Don't propagate PGAPPNAME through pg_ctl in tests

When libpq is loaded in the server (for instance, by
libpqwalreceiver), it may use libpq environment variables set in the
postmaster environment for connection parameter defaults.  This has
some confusing effects in our test suites.  For example, the TAP test
infrastructure sets PGAPPNAME to allow identifying clients in the
server log.  But this environment variable is also inherited by
temporary servers started with pg_ctl and is then in turn used by
libpqwalreceiver as the application_name for connecting to remote
servers where it then shows up in pg_stat_replication and is relevant
for things like synchronous_standby_names.  Replication already has a
suitable default for application_name, and overriding that
accidentally then requires the individual test cases to re-override
that, which is all very confusing and unnecessary.

To fix, unset PGAPPNAME temporarily before running pg_ctl start or
restart in the tests.

More comprehensive approaches like unsetting all environment variables
in pg_ctl were considered but might be too complicated to achieve
portably.

The now unnecessary re-overriding of application_name by test cases is
also removed.

Reviewed-by: Noah Misch <noah@leadboat.com>
Discussion: https://www.postgresql.org/message-id/flat/33383613-690e-6f1b-d5ba-4957ff40f6ce@2ndquadrant.com

Author: petere

src/bin/pg_rewind/t/RewindTest.pm

@@ -160,7 +160,7 @@ sub create_standby
 
 	$node_standby->append_conf(
 		"postgresql.conf", qq(
-primary_conninfo='$connstr_master application_name=rewind_standby'
+primary_conninfo='$connstr_master'
 ));
 
 	$node_standby->set_standby_mode();
@@ -180,7 +180,7 @@ sub promote_standby
 	# up standby
 
 	# Wait for the standby to receive and write all WAL.
-	$node_master->wait_for_catchup('rewind_standby', 'write');
+	$node_master->wait_for_catchup($node_standby, 'write');
 
 	# Now promote standby and insert some new data on master, this will put
 	# the master out-of-sync with the standby.

src/test/perl/PostgresNode.pm

@@ -698,12 +698,24 @@ sub start
 	my $port   = $self->port;
 	my $pgdata = $self->data_dir;
 	my $name   = $self->name;
+	my $ret;
+
 	BAIL_OUT("node \"$name\" is already running") if defined $self->{_pid};
+
 	print("### Starting node \"$name\"\n");
-	# Note: We set the cluster_name here, not in postgresql.conf (in
-	# sub init) so that it does not get copied to standbys.
-	my $ret = TestLib::system_log('pg_ctl', '-D', $self->data_dir, '-l',
-		$self->logfile, '-o', "--cluster-name=$name", 'start');
+
+	{
+		# Temporarily unset PGAPPNAME so that the server doesn't
+		# inherit it.  Otherwise this could affect libpqwalreceiver
+		# connections in confusing ways.
+		local %ENV = %ENV;
+		delete $ENV{PGAPPNAME};
+
+		# Note: We set the cluster_name here, not in postgresql.conf (in
+		# sub init) so that it does not get copied to standbys.
+		$ret = TestLib::system_log('pg_ctl', '-D', $self->data_dir, '-l',
+			$self->logfile, '-o', "--cluster-name=$name", 'start');
+	}
 
 	if ($ret != 0)
 	{
@@ -776,9 +788,17 @@ sub restart
 	my $pgdata  = $self->data_dir;
 	my $logfile = $self->logfile;
 	my $name    = $self->name;
+
 	print "### Restarting node \"$name\"\n";
-	TestLib::system_or_bail('pg_ctl', '-D', $pgdata, '-l', $logfile,
-		'restart');
+
+	{
+		local %ENV = %ENV;
+		delete $ENV{PGAPPNAME};
+
+		TestLib::system_or_bail('pg_ctl', '-D', $pgdata, '-l', $logfile,
+			'restart');
+	}
+
 	$self->_update_pid(1);
 	return;
 }
@@ -835,7 +855,7 @@ sub enable_streaming
 	print "### Enabling streaming replication for node \"$name\"\n";
 	$self->append_conf(
 		'postgresql.conf', qq(
-primary_conninfo='$root_connstr application_name=$name'
+primary_conninfo='$root_connstr'
 ));
 	$self->set_standby_mode();
 	return;

src/test/recovery/t/004_timeline_switch.pl

@@ -50,7 +50,7 @@
 my $connstr_1 = $node_standby_1->connstr;
 $node_standby_2->append_conf(
 	'postgresql.conf', qq(
-primary_conninfo='$connstr_1 application_name=@{[$node_standby_2->name]}'
+primary_conninfo='$connstr_1'
 ));
 $node_standby_2->restart;
 

src/test/subscription/t/001_rep_changes.pl

@@ -63,12 +63,11 @@
 $node_publisher->safe_psql('postgres',
 	"ALTER PUBLICATION tap_pub_ins_only ADD TABLE tab_ins");
 
