULT_SYNC_METHOD, sync_method_options,
@@ -4910,7 +4927,8 @@ struct config_enum ConfigureNamesEnum[] =
 	{
 		{"password_encryption", PGC_USERSET, CONN_AUTH_AUTH,
 			gettext_noop("Chooses the algorithm for encrypting passwords."),
-			NULL
+			NULL,
+			GUC_DEFAULT_INITDB
 		},
 		&Password_encryption,
 		PASSWORD_TYPE_SCRAM_SHA_256, password_encryption_options,
diff --git a/src/include/utils/guc.h b/src/include/utils/guc.h
index 15c61992f06..2b17cd08fd9 100644
--- a/src/include/utils/guc.h
+++ b/src/include/utils/guc.h
@@ -222,6 +222,8 @@ typedef enum
 #define GUC_DISALLOW_IN_AUTO_FILE \
 							   0x002000 /* can't set in PG_AUTOCONF_FILENAME */
 #define GUC_RUNTIME_COMPUTED   0x004000 /* delay processing in 'postgres -C' */
+#define GUC_DEFAULT_COMPILE	   0x008000	/* default is determined at compile time */
+#define GUC_DEFAULT_INITDB	   0x010000	/* default is determined at during initdb */
 
 #define GUC_UNIT_KB			 0x01000000 /* value is in kilobytes */
 #define GUC_UNIT_BLOCKS		 0x02000000 /* value is in blocks */
-- 
2.34.1

From 0cc261a37af071554a0e2954b3a49ed6b3be2b60 Mon Sep 17 00:00:00 2001
From: Justin Pryzby <pryzbyj@telsasoft.com>
Date: Wed, 25 May 2022 05:14:43 -0500
Subject: [PATCH 2/2] test GUC default values in postgresql.conf.sample

---
 src/test/modules/test_misc/t/003_check_guc.pl | 33 +++++++++++++++++++
 1 file changed, 33 insertions(+)

diff --git a/src/test/modules/test_misc/t/003_check_guc.pl b/src/test/modules/test_misc/t/003_check_guc.pl
index e9f33f3c775..ab6f16dad7b 100644
--- a/src/test/modules/test_misc/t/003_check_guc.pl
+++ b/src/test/modules/test_misc/t/003_check_guc.pl
@@ -106,4 +106,37 @@ foreach my $param (@sample_intersect)
 	);
 }
 
+# Test that GUCs in postgresql.conf.sample show the correct default values
+my $check_defaults = $node->safe_psql(
+	'postgres',
+	"
+	CREATE TABLE sample_conf AS
+	SELECT m[1] AS name, COALESCE(m[3], m[5]) AS sample_value
+	FROM (SELECT regexp_split_to_table(pg_read_file('$sample_file'), '\n') AS ln) conf,
+	regexp_match(ln, '^#?([_[:alpha:]]+) (= ''([^'']*)''|(= ([^[:space:]]*))).*') AS m
+	WHERE ln ~ '^#?[[:alpha:]]'
+	");
+
+$check_defaults = $node->safe_psql(
+	'postgres',
+	"
+	SELECT name, current_setting(name), sc.sample_value, boot_val
+	FROM pg_show_all_settings() psas
+	JOIN sample_conf sc USING(name)
+	WHERE lower(sc.sample_value) != lower(boot_val) -- same value (specified by Cluster.pm)
+	AND sc.sample_value != current_setting(name) -- same value, with human units
+	AND sc.sample_value != current_setting(name)||'.0' -- same value with .0 suffix
+	AND 'DEFAULT_COMPILE' != ALL(pg_settings_get_flags(psas.name)) -- dynamically-set defaults
+	AND 'DEFAULT_INITDB' != ALL(pg_settings_get_flags(psas.name)) -- dynamically-set defaults
+	AND NOT (sc.sample_value ~ '^0' AND current_setting(name) ~ '^0') -- zeros may be written differently
+	AND NOT (sc.sample_value='60s' AND current_setting(name) = '1min') -- two ways to write 1min
+	AND name NOT IN ('krb_server_keyfile', 'wal_retrieve_retry_interval'); -- exceptions
+	");
+
+my @check_defaults_array = split("\n", lc($check_defaults));
+print(STDERR "$check_defaults\n");
+
+is (@check_defaults_array, 0,
+	'check for consistency of defaults in postgresql.conf.sample');
+
 done_testing();
-- 
2.34.1

