diff --git a/src/tools/check_keywords.pl b/src/tools/check_keywords.pl
new file mode 100755
index 00000000000..378aabef998
--- /dev/null
+++ b/src/tools/check_keywords.pl
@@ -0,0 +1,178 @@
+#!/usr/bin/perl
+
+# Check that the keyword lists in gram.y and kwlist.h are sane. Run from
+# the top directory, or pass a path to a top directory as argument.
+#
+# $PostgreSQL: pgsql/src/tools/check_keywords.pl,v 1.1 2009/04/29 05:05:57 heikki Exp $
+
+if (@ARGV) {
+	$path = $ARGV[0];
+	shift @ARGV;
+}
+
+if ($path eq '') { $path = "."; }
+
+$[ = 1;			# set array base to 1
+$, = ' ';		# set output field separator
+$\ = "\n";		# set output record separator
+
+$keyword_categories{'unreserved_keyword'} = 'UNRESERVED_KEYWORD';
+$keyword_categories{'col_name_keyword'} = 'COL_NAME_KEYWORD';
+$keyword_categories{'type_func_name_keyword'} = 'TYPE_FUNC_NAME_KEYWORD';
+$keyword_categories{'reserved_keyword'} = 'RESERVED_KEYWORD';
+
+$gram_filename = "$path/src/backend/parser/gram.y";
+open(GRAM, $gram_filename) || die("Could not open $gram_filename!");
+line: while (<GRAM>) {
+    chomp;	# strip record separator
+    @Fld = split(' ', $_, -1);
+
+    $S = $_;
+    # Make sure any braces are split
+    $s = '{', $S =~ s/$s/ { /g;
+    $s = '}', $S =~ s/$s/ } /g;
+    # Any comments are split
+    $s = '[/][*]', $S =~ s#$s# /* #g;
+    $s = '[*][/]', $S =~ s#$s# */ #g;
+
+    if (!($kcat)) {
+	# Is this the beginning of a keyword list?
+	foreach $k (keys %keyword_categories) {
+	    if ($S =~ m/^($k):/) {
+		$kcat = $k;
+		next line;
+	    }
+	}
+	next line;
+    }
+
+    # Now split the line into individual fields
+    $n = (@arr = split(' ', $S));
+
+    # Ok, we're in a keyword list. Go through each field in turn
+    for ($fieldIndexer = 1; $fieldIndexer <= $n; $fieldIndexer++) {
+	if ($arr[$fieldIndexer] eq '*/' && $comment) {
+	    $comment = 0;
+	    next;
+	}
+	elsif ($comment) {
+	    next;
+	}
+	elsif ($arr[$fieldIndexer] eq '/*') {
+	    # start of a multiline comment
+	    $comment = 1;
+	    next;
+	}
+	elsif ($arr[$fieldIndexer] eq '//') {
+	    next line;
+	}
+
+	if ($arr[$fieldIndexer] eq ';') {
+	    # end of keyword list
+	    $line = '';
+	    $kcat = '';
+	    next;
+	}
+
+	if ($arr[$fieldIndexer] eq '|') {
+	    next;
+	}
+	
+	# Put this keyword into the right list
+	push @{$keywords{$kcat}}, $arr[$fieldIndexer];
+    }
+}
+close GRAM;
+
+# Check that all keywords are in alphabetical order
+foreach $kcat (keys %keyword_categories) {
+    $prevkword = '';
+
+    foreach $kword (@{$keywords{$kcat}}) {
+	# Some keyword have a _P suffix. Remove it for the comparison.
+	$bare_kword = $kword;
+	$bare_kword =~ s/_P$//;
+	if ($bare_kword le $prevkword) {
+	    print "'$bare_kword' after '$prevkword' in $kcat list is misplaced";
+	}
+	$prevkword = $bare_kword;
+    }
+}
+
+# Transform the keyword lists into hashes.
+# kwhashes is a hash of hashes, keyed by keyword category id, e.g.
+# UNRESERVED_KEYWORD. Each inner hash is a keyed by keyword id, e.g. ABORT_P
+# with a dummy value.
+while ( my ($kcat, $kcat_id) = each(%keyword_categories) ) {
+    @arr = @{$keywords{$kcat}};
+
+    my $hash;
+    foreach my $item (@arr) { $hash->{$item} = 1 }
+
+    $kwhashes{$kcat_id} = $hash;
+}
+
+# Now read in kwlist.h
+
+$kwlist_filename = "$path/src/include/parser/kwlist.h";
+open(KWLIST, $kwlist_filename) || die("Could not open $kwlist_filename!");
+
+$prevkwstring = '';
+kwlist_line: while (<KWLIST>) {
+    my($line) = $_;
+
+    if ($line =~ /^PG_KEYWORD\(\"(.*)\", (.*), (.*)\)/)
+    {
+	my($kwstring) = $1;
+	my($kwname) = $2;
+	my($kwcat_id) = $3;
+
+	# Check that the list is in alphabetical order
+	if ($kwstring le $prevkwstring) {
+	    print "'$kwstring' after '$prevkwstring' in kwlist.h is misplaced";
+	}
+	$prevkwstring = $kwstring;
+
+	# Check that the keyword string is valid: all lower-case ASCII chars
+	if ($kwstring !~ /^[a-z_]*$/) {
+	    print "'$kwstring' is not a valid keyword string, must be all lower-case ASCII chars";
+	}
+
+	# Check that the keyword name is valid: all upper-case ASCII chars
+	if ($kwname !~ /^[A-Z_]*$/) {
+	    print "'$kwname' is not a valid keyword name, must be all upper-case ASCII chars";
+	}
+
+	# Check that the keyword string matches keyword name
+	$bare_kwname = $kwname;
+	$bare_kwname =~ s/_P$//;
+	if ($bare_kwname ne uc($kwstring)) {
+	    print "keyword name '$kwname' doesn't match keyword string '$kwstring'";
+	}
+
+	# Check that the keyword is present in the grammar
+	%kwhash = %{$kwhashes{$kwcat_id}};
+
+	if (!(%kwhash))	{
+	    #print "Unknown kwcat_id: $kwcat_id";
+	} else {
+	    if (!($kwhash{$kwname})) {
+		print "'$kwname' not present in $kwcat_id section of gram.y";
+	    } else {
+		# Remove it from the hash, so that we can complain at the end
+		# if there's keywords left that were not found in kwlist.h
+		delete $kwhashes{$kwcat_id}->{$kwname};
+	    }
+	}
+    }
+}
+close KWLIST;
+
+# Check that we've paired up all keywords from gram.y with lines in kwlist.h
+while ( my ($kwcat, $kwcat_id) = each(%keyword_categories) ) {
+    %kwhash = %{$kwhashes{$kwcat_id}};
+
+    for my $kw ( keys %kwhash ) {
+	print "'$kw' found in gram.y $kwcat category, but not in kwlist.h"
+    }
+}