Stabilize 035_standby_logical_decoding.pl.

Some tests try to invalidate logical slots on the standby server by
running VACUUM on the primary. The problem is that xl_running_xacts was
getting generated and replayed before the VACUUM command, leading to the
advancement of the active slot's catalog_xmin. Due to this, active slots
were not getting invalidated, leading to test failures.

We fix it by skipping the generation of xl_running_xacts for the required
tests with the help of injection points. As the required interface for
injection points was not present in back branches, we fixed the failing
tests in them by disallowing the slot to become active for the required
cases (where rows_removed conflict could be generated).

Author: Hayato Kuroda <[email protected]>
Reviewed-by: Bertrand Drouvot <[email protected]>
Reviewed-by: Amit Kapila <[email protected]>
Backpatch-through: 16, where it was introduced
Discussion: https://postgr.es/m/[email protected]

diff --git a/src/test/recovery/t/035_standby_logical_decoding.pl b/src/test/recovery/t/035_standby_logical_decoding.pl
index 4eca17885d6ea064eae03871b57b8bbe1f2e24f9..58c4402e80e6c6e19c2fd79e5bfd096767fb4a7b 100644 (file)
--- a/src/test/recovery/t/035_standby_logical_decoding.pl
+++ b/src/test/recovery/t/035_standby_logical_decoding.pl
@@ -205,9 +205,6 @@ sub reactive_slots_change_hfs_and_wait_for_xmins
 
    change_hot_standby_feedback_and_wait_for_xmins($hsf, $invalidated);
 
-   $handle =
-     make_slot_active($node_standby, $slot_prefix, 1, \$stdout, \$stderr);
-
    # reset stat: easier to check for confl_active_logicalslot in pg_stat_database_conflicts
    $node_standby->psql('testdb', q[select pg_stat_reset();]);
 }
@@ -215,7 +212,7 @@ sub reactive_slots_change_hfs_and_wait_for_xmins
 # Check invalidation in the logfile and in pg_stat_database_conflicts
 sub check_for_invalidation
 {
-   my ($slot_prefix, $log_start, $test_name) = @_;
+   my ($slot_prefix, $log_start, $test_name, $checks_active_slot) = @_;
 
    my $active_slot = $slot_prefix . 'activeslot';
    my $inactive_slot = $slot_prefix . 'inactiveslot';
@@ -231,13 +228,17 @@ sub check_for_invalidation
            $log_start),
        "activeslot slot invalidation is logged $test_name");
 
-   # Verify that pg_stat_database_conflicts.confl_active_logicalslot has been updated
-   ok( $node_standby->poll_query_until(
-           'postgres',
-           "select (confl_active_logicalslot = 1) from pg_stat_database_conflicts where datname = 'testdb'",
-           't'),
-       'confl_active_logicalslot updated'
-   ) or die "Timed out waiting confl_active_logicalslot to be updated";
+   if ($checks_active_slot)
+   {
+       # Verify that pg_stat_database_conflicts.confl_active_logicalslot has
+       # been updated
+       ok( $node_standby->poll_query_until(
+               'postgres',
+               "select (confl_active_logicalslot = 1) from pg_stat_database_conflicts where datname = 'testdb'",
+               't'),
+           'confl_active_logicalslot updated'
+       ) or die "Timed out waiting confl_active_logicalslot to be updated";
+   }
 }
 
 # Launch $sql query, wait for a new snapshot that has a newer horizon and
@@ -250,7 +251,11 @@ sub check_for_invalidation
 # seeing a xl_running_xacts that would advance an active replication slot's
 # catalog_xmin.  Advancing the active replication slot's catalog_xmin
 # would break some tests that expect the active slot to conflict with
-# the catalog xmin horizon.
+# the catalog xmin horizon.  Even with the above precaution, there is a risk
+# of xl_running_xacts record being logged and replayed before the VACUUM
+# command, leading to the test failure.  So, we ensured that replication slots
+# are not activated for tests that can invalidate slots due to 'rows_removed'
+# conflict reason.
 sub wait_until_vacuum_can_remove
 {
    my ($vac_option, $sql, $to_vac) = @_;
@@ -532,11 +537,8 @@ $node_subscriber->safe_psql('postgres', "DROP SUBSCRIPTION tap_sub");
 $node_subscriber->stop;
 
 ##################################################
-# Recovery conflict: Invalidate conflicting slots, including in-use slots
+# Recovery conflict: Invalidate conflicting slots
 # Scenario 1: hot_standby_feedback off and vacuum FULL
-#
-# In passing, ensure that replication slot stats are not removed when the
-# active slot is invalidated.
 ##################################################
 
 # One way to produce recovery conflict is to create/drop a relation and
@@ -550,10 +552,6 @@ reactive_slots_change_hfs_and_wait_for_xmins('behaves_ok_', 'vacuum_full_',
 $node_primary->safe_psql('testdb',
    qq[INSERT INTO decoding_test(x,y) SELECT 100,'100';]);
 