From 963b56636b9f7fd4a78e502c6acba07919518910 Mon Sep 17 00:00:00 2001
From: Justin Pryzby <pryzbyj@telsasoft.com>
Date: Tue, 19 Jul 2022 08:31:56 -0500
Subject: [PATCH 1/2] pg_settings_get_flags(): add DEFAULT_COMPILE and
 DEFAULT_INITDB ..

for settings which vary by ./configure or platform or initdb

Note that this is independent from PGC_S_DYNAMIC_DEFAULT.
---
 doc/src/sgml/func.sgml              | 15 ++++++
 src/backend/utils/misc/guc_funcs.c  |  6 ++-
 src/backend/utils/misc/guc_tables.c | 76 ++++++++++++++++++-----------
 src/include/utils/guc.h             |  2 +
 4 files changed, 69 insertions(+), 30 deletions(-)

diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index e13fce6f6b1..17069d2249e 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -24945,6 +24945,21 @@ SELECT collation for ('foo' COLLATE "de_DE");
      <row><entry>Flag</entry><entry>Description</entry></row>
     </thead>
     <tbody>
+
+     <row>
+      <entry><literal>DEFAULT_COMPILE</literal></entry>
+      <entry>Parameters with this flag have default values which vary by
+      platform, or compile-time options.
+      </entry>
+     </row>
+
+     <row>
+      <entry><literal>DEFAULT_INITDB</literal></entry>
+      <entry>Parameters with this flag have default values which are
+      determined dynamically during initdb.
+      </entry>
+     </row>
+
      <row>
       <entry><literal>EXPLAIN</literal></entry>
       <entry>Parameters with this flag are included in
diff --git a/src/backend/utils/misc/guc_funcs.c b/src/backend/utils/misc/guc_funcs.c
index 52c361e9755..183943c1973 100644
--- a/src/backend/utils/misc/guc_funcs.c
+++ b/src/backend/utils/misc/guc_funcs.c
@@ -551,7 +551,7 @@ ShowAllGUCConfig(DestReceiver *dest)
 Datum
 pg_settings_get_flags(PG_FUNCTION_ARGS)
 {
-#define MAX_GUC_FLAGS	6
+#define MAX_GUC_FLAGS	8
 	char	   *varname = TextDatumGetCString(PG_GETARG_DATUM(0));
 	struct config_generic *record;
 	int			cnt = 0;
@@ -564,6 +564,10 @@ pg_settings_get_flags(PG_FUNCTION_ARGS)
 	if (record == NULL)
 		PG_RETURN_NULL();
 
