diff --git a/src/backend/utils/mb/Unicode/Makefile b/src/backend/utils/mb/Unicode/Makefile
index 9084f03009..da307d8eb9 100644
--- a/src/backend/utils/mb/Unicode/Makefile
+++ b/src/backend/utils/mb/Unicode/Makefile
@@ -122,7 +122,7 @@ euc-jis-2004-std.txt sjis-0213-2004-std.txt:
 	$(DOWNLOAD) http://x0213.org/codetable/$(@F)
 
 gb-18030-2000.xml windows-949-2000.xml:
-	$(DOWNLOAD) https://ssl.icu-project.org/repos/icu/data/trunk/charset/data/xml/$(@F)
+	$(DOWNLOAD) https://raw.githubusercontent.com/unicode-org/icu-data/master/charset/data/xml/$(@F)
 
 GB2312.TXT:
 	$(DOWNLOAD) 'http://trac.greenstone.org/browser/trunk/gsdl/unicode/MAPPINGS/EASTASIA/GB/GB2312.TXT?rev=1842&format=txt'
diff --git a/src/backend/utils/mb/Unicode/UCS_to_EUC_JIS_2004.pl b/src/backend/utils/mb/Unicode/UCS_to_EUC_JIS_2004.pl
index 092a5b44f5..6d1681a18a 100755
--- a/src/backend/utils/mb/Unicode/UCS_to_EUC_JIS_2004.pl
+++ b/src/backend/utils/mb/Unicode/UCS_to_EUC_JIS_2004.pl
@@ -24,12 +24,13 @@ my @all;
 
 while (my $line = <$in>)
 {
-	if ($line =~ /^0x(.*)[ \t]*U\+(.*)\+(.*)[ \t]*#(.*)$/)
+	if ($line =~ /^0x(\w+)\s*U\+(\w+)\+(\w+)\s*#\s*(\S.*)?\s*$/)
 	{
 
 		# combined characters
 		my ($c, $u1, $u2) = ($1, $2, $3);
-		my $rest = "U+" . $u1 . "+" . $u2 . $4;
+		# The "\t \t" below is just to avoid insubstantial diffs.
+		my $rest = "U+" . $u1 . "+" . $u2 . "\t \t" . $4;
 		my $code = hex($c);
 		my $ucs1 = hex($u1);
 		my $ucs2 = hex($u2);
@@ -45,7 +46,7 @@ while (my $line = <$in>)
 			l          => $.
 		  };
 	}
-	elsif ($line =~ /^0x(.*)[ \t]*U\+(.*)[ \t]*#(.*)$/)
+	elsif ($line =~ /^0x(\w+)\s*U\+(\w+)\s*#\s*(\S.*)?\s*$/)
 	{
 
 		# non-combined characters
diff --git a/src/backend/utils/mb/Unicode/UCS_to_EUC_JP.pl b/src/backend/utils/mb/Unicode/UCS_to_EUC_JP.pl
index 1d88c0296e..d8bed27e1b 100755
--- a/src/backend/utils/mb/Unicode/UCS_to_EUC_JP.pl
+++ b/src/backend/utils/mb/Unicode/UCS_to_EUC_JP.pl
@@ -80,7 +80,8 @@ foreach my $i (@$ct932)
 	}
 }
 
-foreach my $i (@mapping)
+# extract only SJIS characers
+foreach my $i (grep defined $_->{sjis}, @mapping)
 {
 	my $sjis = $i->{sjis};
 
diff --git a/src/backend/utils/mb/Unicode/UCS_to_SHIFT_JIS_2004.pl b/src/backend/utils/mb/Unicode/UCS_to_SHIFT_JIS_2004.pl
index b516e91306..b86714dd46 100755
--- a/src/backend/utils/mb/Unicode/UCS_to_SHIFT_JIS_2004.pl
+++ b/src/backend/utils/mb/Unicode/UCS_to_SHIFT_JIS_2004.pl
@@ -24,12 +24,13 @@ my @mapping;
 
 while (my $line = <$in>)
 {
-	if ($line =~ /^0x(.*)[ \t]*U\+(.*)\+(.*)[ \t]*#(.*)$/)
+	if ($line =~ /^0x(\w+)\s*U\+(\w+)\+(\w+)\s*#\s*(\S.*)?\s*$/)
 	{
 
 		# combined characters
 		my ($c, $u1, $u2) = ($1, $2, $3);
-		my $rest = "U+" . $u1 . "+" . $u2 . $4;
+		# The "\t \t" below is just to avoid insubstantial diffs.
+		my $rest = "U+" . $u1 . "+" . $u2 . "\t \t" . $4;
 		my $code = hex($c);
 		my $ucs1 = hex($u1);
 		my $ucs2 = hex($u2);
@@ -45,7 +46,7 @@ while (my $line = <$in>)
 			l          => $.
 		  };
 	}
-	elsif ($line =~ /^0x(.*)[ \t]*U\+(.*)[ \t]*#(.*)$/)
+	elsif ($line =~ /^0x(\w+)\s*U\+(\w+)\s*#\s*(\S.*)?\s*$/)
 	{
 
