diff --git a/contrib/intarray/bench/bench.pl b/contrib/intarray/bench/bench.pl
index 92035d6c06..daf3febc80 100755
--- a/contrib/intarray/bench/bench.pl
+++ b/contrib/intarray/bench/bench.pl
@@ -1,6 +1,7 @@
 #!/usr/bin/perl
 
 use strict;
+use warnings;
 
 # make sure we are in a sane environment.
 use DBI();
diff --git a/contrib/intarray/bench/create_test.pl b/contrib/intarray/bench/create_test.pl
index d2c678bb53..3f2a6e4da2 100755
--- a/contrib/intarray/bench/create_test.pl
+++ b/contrib/intarray/bench/create_test.pl
@@ -3,6 +3,8 @@
 # contrib/intarray/bench/create_test.pl
 
 use strict;
+use warnings;
+
 print <<EOT;
 create table message (
 	mid	int not null,
diff --git a/contrib/seg/seg-validate.pl b/contrib/seg/seg-validate.pl
index b8957ed984..9fa0887e71 100755
--- a/contrib/seg/seg-validate.pl
+++ b/contrib/seg/seg-validate.pl
@@ -1,6 +1,7 @@
 #!/usr/bin/perl
 
 use strict;
+use warnings;
 
 my $integer = '[+-]?[0-9]+';
 my $real    = '[+-]?[0-9]+\.[0-9]+';
diff --git a/contrib/seg/sort-segments.pl b/contrib/seg/sort-segments.pl
index 04eafd92f2..2e3c9734a9 100755
--- a/contrib/seg/sort-segments.pl
+++ b/contrib/seg/sort-segments.pl
@@ -3,6 +3,7 @@
 # this script will sort any table with the segment data type in its last column
 
 use strict;
+use warnings;
 
 my @rows;
 
diff --git a/doc/src/sgml/mk_feature_tables.pl b/doc/src/sgml/mk_feature_tables.pl
index 476e50e66d..ee158cb196 100644
--- a/doc/src/sgml/mk_feature_tables.pl
+++ b/doc/src/sgml/mk_feature_tables.pl
@@ -1,8 +1,9 @@
-# /usr/bin/perl -w
+# /usr/bin/perl
 
 # doc/src/sgml/mk_feature_tables.pl
 
 use strict;
+use warnings;
 
 my $yesno = $ARGV[0];
 
diff --git a/src/backend/catalog/genbki.pl b/src/backend/catalog/genbki.pl
index ad24f4dcb9..da34124595 100644
--- a/src/backend/catalog/genbki.pl
+++ b/src/backend/catalog/genbki.pl
@@ -1,4 +1,4 @@
-#!/usr/bin/perl -w
+#!/usr/bin/perl
 #----------------------------------------------------------------------
 #
 # genbki.pl
diff --git a/src/backend/utils/Gen_fmgrtab.pl b/src/backend/utils/Gen_fmgrtab.pl
index 7c68dbec22..b7c7b4c8fa 100644
--- a/src/backend/utils/Gen_fmgrtab.pl
+++ b/src/backend/utils/Gen_fmgrtab.pl
@@ -1,4 +1,4 @@
-#! /usr/bin/perl -w
+#! /usr/bin/perl
 #-------------------------------------------------------------------------
 #
 # Gen_fmgrtab.pl
diff --git a/src/backend/utils/mb/Unicode/UCS_to_BIG5.pl b/src/backend/utils/mb/Unicode/UCS_to_BIG5.pl
index 4c8aaf751c..84c9c53541 100755
--- a/src/backend/utils/mb/Unicode/UCS_to_BIG5.pl
+++ b/src/backend/utils/mb/Unicode/UCS_to_BIG5.pl
@@ -25,6 +25,8 @@
 #		 # and Unicode name (not used in this script)
 
 use strict;
+use warnings;
+
 use convutils;
 
 my $this_script = 'src/backend/utils/mb/Unicode/UCS_to_BIG5.pl';
diff --git a/src/backend/utils/mb/Unicode/UCS_to_EUC_CN.pl b/src/backend/utils/mb/Unicode/UCS_to_EUC_CN.pl
index b493a13838..1596b64238 100755
--- a/src/backend/utils/mb/Unicode/UCS_to_EUC_CN.pl
+++ b/src/backend/utils/mb/Unicode/UCS_to_EUC_CN.pl
@@ -14,6 +14,8 @@
 # and the "b" field is the hex byte sequence for GB18030
 
 use strict;
+use warnings;
+
 use convutils;
 
 my $this_script = 'src/backend/utils/mb/Unicode/UCS_to_EUC_CN.pl';
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 4faf597271..092a5b44f5 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
@@ -8,6 +8,8 @@
 # "euc-jis-2004-std.txt" (http://x0213.org)
 
 use strict;
+use warnings;
+
 use convutils;
 
 my $this_script = 'src/backend/utils/mb/Unicode/UCS_to_EUC_JIS_2004.pl';
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 86743a4074..1d88c0296e 100755
--- a/src/backend/utils/mb/Unicode/UCS_to_EUC_JP.pl
+++ b/src/backend/utils/mb/Unicode/UCS_to_EUC_JP.pl
@@ -12,6 +12,8 @@
 # organization's ftp site.
 