+	if (record->flags & GUC_DEFAULT_COMPILE)
+		flags[cnt++] = CStringGetTextDatum("DEFAULT_COMPILE");
+	if (record->flags & GUC_DEFAULT_INITDB)
+		flags[cnt++] = CStringGetTextDatum("DEFAULT_INITDB");
 	if (record->flags & GUC_EXPLAIN)
 		flags[cnt++] = CStringGetTextDatum("EXPLAIN");
 	if (record->flags & GUC_NO_RESET)
diff --git a/src/backend/utils/misc/guc_tables.c b/src/backend/utils/misc/guc_tables.c
index 2f42cebaf62..94b0aa24a98 100644
--- a/src/backend/utils/misc/guc_tables.c
+++ b/src/backend/utils/misc/guc_tables.c
@@ -1233,7 +1233,7 @@ struct config_bool ConfigureNamesBool[] =
 		{"debug_assertions", PGC_INTERNAL, PRESET_OPTIONS,
 			gettext_noop("Shows whether the running server has assertion checks enabled."),
 			NULL,
-			GUC_NOT_IN_SAMPLE | GUC_DISALLOW_IN_FILE
+			GUC_NOT_IN_SAMPLE | GUC_DISALLOW_IN_FILE | GUC_DEFAULT_COMPILE
 		},
 		&assert_enabled,
 		DEFAULT_ASSERT_ENABLED,
@@ -1425,7 +1425,8 @@ struct config_bool ConfigureNamesBool[] =
 	{
 		{"update_process_title", PGC_SUSET, PROCESS_TITLE,
 			gettext_noop("Updates the process title to show the active SQL command."),
-			gettext_noop("Enables updating of the process title every time a new SQL command is received by the server.")
+			gettext_noop("Enables updating of the process title every time a new SQL command is received by the server."),
+			GUC_DEFAULT_COMPILE
 		},
 		&update_process_title,
 		DEFAULT_UPDATE_PROCESS_TITLE,
@@ -2180,7 +2181,8 @@ struct config_int ConfigureNamesInt[] =
 	{
 		{"max_connections", PGC_POSTMASTER, CONN_AUTH_SETTINGS,
 			gettext_noop("Sets the maximum number of concurrent connections."),
-			NULL
+			NULL,
+			GUC_DEFAULT_INITDB
 		},
 		&MaxConnections,
 		100, 1, MAX_BACKENDS,
@@ -2228,7 +2230,7 @@ struct config_int ConfigureNamesInt[] =
 		{"shared_buffers", PGC_POSTMASTER, RESOURCES_MEM,
 			gettext_noop("Sets the number of shared memory buffers used by the server."),
 			NULL,
-			GUC_UNIT_BLOCKS
+			GUC_UNIT_BLOCKS | GUC_DEFAULT_INITDB
 		},
 		&NBuffers,
 		16384, 16, INT_MAX / 2,
@@ -2282,7 +2284,8 @@ struct config_int ConfigureNamesInt[] =
 	{
 		{"port", PGC_POSTMASTER, CONN_AUTH_SETTINGS,
 			gettext_noop("Sets the TCP port the server listens on."),
-			NULL
+			NULL,
+			GUC_DEFAULT_COMPILE
 		},
 		&PostPortNumber,
 		DEF_PGPORT, 1, 65535,
@@ -2311,7 +2314,8 @@ struct config_int ConfigureNamesInt[] =
 						 "to be a numeric mode specification in the form "
 						 "accepted by the chmod and umask system calls. "
 						 "(To use the customary octal format the number must "
-						 "start with a 0 (zero).)")
+						 "start with a 0 (zero).)"),
+			GUC_DEFAULT_INITDB
 		},
 		&Log_file_mode,
 		0600, 0000, 0777,
@@ -2744,7 +2748,7 @@ struct config_int ConfigureNamesInt[] =
 		{"checkpoint_flush_after", PGC_SIGHUP, WAL_CHECKPOINTS,
 			gettext_noop("Number of pages after which previously performed writes are flushed to disk."),
 			NULL,
-			GUC_UNIT_BLOCKS
+			GUC_UNIT_BLOCKS | GUC_DEFAULT_COMPILE
 		},
 		&checkpoint_flush_after,
 		DEFAULT_CHECKPOINT_FLUSH_AFTER, 0, WRITEBACK_MAX_PENDING_FLUSHES,
@@ -2962,7 +2966,7 @@ struct config_int ConfigureNamesInt[] =
 		{"bgwriter_flush_after", PGC_SIGHUP, RESOURCES_BGWRITER,
 			gettext_noop("Number of pages after which previously performed writes are flushed to disk."),
 			NULL,
-			GUC_UNIT_BLOCKS
+			GUC_UNIT_BLOCKS | GUC_DEFAULT_COMPILE
 		},
 		&bgwriter_flush_after,
 		DEFAULT_BGWRITER_FLUSH_AFTER, 0, WRITEBACK_MAX_PENDING_FLUSHES,
@@ -2975,7 +2979,7 @@ struct config_int ConfigureNamesInt[] =
 			RESOURCES_ASYNCHRONOUS,
