[PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection

agora inbox for [email protected]  
help / color / mirror / Atom feed

[PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
275+ messages / 2 participants
[nested] [flat]

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits
@ 2025-03-07 14:44  Andres Freund <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Andres Freund @ 2025-03-07 14:44 UTC (permalink / raw)

The test occasionally failed due to unexpected connection limit errors being
encountered after having waited for FATAL errors on another connection. These
spurious failures were caused by the the backend reporting FATAL errors to the
client before detaching from the PGPROC entry. Adding a sleep(1) before
proc_exit() makes it easy to reproduce that problem.

To fix the issue, add a helper function that waits for postmaster to notice
the process having exited. For now this is implemented by waiting for the
DEBUG2 message that postmaster logs in that case. That's not the prettiest
fix, but simple. If we notice this problem elsewhere, it might be worthwhile
to make this more general, e.g. by adding an injection point.

Reported-by: Tomas Vondra <[email protected]>
Diagnosed-by: Heikki Linnakangas <[email protected]>
Reviewed-by: Heikki Linnakangas <[email protected]>
Discussion: https://postgr.es/m/ggflhkciwdyotpoie323chu2c2idpjk5qimrn462encwx2io7s@thmcxl7i6dpw
---
 .../postmaster/t/002_connection_limits.pl     | 35 +++++++++++++++++--
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/test/postmaster/t/002_connection_limits.pl b/src/test/postmaster/t/002_connection_limits.pl
index 8cfa6e0ced5..2c185eef6eb 100644
--- a/src/test/postmaster/t/002_connection_limits.pl
+++ b/src/test/postmaster/t/002_connection_limits.pl
@@ -20,6 +20,7 @@ $node->append_conf('postgresql.conf', "max_connections = 6");
 $node->append_conf('postgresql.conf', "reserved_connections = 2");
 $node->append_conf('postgresql.conf', "superuser_reserved_connections = 1");
 $node->append_conf('postgresql.conf', "log_connections = on");
+$node->append_conf('postgresql.conf', "log_min_messages=debug2");
 $node->start;
 
 $node->safe_psql(
@@ -45,13 +46,39 @@ sub background_psql_as_user
 		extra_params => [ '-U', $user ]);
 }
 
+# Like connect_fails(), except that we also wait for the failed backend to
+# have exited.
+#
+# This tests needs to wait for client processes to exit because the error
+# message for a failed connection is reported before the backend has detached
+# from shared memory. If we didn't wait, subsequent tests might hit connection
+# limits spuriously.
+#
+# This can't easily be generalized, as detecting process exit requires
+# log_min_messages to be at least DEBUG2 and is not concurrency safe, as we
+# can't easily be sure the right process exited. In this test that's not a
+# problem though, we only have one new connection at a time.
+sub connect_fails_wait
+{
+	local $Test::Builder::Level = $Test::Builder::Level + 1;
+	my ($node, $connstr, $test_name, %params) = @_;
+
+	my $log_location = -s $node->logfile;
+
+	$node->connect_fails($connstr, $test_name, %params);
+	$node->wait_for_log(qr/DEBUG:  client backend.*exited with exit code 1/,
+		$log_location);
+	ok(1, "$test_name: client backend process exited");
+}
+
 my @sessions = ();
 my @raw_connections = ();
 
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
 push(@sessions, background_psql_as_user('regress_regular'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -60,7 +87,8 @@ $node->connect_fails(
 
 push(@sessions, background_psql_as_user('regress_reserved'));
 push(@sessions, background_psql_as_user('regress_reserved'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_regular",
 	"reserved_connections limit",
 	expected_stderr =>
@@ -68,7 +96,8 @@ $node->connect_fails(
 );
 
 push(@sessions, background_psql_as_user('regress_superuser'));
-$node->connect_fails(
+connect_fails_wait(
+	$node,
 	"dbname=postgres user=regress_superuser",
 	"superuser_reserved_connections limit",
 	expected_stderr => qr/FATAL:  sorry, too many clients already/);
-- 
2.48.1.76.g4e746b1a31.dirty


--q4d36jgrlhdhudrc
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
	filename="v2-0004-tests-Don-t-fail-due-to-high-default-timeout-in-p.patch"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

* [PATCH 3/9] remove excess parens around ereport
@ 2026-03-12 15:09  Álvaro Herrera <[email protected]>
  0 siblings, 0 replies; 275+ messages in thread

From: Álvaro Herrera @ 2026-03-12 15:09 UTC (permalink / raw)

