mirror of https://github.com/postgres/postgres
Uses page-based mechanism to ensure we’re using the correct timeline. Tests are included to exercise the functionality using a cold disk-level copy of the master that's started up as a replica with slots intact, but the intended use of the functionality is with later features. Craig Ringer, reviewed by Simon Riggs and Andres Freundpull/17/merge
Simon Riggs
9 years ago
parent
9ca2dd578d
commit
1148e22a82
@ -0,0 +1,130 @@ |
||||
# Demonstrate that logical can follow timeline switches. |
||||
# |
||||
# Logical replication slots can follow timeline switches but it's |
||||
# normally not possible to have a logical slot on a replica where |
||||
# promotion and a timeline switch can occur. The only ways |
||||
# we can create that circumstance are: |
||||
# |
||||
# * By doing a filesystem-level copy of the DB, since pg_basebackup |
||||
# excludes pg_replslot but we can copy it directly; or |
||||
# |
||||
# * by creating a slot directly at the C level on the replica and |
||||
# advancing it as we go using the low level APIs. It can't be done |
||||
# from SQL since logical decoding isn't allowed on replicas. |
||||
# |
||||
# This module uses the first approach to show that timeline following |
||||
# on a logical slot works. |
||||
# |
||||
use strict; |
||||
use warnings; |
||||
|
||||
use PostgresNode; |
||||
use TestLib; |
||||
use Test::More tests => 7; |
||||
use RecursiveCopy; |
||||
use File::Copy; |
||||
use IPC::Run (); |
||||
use Scalar::Util qw(blessed); |
||||
|
||||
my ($stdout, $stderr, $ret); |
||||
|
||||
# Initialize master node |
||||
my $node_master = get_new_node('master'); |
||||
$node_master->init(allows_streaming => 1, has_archiving => 1); |
||||
$node_master->append_conf('postgresql.conf', "wal_level = 'logical'\n"); |
||||
$node_master->append_conf('postgresql.conf', "max_replication_slots = 2\n"); |
||||
$node_master->append_conf('postgresql.conf', "max_wal_senders = 2\n"); |
||||
$node_master->append_conf('postgresql.conf', "log_min_messages = 'debug2'\n"); |
||||
$node_master->dump_info; |
||||
$node_master->start; |
||||
|
||||
diag "Testing logical timeline following with a filesystem-level copy"; |
||||
|
||||
$node_master->safe_psql('postgres', |
||||
"SELECT pg_create_logical_replication_slot('before_basebackup', 'test_decoding');" |
||||
); |
||||
$node_master->safe_psql('postgres', "CREATE TABLE decoding(blah text);"); |
||||
$node_master->safe_psql('postgres', |
||||
"INSERT INTO decoding(blah) VALUES ('beforebb');"); |
||||
$node_master->safe_psql('postgres', 'CHECKPOINT;'); |
||||
|
||||
my $backup_name = 'b1'; |
||||
$node_master->backup_fs_hot($backup_name); |
||||
|
||||
my $node_replica = get_new_node('replica'); |
||||
$node_replica->init_from_backup( |
||||
$node_master, $backup_name, |
||||
has_streaming => 1, |
||||
has_restoring => 1); |
||||
$node_replica->start; |
||||
|
||||
$node_master->safe_psql('postgres', |
||||
"SELECT pg_create_logical_replication_slot('after_basebackup', 'test_decoding');" |
||||
); |
||||
$node_master->safe_psql('postgres', |
||||
"INSERT INTO decoding(blah) VALUES ('afterbb');"); |
||||
$node_master->safe_psql('postgres', 'CHECKPOINT;'); |
||||
|
||||
# Verify that only the before base_backup slot is on the replica |
||||
$stdout = $node_replica->safe_psql('postgres', |
||||
'SELECT slot_name FROM pg_replication_slots ORDER BY slot_name'); |
||||
is($stdout, 'before_basebackup', |
||||
'Expected to find only slot before_basebackup on replica'); |
||||
|
||||
# Boom, crash |
||||
$node_master->stop('immediate'); |
||||
|
||||
$node_replica->promote; |
||||
$node_replica->poll_query_until('postgres', |
||||
"SELECT NOT pg_is_in_recovery();"); |
||||
|
||||
$node_replica->safe_psql('postgres', |
||||
"INSERT INTO decoding(blah) VALUES ('after failover');"); |
||||
|
||||
# Shouldn't be able to read from slot created after base backup |
||||
($ret, $stdout, $stderr) = $node_replica->psql('postgres', |
||||
"SELECT data FROM pg_logical_slot_peek_changes('after_basebackup', NULL, NULL, 'include-xids', '0', 'skip-empty-xacts', '1');" |
||||
); |
||||
is($ret, 3, 'replaying from after_basebackup slot fails'); |
||||
like( |
||||
$stderr, |
||||
qr/replication slot "after_basebackup" does not exist/, |
||||
'after_basebackup slot missing'); |
||||
|
||||
# Should be able to read from slot created before base backup |
||||
($ret, $stdout, $stderr) = $node_replica->psql( |
||||
'postgres', |
||||
"SELECT data FROM pg_logical_slot_peek_changes('before_basebackup', NULL, NULL, 'include-xids', '0', 'skip-empty-xacts', '1');", |
||||
timeout => 30); |
||||
is($ret, 0, 'replay from slot before_basebackup succeeds'); |
||||
|
||||
my $final_expected_output_bb = q(BEGIN |
||||
table public.decoding: INSERT: blah[text]:'beforebb' |
||||
COMMIT |
||||
BEGIN |
||||
table public.decoding: INSERT: blah[text]:'afterbb' |
||||
COMMIT |
||||
BEGIN |
||||
table public.decoding: INSERT: blah[text]:'after failover' |
||||
COMMIT); |
||||
is($stdout, $final_expected_output_bb, 'decoded expected data from slot before_basebackup'); |
||||
is($stderr, '', 'replay from slot before_basebackup produces no stderr'); |
||||
|
||||
# So far we've peeked the slots, so when we fetch the same info over |
||||
# pg_recvlogical we should get complete results. First, find out the commit lsn |
||||
# of the last transaction. There's no max(pg_lsn), so: |
||||
|
||||
my $endpos = $node_replica->safe_psql('postgres', "SELECT location FROM pg_logical_slot_peek_changes('before_basebackup', NULL, NULL) ORDER BY location DESC LIMIT 1;"); |
||||
|
||||
# now use the walsender protocol to peek the slot changes and make sure we see |
||||
# the same results. |
||||
|
||||
$stdout = $node_replica->pg_recvlogical_upto('postgres', 'before_basebackup', |
||||
$endpos, 30, 'include-xids' => '0', 'skip-empty-xacts' => '1'); |
||||
|
||||
# walsender likes to add a newline |
||||
chomp($stdout); |
||||
is($stdout, $final_expected_output_bb, 'got same output from walsender via pg_recvlogical on before_basebackup'); |
||||
|
||||
# We don't need the standby anymore |
||||
$node_replica->teardown_node(); |
||||
Loading…
Reference in new issue