 			gettext_noop("Number of simultaneous requests that can be handled efficiently by the disk subsystem."),
 			NULL,
-			GUC_EXPLAIN
+			GUC_EXPLAIN | GUC_DEFAULT_COMPILE
 		},
 		&effective_io_concurrency,
 		DEFAULT_EFFECTIVE_IO_CONCURRENCY,
@@ -2989,7 +2993,7 @@ struct config_int ConfigureNamesInt[] =
 			RESOURCES_ASYNCHRONOUS,
 			gettext_noop("A variant of effective_io_concurrency that is used for maintenance work."),
 			NULL,
-			GUC_EXPLAIN
+			GUC_EXPLAIN | GUC_DEFAULT_COMPILE
 		},
 		&maintenance_io_concurrency,
 		DEFAULT_MAINTENANCE_IO_CONCURRENCY,
@@ -3002,7 +3006,7 @@ struct config_int ConfigureNamesInt[] =
 		{"backend_flush_after", PGC_USERSET, RESOURCES_ASYNCHRONOUS,
 			gettext_noop("Number of pages after which previously performed writes are flushed to disk."),
 			NULL,
-			GUC_UNIT_BLOCKS
+			GUC_UNIT_BLOCKS | GUC_DEFAULT_COMPILE
 		},
 		&backend_flush_after,
 		DEFAULT_BACKEND_FLUSH_AFTER, 0, WRITEBACK_MAX_PENDING_FLUSHES,
@@ -3457,7 +3461,7 @@ struct config_int ConfigureNamesInt[] =
 		{"debug_discard_caches", PGC_SUSET, DEVELOPER_OPTIONS,
 			gettext_noop("Aggressively flush system caches for debugging purposes."),
 			NULL,
-			GUC_NOT_IN_SAMPLE
+			GUC_NOT_IN_SAMPLE | GUC_DEFAULT_COMPILE
 		},
 		&debug_discard_caches,
 #ifdef DISCARD_CACHES_ENABLED
@@ -3951,7 +3955,8 @@ struct config_string ConfigureNamesString[] =
 	{
 		{"log_timezone", PGC_SIGHUP, LOGGING_WHAT,
 			gettext_noop("Sets the time zone to use in log messages."),
-			NULL
+			NULL,
+			GUC_DEFAULT_INITDB
 		},
 		&log_timezone_string,
 		"GMT",
@@ -3963,7 +3968,7 @@ struct config_string ConfigureNamesString[] =
 			gettext_noop("Sets the display format for date and time values."),
 			gettext_noop("Also controls interpretation of ambiguous "
 						 "date inputs."),
-			GUC_LIST_INPUT | GUC_REPORT
+			GUC_LIST_INPUT | GUC_REPORT | GUC_DEFAULT_INITDB
 		},
 		&datestyle_string,
 		"ISO, MDY",
@@ -4077,7 +4082,8 @@ struct config_string ConfigureNamesString[] =
 	{
 		{"lc_messages", PGC_SUSET, CLIENT_CONN_LOCALE,
 			gettext_noop("Sets the language in which messages are displayed."),
-			NULL
+			NULL,
+			GUC_DEFAULT_INITDB
 		},
 		&locale_messages,
 		"",
@@ -4087,7 +4093,8 @@ struct config_string ConfigureNamesString[] =
 	{
 		{"lc_monetary", PGC_USERSET, CLIENT_CONN_LOCALE,
 			gettext_noop("Sets the locale for formatting monetary amounts."),
-			NULL
+			NULL,
+			GUC_DEFAULT_INITDB
 		},
 		&locale_monetary,
 		"C",
@@ -4097,7 +4104,8 @@ struct config_string ConfigureNamesString[] =
 	{
 		{"lc_numeric", PGC_USERSET, CLIENT_CONN_LOCALE,
 			gettext_noop("Sets the locale for formatting numbers."),
-			NULL
+			NULL,
+			GUC_DEFAULT_INITDB
 		},
 		&locale_numeric,
 		"C",
@@ -4107,7 +4115,8 @@ struct config_string ConfigureNamesString[] =
 	{
 		{"lc_time", PGC_USERSET, CLIENT_CONN_LOCALE,
 			gettext_noop("Sets the locale for formatting date and time values."),
-			NULL
+			NULL,
+			GUC_DEFAULT_INITDB
 		},
 		&locale_time,
 		"C",
@@ -4266,7 +4275,8 @@ struct config_string ConfigureNamesString[] =
 		{"TimeZone", PGC_USERSET, CLIENT_CONN_LOCALE,
 			gettext_noop("Sets the time zone for displaying and interpreting time stamps."),
 			NULL,
-			GUC_REPORT
+			GUC_REPORT | GUC_DEFAULT_INITDB
+
 		},
 		&timezone_string,
 		"GMT",
@@ -4297,7 +4307,7 @@ struct config_string ConfigureNamesString[] =
 		{"unix_socket_directories", PGC_POSTMASTER, CONN_AUTH_SETTINGS,
 			gettext_noop("Sets the directories where Unix-domain sockets will be created."),
 			NULL,
-			GUC_LIST_INPUT | GUC_LIST_QUOTE | GUC_SUPERUSER_ONLY
+			GUC_LIST_INPUT | GUC_LIST_QUOTE | GUC_SUPERUSER_ONLY | GUC_DEFAULT_COMPILE
