1# Copyright (c) 2021, PostgreSQL Global Development Group
2
3# Tests for already-propagated WAL segments ending in incomplete WAL records.
4
5use strict;
6use warnings;
7
8use FindBin;
9use PostgresNode;
10use TestLib;
11use Test::More;
12
13plan tests => 3;
14
15# Test: Create a physical replica that's missing the last WAL file,
16# then restart the primary to create a divergent WAL file and observe
17# that the replica replays the "overwrite contrecord" from that new
18# file.
19
20my $node = PostgresNode->get_new_node('primary');
21$node->init(allows_streaming => 1);
22$node->append_conf('postgresql.conf', 'wal_keep_segments=16');
23$node->start;
24
25$node->safe_psql('postgres', 'create table filler (a int, b text)');
26
27# Now consume all remaining room in the current WAL segment, leaving
28# space enough only for the start of a largish record.
29$node->safe_psql(
30	'postgres', q{
31DO $$
32DECLARE
33    wal_segsize int := setting::int FROM pg_settings WHERE name = 'wal_segment_size';
34    remain int;
35    iters  int := 0;
36BEGIN
37    LOOP
38        INSERT into filler
39        select g, repeat(md5(g::text), (random() * 60 + 1)::int)
40        from generate_series(1, 10) g;
41
42        remain := wal_segsize - (pg_current_wal_insert_lsn() - '0/0') % wal_segsize;
43        IF remain < 2 * setting::int from pg_settings where name = 'block_size' THEN
44            RAISE log 'exiting after % iterations, % bytes to end of WAL segment', iters, remain;
45            EXIT;
46        END IF;
47        iters := iters + 1;
48    END LOOP;
49END
50$$;
51});
52
53my $initfile = $node->safe_psql('postgres',
54	'SELECT pg_walfile_name(pg_current_wal_insert_lsn())');
55$node->safe_psql('postgres',
56	qq{SELECT pg_logical_emit_message(true, 'test 026', repeat('xyzxz', 123456))}
57);
58#$node->safe_psql('postgres', qq{create table foo ()});
59my $endfile = $node->safe_psql('postgres',
60	'SELECT pg_walfile_name(pg_current_wal_insert_lsn())');
61ok($initfile != $endfile, "$initfile differs from $endfile");
62
63# Now stop abruptly, to avoid a stop checkpoint.  We can remove the tail file
64# afterwards, and on startup the large message should be overwritten with new
65# contents
66$node->stop('immediate');
67
68unlink $node->basedir . "/pgdata/pg_wal/$endfile"
69  or die "could not unlink " . $node->basedir . "/pgdata/pg_wal/$endfile: $!";
70
71# OK, create a standby at this spot.
72$node->backup_fs_cold('backup');
73my $node_standby = PostgresNode->get_new_node('standby');
74$node_standby->init_from_backup($node, 'backup', has_streaming => 1);
75
76$node_standby->start;
77$node->start;
78
79$node->safe_psql('postgres',
80	qq{create table foo (a text); insert into foo values ('hello')});
81$node->safe_psql('postgres',
82	qq{SELECT pg_logical_emit_message(true, 'test 026', 'AABBCC')});
83
84my $until_lsn = $node->safe_psql('postgres', "SELECT pg_current_wal_lsn()");
85my $caughtup_query =
86  "SELECT '$until_lsn'::pg_lsn <= pg_last_wal_replay_lsn()";
87$node_standby->poll_query_until('postgres', $caughtup_query)
88  or die "Timed out while waiting for standby to catch up";
89
90ok($node_standby->safe_psql('postgres', 'select * from foo') eq 'hello',
91	'standby replays past overwritten contrecord');
92
93# Verify message appears in standby's log
94my $log = slurp_file($node_standby->logfile);
95like(
96	$log,
97	qr[successfully skipped missing contrecord at],
98	"found log line in standby");
99
100$node->stop;
101$node_standby->stop;
102