 use strict;
+use warnings;
+
 use convutils;
 
 my $this_script = 'src/backend/utils/mb/Unicode/UCS_to_EUC_JP.pl';
diff --git a/src/backend/utils/mb/Unicode/UCS_to_EUC_KR.pl b/src/backend/utils/mb/Unicode/UCS_to_EUC_KR.pl
index a81a7d61ce..b560f9f37e 100755
--- a/src/backend/utils/mb/Unicode/UCS_to_EUC_KR.pl
+++ b/src/backend/utils/mb/Unicode/UCS_to_EUC_KR.pl
@@ -17,6 +17,8 @@
 #		 # and Unicode name (not used in this script)
 
 use strict;
+use warnings;
+
 use convutils;
 
 my $this_script = 'src/backend/utils/mb/Unicode/UCS_to_EUC_KR.pl';
diff --git a/src/backend/utils/mb/Unicode/UCS_to_EUC_TW.pl b/src/backend/utils/mb/Unicode/UCS_to_EUC_TW.pl
index b9ec01dd85..0f52183ff5 100755
--- a/src/backend/utils/mb/Unicode/UCS_to_EUC_TW.pl
+++ b/src/backend/utils/mb/Unicode/UCS_to_EUC_TW.pl
@@ -18,6 +18,8 @@
 #		 # and Unicode name (not used in this script)
 
 use strict;
+use warnings;
+
 use convutils;
 
 my $this_script = 'src/backend/utils/mb/Unicode/UCS_to_EUC_TW.pl';
diff --git a/src/backend/utils/mb/Unicode/UCS_to_GB18030.pl b/src/backend/utils/mb/Unicode/UCS_to_GB18030.pl
index 779e3f7f01..57e63b4004 100755
--- a/src/backend/utils/mb/Unicode/UCS_to_GB18030.pl
+++ b/src/backend/utils/mb/Unicode/UCS_to_GB18030.pl
@@ -14,6 +14,8 @@
 # and the "b" field is the hex byte sequence for GB18030
 
 use strict;
+use warnings;
+
 use convutils;
 
 my $this_script = 'src/backend/utils/mb/Unicode/UCS_to_GB18030.pl';
diff --git a/src/backend/utils/mb/Unicode/UCS_to_JOHAB.pl b/src/backend/utils/mb/Unicode/UCS_to_JOHAB.pl
index c1967e00da..0bcea9e0d4 100755
--- a/src/backend/utils/mb/Unicode/UCS_to_JOHAB.pl
+++ b/src/backend/utils/mb/Unicode/UCS_to_JOHAB.pl
@@ -16,6 +16,8 @@
 #		 # and Unicode name (not used in this script)
 
 use strict;
+use warnings;
+
 use convutils;
 
 my $this_script = 'src/backend/utils/mb/Unicode/UCS_to_JOHAB.pl';
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 cac9a9c87d..b516e91306 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
@@ -8,6 +8,8 @@
 # "sjis-0213-2004-std.txt" (http://x0213.org)
 
 use strict;
+use warnings;
+
 use convutils;
 
 # first generate UTF-8 --> SHIFT_JIS_2004 table
diff --git a/src/backend/utils/mb/Unicode/UCS_to_SJIS.pl b/src/backend/utils/mb/Unicode/UCS_to_SJIS.pl
index c65091159b..5f4512ec87 100755
--- a/src/backend/utils/mb/Unicode/UCS_to_SJIS.pl
+++ b/src/backend/utils/mb/Unicode/UCS_to_SJIS.pl
@@ -11,6 +11,8 @@
 # ftp site.
 