 		},
 		&Unix_socket_directories,
 		DEFAULT_PGSOCKET_DIR,
@@ -4378,7 +4388,7 @@ struct config_string ConfigureNamesString[] =
 		{"ssl_library", PGC_INTERNAL, PRESET_OPTIONS,
 			gettext_noop("Shows the name of the SSL library."),
 			NULL,
-			GUC_NOT_IN_SAMPLE | GUC_DISALLOW_IN_FILE
+			GUC_NOT_IN_SAMPLE | GUC_DISALLOW_IN_FILE | GUC_DEFAULT_COMPILE
 		},
 		&ssl_library,
 #ifdef USE_SSL
@@ -4453,7 +4463,9 @@ struct config_string ConfigureNamesString[] =
 	{
 		{"default_text_search_config", PGC_USERSET, CLIENT_CONN_LOCALE,
 			gettext_noop("Sets default text search configuration."),
-			NULL
+			NULL,
+			GUC_DEFAULT_INITDB
+
 		},
 		&TSCurrentConfig,
 		"pg_catalog.simple",
@@ -4464,7 +4476,7 @@ struct config_string ConfigureNamesString[] =
 		{"ssl_ciphers", PGC_SIGHUP, CONN_AUTH_SSL,
 			gettext_noop("Sets the list of allowed SSL ciphers."),
 			NULL,
-			GUC_SUPERUSER_ONLY
+			GUC_SUPERUSER_ONLY | GUC_DEFAULT_COMPILE
 		},
 		&SSLCipherSuites,
 #ifdef USE_OPENSSL
@@ -4479,7 +4491,7 @@ struct config_string ConfigureNamesString[] =
 		{"ssl_ecdh_curve", PGC_SIGHUP, CONN_AUTH_SSL,
 			gettext_noop("Sets the curve to use for ECDH."),
 			NULL,
-			GUC_SUPERUSER_ONLY
+			GUC_SUPERUSER_ONLY | GUC_DEFAULT_COMPILE
 		},
 		&SSLECDHCurve,
 #ifdef USE_SSL
@@ -4738,7 +4750,8 @@ struct config_enum ConfigureNamesEnum[] =
 	{
 		{"syslog_facility", PGC_SIGHUP, LOGGING_WHERE,
 			gettext_noop("Sets the syslog \"facility\" to be used when syslog enabled."),
-			NULL
+			NULL,
+			GUC_DEFAULT_COMPILE
 		},
 		&syslog_facility,
 		DEFAULT_SYSLOG_FACILITY,
@@ -4847,7 +4860,9 @@ struct config_enum ConfigureNamesEnum[] =
 	{
 		{"dynamic_shared_memory_type", PGC_POSTMASTER, RESOURCES_MEM,
 			gettext_noop("Selects the dynamic shared memory implementation used."),
-			NULL
+			NULL,
+			/* platform-specific default, which is also overriden during initdb */
+			GUC_DEFAULT_COMPILE | GUC_DEFAULT_INITDB
 		},
 		&dynamic_shared_memory_type,
 		DEFAULT_DYNAMIC_SHARED_MEMORY_TYPE, dynamic_shared_memory_options,
@@ -4857,7 +4872,8 @@ struct config_enum ConfigureNamesEnum[] =
 	{
 		{"shared_memory_type", PGC_POSTMASTER, RESOURCES_MEM,
 			gettext_noop("Selects the shared memory implementation used for the main shared memory region."),
-			NULL
+			NULL,
+			GUC_DEFAULT_COMPILE
 		},
 		&shared_memory_type,
 		DEFAULT_SHARED_MEMORY_TYPE, shared_memory_options,
@@ -4867,7 +4883,8 @@ struct config_enum ConfigureNamesEnum[] =
 	{
 		{"wal_sync_method", PGC_SIGHUP, WAL_SETTINGS,
 			gettext_noop("Selects the method used for forcing WAL updates to disk."),
-			NULL
+			NULL,
+			GUC_DEFAULT_COMPILE
 		},
 		&sync_method,
 		DEFAULT_SYNC_METHOD, sync_method_options,
@@ -4931,7 +4948,8 @@ struct config_enum ConfigureNamesEnum[] =
 	{
 		{"password_encryption", PGC_USERSET, CONN_AUTH_AUTH,
 			gettext_noop("Chooses the algorithm for encrypting passwords."),
-			NULL
+			NULL,
+			GUC_DEFAULT_INITDB
 		},
 		&Password_encryption,
 		PASSWORD_TYPE_SCRAM_SHA_256, password_encryption_options,
diff --git a/src/include/utils/guc.h b/src/include/utils/guc.h
index ba89d013e64..2b98595b3ea 100644
--- a/src/include/utils/guc.h
+++ b/src/include/utils/guc.h
@@ -221,6 +221,8 @@ typedef enum
 #define GUC_DISALLOW_IN_AUTO_FILE \
 							   0x002000 /* can't set in PG_AUTOCONF_FILENAME */
 #define GUC_RUNTIME_COMPUTED   0x004000 /* delay processing in 'postgres -C' */
+#define GUC_DEFAULT_COMPILE	   0x008000	/* default is determined at compile time */
+#define GUC_DEFAULT_INITDB	   0x010000	/* default is determined at during initdb */
 