---
 src/backend/commands/cluster.c | 78 ++++++++++++++++++----------------
 1 file changed, 41 insertions(+), 37 deletions(-)

diff --git a/src/backend/commands/cluster.c b/src/backend/commands/cluster.c
index db3980b84f5..af47354e382 100644
--- a/src/backend/commands/cluster.c
+++ b/src/backend/commands/cluster.c
@@ -992,10 +992,10 @@ check_repack_concurrently_requirements(Relation rel, Oid *ident_idx_p)
 	/* Data changes in system relations are not logically decoded. */
 	if (IsCatalogRelation(rel))
 		ereport(ERROR,
-				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-				 errmsg("cannot repack relation \"%s\"",
-						RelationGetRelationName(rel)),
-				 errhint("REPACK CONCURRENTLY is not supported for catalog relations.")));
+				errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				errmsg("cannot repack relation \"%s\"",
+					   RelationGetRelationName(rel)),
+				errhint("REPACK CONCURRENTLY is not supported for catalog relations."));
 
 	/*
 	 * reorderbuffer.c does not seem to handle processing of TOAST relation
@@ -1003,28 +1003,28 @@ check_repack_concurrently_requirements(Relation rel, Oid *ident_idx_p)
 	 */
 	if (IsToastRelation(rel))
 		ereport(ERROR,
-				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-				 errmsg("cannot repack relation \"%s\"",
-						RelationGetRelationName(rel)),
-				 errhint("REPACK CONCURRENTLY is not supported for TOAST relations, unless the main relation is repacked too.")));
+				errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				errmsg("cannot repack relation \"%s\"",
+					   RelationGetRelationName(rel)),
+				errhint("REPACK CONCURRENTLY is not supported for TOAST relations, unless the main relation is repacked too."));
 
 	relpersistence = rel->rd_rel->relpersistence;
 	if (relpersistence != RELPERSISTENCE_PERMANENT)
 		ereport(ERROR,
-				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
-				 errmsg("cannot repack relation \"%s\"",
-						RelationGetRelationName(rel)),
-				 errhint("REPACK CONCURRENTLY is only allowed for permanent relations.")));
+				errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+				errmsg("cannot repack relation \"%s\"",
+					   RelationGetRelationName(rel)),
+				errhint("REPACK CONCURRENTLY is only allowed for permanent relations."));
 
 	/* With NOTHING, WAL does not contain the old tuple. */
 	replident = rel->rd_rel->relreplident;
 	if (replident == REPLICA_IDENTITY_NOTHING)
 		ereport(ERROR,
-				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
-				 errmsg("cannot repack relation \"%s\"",
-						RelationGetRelationName(rel)),
-				 errhint("Relation \"%s\" has insufficient replication identity.",
-						 RelationGetRelationName(rel))));
+				errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+				errmsg("cannot repack relation \"%s\"",
+					   RelationGetRelationName(rel)),
+				errhint("Relation \"%s\" has insufficient replication identity.",
+						RelationGetRelationName(rel)));
 
 	/*
 	 * If the identity index is not set due to replica identity being, PK
@@ -1035,11 +1035,11 @@ check_repack_concurrently_requirements(Relation rel, Oid *ident_idx_p)
 		ident_idx = rel->rd_pkindex;
 	if (!OidIsValid(ident_idx))
 		ereport(ERROR,
-				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
-				 errmsg("cannot process relation \"%s\"",
-						RelationGetRelationName(rel)),
-				 errhint("Relation \"%s\" has no identity index.",
-						 RelationGetRelationName(rel))));
+				errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+				errmsg("cannot process relation \"%s\"",
+					   RelationGetRelationName(rel)),
+				errhint("Relation \"%s\" has no identity index.",
+						RelationGetRelationName(rel)));
 
 	*ident_idx_p = ident_idx;
 }
@@ -2793,20 +2793,21 @@ decode_concurrent_changes(LogicalDecodingContext *ctx,
 			ReadLocalXLogPageNoWaitPrivate *priv;
 
 			if (errm)
-				ereport(ERROR, (errmsg("%s", errm)));
+				ereport(ERROR,
+						errmsg("%s", errm));
 
 			/*
 			 * In the decoding loop we do not want to get blocked when there
 			 * is no more WAL available, otherwise the loop would become
 			 * uninterruptible.
 			 */
-			priv = (ReadLocalXLogPageNoWaitPrivate *)
-				ctx->reader->private_data;
+			priv = (ReadLocalXLogPageNoWaitPrivate *) ctx->reader->private_data;
 			if (priv->end_of_wal)
 				/* Do not miss the end of WAL condition next time. */
 				priv->end_of_wal = false;
 			else
-				ereport(ERROR, (errmsg("could not read WAL record")));
+				ereport(ERROR,
+						errmsg("could not read WAL record"));
 		}
 
