Fix unstable log verification in test_autovacuum.

The test in test_autovacuum was unstable because it called
log_contains() immediately after verifying autovacuum_count in
pg_stat_user_tables. This created a race condition where the
statistics could be updated before the autovacuum logs were fully
flushed to disk.

This commit replaces log_contains() with wait_for_log() to ensure the
test waits for the parallel vacuum messages to appear. Additionally,
remove the checks of the autovacuum count. Verifying the log messages
is sufficient to confirm parallel autovacuum behavior, as logging is
only enabled for the specific table under test.

Per report from buildfarm member flaviventris.

Author: Sami Imseih <samimseih@gmail.com>
Discussion: https://postgr.es/m/525d0f48-93f7-493f-a988-f39b460a79bc@gmail.com

diff --git a/src/test/modules/test_autovacuum/t/001_parallel_autovacuum.pl b/src/test/modules/test_autovacuum/t/001_parallel_autovacuum.pl
index fc4dd22f5eb1de7d35e654eccce6813a3058c00a..22f40cb1d50d76214763500a9587c80d84d4104d 100644 (file)
--- a/src/test/modules/test_autovacuum/t/001_parallel_autovacuum.pl
+++ b/src/test/modules/test_autovacuum/t/001_parallel_autovacuum.pl
@@ -15,8 +15,7 @@ if ($ENV{enable_injection_points} ne 'yes')
 }
 
 # Before each test we should disable autovacuum for 'test_autovac' table and
-# generate some dead tuples in it. Returns the current autovacuum_count of
-# the table test_autovac.
+# generate some dead tuples in it.
 sub prepare_for_next_test
 {
        my ($node, $test_number) = @_;
@@ -26,24 +25,6 @@ sub prepare_for_next_test
                ALTER TABLE test_autovac SET (autovacuum_enabled = false);
                UPDATE test_autovac SET col_1 = $test_number;
        });
-
-       my $count = $node->safe_psql(
-               'postgres', qq{
-               SELECT autovacuum_count FROM pg_stat_user_tables WHERE relname = 'test_autovac'
-       });
-
-       return $count;
-}
-
-# Wait for the table to be vacuumed by an autovacuum worker.
-sub wait_for_autovacuum_complete
-{
-       my ($node, $old_count) = @_;
-
-       $node->poll_query_until(
-               'postgres', qq{
-               SELECT autovacuum_count > $old_count FROM pg_stat_user_tables WHERE relname = 'test_autovac'
-       });
 }
 
 my $node = PostgreSQL::Test::Cluster->new('main');
@@ -119,7 +100,7 @@ $node->safe_psql(
 # Our table has enough indexes and appropriate reloptions, so autovacuum must
 # be able to process it in parallel mode. Just check if it can do it.
 
-my $av_count = prepare_for_next_test($node, 1);
+prepare_for_next_test($node, 1);
 my $log_offset = -s $node->logfile;
 
 $node->safe_psql(
@@ -127,18 +108,17 @@ $node->safe_psql(
        ALTER TABLE test_autovac SET (autovacuum_enabled = true);
 });
 
-# Wait until the parallel autovacuum on table is completed. At the same time,
-# we check that the required number of parallel workers has been started.
-wait_for_autovacuum_complete($node, $av_count);
-ok( $node->log_contains(
-               qr/parallel workers: index vacuum: 2 planned, 2 launched in total/,
-               $log_offset));
+# Wait for parallel autovacuum to complete; check worker count matches reloptions.
+$node->wait_for_log(
+       qr/parallel workers: index vacuum: 2 planned, 2 launched in total/,
+       $log_offset);
+ok(1, "parallel autovacuum on test_autovac table");
 
 # Test 2:
 # Check whether parallel autovacuum leader can propagate cost-based parameters
 # to the parallel workers.
 
-$av_count = prepare_for_next_test($node, 2);
+prepare_for_next_test($node, 2);
 $log_offset = -s $node->logfile;
 
 $node->safe_psql(
@@ -183,5 +163,9 @@ $node->safe_psql(
        SELECT injection_points_detach('autovacuum-start-parallel-vacuum');
 });
 
+ok(1,
+       "vacuum delay parameter changes are propagated to parallel vacuum workers"
+);
+
 $node->stop;
 done_testing();