Author:     Noah Misch <noah@leadboat.com>
Commit:     Noah Misch <noah@leadboat.com>

    

diff --git a/contrib/amcheck/Makefile b/contrib/amcheck/Makefile
index b82f221..9a7f4f7 100644
--- a/contrib/amcheck/Makefile
+++ b/contrib/amcheck/Makefile
@@ -13,6 +13,7 @@ PGFILEDESC = "amcheck - function for verifying relation integrity"
 REGRESS = check check_btree check_heap
 
 TAP_TESTS = 1
+EXTRA_INSTALL=contrib/pg_walinspect
 
 ifdef USE_PGXS
 PG_CONFIG = pg_config
diff --git a/contrib/amcheck/t/004_pitr.pl b/contrib/amcheck/t/004_pitr.pl
new file mode 100644
index 0000000..ec6d87e
--- /dev/null
+++ b/contrib/amcheck/t/004_pitr.pl
@@ -0,0 +1,65 @@
+
+# Copyright (c) 2021-2023, PostgreSQL Global Development Group
+
+# Test integrity of intermediate states by PITR to those states
+use strict;
+use warnings;
+use PostgreSQL::Test::Cluster;
+use PostgreSQL::Test::Utils;
+use Test::More;
+
+# origin node: generate WAL records of interest.
+my $origin = PostgreSQL::Test::Cluster->new('origin');
+$origin->init(has_archiving => 1, allows_streaming => 1);
+$origin->append_conf('postgresql.conf', 'autovacuum = off');
+$origin->start;
+$origin->backup('my_backup');
+# Create a table with each of 6 PK values spanning 1/4 of a block.  Delete the
+# first four, so one index leaf is eligible for deletion.  Make a replication
+# slot just so pg_walinspect will always have access to later WAL.
+my $setup = <<EOSQL;
+BEGIN;
+CREATE EXTENSION amcheck;
+CREATE EXTENSION pg_walinspect;
+CREATE TABLE not_leftmost (c text STORAGE PLAIN);
+INSERT INTO not_leftmost
+  SELECT repeat(n::text, database_block_size / 4)
+  FROM generate_series(1,6) t(n), pg_control_init();
+ALTER TABLE not_leftmost ADD CONSTRAINT not_leftmost_pk PRIMARY KEY (c);
+DELETE FROM not_leftmost WHERE c ~ '^[1-4]';
+SELECT pg_create_physical_replication_slot('for_walinspect', true, false);
+COMMIT;
+EOSQL
+$origin->safe_psql('postgres', $setup);
+my $before_vacuum_lsn =
+  $origin->safe_psql('postgres', "SELECT pg_current_wal_lsn()");
+# VACUUM to delete the aforementioned leaf page.  Find the LSN of that
+# UNLINK_PAGE record.
+my $exec = <<EOSQL;
+VACUUM VERBOSE not_leftmost;
+SELECT max(start_lsn)
+  FROM pg_get_wal_records_info('$before_vacuum_lsn', 'FFFFFFFF/FFFFFFFF')
+  WHERE resource_manager = 'Btree' AND record_type = 'UNLINK_PAGE';
+EOSQL
+my $unlink_lsn = $origin->safe_psql('postgres', $exec);
+$origin->stop;
+
+# replica node: amcheck at notable points in the WAL stream
+my $replica = PostgreSQL::Test::Cluster->new('replica');
+$replica->init_from_backup($origin, 'my_backup', has_restoring => 1);
+$replica->append_conf('postgresql.conf',
+	"recovery_target_lsn = '$unlink_lsn'");
+$replica->append_conf('postgresql.conf', 'recovery_target_inclusive = off');
+$replica->append_conf('postgresql.conf', 'recovery_target_action = promote');
+$replica->start;
+$replica->poll_query_until('postgres', "SELECT pg_is_in_recovery() = 'f';")
+  or die "Timed out while waiting for PITR promotion";
+# recovery done; run amcheck
+is( $replica->psql(
+		'postgres', "SELECT bt_index_parent_check('not_leftmost_pk', true)"),
+	0);
+is( $replica->psql(
+		'postgres', "SELECT bt_index_check('not_leftmost_pk', true)"),
+	0);
+
+done_testing();