 		/*
@@ -2852,7 +2853,8 @@ decode_concurrent_changes(LogicalDecodingContext *ctx,
 							 timeout);
 			if (res != WAIT_LSN_RESULT_SUCCESS &&
 				res != WAIT_LSN_RESULT_TIMEOUT)
-				ereport(ERROR, (errmsg("waiting for WAL failed")));
+				ereport(ERROR,
+						errmsg("waiting for WAL failed"));
 		}
 	}
 
@@ -3050,7 +3052,8 @@ apply_concurrent_update(Relation rel, HeapTuple tup, HeapTuple tup_target,
 					  &tmfd, &lockmode, &update_indexes,
 					  false /* wal_logical */ );
 	if (res != TM_Ok)
-		ereport(ERROR, (errmsg("failed to apply concurrent UPDATE")));
+		ereport(ERROR,
+				errmsg("failed to apply concurrent UPDATE"));
 
 	ExecStoreHeapTuple(tup, index_slot, false);
 
@@ -3091,7 +3094,8 @@ apply_concurrent_delete(Relation rel, HeapTuple tup_target)
 					  false /* wal_logical */ );
 
 	if (res != TM_Ok)
-		ereport(ERROR, (errmsg("failed to apply concurrent DELETE")));
+		ereport(ERROR,
+				errmsg("failed to apply concurrent DELETE"));
 
 	pgstat_progress_incr_param(PROGRESS_REPACK_HEAP_TUPLES_DELETED, 1);
 }
@@ -3576,7 +3580,7 @@ rebuild_relation_finish_concurrent(Relation NewHeap, Relation OldHeap,
 		 * Should not happen, given our lock on the old relation.
 		 */
 		ereport(ERROR,
-				(errmsg("identity index missing on the new relation")));
+				errmsg("identity index missing on the new relation"));
 
 	/* Gather information to apply concurrent changes. */
 	chgdst.rel = NewHeap;
@@ -3864,9 +3868,9 @@ start_decoding_worker(Oid relid)
 	decoding_worker = palloc0_object(DecodingWorker);
 	if (!RegisterDynamicBackgroundWorker(&bgw, &decoding_worker->handle))
 		ereport(ERROR,
-				(errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED),
-				 errmsg("out of background worker slots"),
-				 errhint("You might need to increase \"%s\".", "max_worker_processes")));
+				errcode(ERRCODE_CONFIGURATION_LIMIT_EXCEEDED),
+				errmsg("out of background worker slots"),
+				errhint("You might need to increase \"%s\".", "max_worker_processes"));
 
 	decoding_worker->seg = seg;
 	decoding_worker->error_mqh = mqh;
@@ -3921,8 +3925,8 @@ stop_decoding_worker(void)
 
 	if (status == BGWH_POSTMASTER_DIED)
 		ereport(FATAL,
-				(errcode(ERRCODE_ADMIN_SHUTDOWN),
-				 errmsg("postmaster exited during REPACK command")));
+				errcode(ERRCODE_ADMIN_SHUTDOWN),
+				errmsg("postmaster exited during REPACK command"));
 
 	shm_mq_detach(decoding_worker->error_mqh);
 
@@ -3979,8 +3983,8 @@ RepackWorkerMain(Datum main_arg)
 	seg = dsm_attach(DatumGetUInt32(main_arg));
 	if (seg == NULL)
 		ereport(ERROR,
-				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
-				 errmsg("could not map dynamic shared memory segment")));
+				errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+				errmsg("could not map dynamic shared memory segment"));
 
 	shared = (DecodingWorkerShared *) dsm_segment_address(seg);
 
-- 
2.47.3


--pnppmxqkefjd4hu2
Content-Type: text/plain; charset=utf-8
Content-Disposition: attachment;
	filename="0004-XLogRecPtrIsInvalid-XLogRecPtrIsValid.nocfbot.txt"



^ permalink  raw  reply  [nested|flat] 275+ messages in thread

end of thread, other threads:[~2026-03-12 15:09 UTC | newest]

Thread overview: 275+ messages (download: mbox mbox.gz follow: Atom feed)
-- links below jump to the message on this page --
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2025-03-07 14:44 [PATCH v2 3/4] tests: Fix race condition in postmaster/002_connection_limits Andres Freund <[email protected]>
2026-03-12 15:09 [PATCH 3/9] remove excess parens around ereport Álvaro Herrera <[email protected]>

This inbox is served by agora; see mirroring instructions
for how to clone and mirror all data and code used for this inbox