 #define GUC_UNIT_KB			 0x01000000 /* value is in kilobytes */
 #define GUC_UNIT_BLOCKS		 0x02000000 /* value is in blocks */
-- 
2.34.1

From 107e96e12dd25c8360470bd4b65f975925300d86 Mon Sep 17 00:00:00 2001
From: Justin Pryzby <pryzbyj@telsasoft.com>
Date: Wed, 25 May 2022 05:14:43 -0500
Subject: [PATCH 2/2] WIP: test GUC default values in postgresql.conf.sample

This tests for consistency between the default values written in
postgresql.conf.sample and defined in guc.c.

Kyotaro Horiguchi and Justin Pryzby

//-os-only: freebsd, macos
---
 src/backend/utils/misc/guc.c                  | 80 +++++++++++++++
 src/include/catalog/pg_proc.dat               |  5 +
 src/test/modules/test_misc/t/003_check_guc.pl | 99 +++++++++++++++++--
 .../unsafe_tests/expected/rolenames.out       | 14 +++
 .../modules/unsafe_tests/sql/rolenames.sql    |  7 ++
 5 files changed, 199 insertions(+), 6 deletions(-)

diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index 53d1d9a06a7..9eef85a4fa4 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -3239,6 +3239,86 @@ parse_and_validate_value(struct config_generic *record,
 	return true;
 }
 
+/*
+ * Helper for pg_config_unitless_value
+ *
+ * Return the the value of the enum at the given index, or NULL if not found.
+ */
+static const char *
+config_enum_lookup_by_value_soft(struct config_enum *record, int val)
+{
+	const struct config_enum_entry *entry;
+
+	for (entry = record->options; entry && entry->name; entry++)
+	{
+		if (entry->val == val)
+			return entry->name;
+	}
+
+	return NULL;
+}
+
+/*
+ * Convert value to unitless value according to the specified GUC variable
+ */
+Datum
+pg_config_unitless_value(PG_FUNCTION_ARGS)
+{
+	char	   *name;
+	char	   *value;
+	struct config_generic *record;
+	const char *result = "";
+	void	   *extra;
+	union config_var_val val;
+	char		buffer[256];
+
+	name = text_to_cstring(PG_GETARG_TEXT_PP(0));
+	value = text_to_cstring(PG_GETARG_TEXT_PP(1));
+
+	record = find_option(name, true, false, ERROR);
+
+	/*
+	 * This function doesn't reveal values of the variables, but be consistent
+	 * with similar functions.
+	 */
+	if ((record->flags & GUC_SUPERUSER_ONLY) &&
+		!ConfigOptionIsVisible(record))
+		ereport(ERROR,
+				errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				errmsg("permission denied to examine \"%s\"", name),
+				errdetail("Only roles with privileges of the \"%s\" role may examine this parameter.",
+						  "pg_read_all_settings"));
+
+	parse_and_validate_value(record, name, value, PGC_S_TEST, WARNING,
+							 &val, &extra);
+
+	switch (record->vartype)
+	{
+		case PGC_BOOL:
+			result = (val.boolval ? "on" : "off");
+			break;
+		case PGC_INT:
+			snprintf(buffer, sizeof(buffer), "%d", val.intval);
+			result = buffer;
+			break;
+		case PGC_REAL:
+			snprintf(buffer, sizeof(buffer), "%g", val.realval);
+			result = buffer;
+			break;
+		case PGC_STRING:
+			result = val.stringval;
+			break;
+		case PGC_ENUM:
+			result = config_enum_lookup_by_value_soft((struct config_enum *) record,
+												 val.intval);
+			break;
+	}
+
+	if (result == NULL)
+		PG_RETURN_NULL();
+
+	PG_RETURN_TEXT_P(cstring_to_text(result));
+}
 
 /*
  * set_config_option: sets option `name' to given value.
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index aa293c43b6a..fe82629b1f6 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -6242,6 +6242,11 @@
   proname => 'pg_settings_get_flags', provolatile => 's', prorettype => '_text',
   proargtypes => 'text', prosrc => 'pg_settings_get_flags' },
 
