use strict;
use warnings FATAL => 'all';
use PostgreSQL::Test::Cluster;
use PostgreSQL::Test::Utils;
use Test::More;

# no. of concurrent txn
my $concurrent_txns = 100;

# max_connections to be set
my $max_connections = $concurrent_txns + 100;

# Setup node
my $node = PostgreSQL::Test::Cluster->new('publisher');
$node->init(allows_streaming => 'logical');
$node->append_conf(
	'postgresql.conf', q[
shared_buffers = 10GB
max_worker_processes = 32
max_parallel_maintenance_workers = 24
max_parallel_workers = 32
synchronous_commit = on
checkpoint_timeout = 1d
max_wal_size = 24GB
min_wal_size = 15GB
autovacuum = off
logical_decoding_work_mem = 10GB
]);
$node->append_conf('postgresql.conf', "max_connections = $max_connections");
$node->start;

# table t1 is not part of any publication
$node->safe_psql(
	'postgres', qq(
	CREATE TABLE t1(a int);
	CREATE TABLE tab_conc1(a int);
	CREATE PUBLICATION regress_pub1 for table tab_conc1,t1;
	SELECT * FROM pg_create_logical_replication_slot('regression_slot1', 'pgoutput');
));

my $psql_timeout_secs = 4 * $PostgreSQL::Test::Utils::timeout_default;

my @background_psqls;

# create $concurrent_txns sessions
foreach my $i (1 .. $concurrent_txns)
{
    my $background_psql = $node->background_psql(
	'postgres',
	on_error_stop => 0,
	timeout => $psql_timeout_secs);

    push (@background_psqls, $background_psql);
}

# begin txn in each session
foreach my $background_psql (@background_psqls)
{
    $background_psql->query_safe('BEGIN;');
    $background_psql->query_safe(qq[INSERT INTO tab_conc1 VALUES (11);]);
}

# unrelated invalidate message is distributed to all $concurrent_txns
foreach my $i (1 .. 1)
{
    $node->safe_psql('postgres', 'ALTER PUBLICATION regress_pub1 DROP TABLE t1;');
    $node->safe_psql('postgres', 'ALTER PUBLICATION regress_pub1 ADD TABLE t1;');
}

foreach my $background_psql (@background_psqls)
{
    $background_psql->query_safe(qq[INSERT INTO tab_conc1 VALUES (12);]);
    $background_psql->query_safe('COMMIT;');
	$background_psql->quit;
}

# Measure the decoding time via SQL interface - pg_logical_slot_get_binary_changes
my $start = Time::HiRes::gettimeofday();
my $result = $node->safe_psql('postgres',
"SELECT count(*) FROM pg_logical_slot_get_binary_changes('regression_slot1', NULL, NULL, 'proto_version', '4', 'publication_names', 'regress_pub1');");
my $end = Time::HiRes::gettimeofday();

printf("time elapsed %f\n", $end - $start);

is($result, 4*$concurrent_txns+1, 'changes were decoded properly');

$node->stop('fast');

done_testing();