From: Drouvot, Bertrand <bertranddrouvot.pg@gmail.com>
To: PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Subject: Add two missing tests in 035_standby_logical_decoding.pl
Date: Wed, 12 Apr 2023 18:15:10 +0200
Message-ID: <2fefa454-5a70-2174-ddbf-4a0e41537139@gmail.com> (raw)
hi hackers,
In the logical decoding on standby thread [1], Andres proposed 2 new tests (that I did
not find the time to complete before the finish line):
- Test that we can subscribe to the standby (with the publication created on the primary)
- Verify that invalidated logical slots do not lead to retaining WAL
Please find those 2 missing tests in the patch proposal attached.
A few words about them:
1) Regarding the subscription test:
It modifies wait_for_catchup() to take into account the case where the requesting
node is in recovery mode. Indeed, without that change, wait_for_subscription_sync() was
failing with:
"
error running SQL: 'psql:<stdin>:1: ERROR: recovery is in progress
HINT: WAL control functions cannot be executed during recovery.'
while running 'psql -XAtq -d port=61441 host=/tmp/45dt3wqs2p dbname='postgres' -f - -v ON_ERROR_STOP=1' with sql 'SELECT pg_current_wal_lsn()'
"
2) Regarding the WAL file not retained test:
As it's not possible to execute pg_switch_wal() and friends on a standby, this is
done on the primary. Also checking that the WAL file (linked to a restart_lsn of an invalidate
slot) has been removed is done directly at the os/directory level.
The attached patch also removes:
"
-log_min_messages = 'debug2'
-log_error_verbosity = verbose
"
as also discussed in [1].
I'm not sure if adding those 2 tests should be considered as an open item. I can add this open item
if we think that makes sense. I'd be happy to do so but it looks like I don't have the privileges
to edit https://wiki.postgresql.org/wiki/PostgreSQL_16_Open_Items
Regards,
--
Bertrand Drouvot
PostgreSQL Contributors Team
RDS Open Source Databases
Amazon Web Services: https://aws.amazon.com
[1]: https://www.postgresql.org/message-id/6d801661-e21b-7326-be1b-f90d904da66a%40gmail.comAttachments:v1-0001-add-missing-tests.patch (text/plain, 8.4K) downloaddiff --git a/src/test/perl/PostgreSQL/Test/Cluster.pm b/src/test/perl/PostgreSQL/Test/Cluster.pmindex 6f7f4e5de4..819667d42a 100644--- a/src/test/perl/PostgreSQL/Test/Cluster.pm+++ b/src/test/perl/PostgreSQL/Test/Cluster.pm@@ -2644,7 +2644,16 @@ sub wait_for_catchup
}
if (!defined($target_lsn))
{
- $target_lsn = $self->lsn('write');+ my $isrecovery = $self->safe_psql('postgres', "SELECT pg_is_in_recovery()");+ chomp($isrecovery);+ if ($isrecovery eq 't')+ {+ $target_lsn = $self->lsn('replay');+ }+ else+ {+ $target_lsn = $self->lsn('write');+ }
}
print "Waiting for replication conn "
. $standby_name . "'s "
diff --git a/src/test/recovery/t/035_standby_logical_decoding.pl b/src/test/recovery/t/035_standby_logical_decoding.plindex 94a8384c31..09bc417356 100644--- a/src/test/recovery/t/035_standby_logical_decoding.pl+++ b/src/test/recovery/t/035_standby_logical_decoding.pl@@ -9,13 +9,19 @@ use warnings;
use PostgreSQL::Test::Cluster;
use PostgreSQL::Test::Utils;
use Test::More;
+use Time::HiRes qw(usleep);-my ($stdin, $stdout, $stderr, $cascading_stdout, $cascading_stderr, $ret, $handle, $slot);+my ($stdin, $stdout, $stderr,+ $cascading_stdout, $cascading_stderr, $subscriber_stdin,+ $subscriber_stdout, $subscriber_stderr, $ret,+ $handle, $slot);
my $node_primary = PostgreSQL::Test::Cluster->new('primary');
my $node_standby = PostgreSQL::Test::Cluster->new('standby');
my $node_cascading_standby = PostgreSQL::Test::Cluster->new('cascading_standby');
+my $node_subscriber = PostgreSQL::Test::Cluster->new('subscriber');
my $default_timeout = $PostgreSQL::Test::Utils::timeout_default;
+my $psql_timeout = IPC::Run::timer(2 * $default_timeout);
my $res;
# Name for the physical slot on primary
@@ -235,8 +241,6 @@ $node_primary->append_conf('postgresql.conf', q{
wal_level = 'logical'
max_replication_slots = 4