-my $appname = 'tap_sub';
 $node_subscriber->safe_psql('postgres',
-	"CREATE SUBSCRIPTION tap_sub CONNECTION '$publisher_connstr application_name=$appname' PUBLICATION tap_pub, tap_pub_ins_only"
+	"CREATE SUBSCRIPTION tap_sub CONNECTION '$publisher_connstr' PUBLICATION tap_pub, tap_pub_ins_only"
 );
 
-$node_publisher->wait_for_catchup($appname);
+$node_publisher->wait_for_catchup('tap_sub');
 
 # Also wait for initial table sync to finish
 my $synced_query =
@@ -103,7 +102,7 @@
 	"DELETE FROM tab_include WHERE a > 20");
 $node_publisher->safe_psql('postgres', "UPDATE tab_include SET a = -a");
 
-$node_publisher->wait_for_catchup($appname);
+$node_publisher->wait_for_catchup('tap_sub');
 
 $result = $node_subscriber->safe_psql('postgres',
 	"SELECT count(*), min(a), max(a) FROM tab_ins");
@@ -146,7 +145,7 @@
 $node_publisher->safe_psql('postgres',
 	"UPDATE tab_full2 SET x = 'bb' WHERE x = 'b'");
 
-$node_publisher->wait_for_catchup($appname);
+$node_publisher->wait_for_catchup('tap_sub');
 
 $result = $node_subscriber->safe_psql('postgres',
 	"SELECT count(*), min(a), max(a) FROM tab_full");
@@ -165,23 +164,23 @@
 # as we need to poll for a change but the test suite will fail none the less
 # when something goes wrong.
 my $oldpid = $node_publisher->safe_psql('postgres',
-	"SELECT pid FROM pg_stat_replication WHERE application_name = '$appname';"
+	"SELECT pid FROM pg_stat_replication WHERE application_name = 'tap_sub';"
 );
 $node_subscriber->safe_psql('postgres',
-	"ALTER SUBSCRIPTION tap_sub CONNECTION 'application_name=$appname $publisher_connstr'"
+	"ALTER SUBSCRIPTION tap_sub CONNECTION '$publisher_connstr sslmode=disable'"
 );
 $node_publisher->poll_query_until('postgres',
-	"SELECT pid != $oldpid FROM pg_stat_replication WHERE application_name = '$appname';"
+	"SELECT pid != $oldpid FROM pg_stat_replication WHERE application_name = 'tap_sub';"
 ) or die "Timed out while waiting for apply to restart";
 
 $oldpid = $node_publisher->safe_psql('postgres',
-	"SELECT pid FROM pg_stat_replication WHERE application_name = '$appname';"
+	"SELECT pid FROM pg_stat_replication WHERE application_name = 'tap_sub';"
 );
 $node_subscriber->safe_psql('postgres',
 	"ALTER SUBSCRIPTION tap_sub SET PUBLICATION tap_pub_ins_only WITH (copy_data = false)"
 );
 $node_publisher->poll_query_until('postgres',
-	"SELECT pid != $oldpid FROM pg_stat_replication WHERE application_name = '$appname';"
+	"SELECT pid != $oldpid FROM pg_stat_replication WHERE application_name = 'tap_sub';"
 ) or die "Timed out while waiting for apply to restart";
 
 $node_publisher->safe_psql('postgres',
@@ -193,7 +192,7 @@
 $node_publisher->stop('fast');
 $node_publisher->start;
 
-$node_publisher->wait_for_catchup($appname);
+$node_publisher->wait_for_catchup('tap_sub');
 
 $result = $node_subscriber->safe_psql('postgres',
 	"SELECT count(*), min(a), max(a) FROM tab_ins");
@@ -216,7 +215,7 @@
 );
 $node_publisher->safe_psql('postgres', "INSERT INTO tab_full VALUES(0)");
 
-$node_publisher->wait_for_catchup($appname);
+$node_publisher->wait_for_catchup('tap_sub');
 
 # note that data are different on provider and subscriber
 $result = $node_subscriber->safe_psql('postgres',
@@ -230,12 +229,12 @@
 
