diff --git a/src/test/perl/TestLib.pm b/src/test/perl/TestLib.pm
index cfe0ca37ecd..1dfa260aa82 100644
--- a/src/test/perl/TestLib.pm
+++ b/src/test/perl/TestLib.pm
@@ -62,16 +62,32 @@ BEGIN
 	delete $ENV{LC_ALL};
 	$ENV{LC_MESSAGES} = 'C';
 
-	delete $ENV{PGCONNECT_TIMEOUT};
-	delete $ENV{PGDATA};
-	delete $ENV{PGDATABASE};
-	delete $ENV{PGHOSTADDR};
-	delete $ENV{PGREQUIRESSL};
-	delete $ENV{PGSERVICE};
-	delete $ENV{PGSSLMODE};
-	delete $ENV{PGUSER};
-	delete $ENV{PGPORT};
-	delete $ENV{PGHOST};
+	my @envkeys = qw (
+	  PGCLIENTENCODING
+	  PGCONNECT_TIMEOUT
+	  PGDATA
+	  PGDATABASE
+	  PGGSSLIB
+	  PGHOSTADDR
+	  PGKRBSRVNAME
+	  PGPASSFILE
+	  PGPASSWORD
+	  PGREQUIREPEER
+	  PGREQUIRESSL
+	  PGSERVICE
+	  PGSERVICEFILE
+	  PGSSLCERT
+	  PGSSLCRL
+	  PGSSLCRLDIR
+	  PGSSLKEY
+	  PGSSLMODE
+	  PGSSLROOTCERT
+	  PGTARGETSESSIONATTRS
+	  PGUSER
+	  PGPORT
+	  PGHOST
+	);
+	delete @ENV{@envkeys};
 
 	$ENV{PGAPPNAME} = basename($0);