max_wal_senders = 4
-log_min_messages = 'debug2'-log_error_verbosity = verbose
});
$node_primary->dump_info;
$node_primary->start;
@@ -269,7 +273,8 @@ $node_standby->init_from_backup(
has_streaming => 1,
has_restoring => 1);
$node_standby->append_conf('postgresql.conf',
- qq[primary_slot_name = '$primary_slotname']);+ qq[primary_slot_name = '$primary_slotname'+ max_replication_slots = 5]);
$node_standby->start;
$node_primary->wait_for_replay_catchup($node_standby);
$node_standby->safe_psql('testdb', qq[SELECT * FROM pg_create_physical_replication_slot('$standby_physical_slotname');]);
@@ -287,6 +292,27 @@ $node_cascading_standby->append_conf('postgresql.conf',
$node_cascading_standby->start;
$node_standby->wait_for_replay_catchup($node_cascading_standby, $node_primary);
+#######################+# Initialize subscriber node+#######################+$node_subscriber->init(allows_streaming => 'logical');+$node_subscriber->append_conf('postgresql.conf', 'max_replication_slots = 4');+$node_subscriber->start;++my %psql_subscriber = (+ 'subscriber_stdin' => '',+ 'subscriber_stdout' => '',+ 'subscriber_stderr' => '');+$psql_subscriber{run} = IPC::Run::start(+ [ 'psql', '-XA', '-f', '-', '-d', $node_subscriber->connstr('postgres') ],+ '<',+ \$psql_subscriber{subscriber_stdin},+ '>',+ \$psql_subscriber{subscriber_stdout},+ '2>',+ \$psql_subscriber{subscriber_stderr},+ $psql_timeout);+
##################################################
# Test that logical decoding on the standby
# behaves correctly.
@@ -367,6 +393,58 @@ is( $node_primary->psql(
3,
'replaying logical slot from another database fails');
+##################################################+# Test that we can subscribe on the standby with the publication+# created on the primary.+##################################################++# Create a table on the primary+$node_primary->safe_psql('postgres',+ "CREATE TABLE tab_rep (a int primary key)");++# Create a table (same structure) on the subscriber node+$node_subscriber->safe_psql('postgres',+ "CREATE TABLE tab_rep (a int primary key)");++# Create a publication on the primary+$node_primary->safe_psql('postgres',+ "CREATE PUBLICATION tap_pub for table tab_rep");++# Subscribe on the standby+my $standby_connstr = $node_standby->connstr . ' dbname=postgres';+$psql_subscriber{subscriber_stdin} .=+ qq[CREATE SUBSCRIPTION tap_sub CONNECTION '$standby_connstr' PUBLICATION tap_pub;];+$psql_subscriber{subscriber_stdin} .= "\n";++$psql_subscriber{run}->pump_nb();++# Speed up the subscription creation+$node_primary->safe_psql('postgres', "SELECT pg_log_standby_snapshot()");++# Explicitly shut down psql instance gracefully - to avoid hangs+# or worse on windows+$psql_subscriber{subscriber_stdin} .= "\\q\n";+$psql_subscriber{run}->finish;++# Insert some rows on the primary+$node_primary->safe_psql('postgres',+ qq[INSERT INTO tab_rep select generate_series(1,10);]);++$node_primary->wait_for_replay_catchup($node_standby);++# To speed up the wait_for_subscription_sync+$node_primary->safe_psql('postgres', "SELECT pg_log_standby_snapshot()");+$node_subscriber->wait_for_subscription_sync($node_standby, 'tap_sub');++# Check that the subscriber can see the rows inserted in the primary+$result =+ $node_subscriber->safe_psql('postgres', "SELECT count(*) FROM tab_rep");+is($result, qq(10), 'check replicated inserts after subscription on standby');++# We do not need the subscriber anymore+$node_subscriber->safe_psql('postgres', "DROP SUBSCRIPTION tap_sub");+$node_subscriber->stop;+
##################################################
# Recovery conflict: Invalidate conflicting slots, including in-use slots
# Scenario 1: hot_standby_feedback off and vacuum FULL
@@ -410,9 +488,82 @@ $node_standby->restart;
check_slots_conflicting_status(1);
##################################################
-# Verify that invalidated logical slots do not lead to retaining WAL+# Verify that invalidated logical slots do not lead to retaining WAL.
