Hackers,
As promised in [1], attached are some basic tests for the low-level
backup method.
There are currently no tests for the low-level backup method.
pg_backup_start() and pg_backup_stop() are called but not exercised in
any real fashion.
There is a lot more that can be done, but this at least supplies some
basic tests and provides a place for future improvement.
Regards,
-David
[1]
https://www.postgresql.org/message-id/2daf8adc-8db7-4204-a7f2-a7e94e2bfa4b%40pgmasters.netFrom b1a10ab4ab912e6f174206fcb8ce67496f93df83 Mon Sep 17 00:00:00 2001
From: David Steele <da...@pgmasters.net>
Date: Sat, 11 Nov 2023 19:12:49 +0000
Subject: Add basic tests for the low-level backup method.
There are currently no tests for the low-level backup method. pg_backup_start()
and pg_backup_stop() are called but not exercised in any real fashion.
There is a lot more that can be done, but this at least provides some basic
tests and provides a place for future improvement.
---
src/test/recovery/t/040_low_level_backup.pl | 101 ++++++++++++++++++++
1 file changed, 101 insertions(+)
create mode 100644 src/test/recovery/t/040_low_level_backup.pl
diff --git a/src/test/recovery/t/040_low_level_backup.pl
b/src/test/recovery/t/040_low_level_backup.pl
new file mode 100644
index 00000000000..3f30cb6b59c
--- /dev/null
+++ b/src/test/recovery/t/040_low_level_backup.pl
@@ -0,0 +1,101 @@
+
+# Copyright (c) 2023, PostgreSQL Global Development Group
+
+# Test low-level backup method by using pg_backup_start() and pg_backup_stop()
+# to create backups.
+
+use strict;
+use warnings;
+
+use File::Copy qw(copy);
+use File::Path qw(remove_tree);
+use PostgreSQL::Test::Cluster;
+use PostgreSQL::Test::Utils;
+use Test::More;
+
+# Start primary node with archiving
+my $node_primary = PostgreSQL::Test::Cluster->new('primary');
+$node_primary->init(has_archiving => 1, allows_streaming => 1);
+$node_primary->start;
+
+# Start backup
+my $backup_name = 'backup1';
+my $psql = $node_primary->background_psql('postgres');
+
+$psql->query_safe("SET client_min_messages TO WARNING");
+$psql->set_query_timer_restart();
+$psql->query_safe("select pg_backup_start('test label')");
+
+# Copy files
+my $backup_dir = $node_primary->backup_dir() . '/' . $backup_name;
+
+PostgreSQL::Test::RecursiveCopy::copypath(
+ $node_primary->data_dir(), $backup_dir);
+
+# Cleanup files/paths that should not be in the backup. Also remove pg_control
+# because it needs to be copied later and it will be obvious if the copy fails.
+unlink("$backup_dir/postmaster.pid")
+ or BAIL_OUT("unable to unlink $backup_dir/postmaster.pid");
+unlink("$backup_dir/postmaster.opts")
+ or BAIL_OUT("unable to unlink $backup_dir/postmaster.opts");
+unlink("$backup_dir/global/pg_control")
+ or BAIL_OUT("unable to unlink $backup_dir/global/pg_control");
+
+remove_tree("$backup_dir/pg_wal", {keep_root => 1})
+ or BAIL_OUT("unable to unlink contents of $backup_dir/pg_wal");
+
+# Create a table that will be used to verify that recovery started at the
+# correct location, rather than the location recorded in pg_control
+$psql->query_safe("create table canary (id int)");
+
+# Advance the checkpoint location in pg_control past the location where the
+# backup started. Switch the WAL to make it really obvious that the location
+# is different and to put the checkpoint in a new WAL segment.
+$psql->query_safe("select pg_switch_wal()");
+$psql->query_safe("checkpoint");
+
+# Copy pg_control last so it contains the new checkpoint
+copy($node_primary->data_dir() . '/global/pg_control',
+ "$backup_dir/global/pg_control")
+ or BAIL_OUT("unable to copy global/pg_control");
+
+# Stop backup and get backup_label
+my $backup_label = $psql->query_safe("select labelfile from pg_backup_stop()");
+
+# Rather than writing out backup_label, try to recover the backup without
+# backup_label to demonstrate that recovery will not work correctly without it,
+# i.e. the canary table will be missing and the cluster will be corrupt.
Provide
+# only the WAL segment that recovery will think it needs.
+#
+# The point of this test is to explicitly demonstrate that backup_label is
+# being used in a later test to get the correct recovery info.
+my $node_replica = PostgreSQL::Test::Cluster->new('replica_fail');
+$node_replica->init_from_backup($node_primary, $backup_name);
+my $canary_query = "select count(*) from pg_class where relname = 'canary'";
+
+copy($node_primary->archive_dir() . '/000000010000000000000003',
+ $node_replica->data_dir() . '/pg_wal/000000010000000000000003')
+ or BAIL_OUT("unable to copy 000000010000000000000003");
+
+$node_replica->start;
+
+ok($node_replica->safe_psql('postgres', $canary_query) == 0,
+ 'canary is missing');
+
+$node_replica->teardown_node();
+$node_replica->clean_node();
+
+# Save backup_label into the backup directory and recover using the primary's
+# archive. This time recovery will succeed and the canary table will be
+# present.
+append_to_file("$backup_dir/backup_label", $backup_label);
+
+$node_replica = PostgreSQL::Test::Cluster->new('replica_success');
+$node_replica->init_from_backup($node_primary, $backup_name,
+ has_restoring => 1);
+$node_replica->start;
+
+ok($node_replica->safe_psql('postgres', $canary_query) == 1,
+ 'canary is present');
+
+done_testing();
--
2.34.1