 # check restart on rename
 $oldpid = $node_publisher->safe_psql('postgres',
-	"SELECT pid FROM pg_stat_replication WHERE application_name = '$appname';"
+	"SELECT pid FROM pg_stat_replication WHERE application_name = 'tap_sub';"
 );
 $node_subscriber->safe_psql('postgres',
 	"ALTER SUBSCRIPTION tap_sub RENAME TO tap_sub_renamed");
 $node_publisher->poll_query_until('postgres',
-	"SELECT pid != $oldpid FROM pg_stat_replication WHERE application_name = '$appname';"
+	"SELECT pid != $oldpid FROM pg_stat_replication WHERE application_name = 'tap_sub_renamed';"
 ) or die "Timed out while waiting for apply to restart";
 
 # check all the cleanup

src/test/subscription/t/002_types.pl

@@ -107,12 +107,11 @@
 $node_publisher->safe_psql('postgres',
 	"CREATE PUBLICATION tap_pub FOR ALL TABLES");
 
-my $appname = 'tap_sub';
 $node_subscriber->safe_psql('postgres',
-	"CREATE SUBSCRIPTION tap_sub CONNECTION '$publisher_connstr application_name=$appname' PUBLICATION tap_pub WITH (slot_name = tap_sub_slot)"
+	"CREATE SUBSCRIPTION tap_sub CONNECTION '$publisher_connstr' PUBLICATION tap_pub WITH (slot_name = tap_sub_slot)"
 );
 
-$node_publisher->wait_for_catchup($appname);
+$node_publisher->wait_for_catchup('tap_sub');
 
 # Wait for initial sync to finish as well
 my $synced_query =
@@ -251,7 +250,7 @@
 	INSERT INTO tst_dom_constr VALUES (10);
 ));
 
-$node_publisher->wait_for_catchup($appname);
+$node_publisher->wait_for_catchup('tap_sub');
 
 # Check the data on subscriber
 my $result = $node_subscriber->safe_psql(
@@ -372,7 +371,7 @@
 	UPDATE tst_hstore SET b = '"also"=>"updated"' WHERE a = 3;
 ));
 
-$node_publisher->wait_for_catchup($appname);
+$node_publisher->wait_for_catchup('tap_sub');
 
 # Check the data on subscriber
 $result = $node_subscriber->safe_psql(
@@ -492,7 +491,7 @@
 	DELETE FROM tst_hstore WHERE a = 1;
 ));
 
-$node_publisher->wait_for_catchup($appname);
+$node_publisher->wait_for_catchup('tap_sub');
 
 # Check the data on subscriber
 $result = $node_subscriber->safe_psql(
@@ -554,7 +553,7 @@
 # which needs an active snapshot in order to operate.
 $node_publisher->safe_psql('postgres', "INSERT INTO tst_dom_constr VALUES (11)");
 
-$node_publisher->wait_for_catchup($appname);
+$node_publisher->wait_for_catchup('tap_sub');
 
 $result =
   $node_subscriber->safe_psql('postgres', "SELECT sum(a) FROM tst_dom_constr");

src/test/subscription/t/003_constraints.pl

@@ -34,19 +34,18 @@
 $node_publisher->safe_psql('postgres',
 	"CREATE PUBLICATION tap_pub FOR ALL TABLES;");
 
-my $appname = 'tap_sub';
 $node_subscriber->safe_psql('postgres',
-	"CREATE SUBSCRIPTION tap_sub CONNECTION '$publisher_connstr application_name=$appname' PUBLICATION tap_pub WITH (copy_data = false)"
+	"CREATE SUBSCRIPTION tap_sub CONNECTION '$publisher_connstr' PUBLICATION tap_pub WITH (copy_data = false)"
 );
 
-$node_publisher->wait_for_catchup($appname);
+$node_publisher->wait_for_catchup('tap_sub');
 
 $node_publisher->safe_psql('postgres',
 	"INSERT INTO tab_fk (bid) VALUES (1);");
 $node_publisher->safe_psql('postgres',
 	"INSERT INTO tab_fk_ref (id, bid) VALUES (1, 1);");
 
-$node_publisher->wait_for_catchup($appname);
+$node_publisher->wait_for_catchup('tap_sub');
 
 # Check data on subscriber
 my $result = $node_subscriber->safe_psql('postgres',
@@ -64,7 +63,7 @@
 $node_publisher->safe_psql('postgres',
 	"INSERT INTO tab_fk_ref (id, bid) VALUES (2, 2);");
 
-$node_publisher->wait_for_catchup($appname);
+$node_publisher->wait_for_catchup('tap_sub');
 
 # FK is not enforced on subscriber
 $result = $node_subscriber->safe_psql('postgres',
@@ -98,7 +97,7 @@ BEGIN
 $node_publisher->safe_psql('postgres',
 	"INSERT INTO tab_fk_ref (id, bid) VALUES (10, 10);");
 