##################################################
-# XXXXX TODO++# Get the restart_lsn from an invalidated slot+my $restart_lsn = $node_standby->safe_psql('postgres',+ "SELECT restart_lsn from pg_replication_slots WHERE slot_name = 'vacuum_full_activeslot' and conflicting is true;"+);++chomp($restart_lsn);++# Get the WAL file name associated to this lsn on the primary+my $walfile_name = $node_primary->safe_psql('postgres',+ "SELECT pg_walfile_name('$restart_lsn')");++chomp($walfile_name);++# Check the WAL file is still on the primary+ok(-f $node_primary->data_dir . '/pg_wal/' . $walfile_name,+ "WAL file still on the primary");++# Get the number of WAL files on the standby+my $nb_standby_files = $node_standby->safe_psql('postgres',+ "SELECT COUNT(*) FROM pg_ls_dir('pg_wal')");++chomp($nb_standby_files);++# Switch WAL files on the primary+my @c = (1 .. $nb_standby_files);++$node_primary->safe_psql('postgres', "create table retain_test(a int)");++for (@c)+{+ $node_primary->safe_psql(+ 'postgres', "SELECT pg_switch_wal();+ insert into retain_test values("+ . $_ . ");");+}++# Ask for a checkpoint+$node_primary->safe_psql('postgres', 'checkpoint;');++# Check that the WAL file has not been retained on the primary+ok(!-f $node_primary->data_dir . '/pg_wal/' . $walfile_name,+ "WAL file not on the primary anymore");++# Wait for the standby to catch up+$node_primary->wait_for_catchup($node_standby);++# Generate another WAL switch, more activity and a checkpoint+$node_primary->safe_psql(+ 'postgres', "SELECT pg_switch_wal();+ insert into retain_test values(1);");+$node_primary->safe_psql('postgres', 'checkpoint;');++# Wait for the standby to catch up+$node_primary->wait_for_catchup($node_standby);++# Verify that the wal file has not been retained on the standby+my $standby_walfile = $node_standby->data_dir . '/pg_wal/' . $walfile_name;++# We can not test if the WAL file still exists immediately.+# We need to let some time to the standby to actually "remove" it.+my $i = 0;+while (1)+{+ last if !-f $standby_walfile;+ if ($i++ == 10 * $default_timeout)+ {+ die+ "could not determine if WAL file has been retained or not, can't continue";+ }+ usleep(100_000);+}++ok(1, "invalidated logical slots do not lead to retaining WAL");
##################################################
# Recovery conflict: Invalidate conflicting slots, including in-use slots
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To: pgsql-hackers@postgresql.org
Cc: bertranddrouvot.pg@gmail.com, pgsql-hackers@lists.postgresql.org
Subject: Re: Add two missing tests in 035_standby_logical_decoding.pl
In-Reply-To: <2fefa454-5a70-2174-ddbf-4a0e41537139@gmail.com>
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