+{ oid => '9956', descr => 'normalize value to the unit of specified GUC',
+  proname => 'pg_config_unitless_value', provolatile => 's',
+  prorettype => 'text', proargtypes => 'text text',
+  proargnames => '{varname,value}', prosrc => 'pg_config_unitless_value' },
+
 { oid => '3329', descr => 'show config file settings',
   proname => 'pg_show_all_file_settings', prorows => '1000', proretset => 't',
   provolatile => 'v', prorettype => 'record', proargtypes => '',
diff --git a/src/test/modules/test_misc/t/003_check_guc.pl b/src/test/modules/test_misc/t/003_check_guc.pl
index e9f33f3c775..ce2ec1bf9ba 100644
--- a/src/test/modules/test_misc/t/003_check_guc.pl
+++ b/src/test/modules/test_misc/t/003_check_guc.pl
@@ -11,6 +11,26 @@ my $node = PostgreSQL::Test::Cluster->new('main');
 $node->init;
 $node->start;
 
+# These are non-variables but that are mistakenly parsed as variable
+# settings in the loop below.
+my %skip_names =
+  map { $_ => 1 } ('include', 'include_dir', 'include_if_exists');
+
+# The following parameters have defaults which are
+# environment-dependent and may not match the default
+# values written in the sample config file.
+my %ignore_parameters =
+  map { $_ => 1 } (
+	  'data_directory',
+	  'hba_file',
+	  'ident_file',
+	  'krb_server_keyfile',
+	  'timezone_abbreviations',
+	  'lc_messages',
+	  'max_stack_depth', # XXX
+	  'wal_buffers', # XXX
+	  );
+
 # Grab the names of all the parameters that can be listed in the
 # configuration sample file.  config_file is an exception, it is not
 # in postgresql.conf.sample but is part of the lists from guc_tables.c.
@@ -42,7 +62,7 @@ my @gucs_in_file;
 
 # Read the sample file line-by-line, checking its contents to build a list
 # of everything known as a GUC.
-my $num_tests = 0;
+my @file_vals = ();
 open(my $contents, '<', $sample_file)
   || die "Could not open $sample_file: $!";
 while (my $line = <$contents>)
@@ -52,19 +72,28 @@ while (my $line = <$contents>)
 	# file.
 	# - Valid configuration options are followed immediately by " = ",
 	# with one space before and after the equal sign.
-	if ($line =~ m/^#?([_[:alpha:]]+) = .*/)
+	if ($line =~ m/^#?([_[:alpha:]]+) = (.*)$/)
 	{
 		# Lower-case conversion matters for some of the GUCs.
 		my $param_name = lc($1);
 
-		# Ignore some exceptions.
-		next if $param_name eq "include";
-		next if $param_name eq "include_dir";
-		next if $param_name eq "include_if_exists";
+		# extract value
+		my $file_value = $2;
+		$file_value =~ s/\s*#.*$//;		# strip trailing comment
+		$file_value =~ s/^'(.*)'$/$1/;	# strip quotes
+
+		next if (defined $skip_names{$param_name});
 
 		# Update the list of GUCs found in the sample file, for the
 		# follow-up tests.
 		push @gucs_in_file, $param_name;
+
+		# Update the list of GUCs whose value is checked for consistency
+		# between the sample file and pg_setting.boot_val
+		if (!defined $ignore_parameters{$param_name})
+		{
+			push(@file_vals, [$param_name, $file_value]);
+		}
 	}
 }
 