 use strict;
+use warnings;
+
 use convutils;
 
 my $this_script = 'src/backend/utils/mb/Unicode/UCS_to_SJIS.pl';
diff --git a/src/backend/utils/mb/Unicode/UCS_to_UHC.pl b/src/backend/utils/mb/Unicode/UCS_to_UHC.pl
index 78b982a22e..3282106d7f 100755
--- a/src/backend/utils/mb/Unicode/UCS_to_UHC.pl
+++ b/src/backend/utils/mb/Unicode/UCS_to_UHC.pl
@@ -14,6 +14,8 @@
 # and the "b" field is the hex byte sequence for UHC
 
 use strict;
+use warnings;
+
 use convutils;
 
 my $this_script = 'src/backend/utils/mb/Unicode/UCS_to_UHC.pl';
diff --git a/src/backend/utils/mb/Unicode/UCS_to_most.pl b/src/backend/utils/mb/Unicode/UCS_to_most.pl
index 7ff724558d..8a7b26a5c5 100755
--- a/src/backend/utils/mb/Unicode/UCS_to_most.pl
+++ b/src/backend/utils/mb/Unicode/UCS_to_most.pl
@@ -16,6 +16,8 @@
 #		 # and Unicode name (not used in this script)
 
 use strict;
+use warnings;
+
 use convutils;
 
 my $this_script = 'src/backend/utils/mb/Unicode/UCS_to_most.pl';
diff --git a/src/backend/utils/mb/Unicode/convutils.pm b/src/backend/utils/mb/Unicode/convutils.pm
index 1903b345cb..2f64a12ea1 100644
--- a/src/backend/utils/mb/Unicode/convutils.pm
+++ b/src/backend/utils/mb/Unicode/convutils.pm
@@ -6,6 +6,7 @@
 package convutils;
 
 use strict;
+use warnings;
 
 use Carp;
 use Exporter 'import';
diff --git a/src/backend/utils/sort/gen_qsort_tuple.pl b/src/backend/utils/sort/gen_qsort_tuple.pl
index b6b2ffa7d0..9ed6cfc7ea 100644
--- a/src/backend/utils/sort/gen_qsort_tuple.pl
+++ b/src/backend/utils/sort/gen_qsort_tuple.pl
@@ -1,4 +1,4 @@
-#!/usr/bin/perl -w
+#!/usr/bin/perl
 
 #
 # gen_qsort_tuple.pl
@@ -26,6 +26,7 @@
 #
 
 use strict;
+use warnings;
 
 my $SUFFIX;
 my $EXTRAARGS;
diff --git a/src/bin/psql/create_help.pl b/src/bin/psql/create_help.pl
index a3b34603ef..ee82e64583 100644
--- a/src/bin/psql/create_help.pl
+++ b/src/bin/psql/create_help.pl
@@ -1,4 +1,4 @@
-#! /usr/bin/perl -w
+#! /usr/bin/perl
 
 #################################################################
 # create_help.pl -- converts SGML docs to internal psql help
@@ -20,6 +20,7 @@
 #
 
 use strict;
+use warnings;
 
 my $docdir = $ARGV[0] or die "$0: missing required argument: docdir\n";
 my $hfile = $ARGV[1] . '.h'
diff --git a/src/interfaces/libpq/test/regress.pl b/src/interfaces/libpq/test/regress.pl
index 3ad638a91b..54db4f1abf 100644
--- a/src/interfaces/libpq/test/regress.pl
+++ b/src/interfaces/libpq/test/regress.pl
@@ -1,6 +1,7 @@
-#!/usr/bin/perl -w
+#!/usr/bin/perl
 
 use strict;
+use warnings;
 
 # use of SRCDIR/SUBDIR is required for supporting VPath builds
 my $srcdir = $ENV{'SRCDIR'} or die 'SRCDIR environment variable is not set';
diff --git a/src/pl/plperl/plc_perlboot.pl b/src/pl/plperl/plc_perlboot.pl
index f41aa80e80..ee1b9bf463 100644
--- a/src/pl/plperl/plc_perlboot.pl
+++ b/src/pl/plperl/plc_perlboot.pl
@@ -1,6 +1,7 @@
 #  src/pl/plperl/plc_perlboot.pl
 
 use strict;
+use warnings;
 
 use 5.008001;
 use vars qw(%_SHARED $_TD);
diff --git a/src/pl/plperl/plperl_opmask.pl b/src/pl/plperl/plperl_opmask.pl
index e4e64b843f..3b33112ff9 100644
--- a/src/pl/plperl/plperl_opmask.pl
+++ b/src/pl/plperl/plperl_opmask.pl
@@ -1,4 +1,4 @@
-#!perl -w
+#!perl
 
 use strict;
 use warnings;
diff --git a/src/test/locale/sort-test.pl b/src/test/locale/sort-test.pl
index b8fc93aab1..b61968b7e0 100755
--- a/src/test/locale/sort-test.pl
+++ b/src/test/locale/sort-test.pl
@@ -1,6 +1,7 @@
 #! /usr/bin/perl
 
 use strict;
+use warnings;
 use locale;
 