-$node_publisher->wait_for_catchup($appname);
+$node_publisher->wait_for_catchup('tap_sub');
 
 # The row should be skipped on subscriber
 $result = $node_subscriber->safe_psql('postgres',

src/test/subscription/t/004_sync.pl

@@ -32,12 +32,11 @@
 $node_publisher->safe_psql('postgres',
 	"CREATE PUBLICATION tap_pub FOR ALL TABLES");
 
-my $appname = 'tap_sub';
 $node_subscriber->safe_psql('postgres',
-	"CREATE SUBSCRIPTION tap_sub CONNECTION '$publisher_connstr application_name=$appname' PUBLICATION tap_pub"
+	"CREATE SUBSCRIPTION tap_sub CONNECTION '$publisher_connstr' PUBLICATION tap_pub"
 );
 
-$node_publisher->wait_for_catchup($appname);
+$node_publisher->wait_for_catchup('tap_sub');
 
 # Also wait for initial table sync to finish
 my $synced_query =
@@ -57,7 +56,7 @@
 
 # recreate the subscription, it will try to do initial copy
 $node_subscriber->safe_psql('postgres',
-	"CREATE SUBSCRIPTION tap_sub CONNECTION '$publisher_connstr application_name=$appname' PUBLICATION tap_pub"
+	"CREATE SUBSCRIPTION tap_sub CONNECTION '$publisher_connstr' PUBLICATION tap_pub"
 );
 
 # but it will be stuck on data copy as it will fail on constraint
@@ -79,7 +78,7 @@
 
 # now check another subscription for the same node pair
 $node_subscriber->safe_psql('postgres',
-	"CREATE SUBSCRIPTION tap_sub2 CONNECTION '$publisher_connstr application_name=$appname' PUBLICATION tap_pub WITH (copy_data = false)"
+	"CREATE SUBSCRIPTION tap_sub2 CONNECTION '$publisher_connstr' PUBLICATION tap_pub WITH (copy_data = false)"
 );
 
 # wait for it to start
@@ -101,7 +100,7 @@
 
 # recreate the subscription again
 $node_subscriber->safe_psql('postgres',
-	"CREATE SUBSCRIPTION tap_sub CONNECTION '$publisher_connstr application_name=$appname' PUBLICATION tap_pub"
+	"CREATE SUBSCRIPTION tap_sub CONNECTION '$publisher_connstr' PUBLICATION tap_pub"
 );
 
 # and wait for data sync to finish again
@@ -120,7 +119,7 @@
 $node_publisher->safe_psql('postgres',
 	"CREATE TABLE tab_rep_next (a) AS SELECT generate_series(1,10)");
 
-$node_publisher->wait_for_catchup($appname);
+$node_publisher->wait_for_catchup('tap_sub');
 
 $result = $node_subscriber->safe_psql('postgres',
 	"SELECT count(*) FROM tab_rep_next");
@@ -143,7 +142,7 @@
 $node_publisher->safe_psql('postgres',
 	"INSERT INTO tab_rep_next SELECT generate_series(1,10)");
 
-$node_publisher->wait_for_catchup($appname);
+$node_publisher->wait_for_catchup('tap_sub');
 
 $result = $node_subscriber->safe_psql('postgres',
 	"SELECT count(*) FROM tab_rep_next");

src/test/subscription/t/005_encoding.pl

@@ -22,15 +22,14 @@
 $node_subscriber->safe_psql('postgres', $ddl);
 
 my $publisher_connstr = $node_publisher->connstr . ' dbname=postgres';
-my $appname           = 'encoding_test';
 
 $node_publisher->safe_psql('postgres',
 	"CREATE PUBLICATION mypub FOR ALL TABLES;");
 $node_subscriber->safe_psql('postgres',
-	"CREATE SUBSCRIPTION mysub CONNECTION '$publisher_connstr application_name=$appname' PUBLICATION mypub;"
+	"CREATE SUBSCRIPTION mysub CONNECTION '$publisher_connstr' PUBLICATION mypub;"
 );
 
-$node_publisher->wait_for_catchup($appname);
+$node_publisher->wait_for_catchup('mysub');
 
 # Wait for initial sync to finish as well
 my $synced_query =
@@ -41,7 +40,7 @@
 $node_publisher->safe_psql('postgres',
 	q{INSERT INTO test1 VALUES (1, E'Mot\xc3\xb6rhead')}); # hand-rolled UTF-8
 
-$node_publisher->wait_for_catchup($appname);
+$node_publisher->wait_for_catchup('mysub');
 
 is( $node_subscriber->safe_psql(
 		'postgres', q{SELECT a FROM test1 WHERE b = E'Mot\xf6rhead'}