@@ -106,4 +135,62 @@ foreach my $param (@sample_intersect)
 	);
 }
 
+# Test that GUCs in postgresql.conf.sample show the correct default values
+my $check_defaults = $node->safe_psql(
+	'postgres',
+	"
+	CREATE TABLE sample_conf AS
+	SELECT m[1] AS name, COALESCE(m[3], m[5]) AS sample_value
+	FROM (SELECT regexp_split_to_table(pg_read_file('$sample_file'), '\n') AS ln) conf,
+	regexp_match(ln, '^#?([_[:alpha:]]+) (= ''([^'']*)''|(= ([^[:space:]]*))).*') AS m
+	WHERE ln ~ '^#?[[:alpha:]]'
+	");
+
+$check_defaults = $node->safe_psql(
+	'postgres',
+	"
+	SELECT name, sc.sample_value, boot_val
+	FROM pg_settings ps
+	JOIN sample_conf sc USING(name)
+        JOIN pg_settings_get_flags(ps.name) AS flags ON true
+	WHERE boot_val != sc.sample_value -- same value
+	AND boot_val != pg_config_unitless_value(name, sc.sample_value) -- same value with different units
+	AND 'DEFAULT_COMPILE' != ALL(flags) -- dynamically-set defaults
+	AND 'DEFAULT_INITDB' != ALL(flags) -- dynamically-set defaults
+	AND name NOT IN ('max_stack_depth', 'krb_server_keyfile'); -- exceptions
+	");
+
+my @check_defaults_array = split("\n", lc($check_defaults));
+
+is (@check_defaults_array, 0,
+	"check for consistency of defaults in postgresql.conf.sample: $check_defaults");
+
+# XXX An alternative, perl implementation of the same thing:
+
+# Check if GUC values in config-file and boot value match
+my $values = $node->safe_psql(
+	'postgres',
+	'SELECT f.n, pg_config_unitless_value(f.n, f.v), s.boot_val, \'!\' '.
+	'FROM (VALUES '.
+	join(',', map { "('${$_}[0]','${$_}[1]')" } @file_vals).
+	') f(n,v) '.
+	"JOIN pg_settings s ON (s.name = f.n)".
+	"JOIN pg_settings_get_flags(s.name) AS flags ON true ".
+	"AND 'DEFAULT_COMPILE' != ALL(flags) -- dynamically-set defaults ".
+	"AND 'DEFAULT_INITDB' != ALL(flags) -- dynamically-set defaults");
+
+my $fails = "";
+foreach my $l (split("\n", $values))
+{
+	# $l: <varname>|<fileval>|<boot_val>|!
+	my @t = split("\\|", $l);
+	if ($t[1] ne $t[2])
+	{
+		$fails .= "\n" if ($fails ne "");
+		$fails .= "$t[0]: file \"$t[1]\" != boot_val \"$t[2]\"";
+	}
+}
+
+is($fails, "", "check if GUC values in .sample and boot value match");
+
 done_testing();
diff --git a/src/test/modules/unsafe_tests/expected/rolenames.out b/src/test/modules/unsafe_tests/expected/rolenames.out
index 61396b2a805..1bba9c87239 100644
--- a/src/test/modules/unsafe_tests/expected/rolenames.out
+++ b/src/test/modules/unsafe_tests/expected/rolenames.out
@@ -1082,6 +1082,20 @@ DETAIL:  Only roles with privileges of the "pg_read_all_settings" role may exami
 RESET SESSION AUTHORIZATION;
 ERROR:  current transaction is aborted, commands ignored until end of transaction block
 ROLLBACK;
+BEGIN;
+SET SESSION AUTHORIZATION regress_role_haspriv;
+-- passes with role member of pg_read_all_settings
+SELECT pg_config_unitless_value('session_preload_libraries', 'val');
+ pg_config_unitless_value 
+--------------------------
+ val
+(1 row)
+
+SET SESSION AUTHORIZATION regress_role_nopriv;
+SELECT pg_config_unitless_value('session_preload_libraries', 'val');
+ERROR:  permission denied to examine "session_preload_libraries"
+DETAIL:  Only roles with privileges of the "pg_read_all_settings" role may examine this parameter.
+ROLLBACK;
 REVOKE pg_read_all_settings FROM regress_role_haspriv;
 -- clean up
 \c
diff --git a/src/test/modules/unsafe_tests/sql/rolenames.sql b/src/test/modules/unsafe_tests/sql/rolenames.sql
index adac36536db..355aa32c2ac 100644
--- a/src/test/modules/unsafe_tests/sql/rolenames.sql
+++ b/src/test/modules/unsafe_tests/sql/rolenames.sql
@@ -492,6 +492,13 @@ SET SESSION AUTHORIZATION regress_role_nopriv;
 SHOW session_preload_libraries;
 RESET SESSION AUTHORIZATION;
 ROLLBACK;
+BEGIN;
+SET SESSION AUTHORIZATION regress_role_haspriv;
+-- passes with role member of pg_read_all_settings
+SELECT pg_config_unitless_value('session_preload_libraries', 'val');
+SET SESSION AUTHORIZATION regress_role_nopriv;
+SELECT pg_config_unitless_value('session_preload_libraries', 'val');
+ROLLBACK;
 REVOKE pg_read_all_settings FROM regress_role_haspriv;
 
 -- clean up
-- 
2.34.1