 open(my $in_fh, '<', $ARGV[0]) || die;
diff --git a/src/test/perl/SimpleTee.pm b/src/test/perl/SimpleTee.pm
index 9de7b1ac32..74409bde6d 100644
--- a/src/test/perl/SimpleTee.pm
+++ b/src/test/perl/SimpleTee.pm
@@ -9,6 +9,7 @@
 
 package SimpleTee;
 use strict;
+use warnings;
 
 sub TIEHANDLE
 {
diff --git a/src/tools/fix-old-flex-code.pl b/src/tools/fix-old-flex-code.pl
index 2954cf5a72..1bbb7cdb84 100644
--- a/src/tools/fix-old-flex-code.pl
+++ b/src/tools/fix-old-flex-code.pl
@@ -1,4 +1,4 @@
-#!/usr/bin/perl -w
+#!/usr/bin/perl
 #----------------------------------------------------------------------
 #
 # fix-old-flex-code.pl
diff --git a/src/tools/msvc/build.pl b/src/tools/msvc/build.pl
index 2e47f24783..3c886fcd49 100644
--- a/src/tools/msvc/build.pl
+++ b/src/tools/msvc/build.pl
@@ -3,6 +3,7 @@
 # src/tools/msvc/build.pl
 
 use strict;
+use warnings;
 
 use File::Basename;
 use File::Spec;
diff --git a/src/tools/msvc/pgbison.pl b/src/tools/msvc/pgbison.pl
index 490df83367..774d5be059 100644
--- a/src/tools/msvc/pgbison.pl
+++ b/src/tools/msvc/pgbison.pl
@@ -3,6 +3,8 @@
 # src/tools/msvc/pgbison.pl
 
 use strict;
+use warnings;
+
 use File::Basename;
 
 # assume we are in the postgres source root
diff --git a/src/tools/msvc/pgflex.pl b/src/tools/msvc/pgflex.pl
index aceed5ffd6..26c73dbfad 100644
--- a/src/tools/msvc/pgflex.pl
+++ b/src/tools/msvc/pgflex.pl
@@ -3,6 +3,8 @@
 # src/tools/msvc/pgflex.pl
 
 use strict;
+use warnings;
+
 use File::Basename;
 
 # silence flex bleatings about file path style
diff --git a/src/tools/msvc/vcregress.pl b/src/tools/msvc/vcregress.pl
index 82dca29a61..c39178a93c 100644
--- a/src/tools/msvc/vcregress.pl
+++ b/src/tools/msvc/vcregress.pl
@@ -3,6 +3,7 @@
 # src/tools/msvc/vcregress.pl
 
 use strict;
+use warnings;
 
 our $config;
 
diff --git a/src/tools/perlcheck/perlcriticrc b/src/tools/perlcheck/perlcriticrc
index bd848a9a65..314c83c6a5 100644
--- a/src/tools/perlcheck/perlcriticrc
+++ b/src/tools/perlcheck/perlcriticrc
@@ -19,6 +19,10 @@ verbose = %f: %m at line %l, column %c.  %e.  ([%p] Severity: %s)\n
 # allow octal constants with leading zeros
 [-ValuesAndExpressions::ProhibitLeadingZeros]
 
+# insist on use of the warnings pragma
+[TestingAndDebugging::RequireUseWarnings]
+severity = 5
+
 # for now raise severity of this to level 5
 [Subroutines::RequireFinalReturn]
 severity = 5
diff --git a/src/tools/pginclude/pgcheckdefines b/src/tools/pginclude/pgcheckdefines
index 4edf7fc56e..0a760d6eca 100755
--- a/src/tools/pginclude/pgcheckdefines
+++ b/src/tools/pginclude/pgcheckdefines
@@ -1,4 +1,4 @@
-#! /usr/bin/perl -w
+#! /usr/bin/perl
 
 #
 # This script looks for symbols that are referenced in #ifdef or defined()
@@ -21,6 +21,7 @@
 #
 
 use strict;
+use warnings;
 
 use Cwd;
 use File::Basename;
diff --git a/src/tools/version_stamp.pl b/src/tools/version_stamp.pl
index cb59ad234a..fcd3f18048 100755
--- a/src/tools/version_stamp.pl
+++ b/src/tools/version_stamp.pl
@@ -1,4 +1,4 @@
-#! /usr/bin/perl -w
+#! /usr/bin/perl
 
 #################################################################
 # version_stamp.pl -- update version stamps throughout the source tree
@@ -21,6 +21,7 @@
 #
 
 use strict;
+use warnings;
 
 # Major version is hard-wired into the script.  We update it when we branch
 # a new development version.