-$node_standby->poll_query_until('testdb',
-   qq[SELECT total_txns > 0 FROM pg_stat_replication_slots WHERE slot_name = 'vacuum_full_activeslot']
-) or die "replication slot stats of vacuum_full_activeslot not updated";
-
 # This should trigger the conflict
 wait_until_vacuum_can_remove(
    'full', 'CREATE TABLE conflict_test(x integer, y text);
@@ -562,19 +560,11 @@ wait_until_vacuum_can_remove(
 $node_primary->wait_for_replay_catchup($node_standby);
 
 # Check invalidation in the logfile and in pg_stat_database_conflicts
-check_for_invalidation('vacuum_full_', 1, 'with vacuum FULL on pg_class');
+check_for_invalidation('vacuum_full_', 1, 'with vacuum FULL on pg_class', 0);
 
 # Verify reason for conflict is 'rows_removed' in pg_replication_slots
 check_slots_conflict_reason('vacuum_full_', 'rows_removed');
 
-# Ensure that replication slot stats are not removed after invalidation.
-is( $node_standby->safe_psql(
-       'testdb',
-       qq[SELECT total_txns > 0 FROM pg_stat_replication_slots WHERE slot_name = 'vacuum_full_activeslot']
-   ),
-   't',
-   'replication slot stats not removed after invalidation');
-
 $handle =
   make_slot_active($node_standby, 'vacuum_full_', 0, \$stdout, \$stderr);
 
@@ -639,7 +629,7 @@ ok(!-f "$standby_walfile",
    "invalidated logical slots do not lead to retaining WAL");
 
 ##################################################
-# Recovery conflict: Invalidate conflicting slots, including in-use slots
+# Recovery conflict: Invalidate conflicting slots
 # Scenario 2: conflict due to row removal with hot_standby_feedback off.
 ##################################################
 
@@ -660,7 +650,7 @@ wait_until_vacuum_can_remove(
 $node_primary->wait_for_replay_catchup($node_standby);
 
 # Check invalidation in the logfile and in pg_stat_database_conflicts
-check_for_invalidation('row_removal_', $logstart, 'with vacuum on pg_class');
+check_for_invalidation('row_removal_', $logstart, 'with vacuum on pg_class', 0);
 
 # Verify reason for conflict is 'rows_removed' in pg_replication_slots
 check_slots_conflict_reason('row_removal_', 'rows_removed');
@@ -696,7 +686,7 @@ $node_primary->wait_for_replay_catchup($node_standby);
 
 # Check invalidation in the logfile and in pg_stat_database_conflicts
 check_for_invalidation('shared_row_removal_', $logstart,
-   'with vacuum on pg_authid');
+   'with vacuum on pg_authid', 0);
 
 # Verify reason for conflict is 'rows_removed' in pg_replication_slots
 check_slots_conflict_reason('shared_row_removal_', 'rows_removed');
@@ -720,6 +710,10 @@ $logstart = -s $node_standby->logfile;
 reactive_slots_change_hfs_and_wait_for_xmins('shared_row_removal_',
    'no_conflict_', 0, 1);
 
+# As this scenario is not expected to produce any conflict, so activate the slot.
+# See comments atop wait_until_vacuum_can_remove().
+make_slot_active($node_standby, 'no_conflict_', 1, \$stdout, \$stderr);
+
 # This should not trigger a conflict
 wait_until_vacuum_can_remove(
    '', 'CREATE TABLE conflict_test(x integer, y text);
@@ -763,7 +757,7 @@ change_hot_standby_feedback_and_wait_for_xmins(1, 0);
 $node_standby->restart;
 
 ##################################################
-# Recovery conflict: Invalidate conflicting slots, including in-use slots
+# Recovery conflict: Invalidate conflicting slots
 # Scenario 5: conflict due to on-access pruning.
 ##################################################
 
@@ -788,7 +782,7 @@ $node_primary->safe_psql('testdb', qq[UPDATE prun SET s = 'E';]);
 $node_primary->wait_for_replay_catchup($node_standby);
 
 # Check invalidation in the logfile and in pg_stat_database_conflicts
-check_for_invalidation('pruning_', $logstart, 'with on-access pruning');
+check_for_invalidation('pruning_', $logstart, 'with on-access pruning', 0);
 
 # Verify reason for conflict is 'rows_removed' in pg_replication_slots
 check_slots_conflict_reason('pruning_', 'rows_removed');
@@ -832,7 +826,7 @@ $node_primary->restart;
 $node_primary->wait_for_replay_catchup($node_standby);
 
 # Check invalidation in the logfile and in pg_stat_database_conflicts
-check_for_invalidation('wal_level_', $logstart, 'due to wal_level');
+check_for_invalidation('wal_level_', $logstart, 'due to wal_level', 1);
 
 # Verify reason for conflict is 'wal_level_insufficient' in pg_replication_slots
 check_slots_conflict_reason('wal_level_', 'wal_level_insufficient');