 		# non-combined characters
diff --git a/src/backend/utils/mb/Unicode/convutils.pm b/src/backend/utils/mb/Unicode/convutils.pm
index 2f64a12ea1..9d97061c6f 100644
--- a/src/backend/utils/mb/Unicode/convutils.pm
+++ b/src/backend/utils/mb/Unicode/convutils.pm
@@ -380,7 +380,8 @@ sub print_radix_table
 	  {
 		header  => "Dummy map, for invalid values",
 		min_idx => 0,
-		max_idx => $widest_range
+		max_idx => $widest_range,
+		label => "dummy map"
 	  };
 
 	###
@@ -471,35 +472,37 @@ sub print_radix_table
 	}
 
 	# Also look up the positions of the roots in the table.
-	my $b1root = $segmap{"1-byte"};
-	my $b2root = $segmap{"2-byte"};
-	my $b3root = $segmap{"3-byte"};
-	my $b4root = $segmap{"4-byte"};
+	# Missing map represents dummy mapping.
+	my $b1root = $segmap{"1-byte"} || 0;
+	my $b2root = $segmap{"2-byte"} || 0;
+	my $b3root = $segmap{"3-byte"} || 0;
+	my $b4root = $segmap{"4-byte"} || 0;
 
 	# And the lower-upper values of each level in each radix tree.
-	my $b1_lower = $min_idx{1}{1};
-	my $b1_upper = $max_idx{1}{1};
+	# Missing values represent zero.
+	my $b1_lower = $min_idx{1}{1} || 0;
+	my $b1_upper = $max_idx{1}{1} || 0;
 
-	my $b2_1_lower = $min_idx{2}{1};
-	my $b2_1_upper = $max_idx{2}{1};
-	my $b2_2_lower = $min_idx{2}{2};
-	my $b2_2_upper = $max_idx{2}{2};
+	my $b2_1_lower = $min_idx{2}{1} || 0;
+	my $b2_1_upper = $max_idx{2}{1} || 0;
+	my $b2_2_lower = $min_idx{2}{2} || 0;
+	my $b2_2_upper = $max_idx{2}{2} || 0;
 
-	my $b3_1_lower = $min_idx{3}{1};
-	my $b3_1_upper = $max_idx{3}{1};
-	my $b3_2_lower = $min_idx{3}{2};
-	my $b3_2_upper = $max_idx{3}{2};
-	my $b3_3_lower = $min_idx{3}{3};
-	my $b3_3_upper = $max_idx{3}{3};
+	my $b3_1_lower = $min_idx{3}{1} || 0;
+	my $b3_1_upper = $max_idx{3}{1} || 0;
+	my $b3_2_lower = $min_idx{3}{2} || 0;
+	my $b3_2_upper = $max_idx{3}{2} || 0;
+	my $b3_3_lower = $min_idx{3}{3} || 0;
+	my $b3_3_upper = $max_idx{3}{3} || 0;
 
-	my $b4_1_lower = $min_idx{4}{1};
-	my $b4_1_upper = $max_idx{4}{1};
-	my $b4_2_lower = $min_idx{4}{2};
-	my $b4_2_upper = $max_idx{4}{2};
-	my $b4_3_lower = $min_idx{4}{3};
-	my $b4_3_upper = $max_idx{4}{3};
-	my $b4_4_lower = $min_idx{4}{4};
-	my $b4_4_upper = $max_idx{4}{4};
+	my $b4_1_lower = $min_idx{4}{1} || 0;
+	my $b4_1_upper = $max_idx{4}{1} || 0;
+	my $b4_2_lower = $min_idx{4}{2} || 0;
+	my $b4_2_upper = $max_idx{4}{2} || 0;
+	my $b4_3_lower = $min_idx{4}{3} || 0;
+	my $b4_3_upper = $max_idx{4}{3} || 0;
+	my $b4_4_lower = $min_idx{4}{4} || 0;
+	my $b4_4_upper = $max_idx{4}{4} || 0;
 
 	###
 	### Find the maximum value in the whole table, to determine if we can
@@ -607,7 +610,8 @@ sub print_radix_table
 			for (my $j = 0;
 				$j < $vals_per_line && $i <= $seg->{max_idx}; $j++)
 			{
-				my $val = $seg->{values}->{$i};
+				# missing values represent zero.
+				my $val = $seg->{values}->{$i} || 0;
 
 				printf $out " 0x%0*x", $colwidth, $val;
 				$off++;